STM32L1 ADC: remove adc_inited flag

Author: bcostm

targets/TARGET_STM/TARGET_STM32L1/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_hsi_inited = 0;
     RCC_OscInitTypeDef RCC_OscInitStruct;
     uint32_t function = (uint32_t)NC;
 
@@ -49,14 +48,14 @@ 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
     }
@@ -68,41 +67,39 @@ 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;
+    // Configure ADC object structures
+    obj->handle.State = HAL_ADC_STATE_RESET;
+    obj->handle.Init.ClockPrescaler        = ADC_CLOCK_ASYNC_DIV4;
+    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          = 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      = ADC_AUTOWAIT_UNTIL_DATA_READ;  // Enable the dynamic low power Auto Delay: new conversion start only when the previous conversion (for regular group) or previous sequence (for injected group) has been treated by user software.
+    obj->handle.Init.LowPowerAutoPowerOff  = ADC_AUTOPOWEROFF_IDLE_PHASE;   // Enable the auto-off mode: the ADC automatically powers-off after a conversion and automatically wakes-up when a new conversion is triggered (with startup time between trigger and start of sampling).
+    obj->handle.Init.ChannelsBank          = ADC_CHANNELS_BANK_A;
+    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      = 0;                             // Not used
+    obj->handle.Init.ExternalTrigConvEdge  = ADC_EXTERNALTRIGCONVEDGE_NONE;
+    obj->handle.Init.DMAContinuousRequests = DISABLE;
+
+    __HAL_RCC_ADC1_CLK_ENABLE();
+
+    if (HAL_ADC_Init(&obj->handle) != HAL_OK) {
+        error("Cannot initialize ADC");
+    }
 
+    // This section is done only once
+    if (adc_hsi_inited == 0) {
+        adc_hsi_inited = 1;
         // Enable the HSI (to clock the ADC)
         RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI;
         RCC_OscInitStruct.HSIState       = RCC_HSI_ON;
         RCC_OscInitStruct.PLL.PLLState   = RCC_PLL_NONE;
         RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
         HAL_RCC_OscConfig(&RCC_OscInitStruct);
-
-        obj->handle.State = HAL_ADC_STATE_RESET;
-        // Enable ADC clock
-        __ADC1_CLK_ENABLE();
-
-        // Configure ADC
-        obj->handle.Init.ClockPrescaler        = ADC_CLOCK_ASYNC_DIV4;
-        obj->handle.Init.Resolution            = ADC_RESOLUTION12b;
-        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          = 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      = ADC_AUTOWAIT_UNTIL_DATA_READ;  // Enable the dynamic low power Auto Delay: new conversion start only when the previous conversion (for regular group) or previous sequence (for injected group) has been treated by user software.
-        obj->handle.Init.LowPowerAutoPowerOff  = ADC_AUTOPOWEROFF_IDLE_PHASE;   // Enable the auto-off mode: the ADC automatically powers-off after a conversion and automatically wakes-up when a new conversion is triggered (with startup time between trigger and start of sampling).
-        obj->handle.Init.ChannelsBank          = ADC_CHANNELS_BANK_A;
-        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      = 0;                             // Not used
-        obj->handle.Init.ExternalTrigConvEdge  = ADC_EXTERNALTRIGCONVEDGE_NONE;
-        obj->handle.Init.DMAContinuousRequests = DISABLE;
-
-        if (HAL_ADC_Init(&obj->handle) != HAL_OK) {
-            error("Cannot initialize ADC");
-        }
     }
 }
 
@@ -231,7 +228,7 @@ 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;
     }