diff options
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) |