iio: adc: ad7124: Fix missbalanced regulator enable / disable on error.

commit 4573472315f0fa461330545ff2aa2f6da0b1ae76 upstream.

If the devm_regulator_get() call succeeded but not the regulator_enable()
then regulator_disable() would be called on a regulator that was not
enabled.

Fix this by moving regulator enabling / disabling over to
devm_ management via devm_add_action_or_reset.

Alexandru's sign-off here because he pulled Jonathan's patch into
a larger set which Jonathan then applied.

Fixes: b3af341bbd96 ("iio: adc: Add ad7124 support")
Reviewed-by: Alexandru Ardelean <ardeleanalex@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Alexandru Ardelean <aardelean@deviqon.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 13 insertions, 16 deletions

diff --git a/drivers/iio/adc/ad7124.c b/drivers/iio/adc/ad7124.c
index 306bf15023a7..54a357038a5d 100644
--- a/drivers/iio/adc/ad7124.c
+++ b/drivers/iio/adc/ad7124.c
@@ -564,6 +564,11 @@ static int ad7124_setup(struct ad7124_state *st)
 	return ret;
 }
 
+static void ad7124_reg_disable(void *r)
+{
+	regulator_disable(r);
+}
+
 static int ad7124_probe(struct spi_device *spi)
 {
 	const struct spi_device_id *id;
@@ -607,17 +612,20 @@ static int ad7124_probe(struct spi_device *spi)
 		ret = regulator_enable(st->vref[i]);
 		if (ret)
 			return ret;
+
+		ret = devm_add_action_or_reset(&spi->dev, ad7124_reg_disable,
+					       st->vref[i]);
+		if (ret)
+			return ret;
 	}
 
 	st->mclk = devm_clk_get(&spi->dev, "mclk");
-	if (IS_ERR(st->mclk)) {
-		ret = PTR_ERR(st->mclk);
-		goto error_regulator_disable;
-	}
+	if (IS_ERR(st->mclk))
+		return PTR_ERR(st->mclk);
 
 	ret = clk_prepare_enable(st->mclk);
 	if (ret < 0)
-		goto error_regulator_disable;
+		return ret;
 
 	ret = ad7124_soft_reset(st);
 	if (ret < 0)
@@ -643,11 +651,6 @@ error_remove_trigger:
 	ad_sd_cleanup_buffer_and_trigger(indio_dev);
 error_clk_disable_unprepare:
 	clk_disable_unprepare(st->mclk);
-error_regulator_disable:
-	for (i = ARRAY_SIZE(st->vref) - 1; i >= 0; i--) {
-		if (!IS_ERR_OR_NULL(st->vref[i]))
-			regulator_disable(st->vref[i]);
-	}
 
 	return ret;
 }
@@ -656,17 +659,11 @@ static int ad7124_remove(struct spi_device *spi)
 {
 	struct iio_dev *indio_dev = spi_get_drvdata(spi);
 	struct ad7124_state *st = iio_priv(indio_dev);
-	int i;
 
 	iio_device_unregister(indio_dev);
 	ad_sd_cleanup_buffer_and_trigger(indio_dev);
 	clk_disable_unprepare(st->mclk);
 
-	for (i = ARRAY_SIZE(st->vref) - 1; i >= 0; i--) {
-		if (!IS_ERR_OR_NULL(st->vref[i]))
-			regulator_disable(st->vref[i]);
-	}
-
 	return 0;
 }