From: Pekka Korpinen pekka.korpinen@iki.fi
commit 558df982d4ead9cac628153d0d7b60feae05ddc8 upstream.
On success i2c_master_send() returns the number of bytes written. The call from iio_write_channel_info(), however, expects the return value to be zero on success.
This bug causes incorrect consumption of the sysfs buffer in iio_write_channel_info(). When writing more than two characters to out_voltage0_raw, the ad5446 write handler is called multiple times causing unexpected behavior.
Fixes: 3ec36a2cf0d5 ("iio:ad5446: Add support for I2C based DACs") Signed-off-by: Pekka Korpinen pekka.korpinen@iki.fi Link: https://lore.kernel.org/r/20210929185755.2384-1-pekka.korpinen@iki.fi Cc: Stable@vger.kernel.org Signed-off-by: Jonathan Cameron Jonathan.Cameron@huawei.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/iio/dac/ad5446.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
--- a/drivers/iio/dac/ad5446.c +++ b/drivers/iio/dac/ad5446.c @@ -527,8 +527,15 @@ static int ad5622_write(struct ad5446_st { struct i2c_client *client = to_i2c_client(st->dev); __be16 data = cpu_to_be16(val); + int ret;
- return i2c_master_send(client, (char *)&data, sizeof(data)); + ret = i2c_master_send(client, (char *)&data, sizeof(data)); + if (ret < 0) + return ret; + if (ret != sizeof(data)) + return -EIO; + + return 0; }
/**