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authorSergiu Cuciurean <sergiu.cuciurean@analog.com>2020-09-16 12:25:35 +0300
committerJonathan Cameron <Jonathan.Cameron@huawei.com>2020-09-16 20:56:22 +0300
commit20be66c193be1a758c507fe28e8f77ad407d5039 (patch)
tree13a4b4d97803087ac877e96bd525cac955240ad3 /drivers/iio/dac
parent2544ea7bd075948dcb0bdebfae739eb235c69728 (diff)
downloadlinux-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.c14
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)