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>

diff --git a/drivers/iio/adc/ad7124.c b/drivers/iio/adc/ad7124.c
index 306bf15023a7878cd5a6e987d63e378bf455162c..54a357038a5da336d22f4613ee090d49e3afe4a8 100644 (file)
--- 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;
 }