On Thu, 14 May 2020 12:06:05 +0300 Sergiu Cuciurean <[email protected]> wrote:
> 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 <[email protected]> Applied to the togreg branch of iio.git. An observation on this one is that, with the local lock we always have the iio_priv() structure where we are calling the various write functions. Those take the indio_dev and use it just to get the iio_priv(). May be worth a follow up to tidy that up and just pass the private state structure directly into the various write functions. Jonathan > --- > 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
