[PATCH v3] iio: amplifiers: ad8366: Change devm_gpiod_get() to optional and add the missed check

[Chuhong Yuan]

Since if there is no GPIO, nothing happens, replace devm_gpiod_get()
with devm_gpiod_get_optional().
Also add IS_ERR() to fix the missing-check bug.

Fixes: cee211f4e5a0 ("iio: amplifiers: ad8366: Add support for the ADA4961 DGA")
Signed-off-by: Chuhong Yuan <hslester96@xxxxxxxxx>
---
Changes in v3:
  - Change devm_gpiod_get() to optional.
  - Modify description.

 drivers/iio/amplifiers/ad8366.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/amplifiers/ad8366.c b/drivers/iio/amplifiers/ad8366.c
index 62167b87caea..8819e8997f76 100644
--- a/drivers/iio/amplifiers/ad8366.c
+++ b/drivers/iio/amplifiers/ad8366.c
@@ -262,8 +262,12 @@ static int ad8366_probe(struct spi_device *spi)
 	case ID_ADA4961:
 	case ID_ADL5240:
 	case ID_HMC1119:
-		st->reset_gpio = devm_gpiod_get(&spi->dev, "reset",
+		st->reset_gpio = devm_gpiod_get_optional(&spi->dev, "reset",
 			GPIOD_OUT_HIGH);
+		if (IS_ERR(st->reset_gpio)) {
+			ret = PTR_ERR(st->reset_gpio);
+			goto error_disable_reg;
+		}
 		indio_dev->channels = ada4961_channels;
 		indio_dev->num_channels = ARRAY_SIZE(ada4961_channels);
 		break;
-- 
2.26.2