diff options
| author | Sergiu Cuciurean <sergiu.cuciurean@analog.com> | 2020-09-16 12:25:35 +0300 |
|---|---|---|
| committer | Jonathan Cameron <Jonathan.Cameron@huawei.com> | 2020-09-16 20:56:22 +0300 |
| commit | 20be66c193be1a758c507fe28e8f77ad407d5039 (patch) | |
| tree | 13a4b4d97803087ac877e96bd525cac955240ad3 /drivers/iio/dac | |
| parent | 2544ea7bd075948dcb0bdebfae739eb235c69728 (diff) | |
| download | linux-20be66c193be1a758c507fe28e8f77ad407d5039.tar.xz | |
iio: dac: ti-dac7612: 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 from potential concurrent write
accesses from userspace. The write operation requires an SPI write, then
toggling of a GPIO, so the lock aims to protect the sanity of the entire
sequence of operation.
This is part of a bigger cleanup.
Link: https://lore.kernel.org/linux-iio/CA+U=Dsoo6YABe5ODLp+eFNPGFDjk5ZeQEceGkqjxXcVEhLWubw@mail.gmail.com/
Signed-off-by: Sergiu Cuciurean <sergiu.cuciurean@analog.com>
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20200916092535.76527-1-alexandru.ardelean@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Diffstat (limited to 'drivers/iio/dac')
| -rw-r--r-- | drivers/iio/dac/ti-dac7612.c | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/drivers/iio/dac/ti-dac7612.c b/drivers/iio/dac/ti-dac7612.c index 07c9f39d54f1..4c0f4b5e9ff4 100644 --- a/drivers/iio/dac/ti-dac7612.c +++ b/drivers/iio/dac/ti-dac7612.c @@ -23,6 +23,14 @@ struct dac7612 { uint16_t cache[2]; /* + * Lock to protect the state of the device from potential concurrent + * write accesses from userspace. The write operation requires an + * SPI write, then toggling of a GPIO, so the lock aims to protect + * the sanity of the entire sequence of operation. + */ + struct mutex lock; + + /* * DMA (thus cache coherency maintenance) requires the * transfer buffers to live in their own cache lines. */ @@ -101,9 +109,9 @@ static int dac7612_write_raw(struct iio_dev *iio_dev, if (val == priv->cache[chan->channel]) return 0; - mutex_lock(&iio_dev->mlock); + mutex_lock(&priv->lock); ret = dac7612_cmd_single(priv, chan->channel, val); - mutex_unlock(&iio_dev->mlock); + mutex_unlock(&priv->lock); return ret; } @@ -145,6 +153,8 @@ static int dac7612_probe(struct spi_device *spi) iio_dev->num_channels = ARRAY_SIZE(priv->cache); iio_dev->name = spi_get_device_id(spi)->name; + mutex_init(&priv->lock); + for (i = 0; i < ARRAY_SIZE(priv->cache); i++) { ret = dac7612_cmd_single(priv, i, 0); if (ret) |