STM32L4 ADC: remove adc_inited flag

Author: bcostm

targets/TARGET_STM/TARGET_STM32L4/analogin_api.c

@@ -36,10 +36,9 @@
 #include "mbed_error.h"
 #include "PeripheralPins.h"
 
-int adc_inited = 0;
-
 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, ...)
@@ -48,14 +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
     }
@@ -67,37 +66,35 @@ 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
-        __HAL_RCC_ADC_CLK_ENABLE();
-        __HAL_RCC_ADC_CONFIG(RCC_ADCCLKSOURCE_SYSCLK);
-
-        obj->handle.State = HAL_ADC_STATE_RESET;
-        // Configure ADC
-        obj->handle.Init.ClockPrescaler        = ADC_CLOCK_ASYNC_DIV2;          // Asynchronous clock mode, input ADC clock
-        obj->handle.Init.Resolution            = ADC_RESOLUTION_12B;
-        obj->handle.Init.DataAlign             = ADC_DATAALIGN_RIGHT;
-        obj->handle.Init.ScanConvMode          = DISABLE;                       // Sequencer disabled (ADC conversion on only 1 channel: channel set on rank 1)
-        obj->handle.Init.EOCSelection          = ADC_EOC_SINGLE_CONV;           // On STM32L1xx ADC, overrun detection is enabled only if EOC selection is set to each conversion (or transfer by DMA enabled, this is not the case in this example).
-        obj->handle.Init.LowPowerAutoWait      = DISABLE;
-        obj->handle.Init.ContinuousConvMode    = DISABLE;                       // Continuous mode disabled to have only 1 conversion at each conversion trig
-        obj->handle.Init.NbrOfConversion       = 1;                             // Parameter discarded because sequencer is disabled
-        obj->handle.Init.DiscontinuousConvMode = DISABLE;                       // Parameter discarded because sequencer is disabled
-        obj->handle.Init.NbrOfDiscConversion   = 1;                             // Parameter discarded because sequencer is disabled
-        obj->handle.Init.ExternalTrigConv      = ADC_SOFTWARE_START;            // Software start to trig the 1st conversion manually, without external event
-        obj->handle.Init.ExternalTrigConvEdge  = ADC_EXTERNALTRIGCONVEDGE_NONE;
-        obj->handle.Init.DMAContinuousRequests = DISABLE;
-        obj->handle.Init.Overrun               = ADC_OVR_DATA_OVERWRITTEN;      // DR register is overwritten with the last conversion result in case of overrun
-        obj->handle.Init.OversamplingMode      = DISABLE;                       // No oversampling
-
-        if (HAL_ADC_Init(&obj->handle) != HAL_OK) {
-            error("Cannot initialize ADC\n");
-        }
-
-        // Calibrate ADC
+    // Configure ADC object structures
+    obj->handle.State = HAL_ADC_STATE_RESET;
+    obj->handle.Init.ClockPrescaler        = ADC_CLOCK_ASYNC_DIV2;          // Asynchronous clock mode, input ADC clock
+    obj->handle.Init.Resolution            = ADC_RESOLUTION_12B;
+    obj->handle.Init.DataAlign             = ADC_DATAALIGN_RIGHT;
+    obj->handle.Init.ScanConvMode          = DISABLE;                       // Sequencer disabled (ADC conversion on only 1 channel: channel set on rank 1)
+    obj->handle.Init.EOCSelection          = ADC_EOC_SINGLE_CONV;           // On STM32L1xx ADC, overrun detection is enabled only if EOC selection is set to each conversion (or transfer by DMA enabled, this is not the case in this example).
+    obj->handle.Init.LowPowerAutoWait      = DISABLE;
+    obj->handle.Init.ContinuousConvMode    = DISABLE;                       // Continuous mode disabled to have only 1 conversion at each conversion trig
+    obj->handle.Init.NbrOfConversion       = 1;                             // Parameter discarded because sequencer is disabled
+    obj->handle.Init.DiscontinuousConvMode = DISABLE;                       // Parameter discarded because sequencer is disabled
+    obj->handle.Init.NbrOfDiscConversion   = 1;                             // Parameter discarded because sequencer is disabled
+    obj->handle.Init.ExternalTrigConv      = ADC_SOFTWARE_START;            // Software start to trig the 1st conversion manually, without external event
+    obj->handle.Init.ExternalTrigConvEdge  = ADC_EXTERNALTRIGCONVEDGE_NONE;
+    obj->handle.Init.DMAContinuousRequests = DISABLE;
+    obj->handle.Init.Overrun               = ADC_OVR_DATA_OVERWRITTEN;      // DR register is overwritten with the last conversion result in case of overrun
+    obj->handle.Init.OversamplingMode      = DISABLE;                       // No oversampling
+
+    // Enable ADC clock
+    __HAL_RCC_ADC_CLK_ENABLE();
+    __HAL_RCC_ADC_CONFIG(RCC_ADCCLKSOURCE_SYSCLK);
+
+    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, ADC_SINGLE_ENDED);
     }
 }
@@ -181,7 +178,7 @@ 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;
     }