From a92d075cb4b5be5f6be75e9f128e8fb32fc5257a Mon Sep 17 00:00:00 2001 From: Pekka Korpinen Date: Wed, 29 Sep 2021 21:57:55 +0300 Subject: [PATCH] iio: dac: ad5446: Fix ad5622_write() return value 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 Link: https://lore.kernel.org/r/20210929185755.2384-1-pekka.korpinen@iki.fi Cc: Signed-off-by: Jonathan Cameron Signed-off-by: Greg Kroah-Hartman --- 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 488ec69967d67..e50718422411d 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; } /*