自定义i2c读写函数

static int kxud9_i2c_read(u8 addr, u8 *data, int len)
{
int err;




struct i2c_msg msgs[] = {
{
.addr = ud9->client->addr,
.flags = ud9->client->flags & I2C_M_TEN,
.len = 1,
.buf = &addr,
},
{
.addr = ud9->client->addr,
.flags = (ud9->client->flags & I2C_M_TEN) | I2C_M_RD,
.len = len,
.buf = data,
},
};
err = i2c_transfer(ud9->client->adapter, msgs, 2);




if(err != 2)
dev_err(&ud9->client->dev, "read transfer error\n");
else
err = 0;




return err;
}




static int kxud9_i2c_write(u8 addr, u8 *data, int len)
{
int err;
int i;
u8 buf[len + 1];




struct i2c_msg msgs[] = {
{
.addr = ud9->client->addr,
.flags = ud9->client->flags & I2C_M_TEN,
.len = len + 1,
.buf = buf,
},
};




buf[0] = addr;
for (i = 0; i < len; i++)
buf[i + 1] = data[i];




err = i2c_transfer(ud9->client->adapter, msgs, 1);




if(err != 1)
dev_err(&ud9->client->dev, "write transfer error\n");
else
err = 0;




return err;
}