iio: ad9523: Fix return value for ad952x_store()

commit 9a5094c upstream.

A sysfs write callback function needs to either return the number of
consumed characters or an error.

The ad952x_store() function currently returns 0 if the input value was "0",
this will signal that no characters have been consumed and the function
will be called repeatedly in a loop indefinitely. Fix this by returning
number of supplied characters to indicate that the whole input string has
been consumed.

Signed-off-by: Lars-Peter Clausen <[email protected]>
Signed-off-by: Alexandru Ardelean <[email protected]>
Fixes: cd1678f ("iio: frequency: New driver for AD9523 SPI Low Jitter Clock Generator")
Cc: <[email protected]>
Signed-off-by: Jonathan Cameron <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

drivers/iio/frequency/ad9523.c

@@ -507,7 +507,7 @@ static ssize_t ad9523_store(struct device *dev,
 		return ret;
 
 	if (!state)
-		return 0;
+		return len;
 
 	mutex_lock(&indio_dev->mlock);
 	switch ((u32)this_attr->address) {