iio: adc: ti-ads124s08: Return reset GPIO lookup errors

commit 7dc4de2 upstream.

devm_gpiod_get_optional() returns NULL when the optional GPIO is absent,
but returns an ERR_PTR when the GPIO provider lookup fails, including
probe deferral.

Probe currently logs the ERR_PTR case as if the reset GPIO were simply
absent and keeps the error pointer in reset_gpio. Later ads124s_reset()
treats any non-NULL reset_gpio as a valid descriptor and passes it to
gpiod_set_value_cansleep().

Return the lookup error instead of retaining the ERR_PTR.

Fixes: e717f8c ("iio: adc: Add the TI ads124s08 ADC code")
Cc: stable@vger.kernel.org
Reviewed-by: Joshua Crofts <joshua.crofts1@gmail.com>
Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: neosys007

drivers/iio/adc/ti-ads124s08.c

@@ -322,7 +322,8 @@ static int ads124s_probe(struct spi_device *spi)
 	ads124s_priv->reset_gpio = devm_gpiod_get_optional(&spi->dev,
 						   "reset", GPIOD_OUT_LOW);
 	if (IS_ERR(ads124s_priv->reset_gpio))
-		dev_info(&spi->dev, "Reset GPIO not defined\n");
+		return dev_err_probe(&spi->dev, PTR_ERR(ads124s_priv->reset_gpio),
+				     "Failed to get reset GPIO\n");
 
 	ads124s_priv->chip_info = &ads124s_chip_info_tbl[spi_id->driver_data];