Update drv_hwtimer.c

STM32的硬件定时器在 APBxCLKDivider 为 RCC_HCLK_DIV1 的时候，timer clocks 频率等于外设总线时钟PCLKx. 反之 timer clocks 为 PCLKx 的2倍.

bsp/stm32/libraries/HAL_Drivers/drv_hwtimer.c

@@ -7,6 +7,7 @@
  * Date           Author       Notes
  * 2018-12-10     zylx         first version
  * 2020-06-16     thread-liu   Porting for stm32mp1
+ * 2020-08-25     linyongkang  Fix the timer clock frequency doubling problem
  */
 
 #include <board.h>
@@ -164,6 +165,12 @@ static void timer_init(struct rt_hwtimer_device *timer, rt_uint32_t state)
         tim = (TIM_HandleTypeDef *)timer->parent.user_data;
         tim_device = (struct stm32_hwtimer *)timer;
 
+        uint32_t FLatency = 0;
+        RCC_ClkInitTypeDef RCC_ClkInitStruct;
+        HAL_RCC_GetClockConfig(&RCC_ClkInitStruct, &FLatency);
+        uint32_t pclk1_doubler = 1 + ( RCC_ClkInitStruct.APB1CLKDivider != RCC_HCLK_DIV1 );
+        uint32_t pclk2_doubler = 1 + ( RCC_ClkInitStruct.APB2CLKDivider != RCC_HCLK_DIV1 );
+
         /* time init */
 #if defined(SOC_SERIES_STM32F2) || defined(SOC_SERIES_STM32F4) || defined(SOC_SERIES_STM32F7)
         if (tim->Instance == TIM9 || tim->Instance == TIM10 || tim->Instance == TIM11)
@@ -176,12 +183,12 @@ static void timer_init(struct rt_hwtimer_device *timer, rt_uint32_t state)
 #endif
         {
 #if !defined(SOC_SERIES_STM32F0) && !defined(SOC_SERIES_STM32G0)
-            prescaler_value = (uint32_t)(HAL_RCC_GetPCLK2Freq() * 2 / 10000) - 1;
+            prescaler_value = (uint32_t)(HAL_RCC_GetPCLK2Freq() * pclk2_doubler / 10000) - 1;
 #endif
         }
         else
         {
-            prescaler_value = (uint32_t)(HAL_RCC_GetPCLK1Freq() * 2 / 10000) - 1;
+            prescaler_value = (uint32_t)(HAL_RCC_GetPCLK1Freq() * pclk1_doubler / 10000) - 1;
         }
         tim->Init.Period            = 10000 - 1;
         tim->Init.Prescaler         = prescaler_value;
@@ -290,6 +297,12 @@ static rt_err_t timer_ctrl(rt_hwtimer_t *timer, rt_uint32_t cmd, void *arg)
         /* set timer frequence */
         freq = *((rt_uint32_t *)arg);
 
+        uint32_t FLatency = 0;
+        RCC_ClkInitTypeDef RCC_ClkInitStruct;
+        HAL_RCC_GetClockConfig(&RCC_ClkInitStruct, &FLatency);
+        uint32_t pclk1_doubler = 1 + ( RCC_ClkInitStruct.APB1CLKDivider != RCC_HCLK_DIV1 );
+        uint32_t pclk2_doubler = 1 + ( RCC_ClkInitStruct.APB2CLKDivider != RCC_HCLK_DIV1 );
+
 #if defined(SOC_SERIES_STM32F2) || defined(SOC_SERIES_STM32F4) || defined(SOC_SERIES_STM32F7)
         if (tim->Instance == TIM9 || tim->Instance == TIM10 || tim->Instance == TIM11)
 #elif defined(SOC_SERIES_STM32L4)
@@ -300,19 +313,13 @@ static rt_err_t timer_ctrl(rt_hwtimer_t *timer, rt_uint32_t cmd, void *arg)
         if (0)
 #endif
         {
-#if defined(SOC_SERIES_STM32L4)
-            val = HAL_RCC_GetPCLK2Freq() / freq;
-#elif defined(SOC_SERIES_STM32F1) || defined(SOC_SERIES_STM32F2) || defined(SOC_SERIES_STM32F4) || defined(SOC_SERIES_STM32F7) || defined(SOC_SERIES_STM32MP1)
-            val = HAL_RCC_GetPCLK2Freq() * 2 / freq;
+#if !defined(SOC_SERIES_STM32F0) && !defined(SOC_SERIES_STM32G0)
+            val = (uint32_t)(HAL_RCC_GetPCLK2Freq() * pclk2_doubler / 10000) - 1;
 #endif
         }
         else
         {
-#if defined(SOC_SERIES_STM32F1) || defined(SOC_SERIES_STM32F2) || defined(SOC_SERIES_STM32F4) || defined(SOC_SERIES_STM32F7) || defined(SOC_SERIES_STM32MP1)
-            val = HAL_RCC_GetPCLK1Freq() * 2 / freq;
-#elif defined(SOC_SERIES_STM32F0) || defined(SOC_SERIES_STM32G0)
-            val = HAL_RCC_GetPCLK1Freq() / freq;
-#endif
+            val = HAL_RCC_GetPCLK1Freq() * pclk1_doubler / freq;
         }
         __HAL_TIM_SET_PRESCALER(tim, val - 1);