[PATCH] iio: adc: exynos_adc: Replace indio_dev->mlock with own device lock

[Alexandru Ardelean]

From: Sergiu Cuciurean <sergiu.cuciurean@xxxxxxxxxx>

As part of the general cleanup of indio_dev->mlock, this change replaces
it with a local lock, to protect potential concurrent access to the
completion callback during a conversion.

Signed-off-by: Sergiu Cuciurean <sergiu.cuciurean@xxxxxxxxxx>
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx>
---
 drivers/iio/adc/exynos_adc.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/iio/adc/exynos_adc.c b/drivers/iio/adc/exynos_adc.c
index 7d23b6c33284..6a49f8dfab22 100644
--- a/drivers/iio/adc/exynos_adc.c
+++ b/drivers/iio/adc/exynos_adc.c
@@ -132,6 +132,8 @@ struct exynos_adc {
 
 	struct completion	completion;
 
+	struct mutex		lock;
+
 	u32			value;
 	unsigned int            version;
 
@@ -542,7 +544,7 @@ static int exynos_read_raw(struct iio_dev *indio_dev,
 		return -EINVAL;
 	}
 
-	mutex_lock(&indio_dev->mlock);
+	mutex_lock(&info->lock);
 	reinit_completion(&info->completion);
 
 	/* Select the channel to be used and Trigger conversion */
@@ -562,7 +564,7 @@ static int exynos_read_raw(struct iio_dev *indio_dev,
 		ret = IIO_VAL_INT;
 	}
 
-	mutex_unlock(&indio_dev->mlock);
+	mutex_unlock(&info->lock);
 
 	return ret;
 }
@@ -573,7 +575,7 @@ static int exynos_read_s3c64xx_ts(struct iio_dev *indio_dev, int *x, int *y)
 	unsigned long timeout;
 	int ret;
 
-	mutex_lock(&indio_dev->mlock);
+	mutex_lock(&info->lock);
 	info->read_ts = true;
 
 	reinit_completion(&info->completion);
@@ -598,7 +600,7 @@ static int exynos_read_s3c64xx_ts(struct iio_dev *indio_dev, int *x, int *y)
 	}
 
 	info->read_ts = false;
-	mutex_unlock(&indio_dev->mlock);
+	mutex_unlock(&info->lock);
 
 	return ret;
 }
@@ -872,6 +874,8 @@ static int exynos_adc_probe(struct platform_device *pdev)
 	indio_dev->channels = exynos_adc_iio_channels;
 	indio_dev->num_channels = info->data->num_channels;
 
+	mutex_init(&info->lock);
+
 	ret = request_irq(info->irq, exynos_adc_isr,
 					0, dev_name(&pdev->dev), info);
 	if (ret < 0) {
-- 
2.25.1