rt-thread/bsp/stm32f10x/drivers/i2c.c

#include "i2c.h"
#include <stm32f10x.h>

void stm32_set_sda(void *data, rt_int32_t state)
{
    if(state == 1)
        GPIO_SetBits(I2C1_GPIO , I2C1_GPIO_SDA);   //GPIOB->BSRRL = I2C1_GPIO_SDA
    else if(state == 0)
        GPIO_ResetBits(I2C1_GPIO , I2C1_GPIO_SDA); //GPIOB->BSRRH = I2C1_GPIO_SDA
}

void stm32_set_scl(void *data, rt_int32_t state)
{
    if(state == 1)
        GPIO_SetBits(I2C1_GPIO , I2C1_GPIO_SCL);   //GPIOB->BSRRL = I2C1_GPIO_SCL
    else if(state == 0)
        GPIO_ResetBits(I2C1_GPIO , I2C1_GPIO_SCL); //GPIOB->BSRRH = I2C1_GPIO_SCL
}

rt_int32_t stm32_get_sda(void *data)
{
    return (rt_int32_t)GPIO_ReadInputDataBit(I2C1_GPIO , I2C1_GPIO_SDA); //return(GPIOB->IDR  & I2C1_GPIO_SDA)
}

rt_int32_t stm32_get_scl(void *data)
{
    return (rt_int32_t)GPIO_ReadInputDataBit(I2C1_GPIO , I2C1_GPIO_SCL); //return(GPIOB->IDR  & I2C1_GPIO_SCL)
}

void stm32_udelay(rt_uint32_t us)
{
    rt_uint32_t delta;
    /* sysTick->LOAD=21000, RT_TICK_PER_SECOND=1000 */
    us = us * (SysTick->LOAD/(1000000/RT_TICK_PER_SECOND));
    delta = SysTick->VAL;
    /* delay us */
    while (delta - SysTick->VAL< us);
}

void stm32_mdelay(rt_uint32_t ms)
{
    stm32_udelay(ms * 1000);
}

static const struct  rt_i2c_bit_ops stm32_i2c_bit_ops =
{
    (void*)0xaa,     //no use in set_sda,set_scl,get_sda,get_scl
    stm32_set_sda,
    stm32_set_scl,
    stm32_get_sda,
    stm32_get_scl,
    stm32_udelay,
    20,
};

static void RCC_Configuration(void)
{
   RCC->APB2ENR|=1<<4;
   RCC_APB2PeriphClockCmd( RCC_I2C, ENABLE );
}


static void GPIO_Configuration(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    GPIO_InitStructure.GPIO_Pin = I2C1_GPIO_SDA | I2C1_GPIO_SCL;
    GPIO_InitStructure.GPIO_Mode =GPIO_Mode_Out_OD ;
    GPIO_InitStructure.GPIO_Speed =GPIO_Speed_50MHz;
    GPIO_Init(I2C1_GPIO, &GPIO_InitStructure);
}

int rt_hw_i2c_init(void)
{
    static struct rt_i2c_bus_device stm32_i2c;

    RCC_Configuration();
    GPIO_Configuration();
    
    rt_memset((void *)&stm32_i2c, 0, sizeof(struct rt_i2c_bus_device));
    stm32_i2c.priv = (void *)&stm32_i2c_bit_ops;
    rt_i2c_bit_add_bus(&stm32_i2c, "i2c1");   
        
    return 0;
}
INIT_BOARD_EXPORT(rt_hw_i2c_init);