epicardium/drivers/MAX30003.h

+/* clang-format off */
+/*******************************************************************************
+ * Copyright (C) 2017 Maxim Integrated Products, Inc., All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL MAXIM INTEGRATED BE LIABLE FOR ANY CLAIM, DAMAGES
+ * OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * Except as contained in this notice, the name of Maxim Integrated
+ * Products, Inc. shall not be used except as stated in the Maxim Integrated
+ * Products, Inc. Branding Policy.
+ *
+ * The mere transfer of this software does not imply any licenses
+ * of trade secrets, proprietary technology, copyrights, patents,
+ * trademarks, maskwork rights, or any other form of intellectual
+ * property whatsoever. Maxim Integrated Products, Inc. retains all
+ * ownership rights.
+ *******************************************************************************
+ */
+
+
+#ifndef _MAX30003_H_
+#define _MAX30003_H_
+
+
+    ///MAX30003 Registers
+    enum Registers_e
+    {
+        NO_OP          = 0x00,
+        STATUS         = 0x01,
+        EN_INT         = 0x02,
+        EN_INT2        = 0x03,
+        MNGR_INT       = 0x04,
+        MNGR_DYN       = 0x05,
+        SW_RST         = 0x08,
+        SYNCH          = 0x09,
+        FIFO_RST       = 0x0A,
+        INFO           = 0x0F,
+        CNFG_GEN       = 0x10,
+        CNFG_ALL       = 0x12,
+        CNFG_EMUX      = 0x14,
+        CNFG_ECG       = 0x15,
+        CNFG_RTOR1     = 0x1D,
+        CNFG_RTOR2     = 0x1E,
+        ECG_FIFO_BURST = 0x20,
+        ECG_FIFO       = 0x21,
+        RTOR           = 0x25,
+        NO_OP2         = 0x7F
+    };
+
+    ///Status register bits
+    union Status_u
+    {
+        ///Access all bits
+        uint32_t all;
+
+        ///Access individual bits
+        struct
+        {
+            uint32_t loff_nl    : 1;
+            uint32_t loff_nh    : 1;
+            uint32_t loff_pl    : 1;
+            uint32_t loff_ph    : 1;
+            uint32_t reserved1  : 4;
+            uint32_t pllint     : 1;
+            uint32_t samp       : 1;
+            uint32_t rrint      : 1;
+            uint32_t lonint     : 1;
+            uint32_t reserved2  : 8;
+            uint32_t dcloffint : 1;
+            uint32_t fstint     : 1;
+            uint32_t eovf       : 1;
+            uint32_t eint       : 1;
+            uint32_t reserved3  : 8;
+        }bits;
+    };
+
+    ///Enable Interrupt registers bits
+    union EnableInterrupts_u
+    {
+        ///Access all bits
+        uint32_t all;
+
+        ///Access individual bits
+        struct 
+        {
+            uint32_t intb_type    : 2;
+            uint32_t reserved1    : 6;
+            uint32_t en_pllint    : 1;
+            uint32_t en_samp      : 1;
+            uint32_t en_rrint     : 1;
+            uint32_t en_loint     : 1;
+            uint32_t reserved2    : 8;
+            uint32_t en_dcloffint : 1;
+            uint32_t en_fstint    : 1;
+            uint32_t en_eovf      : 1;
+            uint32_t en_eint      : 1;
+            uint32_t reserved3    : 8;
+        }bits;
+    };
+
+    ///Manage Interrupt register bits
+    union ManageInterrupts_u
+    {
+        ///Access all bits
+        uint32_t all;
+
+        ///Access individual bits
+        struct 
+        {
+            uint32_t samp_it   : 4;
+            uint32_t clr_samp  : 1;
+            uint32_t reserved1 : 1;
+            uint32_t clr_rrint : 2;
+            uint32_t clr_fast  : 1;
+            uint32_t reserved2 : 12;
+            uint32_t efit      : 5;
+            uint32_t reserved3 : 8;
+        }bits;
+    };
+
+    ///Manage Dynamic Modes register bits
+    union ManageDynamicModes_u
+    {
+        ///Access all bits
+        uint32_t all;
+
+        ///Access individual bits
+        struct 
+        {
+            uint32_t reserved1 : 16;
+            uint32_t fast_th   : 6;
+            uint32_t fast      : 2;
+            uint32_t reserved2 : 8;
+        }bits;
+    };
+
+    ///General Configuration bits
+    union GeneralConfiguration_u
+    {
+        ///Access all bits
+        uint32_t all;
+
+        ///Access individual bits
+        struct 
+        {
+            uint32_t rbiasn     : 1;
+            uint32_t rbiasp     : 1;
+            uint32_t rbiasv     : 2;
+            uint32_t en_rbias   : 2;
+            uint32_t vth        : 2;
+            uint32_t imag       : 3;
+            uint32_t ipol       : 1;
+            uint32_t en_dcloff  : 2;
+            uint32_t reserved1  : 5;
+            uint32_t en_ecg     : 1;
+            uint32_t fmstr      : 2;
+            uint32_t en_ulp_lon : 2;
+            uint32_t reserved2  : 8;
+        }bits;
+    };
+
+    ///Cal Configuration bits
+    union CalConfiguration_u
+    {
+        ///Access all bits
+        uint32_t all;
+
+        ///Access individual bits
+        struct 
+        {
+            uint32_t thigh     : 11;
+            uint32_t fifty     : 1;
+            uint32_t fcal      : 3;
+            uint32_t reserved1 : 5;
+            uint32_t vmag      : 1;
+            uint32_t vmode     : 1;
+            uint32_t en_vcal   : 1;
+            uint32_t reserved2 : 9;
+
+        }bits;
+    };
+
+    ///Mux Configuration bits
+    union MuxConfiguration_u
+    {
+        ///Access all bits
+        uint32_t all;
+
+        ///Access individual bits
+        struct 
+        {
+            uint32_t reserved1 : 16;
+            uint32_t caln_sel  : 2;
+            uint32_t calp_sel  : 2;
+            uint32_t openn     : 1;
+            uint32_t openp     : 1;
+            uint32_t reserved2 : 1;
+            uint32_t pol       : 1;
+            uint32_t reserved3 : 8;
+        }bits;
+    };
+
+    ///ECG Configuration bits
+    union ECGConfiguration_u
+    {
+        ///Access all bits
+        uint32_t all;
+
+        ///Access individual bits
+        struct 
+        {
+            uint32_t reserved1 : 12;
+            uint32_t dlpf      : 2;
+            uint32_t dhpf      : 1;
+            uint32_t reserved2 : 1;
+            uint32_t gain      : 2;
+            uint32_t reserved3 : 4;
+            uint32_t rate      : 2;
+            uint32_t reserved4 : 8;
+        }bits;
+    };
+
+    ///RtoR1 Configuration bits
+    union RtoR1Configuration_u
+    {
+        ///Access all bits
+        uint32_t all;
+
+        ///Access individual bits
+        struct 
+        {
+            uint32_t reserved1 : 8;
+            uint32_t ptsf      : 4;
+            uint32_t pavg      : 2;
+            uint32_t reserved2 : 1;
+            uint32_t en_rtor   : 1;
+            uint32_t rgain     : 4;
+            uint32_t wndw      : 4;
+            uint32_t reserved3 : 8;
+        }bits;
+    };
+
+    ///RtoR2 Configuration bits
+    union RtoR2Configuration_u
+    {
+        ///Access all bits
+        uint32_t all;
+
+        ///Access individual bits
+        struct 
+        {
+            uint32_t reserved1 : 8;
+            uint32_t rhsf      : 3;
+            uint32_t reserved2 : 1;
+            uint32_t ravg      : 2;
+            uint32_t reserved3 : 2;
+            uint32_t hoff      : 6;
+            uint32_t reserved4 : 10;
+        }bits;
+    };
+
+#endif /* _MAX30003_H_ */
+/* clang-format on */

epicardium/drivers/bhi.c

+#include <assert.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "gpio.h"
+#include "bhy_uc_driver.h"
+#include "bhy.h"
+#include "pmic.h"
+
+#include "FreeRTOS.h"
+#include "task.h"
+#include "queue.h"
+
+#include "epicardium.h"
+#include "os/core.h"
+#include "modules/modules.h"
+#include "drivers/drivers.h"
+#include "modules/stream.h"
+#include "user_core/interrupts.h"
+
+/* BHI160 Firmware Blob.  Contents are defined in libcard10. */
+extern uint8_t bhy1_fw[];
+
+/* Interrupt Pin */
+static const gpio_cfg_t bhi160_interrupt_pin = {
+	PORT_0, PIN_13, GPIO_FUNC_IN, GPIO_PAD_PULL_UP
+};
+
+/* clang-format off */
+/* Axis remapping matrices */
+static const int8_t bhi160_mapping_matrix[3 * 3] = {
+	 0, -1,  0,
+	 1,  0,  0,
+	 0,  0,  1,
+};
+static const int8_t bmm150_mapping_matrix[3 * 3] = {
+	-1,  0,  0,
+	 0,  1,  0,
+	 0,  0, -1,
+};
+
+/*
+ * From the official docs:
+ *
+ *    The sic matrix should be calculated for customer platform by logging
+ *    uncalibrated magnetometer data.  The sic matrix here is only an example
+ *    array (identity matrix). Customer should generate their own matrix.  This
+ *    affects magnetometer fusion performance.
+ *
+ * TODO: Get data for card10
+ */
+static const float bhi160_sic_array[3 * 3] = {
+	1.0f, 0.0f, 0.0f,
+	0.0f, 1.0f, 0.0f,
+	0.0f, 0.0f, 1.0f,
+};
+/* clang-format on */
+
+/* BHI160 Task ID */
+static TaskHandle_t bhi160_task_id = NULL;
+
+/* BHI160 Mutex */
+static struct mutex bhi160_mutex = { 0 };
+
+/* Streams */
+static struct stream_info bhi160_streams[10];
+
+/* Active */
+static bool bhi160_sensor_active[10] = { 0 };
+
+/*
+ * Driver State:  A flag that is set when an unrecoverable error occurred.
+ * Effectively, this means the sensor will be disabled until next reboot and any
+ * API calls will fail immediately.
+ */
+static bool bhi160_driver_b0rked = false;
+
+/* -- Utilities -------------------------------------------------------- {{{ */
+/*
+ * Retrieve the data size for a sensor.  This value is needed for the creation
+ * of the sensor's sample queue.
+ */
+static size_t bhi160_lookup_data_size(enum bhi160_sensor_type type)
+{
+	switch (type) {
+	case BHI160_ACCELEROMETER:
+	case BHI160_MAGNETOMETER:
+	case BHI160_ORIENTATION:
+	case BHI160_GYROSCOPE:
+		return sizeof(struct bhi160_data_vector);
+	default:
+		return 0;
+	}
+}
+
+/*
+ * Map a sensor type to the virtual sensor ID used by BHy1.
+ */
+static bhy_virtual_sensor_t bhi160_lookup_vs_id(enum bhi160_sensor_type type)
+{
+	switch (type) {
+	case BHI160_ACCELEROMETER:
+		return VS_ID_ACCELEROMETER;
+	case BHI160_MAGNETOMETER:
+		return VS_ID_MAGNETOMETER;
+	case BHI160_ORIENTATION:
+		return VS_ID_ORIENTATION;
+	case BHI160_GYROSCOPE:
+		return VS_ID_GYROSCOPE;
+	default:
+		return -1;
+	}
+}
+
+/*
+ * Map a sensor type to its stream descriptor.
+ */
+static int bhi160_lookup_sd(enum bhi160_sensor_type type)
+{
+	switch (type) {
+	case BHI160_ACCELEROMETER:
+		return SD_BHI160_ACCELEROMETER;
+	case BHI160_MAGNETOMETER:
+		return SD_BHI160_MAGNETOMETER;
+	case BHI160_ORIENTATION:
+		return SD_BHI160_ORIENTATION;
+	case BHI160_GYROSCOPE:
+		return SD_BHI160_GYROSCOPE;
+	default:
+		return -1;
+	}
+}
+/* }}} */
+
+/* -- API -------------------------------------------------------------- {{{ */
+int epic_bhi160_enable_sensor(
+	enum bhi160_sensor_type sensor_type,
+	struct bhi160_sensor_config *config
+) {
+	int result = 0;
+
+	bhy_virtual_sensor_t vs_id = bhi160_lookup_vs_id(sensor_type);
+	if (vs_id == (bhy_virtual_sensor_t)-1) {
+		return -ENODEV;
+	}
+
+	mutex_lock(&bhi160_mutex);
+	hwlock_acquire(HWLOCK_I2C);
+
+	if (bhi160_driver_b0rked) {
+		result = -ENODEV;
+		goto out_free;
+	}
+
+	struct stream_info *stream = &bhi160_streams[sensor_type];
+	stream->item_size          = bhi160_lookup_data_size(sensor_type);
+	/* TODO: Sanity check length */
+	stream->queue =
+		xQueueCreate(config->sample_buffer_len, stream->item_size);
+	if (stream->queue == NULL) {
+		result = -ENOMEM;
+		goto out_free;
+	}
+
+	result = stream_register(bhi160_lookup_sd(sensor_type), stream);
+	if (result < 0) {
+		goto out_free;
+	}
+
+	result = bhy_enable_virtual_sensor(
+		vs_id,
+		VS_WAKEUP,
+		config->sample_rate,
+		0,
+		VS_FLUSH_NONE,
+		0,
+		config->dynamic_range /* dynamic range is sensor dependent */
+	);
+	if (result != BHY_SUCCESS) {
+		goto out_free;
+	}
+
+	bhi160_sensor_active[sensor_type] = true;
+	/* Return the sensor stream descriptor */
+	result = bhi160_lookup_sd(sensor_type);
+
+out_free:
+	hwlock_release(HWLOCK_I2C);
+	mutex_unlock(&bhi160_mutex);
+	return result;
+}
+
+int epic_bhi160_disable_sensor(enum bhi160_sensor_type sensor_type)
+{
+	int result = 0;
+
+	bhy_virtual_sensor_t vs_id = bhi160_lookup_vs_id(sensor_type);
+	if (vs_id == (bhy_virtual_sensor_t)-1) {
+		return -ENODEV;
+	}
+
+	mutex_lock(&bhi160_mutex);
+	hwlock_acquire(HWLOCK_I2C);
+
+	if (bhi160_driver_b0rked) {
+		result = -ENODEV;
+		goto out_free;
+	}
+
+	struct stream_info *stream = &bhi160_streams[sensor_type];
+	result = stream_deregister(bhi160_lookup_sd(sensor_type), stream);
+	if (result < 0) {
+		goto out_free;
+	}
+
+	vQueueDelete(stream->queue);
+	stream->queue = NULL;
+	result        = bhy_disable_virtual_sensor(vs_id, VS_WAKEUP);
+	if (result < 0) {
+		goto out_free;
+	}
+
+	bhi160_sensor_active[sensor_type] = false;
+
+	result = 0;
+out_free:
+	hwlock_release(HWLOCK_I2C);
+	mutex_unlock(&bhi160_mutex);
+	return result;
+}
+
+void epic_bhi160_disable_all_sensors()
+{
+	for (size_t i = 0; i < sizeof(bhi160_sensor_active); i++) {
+		if (bhi160_sensor_active[i]) {
+			epic_bhi160_disable_sensor(i);
+		}
+	}
+}
+
+/* }}} */
+
+/* -- Driver ----------------------------------------------------------- {{{ */
+/*
+ * Handle a single packet from the FIFO.  For most sensors this means pushing
+ * the sample into its sample queue.
+ */
+static void
+bhi160_handle_packet(bhy_data_type_t data_type, bhy_data_generic_t *sensor_data)
+{
+	uint8_t sensor_id = sensor_data->data_vector.sensor_id;
+	struct bhi160_data_vector data_vector;
+	/*
+	 * Timestamp of the next samples, counting at 32 kHz.
+	 * Currently unused.
+	 */
+	static uint32_t timestamp           = 0;
+	enum bhi160_sensor_type sensor_type = 0;
+	int epic_int                        = 0;
+	bool wakeup                         = false;
+
+	switch (sensor_id) {
+	case VS_ID_TIMESTAMP_MSW_WAKEUP:
+		wakeup = true;
+		/* fall through */
+	case VS_ID_TIMESTAMP_MSW:
+		assert(data_type == BHY_DATA_TYPE_SCALAR_U16);
+		timestamp = sensor_data->data_scalar_u16.data << 16;
+		break;
+	case VS_ID_TIMESTAMP_LSW_WAKEUP:
+		wakeup = true;
+		/* fall through */
+	case VS_ID_TIMESTAMP_LSW:
+		assert(data_type == BHY_DATA_TYPE_SCALAR_U16);
+		timestamp = (timestamp & 0xFFFF0000) |
+			    sensor_data->data_scalar_u16.data;
+		break;
+	case VS_ID_ACCELEROMETER_WAKEUP:
+	case VS_ID_MAGNETOMETER_WAKEUP:
+	case VS_ID_ORIENTATION_WAKEUP:
+	case VS_ID_GYROSCOPE_WAKEUP:
+		wakeup = true;
+		/* fall through */
+	case VS_ID_ACCELEROMETER:
+	case VS_ID_MAGNETOMETER:
+	case VS_ID_ORIENTATION:
+	case VS_ID_GYROSCOPE:
+		switch (sensor_id) {
+		case VS_ID_ACCELEROMETER_WAKEUP:
+		case VS_ID_ACCELEROMETER:
+			sensor_type = BHI160_ACCELEROMETER;
+			epic_int    = EPIC_INT_BHI160_ACCELEROMETER;
+			break;
+		case VS_ID_MAGNETOMETER_WAKEUP:
+		case VS_ID_MAGNETOMETER:
+			sensor_type = BHI160_MAGNETOMETER;
+			epic_int    = EPIC_INT_BHI160_MAGNETOMETER;
+			break;
+		case VS_ID_ORIENTATION_WAKEUP:
+		case VS_ID_ORIENTATION:
+			sensor_type = BHI160_ORIENTATION;
+			epic_int    = EPIC_INT_BHI160_ORIENTATION;
+			break;
+		case VS_ID_GYROSCOPE_WAKEUP:
+		case VS_ID_GYROSCOPE:
+			sensor_type = BHI160_GYROSCOPE;
+			epic_int    = EPIC_INT_BHI160_GYROSCOPE;
+			break;
+		}
+
+		assert(data_type == BHY_DATA_TYPE_VECTOR);
+		if (bhi160_streams[sensor_type].queue == NULL) {
+			break;
+		}
+		data_vector.data_type = BHI160_DATA_TYPE_VECTOR;
+		data_vector.x         = sensor_data->data_vector.x;
+		data_vector.y         = sensor_data->data_vector.y;
+		data_vector.z         = sensor_data->data_vector.z;
+		data_vector.status    = sensor_data->data_vector.status;
+
+		/* Discard overflow.  See discussion in !316. */
+		if (xQueueSend(
+			    bhi160_streams[sensor_type].queue,
+			    &data_vector,
+			    0) != pdTRUE) {
+			if (!bhi160_streams[sensor_type].was_full) {
+				LOG_WARN(
+					"bhi160",
+					"queue full for %d",
+					sensor_type
+				);
+			}
+			bhi160_streams[sensor_type].was_full = true;
+		} else {
+			bhi160_streams[sensor_type].was_full = false;
+		}
+
+		if (wakeup) {
+			interrupt_trigger(epic_int);
+		}
+		break;
+	default:
+		break;
+	}
+}
+
+/*
+ * Fetch all data available from BHI160's FIFO buffer and handle all packets
+ * contained in it.
+ */
+static void bhi160_fetch_fifo(void)
+{
+	/*
+	 * Warning:  The code from the BHy1 docs has some issues.  This
+	 * implementation looks similar, but has a few important differences.
+	 * You'll probably be best of leaving it as it is ...
+	 */
+
+	/*
+	 * FIFO buffer.  Access to this static variable is safe because this
+	 * function is guarded by the bhi160_mutex.
+	 */
+	static uint8_t bhi160_fifo[BHI160_FIFO_SIZE];
+	static size_t start_index = 0;
+
+	BHY_RETURN_FUNCTION_TYPE result = 0;
+	/* Number of bytes left in BHI160's FIFO buffer */
+	uint16_t bytes_left_in_fifo = 1;
+
+	mutex_lock(&bhi160_mutex);
+	hwlock_acquire(HWLOCK_I2C);
+
+	while (bytes_left_in_fifo) {
+		/* Fill local FIFO buffer with as many bytes as possible */
+		uint16_t bytes_read;
+		result = bhy_read_fifo(
+			&bhi160_fifo[start_index],
+			BHI160_FIFO_SIZE - start_index,
+			&bytes_read,
+			&bytes_left_in_fifo
+		);
+
+		if (result != BHY_SUCCESS) {
+			/*
+			 * Honestly not sure how we should handle these errors.
+			 *
+			 * Needs more digging to find out how bhy_read_fifo()
+			 * behaves in error situations (a quick glance at the
+			 * code shows that the function might have written
+			 * _somethings_ into our buffer so we can't just retry
+			 * blindly ...)
+			 *
+			 * For now, just abort everything and disable the
+			 * sensor.  Won't cause havoc at least ...
+			 */
+			LOG_ERR("bhi160",
+				"Error while reading fifo: %d.  Disabling.",
+				result);
+
+			bhi160_driver_b0rked = true;
+			break;
+		}
+
+		/* Add the bytes left from the last transfer on top */
+		bytes_read += start_index;
+
+		/* Handle all full packets received in this transfer */
+		uint8_t *fifo_ptr   = bhi160_fifo;
+		uint16_t bytes_left = bytes_read;
+		while (bytes_left > 0) {
+			bhy_data_generic_t sensor_data;
+			bhy_data_type_t data_type;
+			result = bhy_parse_next_fifo_packet(
+				&fifo_ptr,
+				&bytes_left,
+				&sensor_data,
+				&data_type
+			);
+
+			if (result == BHY_SUCCESS) {
+				bhi160_handle_packet(data_type, &sensor_data);
+			} else {
+				LOG_WARN(
+					"bhi160",
+					"Error in fifo packet: %d.  Ignoring.",
+					result
+				);
+				break;
+			}
+		}
+
+		/* Shift the remaining bytes to the beginning */
+		for (int i = 0; i < bytes_left; i++) {
+			bhi160_fifo[i] =
+				bhi160_fifo[bytes_read - bytes_left + i];
+		}
+		start_index = bytes_left;
+	}
+
+	hwlock_release(HWLOCK_I2C);
+	mutex_unlock(&bhi160_mutex);
+}
+
+/*
+ * Callback for the BHI160 interrupt pin.  This callback is called from the
+ * SDK's GPIO interrupt driver, in interrupt context.
+ */
+static void bhi160_interrupt_callback(void *_)
+{
+	BaseType_t xHigherPriorityTaskWoken = pdFALSE;
+
+	if (bhi160_task_id != NULL && !bhi160_driver_b0rked) {
+		vTaskNotifyGiveFromISR(
+			bhi160_task_id, &xHigherPriorityTaskWoken
+		);
+		portYIELD_FROM_ISR(xHigherPriorityTaskWoken);
+	}
+}
+/* }}} */
+
+void vBhi160Task(void *pvParameters)
+{
+	int ret;
+
+	bhi160_task_id = xTaskGetCurrentTaskHandle();
+
+	mutex_create(&bhi160_mutex);
+	mutex_lock(&bhi160_mutex);
+	hwlock_acquire(HWLOCK_I2C);
+
+	memset(bhi160_streams, 0x00, sizeof(bhi160_streams));
+
+	/*
+	 * The BHI160, coming out of power-on-reset will hold its interrupt line
+	 * high until a firmware image is loaded.  Once that firmware is loaded
+	 * and running, the interrupt line is deasserted and from then on,
+	 * interrupts are signaled using a rising edge.
+	 *
+	 * So, initially we need to configure the IRQ for a falling edge, load
+	 * the firmware and then reconfigure for a rising edge.
+	 */
+	GPIO_Config(&bhi160_interrupt_pin);
+	GPIO_RegisterCallback(
+		&bhi160_interrupt_pin, bhi160_interrupt_callback, NULL
+	);
+	GPIO_IntConfig(&bhi160_interrupt_pin, GPIO_INT_EDGE, GPIO_INT_FALLING);
+	GPIO_IntEnable(&bhi160_interrupt_pin);
+	NVIC_SetPriority(
+		(IRQn_Type)MXC_GPIO_GET_IRQ(bhi160_interrupt_pin.port), 2
+	);
+	NVIC_EnableIRQ((IRQn_Type)MXC_GPIO_GET_IRQ(bhi160_interrupt_pin.port));
+
+	/* Upload firmware */
+	ret = bhy_driver_init(bhy1_fw);
+	if (ret) {
+		LOG_CRIT("bhi160", "BHy1 init failed!  Disabling.");
+
+		/* Disable BHI160 until next reboot */
+		bhi160_driver_b0rked = true;
+		hwlock_release(HWLOCK_I2C);
+		mutex_unlock(&bhi160_mutex);
+		vTaskDelete(NULL);
+	}
+
+	/* Wait for first interrupt, a falling edge */
+	hwlock_release(HWLOCK_I2C);
+	if (ulTaskNotifyTake(pdTRUE, pdMS_TO_TICKS(2000)) == 0) {
+		LOG_CRIT(
+			"bhi160",
+			"Sensor firmware was not loaded correctly.  Disabling."
+		);
+
+		/* Disable BHI160 until next reboot */
+		bhi160_driver_b0rked = true;
+		mutex_unlock(&bhi160_mutex);
+		vTaskDelete(NULL);
+	}
+	hwlock_acquire(HWLOCK_I2C);
+
+	/*
+	 * The firmware is now loaded; as stated above, we now need to
+	 * reconfigure the IRQ for a rising edge.
+	 */
+	GPIO_IntConfig(&bhi160_interrupt_pin, GPIO_INT_EDGE, GPIO_INT_RISING);
+
+	/*
+	 * Remap axes to match card10 layout.
+	 *
+	 * TODO: We set the matrix for the accelerometer twice because on some
+	 * badges, the axis mapping is not applied properly the first time.  We
+	 * should fix this properly at some point.
+	 */
+	bhy_mapping_matrix_set(
+		PHYSICAL_SENSOR_INDEX_ACC, (int8_t *)bhi160_mapping_matrix
+	);
+	bhy_mapping_matrix_set(
+		PHYSICAL_SENSOR_INDEX_ACC, (int8_t *)bhi160_mapping_matrix
+	);
+	bhy_mapping_matrix_set(
+		PHYSICAL_SENSOR_INDEX_MAG, (int8_t *)bmm150_mapping_matrix
+	);
+	bhy_mapping_matrix_set(
+		PHYSICAL_SENSOR_INDEX_GYRO, (int8_t *)bhi160_mapping_matrix
+	);
+
+	/* Set "SIC" matrix.  TODO: Find out what this is about */
+	bhy_set_sic_matrix((float *)bhi160_sic_array);
+
+	hwlock_release(HWLOCK_I2C);
+	mutex_unlock(&bhi160_mutex);
+
+	/* ----------------------------------------- */
+
+	while (1) {
+		bhi160_fetch_fifo();
+
+		/*
+		 * Wait for interrupt.  After two seconds, fetch FIFO anyway in
+		 * case there are any diagnostics or errors.
+		 *
+		 * In the future, reads using epic_stream_read() might also
+		 * trigger a FIFO fetch, from outside this task.
+		 */
+		ulTaskNotifyTake(pdTRUE, pdMS_TO_TICKS(2000));
+	}
+}

epicardium/drivers/bme680.c

+#include "epicardium.h"
+#include "modules/modules.h"
+#include "os/core.h"
+#include "drivers/drivers.h"
+
+#include "card10.h"
+
+#include "bme680.h"
+#include "bosch.h"
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdio.h>
+
+#define HEATR_TEMP 320
+#define HEATR_DUR 150
+
+static bool initialized;
+static struct bme680_dev bme;
+
+static int convert_error(int8_t error)
+{
+	switch (error) {
+	case BME680_OK:
+		return 0;
+	case BME680_E_NULL_PTR:
+		return EFAULT;
+	case BME680_E_COM_FAIL:
+		return EIO;
+	case BME680_E_DEV_NOT_FOUND:
+		return ENODEV;
+	case BME680_E_INVALID_LENGTH:
+		return EINVAL;
+	default:
+		return 1;
+	}
+}
+
+static int8_t
+i2c_write(uint8_t addr, uint8_t reg, uint8_t *p_buf, uint16_t size)
+{
+	int8_t ret;
+	hwlock_acquire(HWLOCK_I2C);
+	ret = card10_bosch_i2c_write(addr, reg, p_buf, size);
+	hwlock_release(HWLOCK_I2C);
+	return ret;
+}
+
+static int8_t i2c_read(uint8_t addr, uint8_t reg, uint8_t *p_buf, uint16_t size)
+{
+	int8_t ret;
+	hwlock_acquire(HWLOCK_I2C);
+	ret = card10_bosch_i2c_read(addr, reg, p_buf, size);
+	hwlock_release(HWLOCK_I2C);
+	return ret;
+}
+
+static void delay(uint32_t msec)
+{
+	if (xTaskGetSchedulerState() == taskSCHEDULER_NOT_STARTED) {
+		card10_bosch_delay(msec);
+	} else {
+		vTaskDelay(pdMS_TO_TICKS(msec));
+	}
+}
+
+int epic_bme680_init()
+{
+	int8_t result = BME680_OK;
+
+	if (bsec_active()) {
+		/* If the proprietary Bosch BSEC libary is in use
+		 * we redirect calls to that. It always runs
+		 * in the background
+		 */
+		return 0;
+	}
+	if (initialized) {
+		return 0;
+	}
+
+	bme.dev_id   = BME680_I2C_ADDR_PRIMARY;
+	bme.intf     = BME680_I2C_INTF;
+	bme.read     = i2c_read;
+	bme.write    = i2c_write;
+	bme.delay_ms = delay;
+
+	/*
+	 * amb_temp can be set to 25 prior to configuring the gas sensor
+	 * or by performing a few temperature readings without operating
+	 * the gas sensor.
+	 */
+	bme.amb_temp = 25;
+
+	result = bme680_init(&bme);
+	if (result != BME680_OK) {
+		LOG_ERR("bme680", "bme680_init error: %d\n", result);
+		return -convert_error(result);
+	}
+
+	/*
+	 * Select the power mode.  Must be set before writing the sensor
+	 * configuration
+	 */
+	bme.power_mode = BME680_FORCED_MODE;
+
+	/* Set the temperature, pressure and humidity settings */
+	bme.tph_sett.os_hum  = BME680_OS_2X;
+	bme.tph_sett.os_pres = BME680_OS_4X;
+	bme.tph_sett.os_temp = BME680_OS_8X;
+	bme.tph_sett.filter  = BME680_FILTER_SIZE_0;
+
+	/* Set the remaining gas sensor settings and link the heating profile */
+	bme.gas_sett.run_gas = BME680_ENABLE_GAS_MEAS;
+	/* Create a ramp heat waveform in 3 steps */
+	bme.gas_sett.heatr_temp = HEATR_TEMP; /* degree Celsius */
+	bme.gas_sett.heatr_dur  = HEATR_DUR;  /* milliseconds */
+
+	/* Set the required sensor settings needed */
+	uint16_t settings_sel = BME680_OST_SEL | BME680_OSP_SEL |
+				BME680_OSH_SEL | BME680_FILTER_SEL |
+				BME680_GAS_SENSOR_SEL;
+
+	result = bme680_set_sensor_settings(settings_sel, &bme);
+	if (result != BME680_OK) {
+		LOG_ERR("bme680",
+			"bme680_set_sensor_settings error: %d\n",
+			result);
+		return -convert_error(result);
+	}
+
+	initialized = true;
+	return 0;
+}
+
+int epic_bme680_deinit()
+{
+	/* This is an intentional NO OP to keep the BME680 always initialized.
+	 *
+	 * If it configured to foreced mode, there is no energy consumption
+	 * penalty.
+	 */
+
+	if (bsec_active()) {
+		return 0;
+	}
+
+#if 0
+	if (!initialized) {
+		return 0;
+	}
+
+	int8_t result = bme680_soft_reset(&bme);
+	if (result != BME680_OK) {
+		LOG_ERR("bme680", "bme680_soft_reset error: %d\n", result);
+	}
+
+	initialized = false;
+#endif
+	return 0;
+}
+
+int epic_bme680_read_sensors(struct bme680_sensor_data *data)
+{
+	int8_t result = BME680_OK;
+
+	if (bsec_active()) {
+		return bsec_read_bme680(data);
+	}
+
+	if (!initialized) {
+		LOG_ERR("bme680", "bme680 sensor not initialized");
+		return -EINVAL;
+	}
+
+	if (data == NULL) {
+		return -EFAULT;
+	}
+
+	uint16_t profile_dur = 0;
+	bme680_get_profile_dur(&profile_dur, &bme);
+
+	result = bme680_set_sensor_mode(&bme); /* Trigger a measurement */
+	if (result != BME680_OK) {
+		LOG_ERR("bme680", "bme680_set_sensor_mode error: %d\n", result);
+		return -convert_error(result);
+	}
+
+	/*
+	 * Wait for the measurement to complete.  Release the I2C lock in the
+	 * meantime.
+	 */
+	vTaskDelay(pdMS_TO_TICKS(profile_dur));
+
+	struct bme680_field_data raw_data;
+	result = bme680_get_sensor_data(&raw_data, &bme);
+	if (result != BME680_OK) {
+		LOG_ERR("bme680", "bme680_get_sensor_data error: %d\n", result);
+		return -convert_error(result);
+	}
+
+	data->temperature    = (float)raw_data.temperature / 100.0f;
+	data->humidity       = raw_data.humidity / 1000.0f;
+	data->pressure       = raw_data.pressure / 100.0f;
+	data->gas_resistance = raw_data.gas_resistance;
+
+	return 0;
+}

epicardium/drivers/bsec.c

+/* Adapted from  bsec_iot_example.c and bsec_iot_ulp_plus_example.c */
+
+#include "card10.h"
+#include "bosch.h"
+#include "bsec_integration.h"
+
+#include "ble/ess.h"
+
+#include "epicardium.h"
+#include "modules/modules.h"
+#include "os/config.h"
+#include "os/core.h"
+
+#include "FreeRTOS.h"
+#include "task.h"
+
+#include "max32665.h"
+#include "gcr_regs.h"
+
+#include <string.h>
+#include <stdio.h>
+
+TaskHandle_t bsec_task_id;
+static int64_t last_bme680_timestamp;
+static bool bsec_task_active;
+static bool debug;
+static struct bsec_sensor_data last_bsec_data;
+#define ULP 0
+
+// From generic_18v_3s_4d/bsec_serialized_configurations_iaq.c
+static const uint8_t bsec_config_generic_18v_3s_4d[454] = {
+	0,   8,   4,   1,   61,  0,   0,   0,   0,   0,   0,   0,   174, 1,
+	0,   0,   48,  0,   1,   0,   0,   192, 168, 71,  64,  49,  119, 76,
+	0,   0,   225, 68,  137, 65,  0,   191, 205, 204, 204, 190, 0,   0,
+	64,  191, 225, 122, 148, 190, 0,   0,   0,   0,   216, 85,  0,   100,
+	0,   0,   0,   0,   0,   0,   0,   0,   28,  0,   2,   0,   0,   244,
+	1,   225, 0,   25,  0,   0,   128, 64,  0,   0,   32,  65,  144, 1,
+	0,   0,   112, 65,  0,   0,   0,   63,  16,  0,   3,   0,   10,  215,
+	163, 60,  10,  215, 35,  59,  10,  215, 35,  59,  9,   0,   5,   0,
+	0,   0,   0,   0,   1,   88,  0,   9,   0,   7,   240, 150, 61,  0,
+	0,   0,   0,   0,   0,   0,   0,   28,  124, 225, 61,  52,  128, 215,
+	63,  0,   0,   160, 64,  0,   0,   0,   0,   0,   0,   0,   0,   205,
+	204, 12,  62,  103, 213, 39,  62,  230, 63,  76,  192, 0,   0,   0,
+	0,   0,   0,   0,   0,   145, 237, 60,  191, 251, 58,  64,  63,  177,
+	80,  131, 64,  0,   0,   0,   0,   0,   0,   0,   0,   93,  254, 227,
+	62,  54,  60,  133, 191, 0,   0,   64,  64,  12,  0,   10,  0,   0,
+	0,   0,   0,   0,   0,   0,   0,   229, 0,   254, 0,   2,   1,   5,
+	48,  117, 100, 0,   44,  1,   112, 23,  151, 7,   132, 3,   197, 0,
+	92,  4,   144, 1,   64,  1,   64,  1,   144, 1,   48,  117, 48,  117,
+	48,  117, 48,  117, 100, 0,   100, 0,   100, 0,   48,  117, 48,  117,
+	48,  117, 100, 0,   100, 0,   48,  117, 48,  117, 100, 0,   100, 0,
+	100, 0,   100, 0,   48,  117, 48,  117, 48,  117, 100, 0,   100, 0,
+	100, 0,   48,  117, 48,  117, 100, 0,   100, 0,   44,  1,   44,  1,
+	44,  1,   44,  1,   44,  1,   44,  1,   44,  1,   44,  1,   44,  1,
+	44,  1,   44,  1,   44,  1,   44,  1,   44,  1,   8,   7,   8,   7,
+	8,   7,   8,   7,   8,   7,   8,   7,   8,   7,   8,   7,   8,   7,
+	8,   7,   8,   7,   8,   7,   8,   7,   8,   7,   112, 23,  112, 23,
+	112, 23,  112, 23,  112, 23,  112, 23,  112, 23,  112, 23,  112, 23,
+	112, 23,  112, 23,  112, 23,  112, 23,  112, 23,  255, 255, 255, 255,
+	255, 255, 255, 255, 220, 5,   220, 5,   220, 5,   255, 255, 255, 255,
+	255, 255, 220, 5,   220, 5,   255, 255, 255, 255, 255, 255, 255, 255,
+	255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+	255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 44,  1,   0,   0,
+	0,   0,   83,  141, 0,   0
+};
+
+/*!
+ * @brief           Capture the system time in microseconds
+ *
+ * @return          system_current_time    current system timestamp in microseconds
+ */
+static int64_t get_timestamp_us()
+{
+	int64_t tick = xTaskGetTickCount();
+	return tick * 1000;
+}
+
+/*!
+ * @brief           Handling of the ready outputs
+ *
+ * @param[in]       timestamp       time in nanoseconds
+ * @param[in]       iaq             IAQ signal
+ * @param[in]       iaq_accuracy    accuracy of IAQ signal
+ * @param[in]       temperature     temperature signal
+ * @param[in]       humidity        humidity signal
+ * @param[in]       pressure        pressure signal
+ * @param[in]       raw_temperature raw temperature signal
+ * @param[in]       raw_humidity    raw humidity signal
+ * @param[in]       gas             raw gas sensor signal
+ * @param[in]       bsec_status     value returned by the bsec_do_steps() call
+ *
+ * @return          none
+ */
+static void output_ready(
+	int64_t timestamp,
+	float iaq,
+	uint8_t iaq_accuracy,
+	float temperature,
+	float humidity,
+	float pressure,
+	float raw_temperature,
+	float raw_humidity,
+	float gas,
+	bsec_library_return_t bsec_status,
+	float static_iaq,
+	float co2_equivalent,
+	float breath_voc_equivalent
+) {
+	last_bsec_data.temperature               = temperature;
+	last_bsec_data.humidity                  = humidity;
+	last_bsec_data.pressure                  = pressure / 100.;
+	last_bsec_data.gas_resistance            = gas;
+	last_bsec_data.timestamp                 = timestamp;
+	last_bsec_data.accuracy                  = iaq_accuracy;
+	last_bsec_data.indoor_air_quality        = iaq;
+	last_bsec_data.static_indoor_air_quality = static_iaq;
+	last_bsec_data.co2_equivalent            = co2_equivalent;
+	last_bsec_data.breath_voc_equivalent     = breath_voc_equivalent;
+
+	__sync_synchronize();
+
+	last_bme680_timestamp = timestamp;
+
+	bleESS_update_from_bsec_data(&last_bsec_data);
+
+	if (debug) {
+		LOG_INFO(
+			"bsec",
+			"time[ms]: %u, IAQ: %u, IAQ ACC[0-3]: %u, T[.1C]: %u, Hum[.1%%]: %u, P[Pa]: %u, Raw T[.1C]: %u, Raw Hum[.1%%]: %u, Gas[Ohm]: %u, Static IAQ: %u, CO2[ppm]: %u, Breath VOC[ppb]: %u",
+			(unsigned int)(timestamp / 1e6),
+			(unsigned int)(iaq),
+			(unsigned int)(iaq_accuracy),
+			(unsigned int)(temperature * 10),
+			(unsigned int)(humidity * 10),
+			(unsigned int)(pressure),
+			(unsigned int)(raw_temperature * 10),
+			(unsigned int)(raw_humidity * 10),
+			(unsigned int)(gas),
+			(unsigned int)(static_iaq),
+			(unsigned int)(co2_equivalent),
+			(unsigned int)(breath_voc_equivalent * 1e3)
+		);
+	}
+}
+
+int epic_bsec_read_sensors(struct bsec_sensor_data *data)
+{
+	if (data == NULL) {
+		return -EFAULT;
+	}
+	if (!bsec_task_active) {
+		return -ENODEV;
+	}
+
+	/* TODO: could also return -EINVAL */
+	while (last_bme680_timestamp == 0)
+		vTaskDelay(pdMS_TO_TICKS(10));
+
+	*data = last_bsec_data;
+	return 0;
+}
+
+static uint32_t bsec_load(char *path, uint8_t *buffer, uint32_t n_buffer)
+{
+	uint32_t len = 0;
+	int fd, res;
+
+	LOG_DEBUG("bsec", "load %s %lu", path, n_buffer);
+
+	if ((fd = epic_file_open(path, "r")) < 0) {
+		LOG_DEBUG("bsec", "Open failed");
+		return 0;
+	}
+
+	uint32_t header;
+	if ((res = epic_file_read(fd, &header, sizeof(header))) !=
+	    sizeof(header)) {
+		LOG_WARN("bsec", "Header failed");
+		goto done;
+	}
+
+	if (header > n_buffer) {
+		LOG_WARN("bsec", "Too large");
+		goto done;
+	}
+
+	if (epic_file_read(fd, buffer, header) != (int)header) {
+		LOG_WARN("bsec", "Read failed");
+		goto done;
+	}
+
+	len = header;
+
+	LOG_DEBUG("bsec", "Success");
+done:
+	epic_file_close(fd);
+	return len;
+}
+/*!
+ * @brief           Load previous library state from non-volatile memory
+ *
+ * @param[in,out]   state_buffer    buffer to hold the loaded state string
+ * @param[in]       n_buffer        size of the allocated state buffer
+ *
+ * @return          number of bytes copied to state_buffer
+ */
+static uint32_t state_load(uint8_t *state_buffer, uint32_t n_buffer)
+{
+	return bsec_load("bsec_iaq.state", state_buffer, n_buffer);
+}
+
+/*!
+ * @brief           Save library state to non-volatile memory
+ *
+ * @param[in]       state_buffer    buffer holding the state to be stored
+ * @param[in]       length          length of the state string to be stored
+ *
+ * @return          none
+ */
+static void state_save(const uint8_t *state_buffer, uint32_t length)
+{
+	int fd, res;
+
+	LOG_DEBUG("bsec", "state_save %d", (int)length);
+
+	if ((fd = epic_file_open("bsec_iaq.state", "w")) < 0) {
+		LOG_WARN("bsec", "Open failed");
+		return;
+	}
+
+	uint32_t header = length;
+	if ((res = epic_file_write(fd, &header, sizeof(header))) !=
+	    sizeof(header)) {
+		LOG_WARN("bsec", "Header failed");
+		goto done;
+	}
+
+	if (epic_file_write(fd, state_buffer, header) != (int)header) {
+		LOG_WARN("bsec", "Write failed");
+		goto done;
+	}
+
+	LOG_DEBUG("bsec", "stack high: %lu", uxTaskGetStackHighWaterMark(NULL));
+done:
+	epic_file_close(fd);
+}
+/*!
+ * @brief           Delete the library state from non-volatile memory
+ *
+ * @return          none
+ */
+static void state_delete(void)
+{
+	LOG_DEBUG("bsec", "state_delete");
+
+	epic_file_unlink("bsec_iaq.state");
+}
+
+static int8_t
+i2c_write(uint8_t addr, uint8_t reg, uint8_t *p_buf, uint16_t size)
+{
+	int8_t ret;
+	hwlock_acquire(HWLOCK_I2C);
+	ret = card10_bosch_i2c_write(addr, reg, p_buf, size);
+	hwlock_release(HWLOCK_I2C);
+	return ret;
+}
+
+static int8_t i2c_read(uint8_t addr, uint8_t reg, uint8_t *p_buf, uint16_t size)
+{
+	int8_t ret;
+	hwlock_acquire(HWLOCK_I2C);
+	ret = card10_bosch_i2c_read(addr, reg, p_buf, size);
+	hwlock_release(HWLOCK_I2C);
+	return ret;
+}
+
+static void delay(uint32_t msec)
+{
+	if (xTaskGetSchedulerState() == taskSCHEDULER_NOT_STARTED) {
+		/* We need to fall back to hardware waits if not running
+		 * in a task context */
+		card10_bosch_delay(msec);
+	} else {
+		vTaskDelay(pdMS_TO_TICKS(msec));
+	}
+}
+
+/*!
+ * @brief           Load library config from non-volatile memory
+ *
+ * @param[in,out]   config_buffer    buffer to hold the loaded state string
+ * @param[in]       n_buffer        size of the allocated state buffer
+ *
+ * @return          number of bytes copied to config_buffer
+ */
+static uint32_t config_load(uint8_t *config_buffer, uint32_t n_buffer)
+{
+	uint32_t len = bsec_load("bsec_iaq.config", config_buffer, n_buffer);
+
+	if (len == 0) {
+		LOG_INFO("bsec", "Using default bsec_config_generic_18v_3s_4d");
+		len = sizeof(bsec_config_generic_18v_3s_4d);
+		memcpy(config_buffer, bsec_config_generic_18v_3s_4d, len);
+	}
+
+	return len;
+}
+
+#if ULP
+void ulp_plus_trigger_iaq()
+{
+	/* We call bsec_update_subscription() in order to instruct BSEC to perform an extra measurement at the next
+     * possible time slot
+     */
+
+	bsec_sensor_configuration_t requested_virtual_sensors[1];
+	uint8_t n_requested_virtual_sensors = 1;
+	bsec_sensor_configuration_t
+		required_sensor_settings[BSEC_MAX_PHYSICAL_SENSOR];
+	uint8_t n_required_sensor_settings = BSEC_MAX_PHYSICAL_SENSOR;
+	bsec_library_return_t status       = BSEC_OK;
+
+	/* To trigger a ULP plus, we request the IAQ virtual sensor with a specific sample rate code */
+	requested_virtual_sensors[0].sensor_id = BSEC_OUTPUT_IAQ;
+	requested_virtual_sensors[0].sample_rate =
+		BSEC_SAMPLE_RATE_ULP_MEASUREMENT_ON_DEMAND;
+
+	/* Call bsec_update_subscription() to enable/disable the requested virtual sensors */
+	status = bsec_update_subscription(
+		requested_virtual_sensors,
+		n_requested_virtual_sensors,
+		required_sensor_settings,
+		&n_required_sensor_settings
+	);
+
+	/* The status code would tell is if the request was accepted. It will be rejected if the sensor is not already in
+     * ULP mode, or if the time difference between requests is too short, for example. */
+}
+#endif
+
+bool bsec_active(void)
+{
+	return bsec_task_active;
+}
+
+int bsec_read_bme680(struct bme680_sensor_data *data)
+{
+	if (!bsec_task_active) {
+		return BME680_E_COM_FAIL;
+	}
+
+	if (data == NULL) {
+		return -EFAULT;
+	}
+
+	while (last_bme680_timestamp == 0)
+		vTaskDelay(pdMS_TO_TICKS(10));
+
+	data->temperature    = last_bsec_data.temperature;
+	data->humidity       = last_bsec_data.humidity;
+	data->pressure       = last_bsec_data.pressure;
+	data->gas_resistance = last_bsec_data.gas_resistance;
+
+	return BME680_OK;
+}
+
+/**
+ * Checks config and activates the BSEC libary if requested.
+ *
+ * Initializes the BSEC library before starting the task to
+ * reduce the stack size needed for the task by at least 250 bytes
+ */
+int bsec_activate(void)
+{
+	return_values_init ret;
+#if ULP
+	float sample_rate = BSEC_SAMPLE_RATE_ULP;
+#else
+	float sample_rate = BSEC_SAMPLE_RATE_LP;
+#endif
+
+	if (!config_get_boolean_with_default("bsec_enable", false)) {
+		return -1;
+	}
+
+	debug = config_get_boolean_with_default("bsec_debug", false);
+
+	float temperature_offset =
+		config_get_integer_with_default("bsec_offset", -22) / 10.;
+	if (temperature_offset != 0.0) {
+		LOG_INFO(
+			"bsec",
+			"BSEC Temp offset %d/10 K",
+			(int)(temperature_offset * 10)
+		);
+	}
+
+	/* Puts AT LEAST 2 * #BSEC_MAX_PROPERTY_BLOB_SIZE = 2 * 454 = 908 bytes onto the stack */
+	ret = bsec_iot_init(
+		sample_rate,
+		-temperature_offset,
+		i2c_write,
+		i2c_read,
+		delay,
+		state_load,
+		config_load
+	);
+
+	if (ret.bsec_status == BSEC_E_CONFIG_VERSIONMISMATCH) {
+		/* BSEC version changed and old state is not compatible anymore */
+		/* If the config is also not valid anymore, the user will have
+		 * to fix that. */
+		state_delete();
+		ret = bsec_iot_init(
+			sample_rate,
+			-temperature_offset,
+			i2c_write,
+			i2c_read,
+			delay,
+			state_load,
+			config_load
+		);
+	}
+
+	if (ret.bme680_status) {
+		LOG_WARN("bsec", "bme680 init failed: %d", ret.bme680_status);
+		/* Could not initialize BME680 */
+		return -1;
+	} else if (ret.bsec_status) {
+		LOG_WARN("bsec", "bsec init failed: %d", ret.bsec_status);
+		/* Could not initialize BSEC library */
+		return -1;
+	}
+	return 0;
+}
+
+void vBSECTask(void *pvParameters)
+{
+	bsec_task_active = true;
+	bsec_task_id     = xTaskGetCurrentTaskHandle();
+
+#if ULP
+	/* State is saved every 100 samples, which means every 100 * 300 secs = 500 minutes  */
+	const int stat_save_interval = 100;
+#else
+	/* State is saved every 10.000 samples, which means every 10.000 * 3 secs = 500 minutes  */
+	const int stat_save_interval = 10000;
+#endif
+
+	/* Call to endless loop function which reads and processes data based on sensor settings */
+	/* Puts AT LEAST 2 * BSEC_MAX_STATE_BLOB_SIZE + 8 * sizeof(bsec_input_t) =
+	 * 2 * 139 + 8 * 20 = 438 bytes onto the stack */
+	bsec_iot_loop(
+		delay,
+		get_timestamp_us,
+		output_ready,
+		state_save,
+		stat_save_interval
+	);
+}

epicardium/modules/buttons.c → epicardium/drivers/buttons.c

 #include "epicardium.h"
 #include "modules/modules.h"
-#include "modules/log.h"
+#include "os/core.h"
 
 #include "portexpander.h"
 #include "MAX77650-Arduino-Library.h"
@@ -16,19 +16,14 @@ static const uint8_t pin_mask[] = {
 uint8_t epic_buttons_read(uint8_t mask)
 {
 	uint8_t ret = 0;
-	if (portexpander_detected() && (mask & 0x7)) {
-		if (hwlock_acquire(HWLOCK_I2C, pdMS_TO_TICKS(100)) < 0) {
-			LOG_ERR("buttons", "Can't acquire I2C bus");
-			return 0;
-		}
 
+	hwlock_acquire(HWLOCK_I2C);
+	if (portexpander_detected() && (mask & 0x7)) {
 		/*
-		 * Not using PB_Get() here as that performs one I2C transcation
+		 * Not using PB_Get() here as that performs one I2C transaction
 		 * per button.
 		 */
-		uint8_t pin_status = ~portexpander_get();
-
-		hwlock_release(HWLOCK_I2C);
+		uint8_t pin_status = ~portexpander_in_get(0xFF);
 
 		for (uint8_t m = 1; m < 0x8; m <<= 1) {
 			if (mask & m && pin_status & pin_mask[m]) {
@@ -41,5 +36,6 @@ uint8_t epic_buttons_read(uint8_t mask)
 		ret |= BUTTON_RESET;
 	}
 
+	hwlock_release(HWLOCK_I2C);
 	return ret;
 }

epicardium/drivers/display/api.c

+#include "epicardium.h"
+#include "drivers/display/lcd.h"
+#include "drivers/display/epic_ctx.h"
+
+#include "FreeRTOS.h"
+#include "LCD_Driver.h"
+#include "gpio.h"
+#include "task.h"
+#include "tmr.h"
+#include "tmr_utils.h"
+
+#include <machine/endian.h>
+#include <string.h>
+
+static TaskHandle_t lock = NULL;
+
+static int check_lock()
+{
+	TaskHandle_t task = xTaskGetCurrentTaskHandle();
+	if (task != lock) {
+		return -EBUSY;
+	} else {
+		return 0;
+	}
+}
+
+static uint16_t rgb888_to_rgb565(uint8_t *bytes)
+{
+	return ((bytes[0] & 0b11111000) << 8) | ((bytes[1] & 0b11111100) << 3) |
+	       (bytes[2] >> 3);
+}
+
+static inline void
+rgb565_to_rgb888(uint16_t pixel, uint8_t *red, uint8_t *green, uint8_t *blue)
+{
+	*blue  = (pixel & 31) << 3;
+	*green = ((pixel >> 5) & 63) << 2;
+	*red   = ((pixel >> 11) & 31) << 3;
+}
+
+int epic_disp_print(
+	int16_t posx,
+	int16_t posy,
+	const char *pString,
+	uint16_t fg,
+	uint16_t bg
+) {
+	return epic_disp_print_adv(DISP_FONT20, posx, posy, pString, fg, bg);
+}
+
+static const float font_map[] = {
+	[DISP_FONT8] = 8.0f,   [DISP_FONT12] = 12.0f, [DISP_FONT16] = 16.0f,
+	[DISP_FONT20] = 20.0f, [DISP_FONT24] = 24.0f,
+};
+
+int epic_disp_print_adv(
+	uint8_t font,
+	int16_t posx,
+	int16_t posy,
+	const char *pString,
+	uint16_t fg,
+	uint16_t bg
+) {
+	uint8_t r, g, b;
+	int cl = check_lock();
+	if (cl < 0) {
+		return cl;
+	}
+
+	if (font >= (sizeof(font_map) / sizeof(font_map[0]))) {
+		return -EINVAL;
+	}
+
+	float font_size = font_map[font];
+	ctx_font_size(epicardium_ctx, font_size);
+
+	if (fg != bg) {
+		/* non-transparent background */
+		rgb565_to_rgb888(bg, &r, &g, &b);
+		ctx_rgba8(epicardium_ctx, r, g, b, 255);
+		float width = ctx_text_width(epicardium_ctx, pString);
+		ctx_rectangle(epicardium_ctx, posx, posy, width, font_size);
+		ctx_fill(epicardium_ctx);
+	}
+
+	rgb565_to_rgb888(fg, &r, &g, &b);
+	ctx_rgba8(epicardium_ctx, r, g, b, 255);
+	ctx_move_to(epicardium_ctx, posx, (float)posy + font_size * 0.8f);
+	ctx_text(epicardium_ctx, pString);
+
+	return 0;
+}
+
+int epic_disp_clear(uint16_t color)
+{
+	int cl = check_lock();
+	if (cl < 0) {
+		return cl;
+	}
+
+	/*
+	 * We could use ctx for this but it's much easier to just clear the
+	 * framebuffer directly.
+	 */
+	for (size_t i = 0; i < sizeof(epicardium_ctx_fb); i += 2) {
+		epicardium_ctx_fb[i]     = color >> 8;
+		epicardium_ctx_fb[i + 1] = color & 0xff;
+	}
+
+	return 0;
+}
+
+int epic_disp_pixel(int16_t x, int16_t y, uint16_t color)
+{
+	int cl = check_lock();
+	if (cl < 0) {
+		return cl;
+	}
+
+	uint8_t r, g, b;
+	rgb565_to_rgb888(color, &r, &g, &b);
+	ctx_set_pixel_u8(epicardium_ctx, x, y, r, g, b, 255);
+
+	return 0;
+}
+
+static uint16_t rgb565_pixel_from_buf(
+	uint8_t *img,
+	enum epic_rgb_format format,
+	int16_t width,
+	int16_t x,
+	int16_t y,
+	uint8_t *alpha
+) {
+	uint16_t tmp16;
+	uint8_t rgba[4];
+
+	switch (format) {
+	case EPIC_RGB565:
+		*alpha = 255;
+		memcpy(&tmp16, &img[y * width * 2 + x * 2], 2);
+		return tmp16;
+	case EPIC_RGBA5551:
+		memcpy(&tmp16, &img[y * width * 2 + x * 2], 2);
+		*alpha = (tmp16 & 0x01) ? 255 : 0;
+		return (tmp16 & 0xFFC0) | ((tmp16 & 0x3E) >> 1);
+	case EPIC_RGB8:
+		*alpha = 255;
+		memcpy(rgba, &img[y * width * 3 + x * 3], 3);
+		return rgb888_to_rgb565(rgba);
+	case EPIC_RGBA8:
+		memcpy(rgba, &img[y * width * 4 + x * 4], 4);
+		*alpha = rgba[3];
+		return rgb888_to_rgb565(rgba);
+	default:
+		return 0xFFFF;
+	}
+}
+
+int epic_disp_blit(
+	int16_t pos_x,
+	int16_t pos_y,
+	int16_t width,
+	int16_t height,
+	void *img,
+	enum epic_rgb_format format
+) {
+	int cl = check_lock();
+	if (cl < 0) {
+		return cl;
+	}
+
+	for (int16_t xsrc = 0; xsrc < width; xsrc += 1) {
+		for (int16_t ysrc = 0; ysrc < height; ysrc += 1) {
+			int16_t xscreen = pos_x + xsrc;
+			int16_t yscreen = pos_y + ysrc;
+			size_t offset   = yscreen * 160 * 2 + xscreen * 2;
+			if (xscreen < 0 || xscreen >= 160 || yscreen < 0 ||
+			    yscreen >= 80) {
+				continue;
+			}
+
+			uint8_t alpha  = 255;
+			uint16_t pixel = rgb565_pixel_from_buf(
+				img, format, width, xsrc, ysrc, &alpha
+			);
+
+			if (alpha == 0) {
+				continue;
+			}
+
+			epicardium_ctx_fb[offset]     = (pixel & 0xFF00) >> 8;
+			epicardium_ctx_fb[offset + 1] = pixel & 0xFF;
+		}
+	}
+
+	return 0;
+}
+
+int epic_disp_line(
+	int16_t xstart,
+	int16_t ystart,
+	int16_t xend,
+	int16_t yend,
+	uint16_t color,
+	enum disp_linestyle linestyle,
+	uint16_t pixelsize
+) {
+	int cl = check_lock();
+	if (cl < 0) {
+		return cl;
+	}
+
+	float xstartf = xstart, ystartf = ystart, xendf = xend, yendf = yend;
+
+	/*
+	 * For odd line widths, shift the line by half a pixel so it aligns
+	 * perfectly with the pixel grid.
+	 */
+	if (pixelsize % 2 == 1) {
+		xstartf += 0.5f;
+		ystartf += 0.5f;
+		yendf += 0.5f;
+		xendf += 0.5f;
+	}
+
+	uint8_t r, g, b;
+	rgb565_to_rgb888(color, &r, &g, &b);
+	ctx_rgba8_stroke(epicardium_ctx, r, g, b, 255);
+
+	ctx_line_width(epicardium_ctx, pixelsize);
+	ctx_move_to(epicardium_ctx, xstartf, ystartf);
+	ctx_line_to(epicardium_ctx, xendf, yendf);
+	ctx_stroke(epicardium_ctx);
+
+	return 0;
+}
+
+int epic_disp_rect(
+	int16_t xstart,
+	int16_t ystart,
+	int16_t xend,
+	int16_t yend,
+	uint16_t color,
+	enum disp_fillstyle fillstyle,
+	uint16_t pixelsize
+) {
+	int cl = check_lock();
+	if (cl < 0)
+		return cl;
+
+	uint8_t r, g, b;
+	rgb565_to_rgb888(color, &r, &g, &b);
+
+	ctx_rectangle(
+		epicardium_ctx,
+		xstart,
+		ystart,
+		xend - xstart + 1,
+		yend - ystart + 1
+	);
+
+	switch (fillstyle) {
+	case FILLSTYLE_EMPTY:
+		ctx_rgba8_stroke(epicardium_ctx, r, g, b, 255);
+		ctx_line_width(epicardium_ctx, pixelsize);
+		ctx_stroke(epicardium_ctx);
+		break;
+	case FILLSTYLE_FILLED:
+		ctx_rgba8(epicardium_ctx, r, g, b, 255);
+		ctx_fill(epicardium_ctx);
+		break;
+	}
+
+	return 0;
+}
+
+int epic_disp_circ(
+	int16_t x,
+	int16_t y,
+	uint16_t rad,
+	uint16_t color,
+	enum disp_fillstyle fillstyle,
+	uint16_t pixelsize
+) {
+	int cl = check_lock();
+	if (cl < 0)
+		return cl;
+
+	uint8_t r, g, b;
+	rgb565_to_rgb888(color, &r, &g, &b);
+
+	ctx_arc(epicardium_ctx, x, y, rad, 0.0f, CTX_PI * 1.95, 0);
+
+	switch (fillstyle) {
+	case FILLSTYLE_EMPTY:
+		ctx_rgba8_stroke(epicardium_ctx, r, g, b, 255);
+		ctx_line_width(epicardium_ctx, pixelsize);
+		ctx_stroke(epicardium_ctx);
+		break;
+	case FILLSTYLE_FILLED:
+		ctx_rgba8(epicardium_ctx, r, g, b, 255);
+		ctx_fill(epicardium_ctx);
+		break;
+	}
+
+	return 0;
+}
+
+int epic_disp_update()
+{
+	int cl = check_lock();
+	if (cl < 0) {
+		return cl;
+	}
+
+	lcd_write_fb(epicardium_ctx_fb);
+
+	return 0;
+}
+
+int epic_disp_framebuffer(union disp_framebuffer *fb)
+{
+	int cl = check_lock();
+	if (cl < 0) {
+		return cl;
+	}
+
+	/*
+	 * Flip the screen because that's what this API call historically
+	 * expects.
+	 */
+	lcd_set_screenflip(true);
+	lcd_write_fb(fb->raw);
+	lcd_set_screenflip(false);
+	return 0;
+}
+
+int epic_disp_backlight(uint16_t brightness)
+{
+	/* TODO: lock? */
+	if (brightness == 0) {
+		lcd_set_sleep(true);
+	} else {
+		lcd_set_sleep(false);
+	}
+	LCD_SetBacklight(brightness);
+	return 0;
+}
+
+int epic_disp_open()
+{
+	TaskHandle_t task = xTaskGetCurrentTaskHandle();
+	if (lock == task) {
+		return 0;
+	} else if (lock == NULL) {
+		lock = task;
+		return 0;
+	} else {
+		return -EBUSY;
+	}
+}
+
+int epic_disp_close()
+{
+	if (check_lock() < 0 && lock != NULL) {
+		return -EBUSY;
+	} else {
+		lock = NULL;
+		return 0;
+	}
+}
+
+void disp_update_backlight_clock(void)
+{
+	LCD_UpdateBacklightClock();
+}
+
+void disp_forcelock()
+{
+	TaskHandle_t task = xTaskGetCurrentTaskHandle();
+	lock              = task;
+}

epicardium/drivers/display/epic_ctx.h

+#pragma once
+
+#include "ctx.h"
+
+extern Ctx *epicardium_ctx;
+extern uint8_t epicardium_ctx_fb[160 * 80 * 2];

epicardium/drivers/display/init.c

+#include "drivers/display/lcd.h"
+#include "drivers/display/epic_ctx.h"
+#include "drivers/drivers.h"
+#include "display.h"
+
+#include "ctx.h"
+
+#include <stdint.h>
+#include <machine/endian.h>
+
+#if BYTE_ORDER == LITTLE_ENDIAN
+#define CARD10_CTX_FORMAT CTX_FORMAT_RGB565_BYTESWAPPED
+#else
+#define CARD10_CTX_FORMAT CTX_FORMAT_RGB565
+#endif
+
+uint8_t epicardium_ctx_fb[160 * 80 * 2] = { 0 };
+Ctx *epicardium_ctx                     = NULL;
+
+void disp_init(void)
+{
+	/*
+	 * The bootloader has already initialized the display, so we only need
+	 * to do the bare minimum here.
+	 */
+	lcd_reconfigure();
+
+	/*
+	 * Initialize the graphics context.
+	 */
+	disp_ctx_reinit();
+}
+
+void disp_ctx_reinit(void)
+{
+	if (epicardium_ctx != NULL) {
+		ctx_free(epicardium_ctx);
+	}
+
+	epicardium_ctx = ctx_new_for_framebuffer(
+		epicardium_ctx_fb, 160, 80, 160 * 2, CARD10_CTX_FORMAT
+	);
+
+	/* set some defaults */
+	ctx_rgba(epicardium_ctx, 1.0f, 1.0f, 1.0f, 1.0f);
+	ctx_rgba_stroke(epicardium_ctx, 1.0f, 1.0f, 1.0f, 1.0f);
+	ctx_font(epicardium_ctx, "ctx-mono");
+}

epicardium/drivers/display/lcd.c

+#include "os/core.h"
+
+#include "MAX77650-Arduino-Library.h"
+#include "gpio.h"
+#include "mxc_delay.h"
+#include "portexpander.h"
+#include "spi.h"
+
+#include <machine/endian.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+/* HAL Interfaces {{{ */
+static const gpio_cfg_t GPIO_PIN_DC = {
+	PORT_1, PIN_6, GPIO_FUNC_OUT, GPIO_PAD_NONE
+};
+
+static void lcd_hw_init(void)
+{
+	GPIO_Config(&GPIO_PIN_DC);
+
+	/* for the reset pin */
+	if (!portexpander_detected()) {
+		/* Open-drain */
+		MAX77650_setDRV(false);
+		/* Output */
+		MAX77650_setDIR(false);
+	}
+}
+
+static void lcd_set_dc(bool state)
+{
+	if (state) {
+		GPIO_OutSet(&GPIO_PIN_DC);
+	} else {
+		GPIO_OutClr(&GPIO_PIN_DC);
+	}
+}
+
+static void lcd_set_rst(bool state)
+{
+	if (!portexpander_detected()) {
+		MAX77650_setDO(state ? true : false);
+	} else {
+		portexpander_out_put(PIN_4, state ? 0xFF : 0);
+	}
+}
+
+/** Bit Rate. Display has 15 MHz limit */
+#define SPI_SPEED (15 * 1000 * 1000)
+
+static void lcd_spi_write(const uint8_t *data, size_t count)
+{
+	const sys_cfg_spi_t spi_master_cfg = {
+		.map    = MAP_A,
+		.ss0    = Enable,
+		.ss1    = Disable,
+		.ss2    = Disable,
+		.num_io = 2,
+	};
+	spi_req_t request = {
+		.ssel     = 0,
+		.deass    = 1,
+		.ssel_pol = SPI17Y_POL_LOW,
+		.tx_data  = data,
+		.rx_data  = NULL,
+		.width    = SPI17Y_WIDTH_1,
+		.len      = count,
+		.bits     = 8,
+		.rx_num   = 0,
+		.tx_num   = 0,
+		.callback = NULL,
+	};
+	if (SPI_Init(SPI2, 0, SPI_SPEED, spi_master_cfg) != 0) {
+		panic("Error configuring display SPI");
+	}
+	SPI_MasterTrans(SPI2, &request);
+}
+
+static void lcd_delay(size_t millis)
+{
+	// TODO: Is this what we want?
+	mxc_delay(millis * 1000);
+}
+/* HAL Interfaces }}} */
+
+enum lcd_commands {
+	/** Sleep In */
+	LCD_SLPIN = 0x10,
+	/** Sleep Out */
+	LCD_SLPOUT = 0x11,
+	/** Display Inversion On */
+	LCD_INVON = 0x21,
+	/** Display On */
+	LCD_DISPON = 0x29,
+	/** Column Address Set */
+	LCD_CASET = 0x2A,
+	/** Row Address Set */
+	LCD_RASET = 0x2B,
+	/** Memory Write */
+	LCD_RAMWR = 0x2C,
+	/** Memory Data Access Control */
+	LCD_MADCTL = 0x36,
+	/** Interface Pixel Format */
+	LCD_COLMOD = 0x3A,
+	/** Frame Rate Control (In normal mode/ Full colors) */
+	LCD_FRMCTR1 = 0xB1,
+	/** Frame Rate Control (In Idle mode/ 8-colors) */
+	LCD_FRMCTR2 = 0xB2,
+	/** Frame Rate Control (In Partial mode/ full colors) */
+	LCD_FRMCTR3 = 0xB3,
+	/** Display Inversion Control */
+	LCD_INVCTR = 0xB4,
+	/** Power Control 1 */
+	LCD_PWCTR1 = 0xC0,
+	/** Power Control 2 */
+	LCD_PWCTR2 = 0xC1,
+	/** Power Control 3 (in Normal mode/ Full colors) */
+	LCD_PWCTR3 = 0xC2,
+	/** Power Control 4 (in Idle mode/ 8-colors) */
+	LCD_PWCTR4 = 0xC3,
+	/** Power Control 5 (in Partial mode/ full-colors) */
+	LCD_PWCTR5 = 0xC4,
+	/** VCOM Control 1 */
+	LCD_VMCTR1 = 0xC5,
+	/** Gamma (+ polarity) Correction Characteristics Setting */
+	LCD_GMCTRP1 = 0xE0,
+	/** Gamma (- polarity) Correction Characteristics Setting */
+	LCD_GMCTRN1 = 0xE1,
+};
+
+enum madctl_bits {
+	MADCTL_MY  = 0x80,
+	MADCTL_MX  = 0x40,
+	MADCTL_MV  = 0x20,
+	MADCTL_ML  = 0x10,
+	MADCTL_RGB = 0x08,
+	MADCTL_MH  = 0x04,
+};
+
+static void
+lcd_send_command(enum lcd_commands cmd, const uint8_t *args, size_t count)
+{
+	lcd_set_dc(false);
+	lcd_spi_write((uint8_t *)&cmd, 1);
+	if (args != NULL && count != 0) {
+		lcd_set_dc(true);
+		lcd_spi_write(args, count);
+	}
+}
+
+static void lcd_hard_reset(void)
+{
+	lcd_delay(20);
+	lcd_set_rst(false);
+	lcd_delay(20);
+	lcd_set_rst(true);
+	lcd_delay(20);
+}
+
+void lcd_set_sleep(bool sleep)
+{
+	static int current_sleep = -1;
+
+	if (sleep == current_sleep) {
+		return;
+	}
+	current_sleep = sleep;
+
+	if (sleep) {
+		lcd_send_command(LCD_SLPIN, NULL, 0);
+	} else {
+		lcd_send_command(LCD_SLPOUT, NULL, 0);
+	}
+}
+
+/**
+ * Perform a minimal initialization under the assumption that the bootloader has
+ * already turned on the display.  This is faster and prevents visible
+ * reinitialization artifacts.
+ */
+void lcd_reconfigure(void)
+{
+	/* Invert Display (twice for unknown reasons ...). */
+	lcd_send_command(LCD_INVON, NULL, 0);
+	lcd_send_command(LCD_INVON, NULL, 0);
+
+	/* Set framerate control values for all modes to the same values. */
+	const uint8_t frmctr[] = { 0x05, 0x3A, 0x3A, 0x05, 0x3A, 0x3A };
+	lcd_send_command(LCD_FRMCTR1, frmctr, 3);
+	lcd_send_command(LCD_FRMCTR2, frmctr, 3);
+	lcd_send_command(LCD_FRMCTR3, frmctr, 6);
+
+	/* Set display inversion control (unsure what this does?). */
+	const uint8_t invctr[] = { 0x03 };
+	lcd_send_command(LCD_INVCTR, invctr, sizeof(invctr));
+
+	/* Configure GVDD voltage to 4.7V. */
+	const uint8_t pwctr1[] = { 0x62, 0x02, 0x04 };
+	lcd_send_command(LCD_PWCTR1, pwctr1, sizeof(pwctr1));
+
+	/* Configure only ignored bits? */
+	const uint8_t pwctr2[] = { 0xC0 };
+	lcd_send_command(LCD_PWCTR2, pwctr2, sizeof(pwctr2));
+
+	/*
+	 * Configure "large" amount of current in operational amplifier and
+	 * booster step-ups for all modes.
+	 */
+	const uint8_t pwctr3[] = { 0x0D, 0x00 }, pwctr4[] = { 0x8D, 0x6A },
+		      pwctr5[] = { 0x8D, 0xEE };
+	lcd_send_command(LCD_PWCTR3, pwctr3, sizeof(pwctr3));
+	lcd_send_command(LCD_PWCTR4, pwctr4, sizeof(pwctr4));
+	lcd_send_command(LCD_PWCTR5, pwctr5, sizeof(pwctr5));
+
+	/* Configure VCOMH voltage to 2.850V. */
+	const uint8_t vmctr1[] = { 0x0E };
+	lcd_send_command(LCD_VMCTR1, vmctr1, sizeof(vmctr1));
+
+	/* Write positive and negative gamma correction values. */
+	const uint8_t gmctrp1[] = {
+		0x10, 0x0E, 0x02, 0x03, 0x0E, 0x07, 0x02, 0x07,
+		0x0A, 0x12, 0x27, 0x37, 0x00, 0x0D, 0x0E, 0x10,
+	};
+	const uint8_t gmctrn1[] = {
+		0x10, 0x0E, 0x03, 0x03, 0x0F, 0x06, 0x02, 0x08,
+		0x0A, 0x13, 0x26, 0x36, 0x00, 0x0D, 0x0E, 0x10,
+	};
+	lcd_send_command(LCD_GMCTRP1, gmctrp1, sizeof(gmctrp1));
+	lcd_send_command(LCD_GMCTRN1, gmctrn1, sizeof(gmctrn1));
+
+	/* Configure 16-bit pixel format. */
+	const uint8_t colmod[] = { 0x05 };
+	lcd_send_command(LCD_COLMOD, colmod, sizeof(colmod));
+
+	/*
+	 * Configure "MADCTL", which defines the pixel and color access order.
+	 */
+	const uint8_t madctl[] = { MADCTL_MX | MADCTL_MV | MADCTL_RGB };
+	/*
+	 * Waveshare Driver:
+	 * const uint8_t madctl[] = { MADCTL_MY | MADCTL_MV | MADCTL_RGB };
+	 */
+	lcd_send_command(LCD_MADCTL, madctl, sizeof(madctl));
+
+	/* Turn the display on. */
+	lcd_send_command(LCD_DISPON, NULL, 0);
+}
+
+/**
+ * Perform a full initialization of the display.  This will ensure the display
+ * is in a deterministic state.
+ */
+void lcd_initialize(void)
+{
+	lcd_hw_init();
+
+	lcd_hard_reset();
+
+	lcd_send_command(LCD_SLPOUT, NULL, 0);
+	lcd_delay(120);
+
+	lcd_reconfigure();
+}
+
+/**
+ * Write a partial display update.
+ *
+ * The rectangle from column ``xstart`` to ``xend`` (inclusive) and row
+ * ``ystart`` to ``yend`` (inclusive) will be updated with the contents of
+ * ``fb``.
+ *
+ * ``fb`` **must** have a size of
+ * ``(xend - xstart + 1) * (yend - ystart + 1) * 2`` bytes.
+ */
+void lcd_write_fb_partial(
+	uint16_t xstart,
+	uint16_t ystart,
+	uint16_t xend,
+	uint16_t yend,
+	const uint8_t *fb
+) {
+	uint16_t param_buffer[2];
+
+	/* Column start and end are offset by 1. */
+	param_buffer[0] = __htons(xstart + 1);
+	param_buffer[1] = __htons(xend + 1);
+	lcd_send_command(
+		LCD_CASET, (uint8_t *)param_buffer, sizeof(param_buffer)
+	);
+
+	/* Row start and end are offset by a magic 26. */
+	param_buffer[0] = __htons(ystart + 26);
+	param_buffer[1] = __htons(yend + 26);
+	lcd_send_command(
+		LCD_RASET, (uint8_t *)param_buffer, sizeof(param_buffer)
+	);
+
+	/* Now write out the actual framebuffer contents. */
+	size_t fb_size = (xend - xstart + 1) * (yend - ystart + 1) * 2;
+	lcd_send_command(LCD_RAMWR, fb, fb_size);
+}
+
+/**
+ * Write out a full framebuffer update.
+ *
+ * ``fb`` **must** be 160 * 80 * 2 = **25600** bytes in size.  The pixels are
+ * ordered in rows starting at the top left of the screen.  Each pixel must have
+ * its bytes laid out as big endian (while the CPU is little endian!).
+ */
+void lcd_write_fb(const uint8_t *fb)
+{
+	lcd_write_fb_partial(0, 0, 159, 79, fb);
+}
+
+/**
+ * Flip the screen orientation upside down.
+ *
+ * Historically we had software perform a flip of the framebuffer before
+ * sending it out.  This function provides a way to make the hardware accept
+ * such a flipped framebuffer.  This exists mostly to support the
+ * :c:func:`epic_disp_framebuffer()` API call for legacy l0dables.
+ */
+void lcd_set_screenflip(bool flipped)
+{
+	const uint8_t madctl_upright[] = { MADCTL_MX | MADCTL_MV | MADCTL_RGB };
+	const uint8_t madctl_flipped[] = { MADCTL_MY | MADCTL_MV | MADCTL_RGB };
+	if (flipped) {
+		lcd_send_command(LCD_MADCTL, madctl_flipped, 1);
+	} else {
+		lcd_send_command(LCD_MADCTL, madctl_upright, 1);
+	}
+}

epicardium/drivers/display/lcd.h

+#pragma once
+
+#include <stdbool.h>
+#include <stdint.h>
+
+void lcd_set_sleep(bool sleep);
+void lcd_reconfigure(void);
+void lcd_initialize(void);
+void lcd_write_fb_partial(
+	uint16_t xstart,
+	uint16_t ystart,
+	uint16_t xend,
+	uint16_t yend,
+	const uint8_t *fb
+);
+void lcd_write_fb(const uint8_t *fb);
+void lcd_set_screenflip(bool flipped);

epicardium/drivers/drivers.h

+#ifndef DRIVERS_H
+#define DRIVERS_H
+
+#include "FreeRTOS.h"
+#include "gpio.h"
+#include "os/mutex.h"
+#include "epicardium.h"
+
+#include <stdint.h>
+#include <stdbool.h>
+
+/* ---------- Serial ------------------------------------------------------- */
+#define SERIAL_READ_BUFFER_SIZE 128
+#define SERIAL_WRITE_STREAM_BUFFER_SIZE 512
+void serial_init();
+void vSerialTask(void *pvParameters);
+void serial_enqueue_char(char chr);
+void serial_flush(void);
+extern TaskHandle_t serial_task_id;
+/* Turn off the print queue and do prints synchroneous from now on. */
+void serial_return_to_synchronous();
+
+// For the eSetBit xTaskNotify task semaphore trigger
+enum serial_notify{
+	SERIAL_WRITE_NOTIFY = 0x01,
+	SERIAL_READ_NOTIFY  = 0x02,
+};
+
+/* ---------- PMIC --------------------------------------------------------- */
+void vPmicTask(void *pvParameters);
+
+/* ---------- Watchdog ----------------------------------------------------- */
+void watchdog_init();
+void watchdog_clearer_init();
+
+/* Critical battery voltage */
+#define BATTERY_CRITICAL   3.40f
+
+enum pmic_amux_signal {
+	PMIC_AMUX_DISABLED    = 0x0,
+	PMIC_AMUX_CHGIN_U     = 0x1,
+	PMIC_AMUX_CHGIN_I     = 0x2,
+	PMIC_AMUX_BATT_U      = 0x3,
+	PMIC_AMUX_BATT_CHG_I  = 0x4,
+	PMIC_AMUX_BATT_DIS_I  = 0x5,
+	PMIC_AMUX_BATT_NULL_I = 0x6,
+	PMIC_AMUX_THM_U       = 0x7,
+	PMIC_AMUX_TBIAS_U     = 0x8,
+	PMIC_AMUX_AGND_U      = 0x9,
+	PMIC_AMUX_SYS_U       = 0xA,
+	_PMIC_AMUX_MAX,
+};
+
+/*
+ * Read a value from the PMIC's AMUX.  The result is already converted into its
+ * proper unit.  See the MAX77650 datasheet for details.
+ */
+int pmic_read_amux(enum pmic_amux_signal sig, float *result);
+
+
+/* ---------- Display ------------------------------------------------------ */
+/* Do display and graphics initialization/configuration. */
+void disp_init(void);
+/* Reinitialize the graphics context. */
+void disp_ctx_reinit(void);
+/* Forces an unlock of the display. Only to be used in Epicardium */
+void disp_forcelock();
+void disp_update_backlight_clock(void);
+
+/* ---------- BHI160 ------------------------------------------------------- */
+#define BHI160_FIFO_SIZE             128
+#define BHI160_MUTEX_WAIT_MS          50
+void vBhi160Task(void *pvParameters);
+
+/* ---------- BME680 ------------------------------------------------------- */
+void bme680_periodic(int period);
+
+/* ---------- MAX86150 ----------------------------------------------------- */
+#define MAX86150_MUTEX_WAIT_MS		50
+void vMAX86150Task(void *pvParameters);
+void max86150_mutex_init(void);
+
+
+/* ---------- MAX30001 ----------------------------------------------------- */
+void vMAX30001Task(void *pvParameters);
+void max30001_mutex_init(void);
+
+/* ---------- GPIO --------------------------------------------------------- */
+extern gpio_cfg_t gpio_configs[];
+
+/* ---------- BSEC / BME680 ------------------------------------------------ */
+int bsec_activate(void);
+void vBSECTask(void *pvParameters);
+bool bsec_active(void);
+struct bme680_sensor_data;
+int bsec_read_bme680(struct bme680_sensor_data *data);
+
+/* ---------- Sleep -------------------------------------------------------- */
+void sleep_deepsleep(void);
+
+/* ---------- RNG ---------------------------------------------------------- */
+void rng_init(void);
+
+#endif /* DRIVERS_H */

epicardium/drivers/gpio.c

+#include "epicardium.h"
+#include "gpio.h"
+#include "max32665.h"
+#include "mxc_sys.h"
+#include "adc.h"
+#include "mxc_errors.h"
+#include "os/core.h"
+#include "modules/modules.h"
+
+/*
+ * Despite what the schematic (currently, 2019-08-18) says these are the correct
+ * pins for wristband GPIO 1-4 (not 0-3 as the schematic states)
+ */
+gpio_cfg_t gpio_configs[] = {
+	[EPIC_GPIO_WRISTBAND_1] = { PORT_0,
+				    PIN_21,
+				    GPIO_FUNC_OUT,
+				    GPIO_PAD_NONE },
+	[EPIC_GPIO_WRISTBAND_2] = { PORT_0,
+				    PIN_22,
+				    GPIO_FUNC_OUT,
+				    GPIO_PAD_NONE },
+	[EPIC_GPIO_WRISTBAND_3] = { PORT_0,
+				    PIN_29,
+				    GPIO_FUNC_OUT,
+				    GPIO_PAD_NONE },
+	[EPIC_GPIO_WRISTBAND_4] = { PORT_0,
+				    PIN_20,
+				    GPIO_FUNC_OUT,
+				    GPIO_PAD_NONE },
+};
+
+static int s_adc_channels[] = {
+	[EPIC_GPIO_WRISTBAND_1] = ADC_CH_5,
+	[EPIC_GPIO_WRISTBAND_2] = ADC_CH_6,
+	/* on P0.29, there is no ADC available
+	 * see GPIO matrix in MAX32665-MAX32668.pdf,
+	 * pages 32,33
+	 */
+	[EPIC_GPIO_WRISTBAND_3] = -1,
+	[EPIC_GPIO_WRISTBAND_4] = ADC_CH_4,
+};
+
+int epic_gpio_set_pin_mode(uint8_t pin, uint8_t mode)
+{
+	if (pin < EPIC_GPIO_WRISTBAND_1 || pin > EPIC_GPIO_WRISTBAND_4)
+		return -EINVAL;
+
+	gpio_cfg_t *cfg = &gpio_configs[pin];
+
+	if (mode & EPIC_GPIO_MODE_ADC) {
+		if (s_adc_channels[pin] == -1) {
+			LOG_WARN("gpio", "ADC not available on pin %d", pin);
+			return -EINVAL;
+		}
+		cfg->func = GPIO_FUNC_ALT1;
+		if (mode & EPIC_GPIO_MODE_OUT) {
+			return -EINVAL;
+		}
+	} else if (mode & EPIC_GPIO_MODE_IN) {
+		cfg->func = GPIO_FUNC_IN;
+		if (mode & EPIC_GPIO_MODE_OUT) {
+			return -EINVAL;
+		}
+	} else if (mode & EPIC_GPIO_MODE_OUT) {
+		cfg->func = GPIO_FUNC_OUT;
+		if (mode & EPIC_GPIO_MODE_IN) {
+			return -EINVAL;
+		}
+	} else {
+		return -EINVAL;
+	}
+
+	if (!(mode & EPIC_GPIO_MODE_ADC)) {
+		if (mode & EPIC_GPIO_PULL_UP) {
+			cfg->pad = GPIO_PAD_PULL_UP;
+		} else if (mode & EPIC_GPIO_PULL_DOWN) {
+			cfg->pad = GPIO_PAD_PULL_DOWN;
+		} else {
+			cfg->pad = GPIO_PAD_NONE;
+		}
+	} else {
+		cfg->pad = GPIO_PAD_NONE;
+	}
+
+	if (GPIO_Config(cfg) != E_NO_ERROR)
+		return -EINVAL;
+	return 0;
+}
+
+int epic_gpio_get_pin_mode(uint8_t pin)
+{
+	if (pin < EPIC_GPIO_WRISTBAND_1 || pin > EPIC_GPIO_WRISTBAND_4)
+		return -EINVAL;
+
+	gpio_cfg_t *cfg = &gpio_configs[pin];
+	int res         = 0;
+	if (cfg->func == GPIO_FUNC_IN)
+		res |= EPIC_GPIO_MODE_IN;
+	else if (cfg->func == GPIO_FUNC_OUT)
+		res |= EPIC_GPIO_MODE_OUT;
+	else if (cfg->func == GPIO_FUNC_ALT1)
+		res |= EPIC_GPIO_MODE_ADC;
+	if (cfg->pad == GPIO_PAD_PULL_UP)
+		res |= EPIC_GPIO_PULL_UP;
+	else if (cfg->pad == GPIO_PAD_PULL_DOWN)
+		res |= EPIC_GPIO_PULL_DOWN;
+
+	return res;
+}
+
+int epic_gpio_write_pin(uint8_t pin, bool on)
+{
+	if (pin < EPIC_GPIO_WRISTBAND_1 || pin > EPIC_GPIO_WRISTBAND_4)
+		return -EINVAL;
+
+	gpio_cfg_t *cfg = &gpio_configs[pin];
+	if (cfg->func == GPIO_FUNC_IN)
+		return -EINVAL;
+
+	if (on)
+		GPIO_OutSet(cfg);
+	else
+		GPIO_OutClr(cfg);
+
+	return 0;
+}
+
+int epic_gpio_read_pin(uint8_t pin)
+{
+	if (pin < EPIC_GPIO_WRISTBAND_1 || pin > EPIC_GPIO_WRISTBAND_4)
+		return -EINVAL;
+
+	gpio_cfg_t *cfg = &gpio_configs[pin];
+	if (cfg->func == GPIO_FUNC_OUT) {
+		return GPIO_OutGet(cfg) != 0;
+	} else if (cfg->func == GPIO_FUNC_IN) {
+		return GPIO_InGet(cfg) != 0;
+	} else if (cfg->func == GPIO_FUNC_ALT1) {
+		hwlock_acquire(HWLOCK_ADC);
+		ADC_StartConvert(s_adc_channels[pin], 0, 0);
+		uint16_t value;
+		int rc = ADC_GetData(&value);
+		hwlock_release(HWLOCK_ADC);
+		if (rc < 0) {
+			return -EIO;
+		}
+		return (int)value;
+	} else {
+		return -EINVAL;
+	}
+}

epicardium/drivers/leds.c

+#include "leds.h"
+#include "pmic.h"
+#include "FreeRTOS.h"
+#include "timers.h"
+#include "task.h"
+#include "epicardium.h"
+#include "modules/modules.h"
+
+#include <stdbool.h>
+
+/*
+ * TODO: create smth like vTaskDelay(pdMS_TO_TICKS(//put ms here)) for us,
+ *       remove blocking delay from /lib/leds.c to avoid process blocking
+ */
+
+#define NUM_LEDS 15 /* Take from lib/card10/leds.c */
+
+static void do_update(void)
+{
+	hwlock_acquire(HWLOCK_LED);
+	hwlock_acquire(HWLOCK_I2C);
+
+	leds_update_power();
+	leds_update();
+
+	hwlock_release(HWLOCK_I2C);
+	hwlock_release(HWLOCK_LED);
+}
+
+void epic_leds_set(int led, uint8_t r, uint8_t g, uint8_t b)
+{
+	if (led == PERSONAL_STATE_LED && personal_state_enabled())
+		return;
+
+	leds_prep(led, r, g, b);
+	do_update();
+}
+
+void epic_leds_set_hsv(int led, float h, float s, float v)
+{
+	if (led == PERSONAL_STATE_LED && personal_state_enabled())
+		return;
+
+	leds_prep_hsv(led, h, s, v);
+	do_update();
+}
+
+void epic_leds_prep(int led, uint8_t r, uint8_t g, uint8_t b)
+{
+	if (led == PERSONAL_STATE_LED && personal_state_enabled())
+		return;
+
+	leds_prep(led, r, g, b);
+}
+
+int epic_leds_get_rgb(int led, uint8_t *rgb)
+{
+	if (led == PERSONAL_STATE_LED && personal_state_enabled())
+		return -EPERM;
+	if (led < 0 || led >= NUM_LEDS)
+		return -EINVAL;
+
+	leds_get_rgb(led, rgb);
+	return 0;
+}
+
+void epic_leds_prep_hsv(int led, float h, float s, float v)
+{
+	if (led == PERSONAL_STATE_LED && personal_state_enabled())
+		return;
+
+	leds_prep_hsv(led, h, s, v);
+}
+
+void epic_leds_set_all(uint8_t *pattern_ptr, uint8_t len)
+{
+	uint8_t(*pattern)[3] = (uint8_t(*)[3])pattern_ptr;
+	for (int i = 0; i < len; i++) {
+		if (i == PERSONAL_STATE_LED && personal_state_enabled())
+			continue;
+
+		leds_prep(i, pattern[i][0], pattern[i][1], pattern[i][2]);
+	}
+	do_update();
+}
+
+void epic_leds_set_all_hsv(float *pattern_ptr, uint8_t len)
+{
+	float(*pattern)[3] = (float(*)[3])pattern_ptr;
+	for (int i = 0; i < len; i++) {
+		if (i == PERSONAL_STATE_LED && personal_state_enabled())
+			continue;
+
+		leds_prep_hsv(i, pattern[i][0], pattern[i][1], pattern[i][2]);
+	}
+	do_update();
+}
+
+void epic_leds_dim_top(uint8_t value)
+{
+	leds_set_dim_top(value);
+	if (personal_state_enabled() == 0) {
+		do_update();
+	}
+}
+
+void epic_leds_dim_bottom(uint8_t value)
+{
+	leds_set_dim_bottom(value);
+	if (personal_state_enabled() == 0) {
+		do_update();
+	}
+}
+
+void epic_leds_set_rocket(int led, uint8_t value)
+{
+	hwlock_acquire(HWLOCK_I2C);
+	pmic_set_led(led, value > 31 ? 31 : value);
+	hwlock_release(HWLOCK_I2C);
+}
+
+int epic_leds_get_rocket(int led)
+{
+	int ret = 0;
+
+	hwlock_acquire(HWLOCK_I2C);
+	ret = pmic_get_led(led);
+	hwlock_release(HWLOCK_I2C);
+	return ret;
+}
+
+static StaticTimer_t flash_timer_data[3];
+static TimerHandle_t flash_timer[] = { NULL, NULL, NULL };
+
+static void rocket_timer_callback(TimerHandle_t flash_timer)
+{
+	uint32_t id = (uint32_t)pvTimerGetTimerID(flash_timer);
+	epic_leds_set_rocket(id, 0);
+}
+
+void epic_leds_flash_rocket(int led, uint8_t value, int millis)
+{
+	int ticks  = millis * (configTICK_RATE_HZ / 1000);
+	int32_t id = led;
+	if (flash_timer[id] == NULL) {
+		flash_timer[id] = xTimerCreateStatic(
+			"flashtimer",
+			ticks,
+			pdFALSE,
+			(void *)id,
+			rocket_timer_callback,
+			&flash_timer_data[id]
+		);
+		epic_leds_set_rocket(led, value);
+	}
+	epic_leds_set_rocket(led, value);
+	xTimerChangePeriod(flash_timer[id], ticks, 0);
+}
+void epic_set_flashlight(bool power)
+{
+	hwlock_acquire(HWLOCK_I2C);
+	leds_flashlight(power);
+	hwlock_release(HWLOCK_I2C);
+}
+
+void epic_leds_update(void)
+{
+	do_update();
+}
+
+void epic_leds_set_powersave(bool eco)
+{
+	hwlock_acquire(HWLOCK_I2C);
+	leds_powersave(eco);
+	hwlock_release(HWLOCK_I2C);
+}
+
+void epic_leds_set_gamma_table(uint8_t rgb_channel, uint8_t *gamma_table)
+{
+	leds_set_gamma_table(rgb_channel, gamma_table);
+}
+
+void epic_leds_clear_all(uint8_t r, uint8_t g, uint8_t b)
+{
+	for (int i = 0; i < NUM_LEDS; i++) {
+		if (i == PERSONAL_STATE_LED && personal_state_enabled())
+			continue;
+
+		leds_prep(i, r, g, b);
+	}
+
+	do_update();
+}

epicardium/modules/light_sensor.c → epicardium/drivers/light_sensor.c

 #include "epicardium.h"
-#include "modules/log.h"
+#include "os/core.h"
+#include "os/work_queue.h"
 #include "modules/modules.h"
 
 #include "mxc_config.h"
@@ -27,26 +28,32 @@ static int light_sensor_init()
 	return 0;
 }
 
-static void readAdcCallback()
+uint16_t epic_light_sensor_read()
 {
-	if (hwlock_acquire(HWLOCK_ADC, 0) != 0) {
-		/* Can't do much about this here ... Retry next time */
-		return;
-	}
+	hwlock_acquire(HWLOCK_ADC);
 
 	ADC_StartConvert(ADC_CH_7, 0, 0);
 	ADC_GetData(&last_value);
 
 	hwlock_release(HWLOCK_ADC);
+	return last_value;
+}
+
+static void workpoll(void *data)
+{
+	epic_light_sensor_read();
+}
+
+static void poll(TimerHandle_t xTimer)
+{
+	workqueue_schedule(workpoll, NULL);
 }
 
 int epic_light_sensor_run()
 {
 	int ret = 0;
 
-	if (hwlock_acquire(HWLOCK_ADC, pdMS_TO_TICKS(500)) != 0) {
-		return -EBUSY;
-	}
+	hwlock_acquire(HWLOCK_ADC);
 
 	light_sensor_init();
 
@@ -56,7 +63,7 @@ int epic_light_sensor_run()
 			READ_FREQ,
 			pdTRUE,
 			NULL,
-			readAdcCallback,
+			poll,
 			&poll_timer_buffer
 		);
 		// since &poll_timer_buffer is not NULL, xTimerCreateStatic should allways succeed, so

epicardium/drivers/max30001.c

+#include <stdio.h>
+#include <string.h>
+
+#include "gpio.h"
+#include "pmic.h"
+#include "spi.h"
+
+#include "MAX30003.h"
+
+#include "FreeRTOS.h"
+#include "task.h"
+#include "queue.h"
+
+#include "epicardium.h"
+#include "os/core.h"
+#include "modules/modules.h"
+#include "modules/stream.h"
+#include "os/mutex.h"
+#include "user_core/interrupts.h"
+
+/* Interrupt Pin */
+static const gpio_cfg_t max30001_interrupt_pin = {
+	PORT_1, PIN_12, GPIO_FUNC_IN, GPIO_PAD_PULL_UP
+};
+
+static const gpio_cfg_t analog_switch = {
+	PORT_0, PIN_31, GPIO_FUNC_OUT, GPIO_PAD_NONE
+};
+
+/* clang-format on */
+
+/* MAX30001 Task ID */
+static TaskHandle_t max30001_task_id = NULL;
+
+/* MAX30001 Mutex */
+static struct mutex max30001_mutex = { 0 };
+
+/* Stream */
+static struct stream_info max30001_stream;
+;
+
+/* Active */
+static bool max30001_sensor_active = false;
+
+static int ecg_enable(int sample_rate, bool enable_internal_pull);
+static int ecg_disable(void);
+
+/* -- API -------------------------------------------------------------- {{{ */
+int epic_max30001_enable_sensor(struct max30001_sensor_config *config)
+{
+	int result = 0;
+
+	mutex_lock(&max30001_mutex);
+	hwlock_acquire(HWLOCK_SPI_ECG);
+
+	struct stream_info *stream = &max30001_stream;
+	;
+	stream->item_size = sizeof(uint16_t);
+	stream->queue =
+		xQueueCreate(config->sample_buffer_len, stream->item_size);
+	if (stream->queue == NULL) {
+		result = -ENOMEM;
+		goto out_free_both;
+	}
+
+	result = stream_register(SD_MAX30001_ECG, stream);
+	if (result < 0) {
+		vQueueDelete(stream->queue);
+		goto out_free_both;
+	}
+
+	result = ecg_enable(config->sample_rate, config->bias);
+
+	if (result < 0) {
+		vQueueDelete(stream->queue);
+		goto out_free_both;
+	}
+
+	if (config->usb) {
+		GPIO_OutSet(&analog_switch); // USB
+	} else {
+		GPIO_OutClr(&analog_switch); // Wrist
+	}
+
+	max30001_sensor_active = true;
+	result                 = SD_MAX30001_ECG;
+
+out_free_both:
+	hwlock_release(HWLOCK_SPI_ECG);
+	mutex_unlock(&max30001_mutex);
+	return result;
+}
+
+int epic_max30001_disable_sensor(void)
+{
+	int result = 0;
+
+	mutex_lock(&max30001_mutex);
+	hwlock_acquire(HWLOCK_SPI_ECG);
+
+	struct stream_info *stream = &max30001_stream;
+	result                     = stream_deregister(SD_MAX30001_ECG, stream);
+	if (result < 0) {
+		goto out_free_both;
+	}
+
+	vQueueDelete(stream->queue);
+	stream->queue = NULL;
+	result        = ecg_disable();
+	if (result < 0) {
+		goto out_free_both;
+	}
+
+	max30001_sensor_active = false;
+
+	result = 0;
+out_free_both:
+	hwlock_release(HWLOCK_SPI_ECG);
+	mutex_unlock(&max30001_mutex);
+	return result;
+}
+
+/* }}} */
+
+/* -- Driver ----------------------------------------------------------- {{{ */
+/*
+ * Handle a single packet from the FIFO.  For most sensors this means pushing
+ * the sample into its sample queue.
+ */
+static void max30001_handle_samples(int16_t *sensor_data, int16_t n)
+{
+	if (max30001_stream.queue == NULL) {
+		return;
+	}
+
+	while (n--) {
+		uint16_t data = -*sensor_data++;
+
+		/* Discard overflow.  See discussion in !316. */
+		if (xQueueSend(max30001_stream.queue, &data, 0) != pdTRUE) {
+			if (!max30001_stream.was_full) {
+				LOG_WARN("max30001", "queue full");
+			}
+			max30001_stream.was_full = true;
+		} else {
+			max30001_stream.was_full = false;
+		}
+	}
+	interrupt_trigger(EPIC_INT_MAX30001_ECG);
+}
+
+/***** Functions *****/
+static uint32_t ecg_read_reg(uint8_t reg)
+{
+	spi_req_t req;
+	uint8_t tx_data[] = { (reg << 1) | 1, 0, 0, 0 };
+	uint8_t rx_data[] = { 0, 0, 0, 0 };
+	req.tx_data       = tx_data;
+	req.rx_data       = rx_data;
+	req.len           = 4;
+	req.bits          = 8;
+	req.width         = SPI17Y_WIDTH_1;
+	req.ssel          = 0;
+	req.deass         = 1;
+	req.ssel_pol      = SPI17Y_POL_LOW;
+	req.tx_num        = 0;
+	req.rx_num        = 0;
+
+	SPI_MasterTrans(SPI0, &req);
+
+	return (rx_data[1] << 16) | (rx_data[2] << 8) | rx_data[3];
+}
+
+static void ecg_write_reg(uint8_t reg, uint32_t data)
+{
+	//printf("write %02x %06lx\n", reg, data);
+	spi_req_t req;
+	uint8_t tx_data[] = {
+		(reg << 1) | 0, data >> 16, (data >> 8) & 0xFF, data & 0xFF
+	};
+	uint8_t rx_data[] = { 0, 0, 0, 0 };
+	req.tx_data       = tx_data;
+	req.rx_data       = rx_data;
+	req.len           = 4;
+	req.bits          = 8;
+	req.width         = SPI17Y_WIDTH_1;
+	req.ssel          = 0;
+	req.deass         = 1;
+	req.ssel_pol      = SPI17Y_POL_LOW;
+	req.tx_num        = 0;
+	req.rx_num        = 0;
+
+	SPI_MasterTrans(SPI0, &req);
+}
+
+static int ecg_enable(int sample_rate, bool enable_internal_pull)
+{
+	// Reset ECG to clear registers
+	ecg_write_reg(SW_RST, 0);
+
+	// General config register setting
+	union GeneralConfiguration_u CNFG_GEN_r;
+	CNFG_GEN_r.bits.en_ecg = 1; // Enable ECG channel
+	if (enable_internal_pull) {
+		CNFG_GEN_r.bits.rbiasn =
+			1; // Enable resistive bias on negative input
+		CNFG_GEN_r.bits.rbiasp =
+			1; // Enable resistive bias on positive input
+		CNFG_GEN_r.bits.en_rbias = 1; // Enable resistive bias
+	} else {
+		CNFG_GEN_r.bits.rbiasn =
+			0; // Enable resistive bias on negative input
+		CNFG_GEN_r.bits.rbiasp =
+			0; // Enable resistive bias on positive input
+		CNFG_GEN_r.bits.en_rbias = 0; // Enable resistive bias
+	}
+
+	CNFG_GEN_r.bits.imag      = 2; // Current magnitude = 10nA
+	CNFG_GEN_r.bits.en_dcloff = 1; // Enable DC lead-off detection
+	ecg_write_reg(CNFG_GEN, CNFG_GEN_r.all);
+
+	// ECG Config register setting
+	union ECGConfiguration_u CNFG_ECG_r;
+	CNFG_ECG_r.bits.dlpf = 1; // Digital LPF cutoff = 40Hz
+	CNFG_ECG_r.bits.dhpf = 1; // Digital HPF cutoff = 0.5Hz
+	//CNFG_ECG_r.bits.gain = 3;       // ECG gain = 160V/V
+	CNFG_ECG_r.bits.gain = 0;
+	if (sample_rate == 128) {
+		CNFG_ECG_r.bits.rate = 2; // Sample rate = 128 sps
+	} else if (sample_rate == 256) {
+		CNFG_ECG_r.bits.rate = 1; // Sample rate = 256 sps
+	} else {
+		return -EINVAL;
+	}
+
+	ecg_write_reg(CNFG_ECG, CNFG_ECG_r.all);
+
+	//R-to-R configuration
+	union RtoR1Configuration_u CNFG_RTOR_r;
+	CNFG_RTOR_r.bits.en_rtor = 1; // Enable R-to-R detection
+	ecg_write_reg(CNFG_RTOR1, CNFG_RTOR_r.all);
+
+	//Manage interrupts register setting
+	union ManageInterrupts_u MNG_INT_r;
+	MNG_INT_r.bits.efit      = 0b00011; // Assert EINT w/ 4 unread samples
+	MNG_INT_r.bits.clr_rrint = 0b01; // Clear R-to-R on RTOR reg. read back
+	ecg_write_reg(MNGR_INT, MNG_INT_r.all);
+
+	//Enable interrupts register setting
+	union EnableInterrupts_u EN_INT_r;
+	EN_INT_r.all            = 0;
+	EN_INT_r.bits.en_eint   = 1; // Enable EINT interrupt
+	EN_INT_r.bits.en_rrint  = 0; // Disable R-to-R interrupt
+	EN_INT_r.bits.intb_type = 3; // Open-drain NMOS with internal pullup
+	ecg_write_reg(EN_INT, EN_INT_r.all);
+
+	//Dyanmic modes config
+	union ManageDynamicModes_u MNG_DYN_r;
+	MNG_DYN_r.bits.fast = 0; // Fast recovery mode disabled
+	ecg_write_reg(MNGR_DYN, MNG_DYN_r.all);
+
+	// MUX Config
+	union MuxConfiguration_u CNFG_MUX_r;
+	CNFG_MUX_r.bits.openn = 0; // Connect ECGN to AFE channel
+	CNFG_MUX_r.bits.openp = 0; // Connect ECGP to AFE channel
+	ecg_write_reg(CNFG_EMUX, CNFG_MUX_r.all);
+
+	ecg_write_reg(SYNCH, 0);
+
+	return 0;
+}
+
+static int ecg_disable(void)
+{
+	// TODO
+	return 0;
+}
+/*
+ * Fetch all data available from FIFO buffer and handle all data
+ * contained in it.
+ */
+static int max30001_fetch_fifo(void)
+{
+	int result = 0;
+
+	mutex_lock(&max30001_mutex);
+	hwlock_acquire(HWLOCK_SPI_ECG);
+
+	uint32_t ecgFIFO, readECGSamples, ETAG[32], status;
+	int16_t ecgSample[32];
+	const uint32_t EINT_STATUS_MASK       = 1 << 23;
+	const uint32_t FIFO_OVF_MASK          = 0x7;
+	const uint32_t FIFO_VALID_SAMPLE_MASK = 0x0;
+	const uint32_t FIFO_FAST_SAMPLE_MASK  = 0x1;
+	const uint32_t ETAG_BITS_MASK         = 0x7;
+
+	status = ecg_read_reg(STATUS); // Read the STATUS register
+
+	// Check if EINT interrupt asserted
+	if ((status & EINT_STATUS_MASK) == EINT_STATUS_MASK) {
+		readECGSamples = 0; // Reset sample counter
+
+		do {
+			ecgFIFO = ecg_read_reg(ECG_FIFO); // Read FIFO
+			ecgSample[readECGSamples] =
+				ecgFIFO >> 8; // Isolate voltage data
+			ETAG[readECGSamples] =
+				(ecgFIFO >> 3) & ETAG_BITS_MASK; // Isolate ETAG
+			readECGSamples++; // Increment sample counter
+
+			// Check that sample is not last sample in FIFO
+		} while (ETAG[readECGSamples - 1] == FIFO_VALID_SAMPLE_MASK ||
+			 ETAG[readECGSamples - 1] == FIFO_FAST_SAMPLE_MASK);
+
+		// Check if FIFO has overflowed
+		if (ETAG[readECGSamples - 1] == FIFO_OVF_MASK) {
+			ecg_write_reg(FIFO_RST, 0); // Reset FIFO
+			LOG_WARN(
+				"max30001",
+				"fifo overflow"); // TODO; handle fifo full
+		}
+		max30001_handle_samples(ecgSample, readECGSamples);
+	}
+
+	hwlock_release(HWLOCK_SPI_ECG);
+	mutex_unlock(&max30001_mutex);
+	return result;
+}
+
+/*
+ * Callback for the MAX30001 interrupt pin.  This callback is called from the
+ * SDK's GPIO interrupt driver, in interrupt context.
+ */
+static void max300001_interrupt_callback(void *_)
+{
+	BaseType_t xHigherPriorityTaskWoken = pdFALSE;
+
+	if (max30001_task_id != NULL) {
+		vTaskNotifyGiveFromISR(
+			max30001_task_id, &xHigherPriorityTaskWoken
+		);
+		portYIELD_FROM_ISR(xHigherPriorityTaskWoken);
+	}
+}
+/* }}} */
+
+void max30001_mutex_init(void)
+{
+	mutex_create(&max30001_mutex);
+}
+
+void vMAX30001Task(void *pvParameters)
+{
+	max30001_task_id = xTaskGetCurrentTaskHandle();
+
+	mutex_lock(&max30001_mutex);
+	hwlock_acquire(HWLOCK_SPI_ECG);
+
+	/* Install interrupt callback */
+	GPIO_Config(&max30001_interrupt_pin);
+	GPIO_RegisterCallback(
+		&max30001_interrupt_pin, max300001_interrupt_callback, NULL
+	);
+	GPIO_IntConfig(
+		&max30001_interrupt_pin, GPIO_INT_EDGE, GPIO_INT_FALLING
+	);
+	GPIO_IntEnable(&max30001_interrupt_pin);
+	NVIC_SetPriority(
+		(IRQn_Type)MXC_GPIO_GET_IRQ(max30001_interrupt_pin.port), 2
+	);
+	NVIC_EnableIRQ(
+		(IRQn_Type)MXC_GPIO_GET_IRQ(max30001_interrupt_pin.port)
+	);
+
+	GPIO_Config(&analog_switch);
+	GPIO_OutClr(&analog_switch); // Wrist
+
+	hwlock_release(HWLOCK_SPI_ECG);
+	mutex_unlock(&max30001_mutex);
+
+	/* ----------------------------------------- */
+
+	while (1) {
+		if (max30001_sensor_active) {
+			int ret = max30001_fetch_fifo();
+			if (ret < 0) {
+				LOG_ERR("max30001", "Unknown error: %d", -ret);
+			}
+		}
+		/*
+		 * Wait for interrupt.  After two seconds, fetch FIFO anyway
+		 *
+		 * In the future, reads using epic_stream_read() might also
+		 * trigger a FIFO fetch, from outside this task.
+		 */
+		ulTaskNotifyTake(pdTRUE, pdMS_TO_TICKS(2000));
+	}
+}

epicardium/drivers/max86150.c

+#include <stdbool.h>
+#include <stddef.h>
+#include <stdio.h>
+#include "max86150.h"
+#include "epicardium.h"
+#include "os/core.h"
+#include "modules/stream.h"
+#include "gpio.h"
+#include "pmic.h"
+#include "user_core/interrupts.h"
+
+#include "FreeRTOS.h"
+#include "task.h"
+#include "queue.h"
+
+#include "modules/modules.h"
+
+static const gpio_cfg_t max86150_interrupt_pin = {
+	PORT_1, PIN_13, GPIO_FUNC_IN, GPIO_PAD_PULL_UP
+};
+
+/* MAX86150 Task ID */
+static TaskHandle_t max86150_task_id = NULL;
+
+/* MAX86150 Mutex */
+static struct mutex max86150_mutex = { 0 };
+
+/* Stream */
+static struct stream_info max86150_stream;
+
+/* Active */
+static bool max86150_sensor_active = false;
+
+int epic_max86150_enable_sensor(
+	struct max86150_sensor_config *config, size_t config_size
+) {
+	int result = 0;
+
+	if (sizeof(struct max86150_sensor_config) != config_size) {
+		return -EINVAL;
+	}
+
+	mutex_lock(&max86150_mutex);
+	hwlock_acquire(HWLOCK_I2C);
+
+	struct stream_info *stream = &max86150_stream;
+	stream->item_size          = sizeof(struct max86150_sensor_data);
+	stream->queue =
+		xQueueCreate(config->sample_buffer_len, stream->item_size);
+	if (stream->queue == NULL) {
+		result = -ENOMEM;
+		goto out_free;
+	}
+
+	uint8_t ppg_sample_rate;
+
+	if (config->ppg_sample_rate == 10) {
+		ppg_sample_rate = MAX86150_PPG_SAMPLERATE_10;
+	} else if (config->ppg_sample_rate == 20) {
+		ppg_sample_rate = MAX86150_PPG_SAMPLERATE_20;
+	} else if (config->ppg_sample_rate == 50) {
+		ppg_sample_rate = MAX86150_PPG_SAMPLERATE_50;
+	} else if (config->ppg_sample_rate == 84) {
+		ppg_sample_rate = MAX86150_PPG_SAMPLERATE_84;
+	} else if (config->ppg_sample_rate == 100) {
+		ppg_sample_rate = MAX86150_PPG_SAMPLERATE_100;
+	} else if (config->ppg_sample_rate == 200) {
+		ppg_sample_rate = MAX86150_PPG_SAMPLERATE_200;
+	} else if (config->ppg_sample_rate == 400) {
+		ppg_sample_rate = MAX86150_PPG_SAMPLERATE_400;
+	} else {
+		result = -EINVAL;
+		goto out_free;
+	}
+
+	result = stream_register(SD_MAX86150, stream);
+	if (result < 0) {
+		vQueueDelete(stream->queue);
+		goto out_free;
+	}
+
+	bool begin_result = max86150_begin();
+	if (!begin_result) {
+		result = -ENODEV;
+		vQueueDelete(stream->queue);
+		goto out_free;
+	}
+
+	max86150_setup(ppg_sample_rate);
+	max86150_get_int1();
+	max86150_get_int2();
+
+	max86150_sensor_active = true;
+	result                 = SD_MAX86150;
+
+out_free:
+	hwlock_release(HWLOCK_I2C);
+	mutex_unlock(&max86150_mutex);
+	return result;
+}
+
+int epic_max86150_disable_sensor(void)
+{
+	int result = 0;
+
+	mutex_lock(&max86150_mutex);
+	hwlock_acquire(HWLOCK_I2C);
+
+	max86150_shut_down();
+	max86150_sensor_active = false;
+
+	struct stream_info *stream = &max86150_stream;
+	result                     = stream_deregister(SD_MAX86150, stream);
+	if (result == 0) {
+		vQueueDelete(stream->queue);
+		stream->queue = NULL;
+	}
+
+	hwlock_release(HWLOCK_I2C);
+	mutex_unlock(&max86150_mutex);
+	return result;
+}
+
+static int max86150_handle_sample(struct max86150_sensor_data *data)
+{
+	//LOG_INFO("max86150", "Sample! %ld, %ld, %ld", data->red, data->ir, data->ecg);
+
+	if (max86150_stream.queue == NULL) {
+		return -ESRCH;
+	}
+
+	/* Discard overflow.  See discussion in !316. */
+	if (xQueueSend(max86150_stream.queue, data, 0) != pdTRUE) {
+		if (!max86150_stream.was_full) {
+			LOG_WARN("max86150", "queue full");
+		}
+		max86150_stream.was_full = true;
+	} else {
+		max86150_stream.was_full = false;
+	}
+
+	return 0;
+}
+
+static int max86150_fetch_fifo(void)
+{
+	int result = 0;
+
+	mutex_lock(&max86150_mutex);
+	hwlock_acquire(HWLOCK_I2C);
+
+	struct max86150_sensor_data sample;
+
+	// There is a recommendation from Maxim not to read the entire FIFO, but rather a fixed number of samples.
+	// See https://os.mbed.com/users/laserdad/code/MAX86150_ECG_PPG//file/3c728f3d1f10/main.cpp/
+	// So we should not use max86150_check() but max86150_get_sample().
+	int n = 0;
+	while (max86150_get_sample(&sample.red, &sample.ir, &sample.ecg) > 0) {
+		n++;
+		result = max86150_handle_sample(&sample);
+		// stop in case of errors
+		if (result < 0) {
+			n = 0;
+			break;
+		}
+	}
+	hwlock_release(HWLOCK_I2C);
+	mutex_unlock(&max86150_mutex);
+
+	if (n > 0) {
+		interrupt_trigger(EPIC_INT_MAX86150);
+	}
+	//LOG_INFO("max86150", "%d", n);
+	return result;
+}
+
+/*
+ * Callback for the MAX86150 interrupt pin.  This callback is called from the
+ * SDK's GPIO interrupt driver, in interrupt context.
+ */
+static void max86150_interrupt_callback(void *_)
+{
+	BaseType_t xHigherPriorityTaskWoken = pdFALSE;
+
+	if (max86150_task_id != NULL) {
+		vTaskNotifyGiveFromISR(
+			max86150_task_id, &xHigherPriorityTaskWoken
+		);
+		portYIELD_FROM_ISR(xHigherPriorityTaskWoken);
+	}
+}
+/* }}} */
+
+void max86150_mutex_init(void)
+{
+	mutex_create(&max86150_mutex);
+}
+
+void vMAX86150Task(void *pvParameters)
+{
+	max86150_task_id = xTaskGetCurrentTaskHandle();
+
+	mutex_lock(&max86150_mutex);
+	hwlock_acquire(HWLOCK_I2C);
+
+	/* Install interrupt callback */
+	GPIO_Config(&max86150_interrupt_pin);
+	GPIO_RegisterCallback(
+		&max86150_interrupt_pin, max86150_interrupt_callback, NULL
+	);
+	GPIO_IntConfig(
+		&max86150_interrupt_pin, GPIO_INT_EDGE, GPIO_INT_FALLING
+	);
+	GPIO_IntEnable(&max86150_interrupt_pin);
+	NVIC_SetPriority(
+		(IRQn_Type)MXC_GPIO_GET_IRQ(max86150_interrupt_pin.port), 2
+	);
+	NVIC_EnableIRQ(
+		(IRQn_Type)MXC_GPIO_GET_IRQ(max86150_interrupt_pin.port)
+	);
+
+	hwlock_release(HWLOCK_I2C);
+	mutex_unlock(&max86150_mutex);
+
+	/* ----------------------------------------- */
+
+	while (1) {
+		if (max86150_sensor_active) {
+			//LOG_INFO("max86150", "Interrupt!");
+			mutex_lock(&max86150_mutex);
+			hwlock_acquire(HWLOCK_I2C);
+
+			int i1 = max86150_get_int1();
+
+			hwlock_release(HWLOCK_I2C);
+			mutex_unlock(&max86150_mutex);
+
+			//LOG_INFO("max86150", "%d", i1);
+
+			if (i1 & 16) {
+				interrupt_trigger(EPIC_INT_MAX86150_PROX);
+			}
+
+			int ret = max86150_fetch_fifo();
+			if (ret < 0) {
+				LOG_ERR("max86150", "Unknown error: %d", -ret);
+			}
+		}
+		/*
+		 * Wait for interrupt.  After two seconds, fetch FIFO anyway
+		 *
+		 * In the future, reads using epic_stream_read() might also
+		 * trigger a FIFO fetch, from outside this task.
+		 */
+		ulTaskNotifyTake(pdTRUE, pdMS_TO_TICKS(2000));
+	}
+}

epicardium/drivers/meson.build

+driver_sources = files(
+  'bhi.c',
+  'bsec.c',
+  'bme680.c',
+  'buttons.c',
+  'gpio.c',
+  'leds.c',
+  'light_sensor.c',
+  'max86150.c',
+  'max30001.c',
+  'pmic.c',
+  'rtc.c',
+  'serial.c',
+  'sleep.c',
+  'rng.c',
+  'usb.c',
+  'vibra.c',
+  'watchdog.c',
+  'ws2812.c',
+
+  'display/lcd.c',
+  'display/api.c',
+  'display/init.c',
+)

epicardium/drivers/pmic.c

+#include "epicardium.h"
+#include "modules/modules.h"
+#include "drivers/drivers.h"
+#include "os/core.h"
+#include "os/config.h"
+#include "user_core/user_core.h"
+
+#include "card10.h"
+#include "pmic.h"
+#include "MAX77650-Arduino-Library.h"
+
+#include "max32665.h"
+#include "mxc_sys.h"
+#include "mxc_pins.h"
+#include "adc.h"
+
+#include "FreeRTOS.h"
+#include "task.h"
+#include "timers.h"
+
+#include <stdio.h>
+#include <string.h>
+
+/* Task ID for the pmic handler */
+static TaskHandle_t pmic_task_id = NULL;
+
+enum {
+	/* An irq was received, probably the power button */
+	PMIC_NOTIFY_IRQ = 1,
+	/* The timer has ticked and we should check the battery voltage again */
+	PMIC_NOTIFY_MONITOR = 2,
+};
+
+void pmic_interrupt_callback(void *_)
+{
+	BaseType_t xHigherPriorityTaskWoken = pdFALSE;
+	if (pmic_task_id != NULL) {
+		xTaskNotifyFromISR(
+			pmic_task_id,
+			PMIC_NOTIFY_IRQ,
+			eSetBits,
+			&xHigherPriorityTaskWoken
+		);
+		portYIELD_FROM_ISR(xHigherPriorityTaskWoken);
+	}
+}
+
+int pmic_read_amux(enum pmic_amux_signal sig, float *result)
+{
+	int ret = 0;
+
+	if (sig > _PMIC_AMUX_MAX) {
+		return -EINVAL;
+	}
+
+	hwlock_acquire(HWLOCK_ADC);
+	hwlock_acquire(HWLOCK_I2C);
+
+	/* Select the correct channel for this measurement.  */
+	MAX77650_setMUX_SEL(sig);
+
+	/*
+	 * According to the datasheet, the voltage will stabilize within 0.3us.
+	 * Just to be sure, we'll wait a little longer.  In the meantime,
+	 * release the I2C mutex.
+	 */
+	hwlock_release(HWLOCK_I2C);
+
+	vTaskDelay(pdMS_TO_TICKS(5));
+	hwlock_acquire(HWLOCK_I2C);
+
+	uint16_t adc_data;
+	ADC_StartConvert(ADC_CH_0, 0, 0);
+	ADC_GetData(&adc_data);
+
+	/* Turn MUX back to neutral so it does not waste power.  */
+	MAX77650_setMUX_SEL(PMIC_AMUX_DISABLED);
+
+	/* Convert ADC measurement to SI Volts */
+	float adc_voltage = (float)adc_data / 1023.0f * 1.22f;
+
+	/*
+	 * Convert value according to PMIC formulas (Table 7)
+	 */
+	switch (sig) {
+	case PMIC_AMUX_CHGIN_U:
+		*result = adc_voltage / 0.167f;
+		break;
+	case PMIC_AMUX_CHGIN_I:
+		*result = adc_voltage / 2.632f;
+		break;
+	case PMIC_AMUX_BATT_U:
+		*result = adc_voltage / 0.272f;
+		break;
+	case PMIC_AMUX_BATT_CHG_I:
+		*result = adc_voltage / 1.25f;
+		break;
+	case PMIC_AMUX_BATT_NULL_I:
+	case PMIC_AMUX_THM_U:
+	case PMIC_AMUX_TBIAS_U:
+	case PMIC_AMUX_AGND_U:
+		*result = adc_voltage;
+		break;
+	case PMIC_AMUX_SYS_U:
+		*result = adc_voltage / 0.26f;
+		break;
+	default:
+		ret = -EINVAL;
+	}
+
+	hwlock_release(HWLOCK_I2C);
+	hwlock_release(HWLOCK_ADC);
+
+	return ret;
+}
+
+/*
+ * Read the interrupt flag register and handle all interrupts which the PMIC has
+ * sent.  In most cases this will be the buttons.
+ */
+static uint8_t pmic_poll_interrupts(void)
+{
+	hwlock_acquire(HWLOCK_I2C);
+
+	uint8_t int_flag = MAX77650_getINT_GLBL();
+	hwlock_release(HWLOCK_I2C);
+
+	/* TODO: Remove when all interrupts are handled */
+	if (int_flag & ~(MAX77650_INT_nEN_F | MAX77650_INT_nEN_R)) {
+		LOG_WARN("pmic", "Unhandled PMIC Interrupt: %x", int_flag);
+	}
+
+	return int_flag;
+}
+
+__attribute__((noreturn)) static void pmic_die(float u_batt)
+{
+	/* Stop core 1 */
+	core1_stop();
+
+	/* Grab the screen */
+	disp_forcelock();
+
+	/* Turn it on in case it was off */
+	epic_disp_backlight(100);
+
+	/* Draw an error screen */
+	epic_disp_clear(0x0000);
+
+	epic_disp_print(0, 0, " Battery", 0xffff, 0x0000);
+	epic_disp_print(0, 20, " critical", 0xffff, 0x0000);
+	epic_disp_print(0, 40, "  !!!!", 0xffff, 0x0000);
+	epic_disp_update();
+
+	/* Vibrate violently */
+	epic_vibra_set(true);
+
+	/* Wait a bit */
+	for (int i = 0; i < 50000000; i++)
+		__NOP();
+
+	/* We have some of headroom to keep the RTC going.
+	 * The battery protection circuit will shut down
+	 * the system at 3.0 V */
+
+	/* TODO: Wake-up when USB is attached again */
+	sleep_deepsleep();
+	card10_reset();
+}
+
+/*
+ * Check the battery voltage.  If it drops too low, turn card10 off.
+ */
+static void pmic_check_battery()
+{
+	float u_batt;
+	int res;
+
+	/**
+	 * 0 = uncertain, ask config
+	 * 1 = disabled
+	 * 2 = enabled
+	 */
+	static int pmic_do_battery_check = 0;
+
+	if (pmic_do_battery_check == 0) {
+		if (config_get_boolean_with_default("battery_check", true)) {
+			pmic_do_battery_check = 2;
+		} else {
+			pmic_do_battery_check = 1;
+			LOG_WARN(
+				"pmic",
+				"Battery check was disabled by config!"
+			);
+		}
+	}
+
+	if (pmic_do_battery_check == 1) {
+		/* Disabled, ignore */
+		return;
+	}
+
+	res = pmic_read_amux(PMIC_AMUX_BATT_U, &u_batt);
+	if (res < 0) {
+		LOG_ERR("pmic",
+			"Failed reading battery voltage: %s (%d)",
+			strerror(-res),
+			res);
+		return;
+	}
+
+	LOG_DEBUG(
+		"pmic",
+		"Battery is at %d.%03d V",
+		(int)u_batt,
+		(int)(u_batt * 1000.0) % 1000
+	);
+
+	if (u_batt < BATTERY_CRITICAL) {
+		pmic_die(u_batt);
+	}
+}
+
+/*
+ * API-call for battery voltage
+ */
+int epic_read_battery_voltage(float *result)
+{
+	return pmic_read_amux(PMIC_AMUX_BATT_U, result);
+}
+
+/*
+ * API-call for battery current
+ */
+int epic_read_battery_current(float *result)
+{
+	return pmic_read_amux(PMIC_AMUX_BATT_CHG_I, result);
+}
+
+/*
+ * API-call for charge voltage
+ */
+int epic_read_chargein_voltage(float *result)
+{
+	return pmic_read_amux(PMIC_AMUX_CHGIN_U, result);
+}
+
+/*
+ * API-call for charge voltage
+ */
+int epic_read_chargein_current(float *result)
+{
+	return pmic_read_amux(PMIC_AMUX_BATT_CHG_I, result);
+}
+
+/*
+ * API-call for system voltage
+ */
+int epic_read_system_voltage(float *result)
+{
+	return pmic_read_amux(PMIC_AMUX_SYS_U, result);
+}
+
+/*
+ * API-call for thermistor voltage
+ *
+ * Thermistor is as 10k at room temperature,
+ * voltage divided with another 10k.
+ * (50% V_bias at room temperature)
+ */
+int epic_read_thermistor_voltage(float *result)
+{
+	return pmic_read_amux(PMIC_AMUX_THM_U, result);
+}
+
+static StaticTimer_t pmic_timer_data;
+static void vPmicTimerCb(TimerHandle_t xTimer)
+{
+	/*
+	 * Tell the PMIC task to check the battery again.
+	 */
+	xTaskNotify(pmic_task_id, PMIC_NOTIFY_MONITOR, eSetBits);
+}
+
+void vPmicTask(void *pvParameters)
+{
+	pmic_task_id       = xTaskGetCurrentTaskHandle();
+	uint8_t interrupts = 0;
+	uint32_t reason    = 0;
+
+	ADC_Init(0x9, NULL);
+	GPIO_Config(&gpio_cfg_adc0);
+
+	TickType_t button_start_tick = 0;
+
+	pmic_check_battery();
+
+	TimerHandle_t pmic_timer = xTimerCreateStatic(
+		"PMIC Timer",
+		pdMS_TO_TICKS(60 * 1000),
+		pdTRUE,
+		NULL,
+		vPmicTimerCb,
+		&pmic_timer_data
+	);
+	if (pmic_timer == NULL) {
+		LOG_CRIT("pmic", "Could not create timer.");
+		vTaskDelay(portMAX_DELAY);
+	}
+	xTimerStart(pmic_timer, 0);
+
+	/* Clear all pending interrupts. */
+	pmic_poll_interrupts();
+
+	while (1) {
+		interrupts |= pmic_poll_interrupts();
+		if (interrupts == 0) {
+			reason |= ulTaskNotifyTake(pdTRUE, portMAX_DELAY);
+		}
+
+		/* New interrupts */
+		if (reason & PMIC_NOTIFY_IRQ) {
+			reason ^= PMIC_NOTIFY_IRQ;
+			interrupts |= pmic_poll_interrupts();
+		}
+
+		if (interrupts & MAX77650_INT_nEN_R) {
+			/* Ignored in this state */
+			/* This can happen if the button is pressed
+			 * during boot and released now. */
+			interrupts ^= MAX77650_INT_nEN_R; /* Mark as handled. */
+		}
+
+		if (interrupts & MAX77650_INT_nEN_F) {
+			/* Button was pressed */
+			interrupts ^= MAX77650_INT_nEN_F; /* Mark as handled. */
+
+			button_start_tick = xTaskGetTickCount();
+			while (true) {
+				TickType_t duration =
+					xTaskGetTickCount() - button_start_tick;
+
+				if (duration > pdMS_TO_TICKS(1000)) {
+					disp_forcelock();
+					disp_ctx_reinit();
+
+					/* Turn it on in case it was off */
+					epic_disp_backlight(100);
+
+					epic_disp_clear(0x0000);
+
+					char buf[20];
+					sprintf(buf,
+						"Off in %d",
+						7 - (int)(duration + 500) /
+								1000);
+					epic_disp_print(
+						0,
+						0,
+						"Sleep zZz..",
+						0xffff,
+						0x0000
+					);
+					epic_disp_print(
+						0, 25, buf, 0xf000, 0x0000
+					);
+					epic_disp_print(
+						0,
+						50,
+						"   Reset ->",
+						0xffff,
+						0x0000
+					);
+					epic_disp_update();
+				}
+
+				if (duration >= pdMS_TO_TICKS(1000)) {
+					if (epic_buttons_read(
+						    BUTTON_RIGHT_TOP)) {
+						disp_forcelock();
+						disp_ctx_reinit();
+
+						/* Turn it on in case it was off */
+						epic_disp_backlight(100);
+
+						epic_disp_clear(0x0000);
+						epic_disp_print(
+							55,
+							30,
+							"Reset!",
+							0xf800,
+							0x0000
+						);
+						epic_disp_update();
+
+						serial_return_to_synchronous();
+						LOG_WARN(
+							"pmic",
+							"Resetting ..."
+						);
+						card10_reset();
+					}
+				}
+
+				if (interrupts & MAX77650_INT_nEN_R) {
+					/* Button is released */
+					interrupts ^=
+						MAX77650_INT_nEN_R; /* Mark as handled. */
+
+					if (duration < pdMS_TO_TICKS(1000)) {
+						return_to_menu();
+					}
+
+					if (duration > pdMS_TO_TICKS(1000)) {
+						serial_return_to_synchronous();
+						LOG_WARN("pmic", "Poweroff");
+						sleep_deepsleep();
+						card10_reset();
+					}
+					break;
+				}
+
+				reason |= ulTaskNotifyTake(
+					pdTRUE, pdMS_TO_TICKS(200)
+				);
+				if (reason & PMIC_NOTIFY_IRQ) {
+					/* New interrupts */
+					reason ^= PMIC_NOTIFY_IRQ;
+					interrupts |= pmic_poll_interrupts();
+				}
+			}
+		}
+
+		if (reason & PMIC_NOTIFY_MONITOR) {
+			reason ^= PMIC_NOTIFY_MONITOR;
+			pmic_check_battery();
+		}
+	}
+}

epicardium/drivers/rng.c

+#include "epicardium.h"
+#include "modules/modules.h"
+#include "drivers/drivers.h"
+
+#include "MAX77650-Arduino-Library.h"
+#include "tiny-AES-c/aes.h"
+#include "SHA256/mark2/sha256.h"
+
+#include "mxc_sys.h"
+#include "adc.h"
+#include "mxc_delay.h"
+#include "rtc.h"
+#include "trng.h"
+
+#include <string.h>
+
+static struct AES_ctx aes_ctx;
+
+int epic_trng_read(uint8_t *dest, size_t size)
+{
+	if (dest == NULL)
+		return -EFAULT;
+
+	TRNG_Init(NULL);
+	TRNG_Read(MXC_TRNG, dest, size);
+
+	return 0;
+}
+
+int epic_csprng_read(uint8_t *dest, size_t size)
+{
+	if (size >= AES_BLOCKLEN) {
+		int block_count = size / AES_BLOCKLEN;
+		AES_CTR_xcrypt_buffer(
+			&aes_ctx, dest, block_count * AES_BLOCKLEN
+		);
+		size -= block_count * AES_BLOCKLEN;
+		dest += block_count * AES_BLOCKLEN;
+	}
+
+	if (size > 0) {
+		uint8_t out[AES_BLOCKLEN];
+		AES_CTR_xcrypt_buffer(&aes_ctx, out, sizeof(out));
+		memcpy(dest, out, size);
+	}
+
+	return 0;
+}
+
+void rng_init(void)
+{
+	uint8_t key[AES_BLOCKLEN];
+	uint8_t iv[AES_BLOCKLEN];
+	uint8_t hash[32];
+	sha256_context ctx;
+	int i;
+
+	sha256_init(&ctx);
+
+	/* Seed from TRNG.
+	 * Takes about 10 ms. */
+	for (i = 0; i < 256; i++) {
+		uint8_t entropy[AES_BLOCKLEN];
+		epic_trng_read(entropy, AES_BLOCKLEN);
+		sha256_hash(&ctx, entropy, AES_BLOCKLEN);
+	}
+
+	// Seed from RTC
+	uint32_t sec, subsec;
+	while (RTC_GetTime(&sec, &subsec) == E_BUSY) {
+		mxc_delay(4000);
+	}
+	sha256_hash(&ctx, &sec, sizeof(sec));
+	sha256_hash(&ctx, &subsec, sizeof(subsec));
+
+	// Seed from SysTick
+	uint32_t systick = SysTick->VAL;
+	sha256_hash(&ctx, &systick, sizeof(systick));
+
+	/* Seed from ADC.
+	 * Takes about 50 ms */
+	ADC_Init(0x9, NULL);
+	GPIO_Config(&gpio_cfg_adc0);
+	MAX77650_setMUX_SEL(PMIC_AMUX_BATT_U);
+	for (i = 0; i < 256; i++) {
+		uint16_t adc_data;
+		ADC_StartConvert(ADC_CH_0, 0, 0);
+		ADC_GetData(&adc_data);
+		sha256_hash(&ctx, &adc_data, sizeof(adc_data));
+	}
+	MAX77650_setMUX_SEL(PMIC_AMUX_DISABLED);
+
+	sha256_done(&ctx, hash);
+	memcpy(key, hash, AES_BLOCKLEN);
+	memcpy(iv, hash + AES_BLOCKLEN, AES_BLOCKLEN);
+	AES_init_ctx_iv(&aes_ctx, key, iv);
+}

epicardium/drivers/rtc.c

+#include "epicardium.h"
+#include "os/core.h"
+#include "modules/modules.h"
+#include "user_core/interrupts.h"
+
+#include "FreeRTOS.h"
+#include "task.h"
+
+#include "rtc.h"
+
+#include <stdint.h>
+
+uint64_t monotonic_offset = 0;
+
+uint32_t epic_rtc_get_monotonic_seconds(void)
+{
+	return epic_rtc_get_seconds() + monotonic_offset / 1000ULL;
+}
+
+uint64_t epic_rtc_get_monotonic_milliseconds(void)
+{
+	return epic_rtc_get_milliseconds() + monotonic_offset;
+}
+
+uint32_t epic_rtc_get_seconds(void)
+{
+	uint32_t sec, subsec;
+
+	/*
+	 * TODO:  Find out what causes the weird behavior of this function.  The
+	 *        time needed for this call seems to depend on the frequency at
+	 *        which it is called.
+	 */
+	while (RTC_GetTime(&sec, &subsec) == E_BUSY) {
+		vTaskDelay(pdMS_TO_TICKS(4));
+	}
+
+	return sec;
+}
+
+uint64_t epic_rtc_get_milliseconds(void)
+{
+	uint32_t sec, subsec;
+
+	while (RTC_GetTime(&sec, &subsec) == E_BUSY) {
+		vTaskDelay(pdMS_TO_TICKS(4));
+	}
+
+	// Without the bias of 999 (0.24 milliseconds), this decoding function is
+	// numerically unstable:
+	//
+	// Encoding 5 milliseconds into 20 subsecs (using the encoding function in
+	// epic_rtc_set_milliseconds) and decoding it without the bias of 999 yields
+	// 4 milliseconds.
+	//
+	// The following invariants should hold when encoding / decoding from and to
+	// milliseconds / subseconds:
+	//
+	// - 0 <= encode(ms) < 4096 for 0 <= ms < 1000
+	// - decode(encode(ms)) == ms for 0 <= ms < 1000
+	// - 0 <= decode(subsec) < 1000 for 0 <= subsec < 4096
+	//
+	// These invariants were proven experimentally.
+	return (subsec * 1000ULL + 999ULL) / 4096 + sec * 1000ULL;
+}
+
+void epic_rtc_set_milliseconds(uint64_t milliseconds)
+{
+	uint32_t sec, subsec;
+	uint64_t old_milliseconds, diff;
+
+	old_milliseconds = epic_rtc_get_milliseconds();
+
+	sec    = milliseconds / 1000;
+	subsec = (milliseconds % 1000);
+	subsec *= 4096;
+	subsec /= 1000;
+
+	while (RTC_Init(MXC_RTC, sec, subsec, NULL) == E_BUSY)
+		;
+	while (RTC_EnableRTCE(MXC_RTC) == E_BUSY)
+		;
+
+	diff = old_milliseconds - milliseconds;
+	monotonic_offset += diff;
+}
+
+/* We need to use interrupt_trigger_unsafe() here */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+void RTC_IRQHandler(void)
+{
+	int flags = RTC_GetFlags();
+
+	if (flags & MXC_F_RTC_CTRL_ALDF) {
+		RTC_ClearFlags(MXC_F_RTC_CTRL_ALDF);
+		interrupt_trigger_unsafe(EPIC_INT_RTC_ALARM);
+	} else {
+		LOG_WARN("rtc", "Unknown IRQ caught!");
+		/* Disable IRQ so it does not retrigger */
+		NVIC_DisableIRQ(RTC_IRQn);
+	}
+}
+#pragma GCC diagnostic pop
+
+int epic_rtc_schedule_alarm(uint32_t timestamp)
+{
+	int res;
+
+	/*
+	 * Check if the timestamp lies in the past and if so, trigger
+	 * immediately.
+	 */
+	if (epic_rtc_get_seconds() >= timestamp) {
+		interrupt_trigger(EPIC_INT_RTC_ALARM);
+		return 0;
+	}
+
+	NVIC_EnableIRQ(RTC_IRQn);
+
+	while ((res = RTC_SetTimeofdayAlarm(MXC_RTC, timestamp)) == E_BUSY)
+		;
+
+	if (res != E_SUCCESS) {
+		return -EINVAL;
+	}
+
+	return 0;
+}