[PATCH 05/15] iio: adc: lpc32xx_adc: do not use internal iio_dev lock

[Nuno Sá <nuno.sa@xxxxxxxxxx>]

The iio_device lock is only meant for internal use. Hence define a
device local lock to protect against concurrent accesses.

Signed-off-by: Nuno Sá <nuno.sa@xxxxxxxxxx>
---
 drivers/iio/adc/lpc32xx_adc.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/iio/adc/lpc32xx_adc.c b/drivers/iio/adc/lpc32xx_adc.c
index b56ce15255cf..4136cf536d58 100644
--- a/drivers/iio/adc/lpc32xx_adc.c
+++ b/drivers/iio/adc/lpc32xx_adc.c
@@ -15,6 +15,7 @@
 #include <linux/io.h>
 #include <linux/module.h>
 #include <linux/mod_devicetable.h>
+#include <linux/mutex.h>
 #include <linux/platform_device.h>
 #include <linux/regulator/consumer.h>
 
@@ -49,6 +50,8 @@ struct lpc32xx_adc_state {
 	struct clk *clk;
 	struct completion completion;
 	struct regulator *vref;
+	/* lock to protect against multiple access to the device */
+	struct mutex lock;
 
 	u32 value;
 };
@@ -64,10 +67,10 @@ static int lpc32xx_read_raw(struct iio_dev *indio_dev,
 
 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
-		mutex_lock(&indio_dev->mlock);
+		mutex_lock(&st->lock);
 		ret = clk_prepare_enable(st->clk);
 		if (ret) {
-			mutex_unlock(&indio_dev->mlock);
+			mutex_unlock(&st->lock);
 			return ret;
 		}
 		/* Measurement setup */
@@ -80,7 +83,7 @@ static int lpc32xx_read_raw(struct iio_dev *indio_dev,
 		wait_for_completion(&st->completion); /* set by ISR */
 		clk_disable_unprepare(st->clk);
 		*val = st->value;
-		mutex_unlock(&indio_dev->mlock);
+		mutex_unlock(&st->lock);
 
 		return IIO_VAL_INT;
 
@@ -158,6 +161,7 @@ static int lpc32xx_adc_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	st = iio_priv(iodev);
+	mutex_init(&st->lock);
 
 	st->adc_base = devm_ioremap(&pdev->dev, res->start,
 				    resource_size(res));
-- 
2.37.3