| Message ID | 20211014173738.2446-1-pekka.korpinen@iki.fi (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
| Series | [v2,RESEND] iio: dac: ad5446: Fix ad5622_write() return value | expand |
On Thu, 14 Oct 2021 20:37:38 +0300 Pekka Korpinen <pekka.korpinen@iki.fi> wrote: > 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> Hi Pekka, No need to resend a patch so soon. Feel free to just sent a 'bump' type message in reply to the original posting. Anyhow, I've picked that up today anyway (and only noticed this whilst marking it applied in patchwork). Thanks, Jonathan > --- > v1->v2: Check against expected result, otherwise -EIO. Add Fixes tag. > > A similar bug was fixed for ad5064.c in 2015 - commit 03fe472ef33b > ("iio:ad5064: Make sure ad5064_i2c_write() returns 0 on success"). > > 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; > } > > /*
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; } /*
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> --- v1->v2: Check against expected result, otherwise -EIO. Add Fixes tag. A similar bug was fixed for ad5064.c in 2015 - commit 03fe472ef33b ("iio:ad5064: Make sure ad5064_i2c_write() returns 0 on success"). drivers/iio/dac/ad5446.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)