On Tue, 10 Dec 2019 16:03:42 -0500 Sasha Levin sashal@kernel.org wrote:
From: Alexandru Ardelean alexandru.ardelean@analog.com
[ Upstream commit c991bf9b650f39481cf3c1137092d4754a2c75de ]
This change replaces indio_dev's mlock with the driver's own lock. The lock is mostly needed to protect state when changing the `dac_cache` info. The lock has been extended to `ad7303_read_raw()`, to make sure that the cache is updated if an SPI-write is already in progress.
This is not a fix. It's undoing some slightly nasty layer violations that we are trying to drive out of IIO, but as far as I know there is no actual bug with what was there before.
I won't do any harm though other than adding noise.
Jonathan
Signed-off-by: Alexandru Ardelean alexandru.ardelean@analog.com Signed-off-by: Jonathan Cameron Jonathan.Cameron@huawei.com Signed-off-by: Sasha Levin sashal@kernel.org
drivers/iio/dac/ad7303.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/drivers/iio/dac/ad7303.c b/drivers/iio/dac/ad7303.c index 8de9f40226e62..14bbac6bee982 100644 --- a/drivers/iio/dac/ad7303.c +++ b/drivers/iio/dac/ad7303.c @@ -41,6 +41,7 @@ struct ad7303_state { struct regulator *vdd_reg; struct regulator *vref_reg;
- struct mutex lock; /*
- DMA (thus cache coherency maintenance) requires the
- transfer buffers to live in their own cache lines.
@@ -79,7 +80,7 @@ static ssize_t ad7303_write_dac_powerdown(struct iio_dev *indio_dev, if (ret) return ret;
- mutex_lock(&indio_dev->mlock);
- mutex_lock(&st->lock);
if (pwr_down) st->config |= AD7303_CFG_POWER_DOWN(chan->channel); @@ -90,7 +91,7 @@ static ssize_t ad7303_write_dac_powerdown(struct iio_dev *indio_dev, * mode, so just write one of the DAC channels again */ ad7303_write(st, chan->channel, st->dac_cache[chan->channel]);
- mutex_unlock(&indio_dev->mlock);
- mutex_unlock(&st->lock); return len;
} @@ -116,7 +117,9 @@ static int ad7303_read_raw(struct iio_dev *indio_dev, switch (info) { case IIO_CHAN_INFO_RAW:
mutex_lock(&st->lock);mutex_unlock(&st->lock);@@ -144,11 +147,11 @@ static int ad7303_write_raw(struct iio_dev *indio_dev, if (val >= (1 << chan->scan_type.realbits) || val < 0) return -EINVAL;
mutex_lock(&indio_dev->mlock);
mutex_lock(&st->lock);
mutex_unlock(&indio_dev->mlock);
mutex_unlock(&st->lock);@@ -211,6 +214,8 @@ static int ad7303_probe(struct spi_device *spi) st->spi = spi;
- mutex_init(&st->lock);
- st->vdd_reg = devm_regulator_get(&spi->dev, "Vdd"); if (IS_ERR(st->vdd_reg)) return PTR_ERR(st->vdd_reg);