Use the proper clock source for any I2C instance

Author: pennam

targets/TARGET_STM/TARGET_STM32H7/i2c_device.c

@@ -16,6 +16,7 @@
 
  #include "i2c_device.h"
  #include "mbed_assert.h"
+ #include "mbed_error.h"
  #include "stm32h7xx_ll_rcc.h"
 
  #if DEVICE_I2C
@@ -335,6 +336,71 @@ static uint32_t I2C_ComputeTiming(uint32_t clock_src_freq, uint32_t i2c_freq)
 
   return ret;
 }
+
+/**
+  * @brief  Get I2C clock source frequency according I2C instance used.
+  * @param  i2c I2C instance name.
+  * @retval I2C clock source frequency in Hz.
+  */
+static uint32_t I2C_GetPclk(I2CName i2c)
+{
+  uint32_t clocksource;
+  uint32_t pclk = 0;
+  PLL3_ClocksTypeDef pll3_clocks;
+
+  if(i2c == I2C_1 || i2c == I2C_2 || i2c == I2C_3) {
+    clocksource = __HAL_RCC_GET_I2C123_SOURCE();
+    switch(clocksource)
+    {
+      case RCC_I2C123CLKSOURCE_D2PCLK1:
+        pclk = HAL_RCC_GetPCLK1Freq();
+        break;
+      case RCC_I2C123CLKSOURCE_PLL3:
+        HAL_RCCEx_GetPLL3ClockFreq(&pll3_clocks);
+        pclk = pll3_clocks.PLL3_R_Frequency;
+        break;
+      case RCC_I2C123CLKSOURCE_HSI:
+        pclk = HSI_VALUE;
+        break;
+      case RCC_I2C123CLKSOURCE_CSI:
+        pclk = CSI_VALUE;
+        break;
+      default:
+        // should not happend
+        error("I2C123: Invalid clock source");
+        break;
+    }
+  }
+  else if(i2c == I2C_4) {
+    clocksource = __HAL_RCC_GET_I2C4_SOURCE();
+    switch(clocksource)
+    {
+      case RCC_I2C4CLKSOURCE_D3PCLK1:
+        pclk = HAL_RCCEx_GetD3PCLK1Freq();
+        break;
+      case RCC_I2C4CLKSOURCE_PLL3:
+        HAL_RCCEx_GetPLL3ClockFreq(&pll3_clocks);
+        pclk = pll3_clocks.PLL3_R_Frequency;
+        break;
+      case RCC_I2C4CLKSOURCE_HSI:
+        pclk = HSI_VALUE;
+        break;
+      case RCC_I2C4CLKSOURCE_CSI:
+        pclk = CSI_VALUE;
+        break;
+      default:
+        // should not happend
+        error("I2C4: Invalid clock source");
+        break;
+    }
+  }
+  else {
+    // should not happend
+    error("I2C: unknown instance");
+  }
+
+  return pclk;
+}
 /**
   * @}
   */
@@ -347,19 +413,16 @@ static uint32_t I2C_ComputeTiming(uint32_t clock_src_freq, uint32_t i2c_freq)
  * @param  hz Required I2C clock in Hz.
  * @retval I2C timing or 0 in case of error.
  */
-uint32_t get_i2c_timing(int hz)
+uint32_t get_i2c_timing(I2CName i2c, int hz)
 {
   uint32_t tim;
+  uint32_t pclk;
 
   I2c_valid_timing_nbr = 0;
 
-  /* we will use D2PCLK1 to calculate I2C timings */
-  MBED_ASSERT(RCC_I2C1CLKSOURCE_D2PCLK1 ==__HAL_RCC_GET_I2C1_SOURCE());
-
-  LL_RCC_ClocksTypeDef rcc_clocks;
-  LL_RCC_GetSystemClocksFreq(&rcc_clocks);
+  pclk = I2C_GetPclk(i2c);
 
-  tim = I2C_ComputeTiming(rcc_clocks.PCLK1_Frequency, hz);
+  tim = I2C_ComputeTiming(pclk, hz);
 
   return tim;
 }

targets/TARGET_STM/TARGET_STM32H7/i2c_device.h

@@ -17,7 +17,7 @@
 #ifndef MBED_I2C_DEVICE_H
 #define MBED_I2C_DEVICE_H
 
-#include "cmsis.h"
+#include "PeripheralNames.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -36,7 +36,7 @@ extern "C" {
 #define I2CAPI_I2C4_CLKSRC RCC_I2C4CLKSOURCE_D3PCLK1
 
 /*  Provide the suitable timing depending on requested frequency */
-extern uint32_t get_i2c_timing(int hz);
+extern uint32_t get_i2c_timing(I2CName i2c, int hz);
 
 
 #ifdef __cplusplus

targets/TARGET_STM/i2c_api.c

@@ -461,7 +461,6 @@ void i2c_frequency(i2c_t *obj, int hz)
 #ifdef I2C_IP_VERSION_V2
     /*  Only predefined timing for below frequencies are supported */
     MBED_ASSERT((hz == 100000) || (hz == 400000) || (hz == 1000000));
-    handle->Init.Timing = get_i2c_timing(hz);
 
     // Enable the Fast Mode Plus capability
     if (hz == 1000000) {
@@ -530,6 +529,12 @@ void i2c_frequency(i2c_t *obj, int hz)
     HAL_I2CEx_ConfigAnalogFilter(handle, I2C_ANALOGFILTER_ENABLE);
 #endif
 
+#ifdef TARGET_STM32H7
+    handle->Init.Timing = get_i2c_timing(obj_s->i2c, hz);
+#else
+    handle->Init.Timing = get_i2c_timing(hz);
+#endif
+
     // I2C configuration
     handle->Init.AddressingMode  = I2C_ADDRESSINGMODE_7BIT;
     handle->Init.DualAddressMode = I2C_DUALADDRESS_DISABLE;