Fwd: [PATCH] Staging: iio: meter: Replace mlock with driver private lock

[Georgiana Chelu <georgiana.chelu93@xxxxxxxxx>]

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: Georgiana Chelu <georgiana.chelu93@xxxxxxxxx>
---
 drivers/staging/iio/meter/ade7758.h      |  2 ++
 drivers/staging/iio/meter/ade7758_core.c | 11 +++++++----
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/staging/iio/meter/ade7758.h
b/drivers/staging/iio/meter/ade7758.h
index 6ae78d8aa24f..728424a6648b 100644
--- a/drivers/staging/iio/meter/ade7758.h
+++ b/drivers/staging/iio/meter/ade7758.h
@@ -112,6 +112,7 @@
  * @tx:                        transmit buffer
  * @rx:                        receive buffer
  * @buf_lock:          mutex to protect tx and rx
+ * @lock:              mutex to protect raw read and write
  **/
 struct ade7758_state {
        struct spi_device       *us;
@@ -119,6 +120,7 @@ struct ade7758_state {
        u8                      *tx;
        u8                      *rx;
        struct mutex            buf_lock;
+       struct mutex            rw_lock; /* protect raw read/write */
        struct spi_transfer     ring_xfer[4];
        struct spi_message      ring_msg;
        /*
diff --git a/drivers/staging/iio/meter/ade7758_core.c
b/drivers/staging/iio/meter/ade7758_core.c
index 7b7ffe5ed186..6b153dd6d40d 100644
--- a/drivers/staging/iio/meter/ade7758_core.c
+++ b/drivers/staging/iio/meter/ade7758_core.c
@@ -523,12 +523,13 @@ static int ade7758_read_raw(struct iio_dev *indio_dev,
                            long mask)
 {
        int ret;
+       struct ade7758_state *st = iio_priv(indio_dev);

        switch (mask) {
        case IIO_CHAN_INFO_SAMP_FREQ:
-               mutex_lock(&indio_dev->mlock);
+               mutex_lock(&st->rw_lock);
                ret = ade7758_read_samp_freq(&indio_dev->dev, val);
-               mutex_unlock(&indio_dev->mlock);
+               mutex_unlock(&st->rw_lock);
                return ret;
        default:
                return -EINVAL;
@@ -542,14 +543,15 @@ static int ade7758_write_raw(struct iio_dev *indio_dev,
                             int val, int val2, long mask)
 {
        int ret;
+       struct ade7758_state *st = iio_priv(indio_dev);

        switch (mask) {
        case IIO_CHAN_INFO_SAMP_FREQ:
                if (val2)
                        return -EINVAL;
-               mutex_lock(&indio_dev->mlock);
+               mutex_lock(&st->rw_lock);
                ret = ade7758_write_samp_freq(&indio_dev->dev, val);
-               mutex_unlock(&indio_dev->mlock);
+               mutex_unlock(&st->rw_lock);
                return ret;
        default:
                return -EINVAL;
@@ -854,6 +856,7 @@ static int ade7758_probe(struct spi_device *spi)
        }
        st->us = spi;
        mutex_init(&st->buf_lock);
+       mutex_init(&st->rw_lock);

        indio_dev->name = spi->dev.driver->name;
        indio_dev->dev.parent = &spi->dev;
--
2.11.0
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