iio: dac: ad5755: Replace indio_dev->mlock with own device lock

As part of the general cleanup of indio_dev->mlock, this change replaces
it with a local lock on the device's state structure.
This also changes some internal functions to pass the pointer to the
state-struct vs a ref to indio_dev just to access the state-struct again.

Signed-off-by: Sergiu Cuciurean <sergiu.cuciurean@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/dac/ad5755.c b/drivers/iio/dac/ad5755.c
index 388ddd1..7723bd3 100644 (file)
--- a/drivers/iio/dac/ad5755.c
+++ b/drivers/iio/dac/ad5755.c
@@ -82,6 +82,7 @@ struct ad5755_chip_info {
  * @pwr_down:  bitmask which contains  hether a channel is powered down or not
  * @ctrl:      software shadow of the channel ctrl registers
  * @channels:  iio channel spec for the device
+ * @lock       lock to protect the data buffer during SPI ops
  * @data:      spi transfer buffers
  */
 struct ad5755_state {
@@ -90,6 +91,7 @@ struct ad5755_state {
        unsigned int                    pwr_down;
        unsigned int                    ctrl[AD5755_NUM_CHANNELS];
        struct iio_chan_spec            channels[AD5755_NUM_CHANNELS];
+       struct mutex                    lock;
 
        /*
         * DMA (thus cache coherency maintenance) requires the
@@ -174,11 +176,12 @@ static int ad5755_write_ctrl_unlocked(struct iio_dev *indio_dev,
 static int ad5755_write(struct iio_dev *indio_dev, unsigned int reg,
        unsigned int val)
 {
+       struct ad5755_state *st = iio_priv(indio_dev);
        int ret;
 
-       mutex_lock(&indio_dev->mlock);
+       mutex_lock(&st->lock);
        ret = ad5755_write_unlocked(indio_dev, reg, val);
-       mutex_unlock(&indio_dev->mlock);
+       mutex_unlock(&st->lock);
 
        return ret;
 }
@@ -186,11 +189,12 @@ static int ad5755_write(struct iio_dev *indio_dev, unsigned int reg,
 static int ad5755_write_ctrl(struct iio_dev *indio_dev, unsigned int channel,
        unsigned int reg, unsigned int val)
 {
+       struct ad5755_state *st = iio_priv(indio_dev);
        int ret;
 
-       mutex_lock(&indio_dev->mlock);
+       mutex_lock(&st->lock);
        ret = ad5755_write_ctrl_unlocked(indio_dev, channel, reg, val);
-       mutex_unlock(&indio_dev->mlock);
+       mutex_unlock(&st->lock);
 
        return ret;
 }
@@ -211,7 +215,7 @@ static int ad5755_read(struct iio_dev *indio_dev, unsigned int addr)
                },
        };
 
-       mutex_lock(&indio_dev->mlock);
+       mutex_lock(&st->lock);
 
        st->data[0].d32 = cpu_to_be32(AD5755_READ_FLAG | (addr << 16));
        st->data[1].d32 = cpu_to_be32(AD5755_NOOP);
@@ -220,7 +224,7 @@ static int ad5755_read(struct iio_dev *indio_dev, unsigned int addr)
        if (ret >= 0)
                ret = be32_to_cpu(st->data[1].d32) & 0xffff;
 
-       mutex_unlock(&indio_dev->mlock);
+       mutex_unlock(&st->lock);
 
        return ret;
 }
@@ -246,7 +250,7 @@ static int ad5755_set_channel_pwr_down(struct iio_dev *indio_dev,
        struct ad5755_state *st = iio_priv(indio_dev);
        unsigned int mask = BIT(channel);
 
-       mutex_lock(&indio_dev->mlock);
+       mutex_lock(&st->lock);
 
        if ((bool)(st->pwr_down & mask) == pwr_down)
                goto out_unlock;
@@ -266,7 +270,7 @@ static int ad5755_set_channel_pwr_down(struct iio_dev *indio_dev,
        }
 
 out_unlock:
-       mutex_unlock(&indio_dev->mlock);
+       mutex_unlock(&st->lock);
 
        return 0;
 }
@@ -746,6 +750,8 @@ static int ad5755_probe(struct spi_device *spi)
        indio_dev->modes = INDIO_DIRECT_MODE;
        indio_dev->num_channels = AD5755_NUM_CHANNELS;
 
+       mutex_init(&st->lock);
+
        if (spi->dev.of_node)
                pdata = ad5755_parse_dt(&spi->dev);
        else