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

From: Sergiu Cuciurean
Date: Thu May 14 2020 - 05:06:49 EST


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@xxxxxxxxxx>
---
drivers/iio/dac/ad5755.c | 22 ++++++++++++++--------
1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/drivers/iio/dac/ad5755.c b/drivers/iio/dac/ad5755.c
index 388ddd14bfd0..7723bd313fc6 100644
--- 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
--
2.17.1