iio: dac: cio-dac: Fix max DAC write value check for 12-bit

commit c3701185ee1973845db088d8b0fc443397ab0eb2 upstream. The CIO-DAC series of devices only supports DAC values up to 12-bit rather than 16-bit. Trying to write a 16-bit value results in only the lower 12 bits affecting the DAC output which is not what the user expects. Instead, adjust the DAC write value check to reject values larger than 12-bit so that they fail explicitly as invalid for the user. Fixes: 3b8df5f ("iio: Add IIO support for the Measurement Computing CIO-DAC family") Cc: [email protected] Signed-off-by: William Breathitt Gray <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Jonathan Cameron <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
vrnsoma · Apr 20, 2023 · 8094711 · 8094711
1 parent 50aeb77
commit 8094711
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/drivers/iio/dac/cio-dac.c b/drivers/iio/dac/cio-dac.c
@@ -74,8 +74,8 @@ static int cio_dac_write_raw(struct iio_dev *indio_dev,
 	if (mask != IIO_CHAN_INFO_RAW)
 		return -EINVAL;
 
-	/* DAC can only accept up to a 16-bit value */
-	if ((unsigned int)val > 65535)
+	/* DAC can only accept up to a 12-bit value */
+	if ((unsigned int)val > 4095)
 		return -EINVAL;
 
 	priv->chan_out_states[chan->channel] = val;