STM32F0 ADC: remove adc_inited flag

Author: bcostm

targets/TARGET_STM/TARGET_STM32F0/analogin_api.c

@@ -33,12 +33,12 @@
 #include "mbed_wait_api.h"
 #include "cmsis.h"
 #include "pinmap.h"
-#include "PeripheralPins.h"
 #include "mbed_error.h"
+#include "PeripheralPins.h"
 
-int adc_inited = 0;
-
-void analogin_init(analogin_t *obj, PinName pin) {
+void analogin_init(analogin_t *obj, PinName pin)
+{
+    static int adc_calibrated = 0;
     uint32_t function = (uint32_t)NC;
 
     // ADC Internal Channels "pins"  (Temperature, Vref, Vbat, ...)
@@ -47,14 +47,14 @@ void analogin_init(analogin_t *obj, PinName pin) {
     if ((pin < 0xF0) || (pin >= 0x100)) {
         // Normal channels
         // Get the peripheral name from the pin and assign it to the object
-        obj->handle.Instance = (ADC_TypeDef *) pinmap_peripheral(pin, PinMap_ADC);
+        obj->handle.Instance = (ADC_TypeDef *)pinmap_peripheral(pin, PinMap_ADC);
         // Get the functions (adc channel) from the pin and assign it to the object
         function = pinmap_function(pin, PinMap_ADC);
         // Configure GPIO
         pinmap_pinout(pin, PinMap_ADC);
     } else {
         // Internal channels
-        obj->handle.Instance = (ADC_TypeDef *) pinmap_peripheral(pin, PinMap_ADC_Internal);
+        obj->handle.Instance = (ADC_TypeDef *)pinmap_peripheral(pin, PinMap_ADC_Internal);
         function = pinmap_function(pin, PinMap_ADC_Internal);
         // No GPIO configuration for internal channels
     }
@@ -66,40 +66,38 @@ void analogin_init(analogin_t *obj, PinName pin) {
     // Save pin number for the read function
     obj->pin = pin;
 
-    // The ADC initialization is done once
-    if (adc_inited == 0) {
-        adc_inited = 1;
-
-        // Enable ADC clock
-        __ADC1_CLK_ENABLE();
-
-        // Configure ADC
-        obj->handle.State = HAL_ADC_STATE_RESET;
-        obj->handle.Init.ClockPrescaler        = ADC_CLOCK_SYNC_PCLK_DIV4;
-        obj->handle.Init.Resolution            = ADC_RESOLUTION12b;
-        obj->handle.Init.DataAlign             = ADC_DATAALIGN_RIGHT;
-        obj->handle.Init.ScanConvMode          = ADC_SCAN_DIRECTION_FORWARD;
-        obj->handle.Init.EOCSelection          = EOC_SINGLE_CONV;
-        obj->handle.Init.LowPowerAutoWait      = DISABLE;
-        obj->handle.Init.LowPowerAutoPowerOff  = DISABLE;
-        obj->handle.Init.ContinuousConvMode    = DISABLE;
-        obj->handle.Init.DiscontinuousConvMode = DISABLE;
-        obj->handle.Init.ExternalTrigConv      = ADC_SOFTWARE_START;
-        obj->handle.Init.ExternalTrigConvEdge  = ADC_EXTERNALTRIGCONVEDGE_NONE;
-        obj->handle.Init.DMAContinuousRequests = DISABLE;
-        obj->handle.Init.Overrun               = OVR_DATA_OVERWRITTEN;
-        if (HAL_ADC_Init(&obj->handle) != HAL_OK) {
-            error("Cannot initialize ADC");
-        }
-        // Run the ADC calibration
-        if (HAL_ADCEx_Calibration_Start(&obj->handle) != HAL_OK) {
-            error("Cannot Start ADC_Calibration");
-        }
+    // Configure ADC object structures
+    obj->handle.State = HAL_ADC_STATE_RESET;
+    obj->handle.Init.ClockPrescaler        = ADC_CLOCK_SYNC_PCLK_DIV4;
+    obj->handle.Init.Resolution            = ADC_RESOLUTION_12B;
+    obj->handle.Init.DataAlign             = ADC_DATAALIGN_RIGHT;
+    obj->handle.Init.ScanConvMode          = ADC_SCAN_DIRECTION_FORWARD;
+    obj->handle.Init.EOCSelection          = EOC_SINGLE_CONV;
+    obj->handle.Init.LowPowerAutoWait      = DISABLE;
+    obj->handle.Init.LowPowerAutoPowerOff  = DISABLE;
+    obj->handle.Init.ContinuousConvMode    = DISABLE;
+    obj->handle.Init.DiscontinuousConvMode = DISABLE;
+    obj->handle.Init.ExternalTrigConv      = ADC_SOFTWARE_START;
+    obj->handle.Init.ExternalTrigConvEdge  = ADC_EXTERNALTRIGCONVEDGE_NONE;
+    obj->handle.Init.DMAContinuousRequests = DISABLE;
+    obj->handle.Init.Overrun               = OVR_DATA_OVERWRITTEN;
+
+    __HAL_RCC_ADC1_CLK_ENABLE();
+
+    if (HAL_ADC_Init(&obj->handle) != HAL_OK) {
+        error("Cannot initialize ADC");
+    }
+
+    // ADC calibration is done only once
+    if (adc_calibrated == 0) {
+        adc_calibrated = 1;
+        HAL_ADCEx_Calibration_Start(&obj->handle);
     }
 }
 
-static inline uint16_t adc_read(analogin_t *obj) {
-    ADC_ChannelConfTypeDef sConfig;
+static inline uint16_t adc_read(analogin_t *obj)
+{
+    ADC_ChannelConfTypeDef sConfig = {0};
 
     // Configure ADC channel
     sConfig.Rank         = ADC_RANK_CHANNEL_NUMBER;
@@ -182,20 +180,22 @@ static inline uint16_t adc_read(analogin_t *obj) {
 
     // Wait end of conversion and get value
     if (HAL_ADC_PollForConversion(&obj->handle, 10) == HAL_OK) {
-        return (HAL_ADC_GetValue(&obj->handle));
+        return (uint16_t)HAL_ADC_GetValue(&obj->handle);
     } else {
         return 0;
     }
 }
 
-uint16_t analogin_read_u16(analogin_t *obj) {
+uint16_t analogin_read_u16(analogin_t *obj)
+{
     uint16_t value = adc_read(obj);
     // 12-bit to 16-bit conversion
     value = ((value << 4) & (uint16_t)0xFFF0) | ((value >> 8) & (uint16_t)0x000F);
     return value;
 }
 
-float analogin_read(analogin_t *obj) {
+float analogin_read(analogin_t *obj)
+{
     uint16_t value = adc_read(obj);
     return (float)value * (1.0f / (float)0xFFF); // 12 bits range
 }