The mode setting logic in ad7816_store_mode was reversed due to
incorrect handling of the strcmp return value. strcmp returns 0 on
match, so the `if (strcmp(buf, "full"))` block executed when the
input was not "full".

This resulted in "full" setting the mode to AD7816_PD (power-down) and
other inputs setting it to AD7816_FULL.

Fix this by checking it against 0 to correctly check for "full" and
"power-down", mapping them to AD7816_FULL and AD7816_PD respectively.

Signed-off-by: Gabriel Shahrouzi <gshahrouzi@gmail.com>
---
 drivers/staging/iio/adc/ad7816.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/staging/iio/adc/ad7816.c b/drivers/staging/iio/adc/ad7816.c
index 6c14d7bcdd675..6b545547660dd 100644
--- a/drivers/staging/iio/adc/ad7816.c
+++ b/drivers/staging/iio/adc/ad7816.c
@@ -136,7 +136,7 @@ static ssize_t ad7816_store_mode(struct device *dev,
 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 	struct ad7816_chip_info *chip = iio_priv(indio_dev);
 
-	if (strcmp(buf, "full")) {
+	if (sysfs_streq(buf, "full")) {
 		gpiod_set_value(chip->rdwr_pin, 1);
 		chip->mode = AD7816_FULL;
 	} else {
-- 
2.43.0

On 4/14/25 9:09 AM, Gabriel Shahrouzi wrote:
> The mode setting logic in ad7816_store_mode was reversed due to
> incorrect handling of the strcmp return value. strcmp returns 0 on
> match, so the `if (strcmp(buf, "full"))` block executed when the
> input was not "full".
> 
> This resulted in "full" setting the mode to AD7816_PD (power-down) and
> other inputs setting it to AD7816_FULL.
> 
> Fix this by checking it against 0 to correctly check for "full" and
> "power-down", mapping them to AD7816_FULL and AD7816_PD respectively.
> 

Sounds like we need a Fixes: tag here that reference the commit
that introduced the bug.

> Signed-off-by: Gabriel Shahrouzi <gshahrouzi@gmail.com>
> ---

On 4/14/25 9:59 AM, David Lechner wrote:
> On 4/14/25 9:09 AM, Gabriel Shahrouzi wrote:
>> The mode setting logic in ad7816_store_mode was reversed due to
>> incorrect handling of the strcmp return value. strcmp returns 0 on
>> match, so the `if (strcmp(buf, "full"))` block executed when the
>> input was not "full".
>>
>> This resulted in "full" setting the mode to AD7816_PD (power-down) and
>> other inputs setting it to AD7816_FULL.
>>
>> Fix this by checking it against 0 to correctly check for "full" and
>> "power-down", mapping them to AD7816_FULL and AD7816_PD respectively.
>>
> 
> Sounds like we need a Fixes: tag here that reference the commit
> that introduced the bug.
> 
>> Signed-off-by: Gabriel Shahrouzi <gshahrouzi@gmail.com>
>> ---

There is also a typo in your email address in the cc: gshahrozui@gmail.com

On Mon, Apr 14, 2025 at 11:02 AM David Lechner <dlechner@baylibre.com> wrote:
>
> On 4/14/25 9:59 AM, David Lechner wrote:
> > On 4/14/25 9:09 AM, Gabriel Shahrouzi wrote:
> >> The mode setting logic in ad7816_store_mode was reversed due to
> >> incorrect handling of the strcmp return value. strcmp returns 0 on
> >> match, so the `if (strcmp(buf, "full"))` block executed when the
> >> input was not "full".
> >>
> >> This resulted in "full" setting the mode to AD7816_PD (power-down) and
> >> other inputs setting it to AD7816_FULL.
> >>
> >> Fix this by checking it against 0 to correctly check for "full" and
> >> "power-down", mapping them to AD7816_FULL and AD7816_PD respectively.
> >>
> >
> > Sounds like we need a Fixes: tag here that reference the commit
> > that introduced the bug.
Sounds good. Included the fixes tag and CC'd stable@vger.kernel.org.
> >
> >> Signed-off-by: Gabriel Shahrouzi <gshahrouzi@gmail.com>
> >> ---
>
> There is also a typo in your email address in the cc: gshahrozui@gmail.com
Whoops - I'll update that.

I just realized I didn't update the version for the second patch
correctly so I'll send in a new one.