[PATCH v2 1/2] staging: iio: adc: ad7192: Replace mlock with driver private lock

[Aastha Gupta <aastha.gupta4104@gmail.com>]

The IIO subsystem is redefining iio_dev->mlock to be used by
the IIO core only for protecting device operating mode changes.
ie. Changes between INDIO_DIRECT_MODE, INDIO_BUFFER_* modes.

In this driver, mlock was being used to protect hardware state
changes.  Replace it with a lock in the devices global data.

Signed-off-by: Aastha Gupta <aastha.gupta4104@gmail.com>
---
 drivers/staging/iio/adc/ad7192.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/iio/adc/ad7192.c b/drivers/staging/iio/adc/ad7192.c
index d11c6de..096d29d 100644
--- a/drivers/staging/iio/adc/ad7192.c
+++ b/drivers/staging/iio/adc/ad7192.c
@@ -162,6 +162,7 @@ struct ad7192_state {
 	u32				scale_avail[8][2];
 	u8				gpocon;
 	u8				devid;
+	struct mutex			lock;
 
 	struct ad_sigma_delta		sd;
 };
@@ -463,10 +464,10 @@ static int ad7192_read_raw(struct iio_dev *indio_dev,
 	case IIO_CHAN_INFO_SCALE:
 		switch (chan->type) {
 		case IIO_VOLTAGE:
-			mutex_lock(&indio_dev->mlock);
+			mutex_lock(&st->lock);
 			*val = st->scale_avail[AD7192_CONF_GAIN(st->conf)][0];
 			*val2 = st->scale_avail[AD7192_CONF_GAIN(st->conf)][1];
-			mutex_unlock(&indio_dev->mlock);
+			mutex_unlock(&st->lock);
 			return IIO_VAL_INT_PLUS_NANO;
 		case IIO_TEMP:
 			*val = 0;
@@ -634,6 +635,8 @@ static int ad7192_probe(struct spi_device *spi)
 
 	st = iio_priv(indio_dev);
 
+	mutex_init(&st->lock);
+
 	st->avdd = devm_regulator_get(&spi->dev, "avdd");
 	if (IS_ERR(st->avdd))
 		return PTR_ERR(st->avdd);
-- 
2.7.4