[PATCH] iio: stm32-dac: Replace indio_dev->mlock with own device lock

[Sergiu Cuciurean]

As part of the general cleanup of indio_dev->mlock, this change replaces
it with a local lock on the device's state structure.

Signed-off-by: Sergiu Cuciurean <sergiu.cuciur...@analog.com>
---
 drivers/iio/dac/stm32-dac.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/iio/dac/stm32-dac.c b/drivers/iio/dac/stm32-dac.c
index f22c1d9129b2..74b9474c8590 100644
--- a/drivers/iio/dac/stm32-dac.c
+++ b/drivers/iio/dac/stm32-dac.c
@@ -26,9 +26,11 @@
 /**
  * struct stm32_dac - private data of DAC driver
  * @common:            reference to DAC common data
+ * @lock: lock to protect the data buffer during regmap ops
  */
 struct stm32_dac {
        struct stm32_dac_common *common;
+       struct mutex            lock;
 };
 
 static int stm32_dac_is_enabled(struct iio_dev *indio_dev, int channel)
@@ -58,10 +60,10 @@ static int stm32_dac_set_enable_state(struct iio_dev 
*indio_dev, int ch,
        int ret;
 
        /* already enabled / disabled ? */
-       mutex_lock(&indio_dev->mlock);
+       mutex_lock(&dac->lock);
        ret = stm32_dac_is_enabled(indio_dev, ch);
        if (ret < 0 || enable == !!ret) {
-               mutex_unlock(&indio_dev->mlock);
+               mutex_unlock(&dac->lock);
                return ret < 0 ? ret : 0;
        }
 
@@ -69,13 +71,13 @@ static int stm32_dac_set_enable_state(struct iio_dev 
*indio_dev, int ch,
                ret = pm_runtime_get_sync(dev);
                if (ret < 0) {
                        pm_runtime_put_noidle(dev);
-                       mutex_unlock(&indio_dev->mlock);
+                       mutex_unlock(&dac->lock);
                        return ret;
                }
        }
 
        ret = regmap_update_bits(dac->common->regmap, STM32_DAC_CR, msk, en);
-       mutex_unlock(&indio_dev->mlock);
+       mutex_unlock(&dac->lock);
        if (ret < 0) {
                dev_err(&indio_dev->dev, "%s failed\n", en ?
                        "Enable" : "Disable");
@@ -328,6 +330,8 @@ static int stm32_dac_probe(struct platform_device *pdev)
        indio_dev->info = &stm32_dac_iio_info;
        indio_dev->modes = INDIO_DIRECT_MODE;
 
+       mutex_init(&dac->lock);
+
        ret = stm32_dac_chan_of_init(indio_dev);
        if (ret < 0)
                return ret;
-- 
2.17.1