• 定义和注册 I2C 设备
• 定义和注册 I2C 驱动

定义和注册 I2C 设备

kernel/arch/arm64/boot/dts/rockchip/rk3399-videostrong-board-mipi.dts&i2c4 {    status = "okay";   
gsl3680: gsl3680@41 {   
           compatible = "gslX680";  
           reg = <0x41>;  
            screen_max_x = <1536>;  
            screen_max_y = <2048>;   
           touch-gpio = <&gpio1 20 IRQ_TYPE_LEVEL_LOW>;   
          reset-gpio = <&gpio0 12 GPIO_ACTIVE_HIGH>;
      };  };

定义和注册 I2C 驱动定义 I2C 驱动

static struct of_device_id gsl_ts_ids[] = {   {.compatible = "gslX680"},   {}    };

static const struct i2c_device_id gsl_ts_id[] = {  
   {GSLX680_I2C_NAME, 0},   
  {}  
  };
MODULE_DEVICE_TABLE(i2c, gsl_ts_id);

static struct i2c_driver gsl_ts_driver = {
     .driver = {
.name = GSLX680_I2C_NAME,
     .owner = THIS_MODULE,  
    .of_match_table = of_match_ptr(gsl_ts_ids),
     },
        .probe      = gsl_ts_probe,
      .remove     = gsl_ts_remove,
      .id_table   = gsl_ts_id,
};

注册 I2C 驱动

i2c_add_driver(&gsl_ts_driver);

通过 I2C 收发数据

• 向从机发送信息：

int i2c_master_send(const struct i2c_client *client, const char *buf, int count) {
       int ret;      struct i2c_adapter *adap = client->adapter;   
   struct i2c_msg msg;      msg.addr = client->addr;  
    msg.flags = client->flags & I2C_M_TEN;
     msg.len = count;      msg.buf = (char *)buf;  
    ret = i2c_transfer(adap, &msg, 1);
          /*      * If everything went ok (i.e. 1 msg transmitted), return #bytes      * transmitted, else error code.      */   
   return (ret == 1) ? count : ret;
}

• 向从机读取信息：

int i2c_master_recv(const struct i2c_client *client, char *buf, int count) {
     struct i2c_adapter *adap = client->adapter;
     struct i2c_msg msg;
     int ret;
     msg.addr = client->addr;  
    msg.flags = client->flags & I2C_M_TEN;  
    msg.flags |= I2C_M_RD;
    msg.len = count;
      msg.buf = buf;  
    ret = i2c_transfer(adap, &msg, 1);           /*       * If everything went ok (i.e. 1 msg received), return #bytes received,      * else error code.      */      return (ret == 1) ? count : ret; }  
  EXPORT_SYMBOL(i2c_master_recv);