I2C通用读写函数

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i2c通用读写函数：

static int i2c_ReadData(char *rxdata, int length, u8 cmd)
{
        int ret;
        u8 read_cmd[1] = {cmd};
        
        struct i2c_msg msgs[] = {
                /*{
                        .addr        = this_client->addr,
                        .flags        = 0,
                        .len        = 1,
                        .buf        = read_cmd,
                },*/
                {
                        .addr        = this_client->addr,
                        .flags        = I2C_M_RD,
                        .len        = length,
                        .buf        = rxdata,
                },
        };


        //printk("IIC addr = %x\n",this_client->addr);
        ret = i2c_transfer(this_client->adapter, msgs, 1);
        if (ret < 0)
                printk("msg %s i2c read error: %d\n", __func__, ret);
        
        return ret;
}




static int i2c_Writedata(char *txdata, int length)
{
        int ret;


        struct i2c_msg msg[] = {
                {
                        .addr        = this_client->addr,
                        .flags        = 0,
                        .len        = length,
                        .buf        = txdata,
                },
        };


        ret = i2c_transfer(this_client->adapter, msg, 1);
        if (ret < 0)
                printk("%s i2c write error: %d\n", __func__, ret);


        return ret;
}


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//Actions平台I2C读写
/**
 * i2c_master_send - issue a single I2C message in master transmit mode
 * @client: Handle to slave device
 * @buf: Data that will be written to the slave
 * @count: How many bytes to write, must be less than 64k since msg.len is u16
 *
 * Returns negative errno, or else the number of bytes written.
 */
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;
}
EXPORT_SYMBOL(i2c_master_send);


/**
 * i2c_master_recv - issue a single I2C message in master receive mode
 * @client: Handle to slave device
 * @buf: Where to store data read from slave
 * @count: How many bytes to read, must be less than 64k since msg.len is u16
 *
 * Returns negative errno, or else the number of bytes read.
 */
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);


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