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

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>

diff --git a/drivers/iio/adc/ad7124.c b/drivers/iio/adc/ad7124.c
index 9d3952b..437116a 100644 (file)
--- a/drivers/iio/adc/ad7124.c
+++ b/drivers/iio/adc/ad7124.c
@@ -850,6 +850,11 @@ 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 ad7124_chip_info *info;
@@ -895,17 +900,20 @@ 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)
@@ -935,11 +943,6 @@ 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;
 }
@@ -948,17 +951,11 @@ 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;
 }