From: Sergiu Cuciurean <sergiu.cuciurean@xxxxxxxxxx> 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@xxxxxxxxxxxxxx/ Signed-off-by: Sergiu Cuciurean <sergiu.cuciurean@xxxxxxxxxx> Signed-off-by: Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx> --- drivers/iio/dac/ti-dac7612.c | 14 ++++++++++++-- 1 file 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 @@ -22,6 +22,14 @@ struct dac7612 { struct gpio_desc *loaddacs; 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) -- 2.17.1
