text: /* mbed Microcontroller Library
   *******************************************************************************
   * Copyright (c) 2015, STMicroelectronics
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions are met:
   *
   * 1. Redistributions of source code must retain the above copyright notice,
   *    this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright notice,
   *    this list of conditions and the following disclaimer in the documentation
   *    and/or other materials provided with the distribution.
   * 3. Neither the name of STMicroelectronics nor the names of its contributors
   *    may be used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
   * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
   * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   *******************************************************************************
   */
  
  
  #include "mbed_assert.h"
  #include "i2c_api.h"
  #include "platform/mbed_wait_api.h"
  
  #if DEVICE_I2C
  
  #include "cmsis.h"
  #include "pinmap.h"
  #include "PeripheralPins.h"
  #include "i2c_device.h" // family specific defines
  
  #ifndef DEBUG_STDIO
  #   define DEBUG_STDIO 0
  #endif
  
  #if DEBUG_STDIO
  #   include <stdio.h>
  #   define DEBUG_PRINTF(...) do { printf(__VA_ARGS__); } while(0)
  #else
  #   define DEBUG_PRINTF(...) {}
  #endif
  
  #if DEVICE_I2C_ASYNCH
      #define I2C_S(obj) (struct i2c_s *) (&((obj)->i2c))
  #else
      #define I2C_S(obj) (struct i2c_s *) (obj)
  #endif
  
  /*  Family specific description for I2C */
  #define I2C_NUM (5)
  static I2C_HandleTypeDef* i2c_handles[I2C_NUM];
  
  /* Timeout values are based on core clock and I2C clock.
     The BYTE_TIMEOUT is computed as twice the number of cycles it would
     take to send 10 bits over I2C. Most Flags should take less than that.
     This is for immediate FLAG or ACK check.
  */
  #define BYTE_TIMEOUT ((SystemCoreClock / obj_s->hz) * 2 * 10)
  /* Timeout values based on I2C clock.
     The BYTE_TIMEOUT_US is computed as 3x the time in us it would
     take to send 10 bits over I2C. Most Flags should take less than that.
     This is for complete transfers check.
  */
  #define BYTE_TIMEOUT_US   ((SystemCoreClock / obj_s->hz) * 3 * 10)
  /* Timeout values for flags and events waiting loops. These timeouts are
     not based on accurate values, they just guarantee that the application will
     not remain stuck if the I2C communication is corrupted. 
  */
  #define FLAG_TIMEOUT ((int)0x1000)
  
  /* GENERIC INIT and HELPERS FUNCTIONS */
  
  #if defined(I2C1_BASE)
  static void i2c1_irq(void)
  {
      I2C_HandleTypeDef * handle = i2c_handles[0];
      HAL_I2C_EV_IRQHandler(handle);
      HAL_I2C_ER_IRQHandler(handle);
  }
  #endif
  #if defined(I2C2_BASE)
  static void i2c2_irq(void)
  {
      I2C_HandleTypeDef * handle = i2c_handles[1];
      HAL_I2C_EV_IRQHandler(handle);
      HAL_I2C_ER_IRQHandler(handle);
  }
  #endif
  #if defined(I2C3_BASE)
  static void i2c3_irq(void)
  {
      I2C_HandleTypeDef * handle = i2c_handles[2];
      HAL_I2C_EV_IRQHandler(handle);
      HAL_I2C_ER_IRQHandler(handle);
  }
  #endif
  #if defined(I2C4_BASE)
  static void i2c4_irq(void)
  {
      I2C_HandleTypeDef * handle = i2c_handles[3];
      HAL_I2C_EV_IRQHandler(handle);
      HAL_I2C_ER_IRQHandler(handle);
  }
  #endif
  #if defined(FMPI2C1_BASE)
  static void i2c5_irq(void)
  {
      I2C_HandleTypeDef * handle = i2c_handles[4];
      HAL_I2C_EV_IRQHandler(handle);
      HAL_I2C_ER_IRQHandler(handle);
  }
  #endif
  
  void i2c_ev_err_enable(i2c_t *obj, uint32_t handler) {
      struct i2c_s *obj_s = I2C_S(obj);
      IRQn_Type irq_event_n = obj_s->event_i2cIRQ;
      IRQn_Type irq_error_n = obj_s->error_i2cIRQ;
      /*  default prio in master case is set to 2 */
      uint32_t prio = 2;
  
      /* Set up ITs using IRQ and handler tables */
      NVIC_SetVector(irq_event_n, handler);
      NVIC_SetVector(irq_error_n, handler);
  
  #if DEVICE_I2CSLAVE
      /*  Set higher priority to slave device than master.
       *  In case a device makes use of both master and slave, the
       *  slave needs higher responsiveness.
       */
      if (obj_s->slave) {
          prio = 1;
      }
  #endif
  
      NVIC_SetPriority(irq_event_n, prio);
      NVIC_SetPriority(irq_error_n, prio);
      NVIC_EnableIRQ(irq_event_n);
      NVIC_EnableIRQ(irq_error_n);
  }
  
  void i2c_ev_err_disable(i2c_t *obj) {
      struct i2c_s *obj_s = I2C_S(obj);
      IRQn_Type irq_event_n = obj_s->event_i2cIRQ;
      IRQn_Type irq_error_n = obj_s->error_i2cIRQ;
  
      HAL_NVIC_DisableIRQ(irq_event_n);
      HAL_NVIC_DisableIRQ(irq_error_n);
  }
  
  uint32_t i2c_get_irq_handler(i2c_t *obj)
  {
      struct i2c_s *obj_s = I2C_S(obj);
      I2C_HandleTypeDef *handle = &(obj_s->handle);
      uint32_t handler = 0;
  
      switch (obj_s->index) {
  #if defined(I2C1_BASE)
          case 0:
              handler = (uint32_t)&i2c1_irq;
              break;
  #endif
  #if defined(I2C2_BASE)
          case 1:
              handler = (uint32_t)&i2c2_irq;
              break;
  #endif
  #if defined(I2C3_BASE)
          case 2:
              handler = (uint32_t)&i2c3_irq;
              break;
  #endif
  #if defined(I2C4_BASE)
          case 3:
              handler = (uint32_t)&i2c4_irq;
              break;
  #endif
  #if defined(FMPI2C1_BASE)
          case 4:
              handler = (uint32_t)&i2c5_irq;
              break;
  #endif
      }
  
      i2c_handles[obj_s->index] = handle;
      return handler;
  }
  
  void i2c_hw_reset(i2c_t *obj) {
      int timeout;
      struct i2c_s *obj_s = I2C_S(obj);
      I2C_HandleTypeDef *handle = &(obj_s->handle);
  
      handle->Instance = (I2C_TypeDef *)(obj_s->i2c);
  
      // wait before reset
      timeout = BYTE_TIMEOUT;
      while ((__HAL_I2C_GET_FLAG(handle, I2C_FLAG_BUSY)) && (--timeout != 0));
  #if defined I2C1_BASE
      if (obj_s->i2c == I2C_1) {
          __HAL_RCC_I2C1_FORCE_RESET();
          __HAL_RCC_I2C1_RELEASE_RESET();
      }
  #endif
  #if defined I2C2_BASE
      if (obj_s->i2c == I2C_2) {
          __HAL_RCC_I2C2_FORCE_RESET();
          __HAL_RCC_I2C2_RELEASE_RESET();
      }
  #endif
  #if defined I2C3_BASE
      if (obj_s->i2c == I2C_3) {
          __HAL_RCC_I2C3_FORCE_RESET();
          __HAL_RCC_I2C3_RELEASE_RESET();
      }
  #endif
  #if defined I2C4_BASE
      if (obj_s->i2c == I2C_4) {
          __HAL_RCC_I2C4_FORCE_RESET();
          __HAL_RCC_I2C4_RELEASE_RESET();
      }
  #endif
  #if defined FMPI2C1_BASE
      if (obj_s->i2c == FMPI2C_1) {
          __HAL_RCC_FMPI2C1_FORCE_RESET();
          __HAL_RCC_FMPI2C1_RELEASE_RESET();
      }
  #endif
  }
  
  void i2c_sw_reset(i2c_t *obj)
  {
      struct i2c_s *obj_s = I2C_S(obj);
      I2C_HandleTypeDef *handle = &(obj_s->handle);
      /*  SW reset procedure:
       *  PE must be kept low during at least 3 APB clock cycles
       *  in order to perform the software reset.
       *  This is ensured by writing the following software sequence:
       *  - Write PE=0
       *  - Check PE=0
       *  - Write PE=1.
       */
      handle->Instance->CR1 &=  ~I2C_CR1_PE;
      while(handle->Instance->CR1 & I2C_CR1_PE);
      handle->Instance->CR1 |=  I2C_CR1_PE;
  }
  
  void i2c_init(i2c_t *obj, PinName sda, PinName scl) {
  
      struct i2c_s *obj_s = I2C_S(obj);
  
      // Determine the I2C to use
      I2CName i2c_sda = (I2CName)pinmap_peripheral(sda, PinMap_I2C_SDA);
      I2CName i2c_scl = (I2CName)pinmap_peripheral(scl, PinMap_I2C_SCL);
      obj_s->sda = sda;
      obj_s->scl = scl;
  
      obj_s->i2c = (I2CName)pinmap_merge(i2c_sda, i2c_scl);
      MBED_ASSERT(obj_s->i2c != (I2CName)NC);
  
  #if defined I2C1_BASE
      // Enable I2C1 clock and pinout if not done
      if (obj_s->i2c == I2C_1) {
          obj_s->index = 0;
          __HAL_RCC_I2C1_CLK_ENABLE();
          // Configure I2C pins
          obj_s->event_i2cIRQ = I2C1_EV_IRQn;
          obj_s->error_i2cIRQ = I2C1_ER_IRQn;
      }
  #endif
  #if defined I2C2_BASE
      // Enable I2C2 clock and pinout if not done
      if (obj_s->i2c == I2C_2) {
          obj_s->index = 1;
          __HAL_RCC_I2C2_CLK_ENABLE();
          obj_s->event_i2cIRQ = I2C2_EV_IRQn;
          obj_s->error_i2cIRQ = I2C2_ER_IRQn;
      }
  #endif
  #if defined I2C3_BASE
      // Enable I2C3 clock and pinout if not done
      if (obj_s->i2c == I2C_3) {
          obj_s->index = 2;
          __HAL_RCC_I2C3_CLK_ENABLE();
          obj_s->event_i2cIRQ = I2C3_EV_IRQn;
          obj_s->error_i2cIRQ = I2C3_ER_IRQn;
      }
  #endif
  #if defined I2C4_BASE
      // Enable I2C3 clock and pinout if not done
      if (obj_s->i2c == I2C_4) {
          obj_s->index = 3;
          __HAL_RCC_I2C4_CLK_ENABLE();
          obj_s->event_i2cIRQ = I2C4_EV_IRQn;
          obj_s->error_i2cIRQ = I2C4_ER_IRQn;
      }
  #endif
  #if defined FMPI2C1_BASE
      // Enable I2C3 clock and pinout if not done
      if (obj_s->i2c == FMPI2C_1) {
          obj_s->index = 4;
          __HAL_RCC_FMPI2C1_CLK_ENABLE();
          obj_s->event_i2cIRQ = FMPI2C1_EV_IRQn;
          obj_s->error_i2cIRQ = FMPI2C1_ER_IRQn;
      }
  #endif
  
      // Configure I2C pins
      pinmap_pinout(sda, PinMap_I2C_SDA);
      pinmap_pinout(scl, PinMap_I2C_SCL);
      pin_mode(sda, OpenDrainNoPull);
      pin_mode(scl, OpenDrainNoPull);
  
      // I2C configuration
      // Default hz value used for timeout computation
      if(!obj_s->hz)
          obj_s->hz = 100000; // 100 kHz per default
  
      // Reset to clear pending flags if any
      i2c_hw_reset(obj);
      i2c_frequency(obj, obj_s->hz );
  
  #if DEVICE_I2CSLAVE
      // I2C master by default
      obj_s->slave = 0;
      obj_s->pending_slave_tx_master_rx = 0;
      obj_s->pending_slave_rx_maxter_tx = 0;
  #endif
  
      // I2C Xfer operation init
      obj_s->event = 0;
      obj_s->XferOperation = I2C_FIRST_AND_LAST_FRAME;
  #ifdef I2C_IP_VERSION_V2
      obj_s->pending_start = 0;
  #endif
  }
  
  void i2c_frequency(i2c_t *obj, int hz)
  {
      int timeout;
      struct i2c_s *obj_s = I2C_S(obj);
      I2C_HandleTypeDef *handle = &(obj_s->handle);
  
      // wait before init
      timeout = BYTE_TIMEOUT;
      while ((__HAL_I2C_GET_FLAG(handle, I2C_FLAG_BUSY)) && (--timeout != 0));
  
  #ifdef I2C_IP_VERSION_V1
      handle->Init.ClockSpeed      = hz;
      handle->Init.DutyCycle       = I2C_DUTYCYCLE_2;
  #endif
  #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) {
  #if defined(I2C1_BASE) && defined(__HAL_SYSCFG_FASTMODEPLUS_ENABLE) && defined (I2C_FASTMODEPLUS_I2C1)
          if (obj_s->i2c == I2C_1) {
              HAL_I2CEx_EnableFastModePlus(I2C_FASTMODEPLUS_I2C1);
          }
  #endif
  #if defined(I2C2_BASE) && defined(__HAL_SYSCFG_FASTMODEPLUS_ENABLE) && defined (I2C_FASTMODEPLUS_I2C2)
          if (obj_s->i2c == I2C_2) {
              HAL_I2CEx_EnableFastModePlus(I2C_FASTMODEPLUS_I2C2);
          }
  #endif
  #if defined(I2C3_BASE) && defined(__HAL_SYSCFG_FASTMODEPLUS_ENABLE) && defined (I2C_FASTMODEPLUS_I2C3)
          if (obj_s->i2c == I2C_3) {
              HAL_I2CEx_EnableFastModePlus(I2C_FASTMODEPLUS_I2C3);
          }
  #endif
  #if defined(I2C4_BASE) && defined(__HAL_SYSCFG_FASTMODEPLUS_ENABLE) && defined (I2C_FASTMODEPLUS_I2C4)
          if (obj_s->i2c == I2C_4) {
              HAL_I2CEx_EnableFastModePlus(I2C_FASTMODEPLUS_I2C4);
          }
  #endif
      }
  #endif //I2C_IP_VERSION_V2
  
      /*##-1- Configure the I2C clock source. The clock is derived from the SYSCLK #*/
  #if defined(I2C1_BASE) && defined (__HAL_RCC_I2C1_CONFIG)
      if (obj_s->i2c == I2C_1) {
          __HAL_RCC_I2C1_CONFIG(I2CAPI_I2C1_CLKSRC);
      }
  #endif
  #if defined(I2C2_BASE) && defined(__HAL_RCC_I2C2_CONFIG)
      if (obj_s->i2c == I2C_2) {
          __HAL_RCC_I2C2_CONFIG(I2CAPI_I2C2_CLKSRC);
      }
  #endif
  #if defined(I2C3_BASE) && defined(__HAL_RCC_I2C3_CONFIG)
      if (obj_s->i2c == I2C_3) {
          __HAL_RCC_I2C3_CONFIG(I2CAPI_I2C3_CLKSRC);
      }
  #endif
  #if defined(I2C4_BASE) && defined(__HAL_RCC_I2C4_CONFIG)
      if (obj_s->i2c == I2C_4) {
          __HAL_RCC_I2C4_CONFIG(I2CAPI_I2C4_CLKSRC);
      }
  #endif
  
  #ifdef I2C_ANALOGFILTER_ENABLE
      /* Enable the Analog I2C Filter */
      HAL_I2CEx_ConfigAnalogFilter(handle,I2C_ANALOGFILTER_ENABLE);
  #endif
  
      // I2C configuration
      handle->Init.AddressingMode  = I2C_ADDRESSINGMODE_7BIT;
      handle->Init.DualAddressMode = I2C_DUALADDRESS_DISABLE;
      handle->Init.GeneralCallMode = I2C_GENERALCALL_DISABLE;
      handle->Init.NoStretchMode   = I2C_NOSTRETCH_DISABLE;
      handle->Init.OwnAddress1     = 0;
      handle->Init.OwnAddress2     = 0;
      HAL_I2C_Init(handle);
  
      /*  store frequency for timeout computation */
      obj_s->hz = hz;
  }
  
  i2c_t *get_i2c_obj(I2C_HandleTypeDef *hi2c){
      /* Aim of the function is to get i2c_s pointer using hi2c pointer */
      /* Highly inspired from magical linux kernel's "container_of" */
      /* (which was not directly used since not compatible with IAR toolchain) */
      struct i2c_s *obj_s;
      i2c_t *obj;
  
      obj_s = (struct i2c_s *)( (char *)hi2c - offsetof(struct i2c_s,handle));
      obj = (i2c_t *)( (char *)obj_s - offsetof(i2c_t,i2c));
  
      return (obj);
  }
  
  void i2c_reset(i2c_t *obj) {
      struct i2c_s *obj_s = I2C_S(obj);
      /*  As recommended in i2c_api.h, mainly send stop */
      i2c_stop(obj);
      /* then re-init */
      i2c_init(obj, obj_s->sda, obj_s->scl);
  }
  
  /*
   *  UNITARY APIS.
   *  For very basic operations, direct registers access is needed
   *  There are 2 different IPs version that need to be supported
   */
  #ifdef I2C_IP_VERSION_V1
  int i2c_start(i2c_t *obj) {
  
      int timeout;
      struct i2c_s *obj_s = I2C_S(obj);
      I2C_HandleTypeDef *handle = &(obj_s->handle);
  
      // Clear Acknowledge failure flag
      __HAL_I2C_CLEAR_FLAG(handle, I2C_FLAG_AF);
  
      // Wait the STOP condition has been previously correctly sent
      // This timeout can be avoid in some specific cases by simply clearing the STOP bit
      timeout = FLAG_TIMEOUT;
      while ((handle->Instance->CR1 & I2C_CR1_STOP) == I2C_CR1_STOP) {
          if ((timeout--) == 0) {
              return 1;
          }
      }
  
      // Generate the START condition
      handle->Instance->CR1 |= I2C_CR1_START;
  
      // Wait the START condition has been correctly sent
      timeout = FLAG_TIMEOUT;
      while (__HAL_I2C_GET_FLAG(handle, I2C_FLAG_SB) == RESET) {
          if ((timeout--) == 0) {
              return 1;
          }
      }
  
      return 0;
  }
  
  int i2c_stop(i2c_t *obj) {
      struct i2c_s *obj_s = I2C_S(obj);
      I2C_TypeDef *i2c = (I2C_TypeDef *)obj_s->i2c;
  
      // Generate the STOP condition
      i2c->CR1 |= I2C_CR1_STOP;
  
      /*  In case of mixed usage of the APIs (unitary + SYNC)
       *  re-init HAL state
       */
      if(obj_s->XferOperation != I2C_FIRST_AND_LAST_FRAME)
              i2c_init(obj, obj_s->sda, obj_s->scl);
  
      return 0;
  }
  
  int i2c_byte_read(i2c_t *obj, int last) {
  
      int timeout;
      struct i2c_s *obj_s = I2C_S(obj);
      I2C_HandleTypeDef *handle = &(obj_s->handle);
  
      if (last) {
          // Don't acknowledge the last byte
          handle->Instance->CR1 &= ~I2C_CR1_ACK;
      } else {
          // Acknowledge the byte
          handle->Instance->CR1 |= I2C_CR1_ACK;
      }
  
      // Wait until the byte is received
      timeout = FLAG_TIMEOUT;
      while (__HAL_I2C_GET_FLAG(handle, I2C_FLAG_RXNE) == RESET) {
          if ((timeout--) == 0) {
              return -1;
          }
      }
  
      return (int)handle->Instance->DR;
  }
  
  int i2c_byte_write(i2c_t *obj, int data) {
  
      int timeout;
      struct i2c_s *obj_s = I2C_S(obj);
      I2C_HandleTypeDef *handle = &(obj_s->handle);
  
      handle->Instance->DR = (uint8_t)data;
  
      // Wait until the byte (might be the address) is transmitted
      timeout = FLAG_TIMEOUT;
      while ((__HAL_I2C_GET_FLAG(handle, I2C_FLAG_TXE) == RESET) &&
              (__HAL_I2C_GET_FLAG(handle, I2C_FLAG_BTF) == RESET) &&
               (__HAL_I2C_GET_FLAG(handle, I2C_FLAG_ADDR) == RESET)) {
          if ((timeout--) == 0) {
              return 2;
          }
      }
  
       if (__HAL_I2C_GET_FLAG(handle, I2C_FLAG_ADDR) != RESET)
       {
           __HAL_I2C_CLEAR_ADDRFLAG(handle);
       }
  
      return 1;
  }
  #endif //I2C_IP_VERSION_V1
  #ifdef I2C_IP_VERSION_V2
  
  int i2c_start(i2c_t *obj) {
      struct i2c_s *obj_s = I2C_S(obj);
      /*  This I2C IP doesn't  */
      obj_s->pending_start = 1;
      return 0;
  }
  
  int i2c_stop(i2c_t *obj) {
      struct i2c_s *obj_s = I2C_S(obj);
      I2C_HandleTypeDef *handle = &(obj_s->handle);
      int timeout = FLAG_TIMEOUT;
  #if DEVICE_I2CSLAVE
      if (obj_s->slave) {
          /*  re-init slave when stop is requested */
          i2c_init(obj, obj_s->sda, obj_s->scl);
          return 0;
      }
  #endif
      // Disable reload mode
      handle->Instance->CR2 &= (uint32_t)~I2C_CR2_RELOAD;
      // Generate the STOP condition
      handle->Instance->CR2 |= I2C_CR2_STOP;
  
      timeout = FLAG_TIMEOUT;
      while (!__HAL_I2C_GET_FLAG(handle, I2C_FLAG_STOPF)) {
          if ((timeout--) == 0) {
              return I2C_ERROR_BUS_BUSY;
          }
      }
  
      /* Clear STOP Flag */
      __HAL_I2C_CLEAR_FLAG(handle, I2C_FLAG_STOPF);
  
      /* Erase slave address, this wiil be used as a marker
       * to know when we need to prepare next start */
      handle->Instance->CR2 &=  ~I2C_CR2_SADD;
  
      /*
       * V2 IP is meant for automatic STOP, not user STOP
       * SW reset the IP state machine before next transaction
       */
      i2c_sw_reset(obj);
  
      /*  In case of mixed usage of the APIs (unitary + SYNC)
       *  re-init HAL state */
      if (obj_s->XferOperation != I2C_FIRST_AND_LAST_FRAME) {
          i2c_init(obj, obj_s->sda, obj_s->scl);
      }
  
      return 0;
  }
  
  int i2c_byte_read(i2c_t *obj, int last) {
      struct i2c_s *obj_s = I2C_S(obj);
      I2C_HandleTypeDef *handle = &(obj_s->handle);
      int timeout = FLAG_TIMEOUT;
      uint32_t tmpreg = handle->Instance->CR2;
      char data;
  #if DEVICE_I2CSLAVE
      if (obj_s->slave) {
          return i2c_slave_read(obj, &data, 1);
      }
  #endif
      /* Then send data when there's room in the TX fifo */
      if ((tmpreg & I2C_CR2_RELOAD) != 0) {
          while (!__HAL_I2C_GET_FLAG(handle, I2C_FLAG_TCR)) {
              if ((timeout--) == 0) {
                  DEBUG_PRINTF("timeout in byte_read\r\n");
                  return -1;
              }
          }
      }
  
      /* Enable reload mode as we don't know how many bytes will be sent */
      /* and set transfer size to 1 */
      tmpreg |= I2C_CR2_RELOAD | (I2C_CR2_NBYTES & (1 << 16));
      /* Set the prepared configuration */
      handle->Instance->CR2 = tmpreg;
  
      timeout = FLAG_TIMEOUT;
      while (!__HAL_I2C_GET_FLAG(handle, I2C_FLAG_RXNE)) {
          if ((timeout--) == 0) {
              return -1;
          }
      }
  
      /* Then Get Byte */
      data = handle->Instance->RXDR;
  
      if (last) {
          /* Disable Address Acknowledge */
          handle->Instance->CR2 |= I2C_CR2_NACK;
      }
  
      return data;
  }
  
  int i2c_byte_write(i2c_t *obj, int data) {
      struct i2c_s *obj_s = I2C_S(obj);
      I2C_HandleTypeDef *handle = &(obj_s->handle);
      int timeout = FLAG_TIMEOUT;
      uint32_t tmpreg = handle->Instance->CR2;
  #if DEVICE_I2CSLAVE
      if (obj_s->slave) {
          return i2c_slave_write(obj, (char *) &data, 1);
      }
  #endif
      if (obj_s->pending_start) {
          obj_s->pending_start = 0;
          //*  First byte after the start is the address */
          tmpreg |= (uint32_t)((uint32_t)data & I2C_CR2_SADD);
          if (data & 0x01) {
               tmpreg |= I2C_CR2_START | I2C_CR2_RD_WRN;
          } else {
               tmpreg |= I2C_CR2_START;
               tmpreg &= ~I2C_CR2_RD_WRN;
          }
          /*  Disable reload first to use it later */
          tmpreg &= ~I2C_CR2_RELOAD;
          /*  Disable Autoend */
          tmpreg &= ~I2C_CR2_AUTOEND;
          /* Do not set any transfer size for now */
          tmpreg |= (I2C_CR2_NBYTES & (1 << 16));
          /* Set the prepared configuration */
          handle->Instance->CR2 = tmpreg;
      } else {
          /* Set the prepared configuration */
          tmpreg = handle->Instance->CR2;
  
          /* Then send data when there's room in the TX fifo */
          if ((tmpreg & I2C_CR2_RELOAD) != 0) {
              while (!__HAL_I2C_GET_FLAG(handle, I2C_FLAG_TCR)) {
                  if ((timeout--) == 0) {
                      DEBUG_PRINTF("timeout in byte_write\r\n");
                      return 2;
                  }
              }
          }
          /*  Enable reload mode as we don't know how many bytes will eb sent */
          tmpreg |= I2C_CR2_RELOAD;
           /*  Set transfer size to 1 */
          tmpreg |= (I2C_CR2_NBYTES & (1 << 16));
         /* Set the prepared configuration */
          handle->Instance->CR2 = tmpreg;
          /*  Prepare next write */
          timeout = FLAG_TIMEOUT;
          while (!__HAL_I2C_GET_FLAG(handle, I2C_FLAG_TXE)) {
              if ((timeout--) == 0) {
                  return 2;
              }
          }
          /*  Write byte */
          handle->Instance->TXDR = data;
      }
  
      return 1;
  }
  #endif //I2C_IP_VERSION_V2
  
  /*
   *  SYNC APIS
   */
  int i2c_read(i2c_t *obj, int address, char *data, int length, int stop) {
      struct i2c_s *obj_s = I2C_S(obj);
      I2C_HandleTypeDef *handle = &(obj_s->handle);
      int count = I2C_ERROR_BUS_BUSY, ret = 0;
      uint32_t timeout = 0;
  
      // Trick to remove compiler warning "left and right operands are identical" in some cases
      uint32_t op1 = I2C_FIRST_AND_LAST_FRAME;
      uint32_t op2 = I2C_LAST_FRAME;
      if ((obj_s->XferOperation == op1) || (obj_s->XferOperation == op2)) {
          if (stop)
              obj_s->XferOperation = I2C_FIRST_AND_LAST_FRAME;
          else
              obj_s->XferOperation = I2C_FIRST_FRAME;
      } else if ((obj_s->XferOperation == I2C_FIRST_FRAME) ||
          (obj_s->XferOperation == I2C_NEXT_FRAME)) {
          if (stop)
              obj_s->XferOperation = I2C_LAST_FRAME;
          else
              obj_s->XferOperation = I2C_NEXT_FRAME;
      }
  
      obj_s->event = 0;
  
       /* Activate default IRQ handlers for sync mode
       * which would be overwritten in async mode
       */
      i2c_ev_err_enable(obj, i2c_get_irq_handler(obj));
  
      ret = HAL_I2C_Master_Sequential_Receive_IT(handle, address, (uint8_t *) data, length, obj_s->XferOperation);
  
      if(ret == HAL_OK) {
          timeout = BYTE_TIMEOUT_US * (length + 1);
          /*  transfer started : wait completion or timeout */
          while(!(obj_s->event & I2C_EVENT_ALL) && (--timeout != 0)) {
              wait_us(1);
          }
  
          i2c_ev_err_disable(obj);
  
          if((timeout == 0) || (obj_s->event != I2C_EVENT_TRANSFER_COMPLETE)) {
              DEBUG_PRINTF(" TIMEOUT or error in i2c_read\r\n");
              /* re-init IP to try and get back in a working state */
              i2c_init(obj, obj_s->sda, obj_s->scl);
          } else {
              count = length;
          }
      } else {
          DEBUG_PRINTF("ERROR in i2c_read:%d\r\n", ret);
      }
  
      return count;
  }
  
  int i2c_write(i2c_t *obj, int address, const char *data, int length, int stop) {
      struct i2c_s *obj_s = I2C_S(obj);
      I2C_HandleTypeDef *handle = &(obj_s->handle);
      int count = I2C_ERROR_BUS_BUSY, ret = 0;
      uint32_t timeout = 0;
  
      // Trick to remove compiler warning "left and right operands are identical" in some cases
      uint32_t op1 = I2C_FIRST_AND_LAST_FRAME;
      uint32_t op2 = I2C_LAST_FRAME;
      if ((obj_s->XferOperation == op1) || (obj_s->XferOperation == op2)) {
          if (stop)
              obj_s->XferOperation = I2C_FIRST_AND_LAST_FRAME;
          else
              obj_s->XferOperation = I2C_FIRST_FRAME;
      } else if ((obj_s->XferOperation == I2C_FIRST_FRAME) ||
          (obj_s->XferOperation == I2C_NEXT_FRAME)) {
          if (stop)
              obj_s->XferOperation = I2C_LAST_FRAME;
          else
              obj_s->XferOperation = I2C_NEXT_FRAME;
      }
  
      obj_s->event = 0;
  
      i2c_ev_err_enable(obj, i2c_get_irq_handler(obj));
  
      ret = HAL_I2C_Master_Sequential_Transmit_IT(handle, address, (uint8_t *) data, length, obj_s->XferOperation); 
  
      if(ret == HAL_OK) {
          timeout = BYTE_TIMEOUT_US * (length + 1);
          /*  transfer started : wait completion or timeout */
          while(!(obj_s->event & I2C_EVENT_ALL) && (--timeout != 0)) {
              wait_us(1);
          }
  
          i2c_ev_err_disable(obj);
  
          if((timeout == 0) || (obj_s->event != I2C_EVENT_TRANSFER_COMPLETE)) {
              DEBUG_PRINTF(" TIMEOUT or error in i2c_write\r\n");
              /* re-init IP to try and get back in a working state */
              i2c_init(obj, obj_s->sda, obj_s->scl);
           } else {
              count = length;
         }
      } else {
          DEBUG_PRINTF("ERROR in i2c_read\r\n");
      }
  
      return count;
  }
  
  void HAL_I2C_MasterTxCpltCallback(I2C_HandleTypeDef *hi2c){
      /* Get object ptr based on handler ptr */
      i2c_t *obj = get_i2c_obj(hi2c);
      struct i2c_s *obj_s = I2C_S(obj);
  
  #if DEVICE_I2C_ASYNCH
      /* Handle potential Tx/Rx use case */
      if ((obj->tx_buff.length) && (obj->rx_buff.length)) {
          if (obj_s->stop) {
              obj_s->XferOperation = I2C_LAST_FRAME;
          } else {
              obj_s->XferOperation = I2C_NEXT_FRAME;
          }
  
          HAL_I2C_Master_Sequential_Receive_IT(hi2c, obj_s->address, (uint8_t*)obj->rx_buff.buffer , obj->rx_buff.length, obj_s->XferOperation); 
      }
      else
  #endif
      {
          /* Set event flag */
          obj_s->event = I2C_EVENT_TRANSFER_COMPLETE;
      }
  }
  
  void HAL_I2C_MasterRxCpltCallback(I2C_HandleTypeDef *hi2c){
      /* Get object ptr based on handler ptr */
      i2c_t *obj = get_i2c_obj(hi2c);
      struct i2c_s *obj_s = I2C_S(obj);
  
      /* Set event flag */
      obj_s->event = I2C_EVENT_TRANSFER_COMPLETE;
  }
  
  void HAL_I2C_ErrorCallback(I2C_HandleTypeDef *hi2c){
      /* Get object ptr based on handler ptr */
      i2c_t *obj = get_i2c_obj(hi2c);
      struct i2c_s *obj_s = I2C_S(obj);
  #if DEVICE_I2CSLAVE
      I2C_HandleTypeDef *handle = &(obj_s->handle);
      uint32_t address = 0;
      /*  Store address to handle it after reset */
      if(obj_s->slave)
          address = handle->Init.OwnAddress1;
  #endif
  
      DEBUG_PRINTF("HAL_I2C_ErrorCallback:%d, index=%d\r\n", (int) hi2c->ErrorCode, obj_s->index);
  
      /* re-init IP to try and get back in a working state */
      i2c_init(obj, obj_s->sda, obj_s->scl);
  
  #if DEVICE_I2CSLAVE
      /*  restore slave address */
      if (address != 0) {
          obj_s->slave = 1;
          i2c_slave_address(obj, 0, address, 0);
      }
  #endif
  
      /* Keep Set event flag */
      obj_s->event = I2C_EVENT_ERROR;
  }
  
  #if DEVICE_I2CSLAVE
  /* SLAVE API FUNCTIONS */
  void i2c_slave_address(i2c_t *obj, int idx, uint32_t address, uint32_t mask) {
      struct i2c_s *obj_s = I2C_S(obj);
      I2C_HandleTypeDef *handle = &(obj_s->handle);
  
      // I2C configuration
      handle->Init.OwnAddress1     = address;
      HAL_I2C_Init(handle);
  
      i2c_ev_err_enable(obj, i2c_get_irq_handler(obj));
  
      HAL_I2C_EnableListen_IT(handle);
  }
  
  void i2c_slave_mode(i2c_t *obj, int enable_slave) {
  
      struct i2c_s *obj_s = I2C_S(obj);
      I2C_HandleTypeDef *handle = &(obj_s->handle);
  
      if (enable_slave) {
          obj_s->slave = 1;
          HAL_I2C_EnableListen_IT(handle);
      } else {
          obj_s->slave = 0;
          HAL_I2C_DisableListen_IT(handle);
      }
  }
  
  // See I2CSlave.h
  #define NoData         0 // the slave has not been addressed
  #define ReadAddressed  1 // the master has requested a read from this slave (slave = transmitter)
  #define WriteGeneral   2 // the master is writing to all slave
  #define WriteAddressed 3 // the master is writing to this slave (slave = receiver)
  
  
  void HAL_I2C_AddrCallback(I2C_HandleTypeDef *hi2c, uint8_t TransferDirection, uint16_t AddrMatchCode) {
      /* Get object ptr based on handler ptr */
      i2c_t *obj = get_i2c_obj(hi2c);
      struct i2c_s *obj_s = I2C_S(obj);
  
      /*  Transfer direction in HAL is from Master point of view */
      if(TransferDirection == I2C_DIRECTION_RECEIVE) {
          obj_s->pending_slave_tx_master_rx = 1;
      }
  
      if(TransferDirection == I2C_DIRECTION_TRANSMIT) {
          obj_s->pending_slave_rx_maxter_tx = 1;
      }
  }
  
  void HAL_I2C_SlaveTxCpltCallback(I2C_HandleTypeDef *I2cHandle){
      /* Get object ptr based on handler ptr */
      i2c_t *obj = get_i2c_obj(I2cHandle);
      struct i2c_s *obj_s = I2C_S(obj);
      obj_s->pending_slave_tx_master_rx = 0;
  }
  
  void HAL_I2C_SlaveRxCpltCallback(I2C_HandleTypeDef *I2cHandle){
      /* Get object ptr based on handler ptr */
      i2c_t *obj = get_i2c_obj(I2cHandle);
      struct i2c_s *obj_s = I2C_S(obj);
      obj_s->pending_slave_rx_maxter_tx = 0;
  }
  
  void HAL_I2C_ListenCpltCallback(I2C_HandleTypeDef *hi2c)
  {
      /* restart listening for master requests */
      HAL_I2C_EnableListen_IT(hi2c);
  }
  
  int i2c_slave_receive(i2c_t *obj) {
  
      struct i2c_s *obj_s = I2C_S(obj);
      int retValue = NoData;
  
       if(obj_s->pending_slave_rx_maxter_tx) {
           retValue = WriteAddressed;
       }
  
       if(obj_s->pending_slave_tx_master_rx) {
              retValue = ReadAddressed;
       }
  
      return (retValue);
  }
  
  int i2c_slave_read(i2c_t *obj, char *data, int length) {
      struct i2c_s *obj_s = I2C_S(obj);
      I2C_HandleTypeDef *handle = &(obj_s->handle);
      int count = 0;
      int ret = 0;
      uint32_t timeout = 0;
  
      /*  Always use I2C_NEXT_FRAME as slave will just adapt to master requests */
      ret = HAL_I2C_Slave_Sequential_Receive_IT(handle, (uint8_t *) data, length, I2C_NEXT_FRAME);
  
      if(ret == HAL_OK) {
          timeout = BYTE_TIMEOUT_US * (length + 1);
          while(obj_s->pending_slave_rx_maxter_tx && (--timeout != 0)) {
              wait_us(1);
          }
  
           if(timeout != 0) {
               count = length;
           } else {
               DEBUG_PRINTF("TIMEOUT or error in i2c_slave_read\r\n");
           }
      }
      return count;
  }
  
  int i2c_slave_write(i2c_t *obj, const char *data, int length) {
      struct i2c_s *obj_s = I2C_S(obj);
      I2C_HandleTypeDef *handle = &(obj_s->handle);
      int count = 0;
      int ret = 0;
      uint32_t timeout = 0;
  
      /*  Always use I2C_NEXT_FRAME as slave will just adapt to master requests */
      ret = HAL_I2C_Slave_Sequential_Transmit_IT(handle, (uint8_t *) data, length, I2C_NEXT_FRAME);
  
      if(ret == HAL_OK) {
          timeout = BYTE_TIMEOUT_US * (length + 1);
          while(obj_s->pending_slave_tx_master_rx && (--timeout != 0)) {
              wait_us(1);
          }
  
           if(timeout != 0) {
               count = length;
           } else {
               DEBUG_PRINTF("TIMEOUT or error in i2c_slave_write\r\n");
           }
      }
  
      return count;
  }
  #endif // DEVICE_I2CSLAVE
  
  #if DEVICE_I2C_ASYNCH
  /* ASYNCH MASTER API FUNCTIONS */
  void HAL_I2C_AbortCpltCallback(I2C_HandleTypeDef *hi2c){
      /* Get object ptr based on handler ptr */
      i2c_t *obj = get_i2c_obj(hi2c);
      struct i2c_s *obj_s = I2C_S(obj);
      I2C_HandleTypeDef *handle = &(obj_s->handle);
  
      /* Disable IT. Not always done before calling macro */
      __HAL_I2C_DISABLE_IT(handle, I2C_IT_ALL);
      i2c_ev_err_disable(obj);
  
      /* Set event flag */
      obj_s->event = I2C_EVENT_ERROR;
  }
  
  void i2c_transfer_asynch(i2c_t *obj, const void *tx, size_t tx_length, void *rx, size_t rx_length, uint32_t address, uint32_t stop, uint32_t handler, uint32_t event, DMAUsage hint) {
  
      // TODO: DMA usage is currently ignored by this way
      (void) hint;
  
      struct i2c_s *obj_s = I2C_S(obj);
      I2C_HandleTypeDef *handle = &(obj_s->handle);
  
      /* Update object */
      obj->tx_buff.buffer = (void *)tx;
      obj->tx_buff.length = tx_length;
      obj->tx_buff.pos = 0;
      obj->tx_buff.width = 8;
  
      obj->rx_buff.buffer = (void *)rx;
      obj->rx_buff.length = rx_length;
      obj->rx_buff.pos = SIZE_MAX;
      obj->rx_buff.width = 8;
  
      obj_s->available_events = event;
      obj_s->event = 0;
      obj_s->address = address;
      obj_s->stop = stop;
  
      i2c_ev_err_enable(obj, handler);
  
      /* Set operation step depending if stop sending required or not */
      if ((tx_length && !rx_length) || (!tx_length && rx_length)) {
          // Trick to remove compiler warning "left and right operands are identical" in some cases
          uint32_t op1 = I2C_FIRST_AND_LAST_FRAME;
          uint32_t op2 = I2C_LAST_FRAME;
          if ((obj_s->XferOperation == op1) || (obj_s->XferOperation == op2)) {
              if (stop)
                  obj_s->XferOperation = I2C_FIRST_AND_LAST_FRAME;
              else
                  obj_s->XferOperation = I2C_FIRST_FRAME;
          } else if ((obj_s->XferOperation == I2C_FIRST_FRAME) ||
              (obj_s->XferOperation == I2C_NEXT_FRAME)) {
              if (stop)
                  obj_s->XferOperation = I2C_LAST_FRAME;
              else
                  obj_s->XferOperation = I2C_NEXT_FRAME;
          }
  
          if (tx_length > 0) {
              HAL_I2C_Master_Sequential_Transmit_IT(handle, address, (uint8_t*)tx, tx_length, obj_s->XferOperation);
          }
          if (rx_length > 0) {
              HAL_I2C_Master_Sequential_Receive_IT(handle, address, (uint8_t*)rx, rx_length, obj_s->XferOperation);
          }
      }
      else if (tx_length && rx_length) {
          /* Two steps operation, don't modify XferOperation, keep it for next step */
          // Trick to remove compiler warning "left and right operands are identical" in some cases
          uint32_t op1 = I2C_FIRST_AND_LAST_FRAME;
          uint32_t op2 = I2C_LAST_FRAME;
          if ((obj_s->XferOperation == op1) || (obj_s->XferOperation == op2)) {
                  HAL_I2C_Master_Sequential_Transmit_IT(handle, address, (uint8_t*)tx, tx_length, I2C_FIRST_FRAME);
          } else if ((obj_s->XferOperation == I2C_FIRST_FRAME) ||
              (obj_s->XferOperation == I2C_NEXT_FRAME)) {
                  HAL_I2C_Master_Sequential_Transmit_IT(handle, address, (uint8_t*)tx, tx_length, I2C_NEXT_FRAME);
          }
      }
  }
  
  
  uint32_t i2c_irq_handler_asynch(i2c_t *obj) {
  
      struct i2c_s *obj_s = I2C_S(obj);
      I2C_HandleTypeDef *handle = &(obj_s->handle);
  
      HAL_I2C_EV_IRQHandler(handle);
      HAL_I2C_ER_IRQHandler(handle);
  
       /*  Return I2C event status */
      return (obj_s->event & obj_s->available_events);
  }
  
  uint8_t i2c_active(i2c_t *obj) {
  
      struct i2c_s *obj_s = I2C_S(obj);
      I2C_HandleTypeDef *handle = &(obj_s->handle);
  
      if (handle->State == HAL_I2C_STATE_READY) {
          return 0;
      }
      else {
          return 1;
      }
  }
  
  void i2c_abort_asynch(i2c_t *obj) {
  
      struct i2c_s *obj_s = I2C_S(obj);
      I2C_HandleTypeDef *handle = &(obj_s->handle);
  
      /* Abort HAL requires DevAddress, but is not used. Use Dummy */
      uint16_t Dummy_DevAddress = 0x00;
  
      HAL_I2C_Master_Abort_IT(handle, Dummy_DevAddress);
  }
  
  #endif // DEVICE_I2C_ASYNCH
  
  #endif // DEVICE_I2C
  