This is a note to let you know that I've just added the patch titled iio: dac: ad5446: Fix ad5622_write() return value to my char-misc git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git in the char-misc-testing branch. The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.) The patch will be merged to the char-misc-next branch sometime soon, after it passes testing, and the merge window is open. If you have any questions about this process, please let me know. >From 558df982d4ead9cac628153d0d7b60feae05ddc8 Mon Sep 17 00:00:00 2001 From: Pekka Korpinen <pekka.korpinen@xxxxxx> Date: Wed, 29 Sep 2021 21:57:55 +0300 Subject: iio: dac: ad5446: Fix ad5622_write() return value 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@xxxxxx> Link: https://lore.kernel.org/r/20210929185755.2384-1-pekka.korpinen@xxxxxx Cc: <Stable@xxxxxxxxxxxxxxx> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx> --- drivers/iio/dac/ad5446.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/iio/dac/ad5446.c b/drivers/iio/dac/ad5446.c index 488ec69967d6..e50718422411 100644 --- a/drivers/iio/dac/ad5446.c +++ b/drivers/iio/dac/ad5446.c @@ -531,8 +531,15 @@ static int ad5622_write(struct ad5446_state *st, unsigned val) { struct i2c_client *client = to_i2c_client(st->dev); __be16 data = cpu_to_be16(val); + int ret; + + ret = i2c_master_send(client, (char *)&data, sizeof(data)); + if (ret < 0) + return ret; + if (ret != sizeof(data)) + return -EIO; - return i2c_master_send(client, (char *)&data, sizeof(data)); + return 0; } /* -- 2.33.1