analog pgio: lock ADC HW

epicardium/modules/gpio.c

@@ -5,6 +5,7 @@
 #include "adc.h"
 #include "mxc_errors.h"
 #include "modules/log.h"
+#include "modules/modules.h"
 
 /*
  * Despite what the schematic (currently, 2019-08-18) says these are the correct
@@ -133,13 +134,18 @@ int epic_gpio_read_pin(uint8_t pin)
 	} else if (cfg->func == GPIO_FUNC_IN) {
 		return GPIO_InGet(cfg) != 0;
 	} else if (cfg->func == GPIO_FUNC_ALT1) {
+		int rc = hwlock_acquire(HWLOCK_ADC, pdMS_TO_TICKS(10));
+		if (!rc) {
 			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;
+		}
+		return rc;
 	} else {
 		return -EINVAL;
 	}