staging: iio: rework regulator handling

Currently, the affected drivers ignore all errors from regulator_get().
The way it is now, it also breaks probe deferral (EPROBE_DEFER). The
correct behavior is to propagate the error to the upper layers so they
can handle it accordingly.

Rework the regulator handling so that it matches the standard behavior.
If the specific design uses a static always-on regulator and does not
explicitly specify it, regulator_get() will return the dummy regulator.

The following semantic patch was used to apply the change:
@r1@
expression reg, dev, en, volt;
@@

reg = \(devm_regulator_get\|regulator_get\)(dev, ...);
if (
- !
   IS_ERR(reg))
+	return PTR_ERR(reg);
(
- {	en = regulator_enable(reg);
-	if (en) return en; }
+
+	en = regulator_enable(reg);
+	if (en) {
+		dev_err(dev, "Failed to enable specified supply\n");
+		return en; }
|
+
- {	en = regulator_enable(reg);
-	if (en)	return en;
-	volt = regulator_get_voltage(reg); }
+	en = regulator_enable(reg);
+	if (en) {
+		dev_err(dev, "Failed to enable specified supply\n");
+		return en;
+	}
+	volt = regulator_get_voltage(reg);
)

@r2@
expression arg;
@@

-	if (!IS_ERR(arg)) regulator_disable(arg);
+	regulator_disable(arg);

Hand-edit the debugging prints with the supply name to become more
specific.

Suggested-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Eva Rachel Retuya <eraretuya@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

2 files changed, 18 insertions, 18 deletions

diff --git a/drivers/staging/iio/adc/ad7192.c b/drivers/staging/iio/adc/ad7192.c
index 41fb32de5992..29e32b71f0f7 100644
--- a/drivers/staging/iio/adc/ad7192.c
+++ b/drivers/staging/iio/adc/ad7192.c
@@ -634,13 +634,15 @@ static int ad7192_probe(struct spi_device *spi)
 	st = iio_priv(indio_dev);
 
 	st->reg = devm_regulator_get(&spi->dev, "avdd");
-	if (!IS_ERR(st->reg)) {
-		ret = regulator_enable(st->reg);
-		if (ret)
-			return ret;
+	if (IS_ERR(st->reg))
+		return PTR_ERR(st->reg);
 
-		voltage_uv = regulator_get_voltage(st->reg);
+	ret = regulator_enable(st->reg);
+	if (ret) {
+		dev_err(&spi->dev, "Failed to enable specified AVdd supply\n");
+		return ret;
 	}
+	voltage_uv = regulator_get_voltage(st->reg);
 
 	if (pdata->vref_mv)
 		st->int_vref_mv = pdata->vref_mv;
@@ -689,8 +691,7 @@ static int ad7192_probe(struct spi_device *spi)
 error_remove_trigger:
 	ad_sd_cleanup_buffer_and_trigger(indio_dev);
 error_disable_reg:
-	if (!IS_ERR(st->reg))
-		regulator_disable(st->reg);
+	regulator_disable(st->reg);
 
 	return ret;
 }
@@ -703,8 +704,7 @@ static int ad7192_remove(struct spi_device *spi)
 	iio_device_unregister(indio_dev);
 	ad_sd_cleanup_buffer_and_trigger(indio_dev);
 
-	if (!IS_ERR(st->reg))
-		regulator_disable(st->reg);
+	regulator_disable(st->reg);
 
 	return 0;
 }
diff --git a/drivers/staging/iio/adc/ad7780.c b/drivers/staging/iio/adc/ad7780.c
index a88236e74cdb..e14960038d3e 100644
--- a/drivers/staging/iio/adc/ad7780.c
+++ b/drivers/staging/iio/adc/ad7780.c
@@ -174,13 +174,15 @@ static int ad7780_probe(struct spi_device *spi)
 	ad_sd_init(&st->sd, indio_dev, spi, &ad7780_sigma_delta_info);
 
 	st->reg = devm_regulator_get(&spi->dev, "avdd");
-	if (!IS_ERR(st->reg)) {
-		ret = regulator_enable(st->reg);
-		if (ret)
-			return ret;
+	if (IS_ERR(st->reg))
+		return PTR_ERR(st->reg);
 
-		voltage_uv = regulator_get_voltage(st->reg);
+	ret = regulator_enable(st->reg);
+	if (ret) {
+		dev_err(&spi->dev, "Failed to enable specified AVdd supply\n");
+		return ret;
 	}
+	voltage_uv = regulator_get_voltage(st->reg);
 
 	st->chip_info =
 		&ad7780_chip_info_tbl[spi_get_device_id(spi)->driver_data];
@@ -222,8 +224,7 @@ static int ad7780_probe(struct spi_device *spi)
 error_cleanup_buffer_and_trigger:
 	ad_sd_cleanup_buffer_and_trigger(indio_dev);
 error_disable_reg:
-	if (!IS_ERR(st->reg))
-		regulator_disable(st->reg);
+	regulator_disable(st->reg);
 
 	return ret;
 }
@@ -236,8 +237,7 @@ static int ad7780_remove(struct spi_device *spi)
 	iio_device_unregister(indio_dev);
 	ad_sd_cleanup_buffer_and_trigger(indio_dev);
 
-	if (!IS_ERR(st->reg))
-		regulator_disable(st->reg);
+	regulator_disable(st->reg);
 
 	return 0;
 }