summaryrefslogtreecommitdiff
path: root/drivers/iio/dac
diff options
context:
space:
mode:
authorSergiu Cuciurean <sergiu.cuciurean@analog.com>2020-09-16 12:23:49 +0300
committerJonathan Cameron <Jonathan.Cameron@huawei.com>2020-09-16 18:51:40 +0100
commit2544ea7bd075948dcb0bdebfae739eb235c69728 (patch)
tree1663e5de288a9d4b0d88cb9f3350a459f9ec2bf5 /drivers/iio/dac
parentd3e0e14d65178d73ee0f991934c5fa89737e3922 (diff)
iio: stm32-dac: 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. The lock protects against potential races when reading the CR reg and then updating, so that the state of pm_runtime is consistent between the two operations. 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> Reviewed-by: Fabrice Gasnier <fabrice.gasnier@st.com> Link: https://lore.kernel.org/r/20200916092349.75647-1-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/stm32-dac.c13
1 files changed, 9 insertions, 4 deletions
diff --git a/drivers/iio/dac/stm32-dac.c b/drivers/iio/dac/stm32-dac.c
index 092c796fa3d9..12dec68c16f7 100644
--- a/drivers/iio/dac/stm32-dac.c
+++ b/drivers/iio/dac/stm32-dac.c
@@ -26,9 +26,12 @@
/**
* struct stm32_dac - private data of DAC driver
* @common: reference to DAC common data
+ * @lock: lock to protect against potential races when reading
+ * and update CR, to keep it in sync with pm_runtime
*/
struct stm32_dac {
struct stm32_dac_common *common;
+ struct mutex lock;
};
static int stm32_dac_is_enabled(struct iio_dev *indio_dev, int channel)
@@ -58,10 +61,10 @@ static int stm32_dac_set_enable_state(struct iio_dev *indio_dev, int ch,
int ret;
/* already enabled / disabled ? */
- mutex_lock(&indio_dev->mlock);
+ mutex_lock(&dac->lock);
ret = stm32_dac_is_enabled(indio_dev, ch);
if (ret < 0 || enable == !!ret) {
- mutex_unlock(&indio_dev->mlock);
+ mutex_unlock(&dac->lock);
return ret < 0 ? ret : 0;
}
@@ -69,13 +72,13 @@ static int stm32_dac_set_enable_state(struct iio_dev *indio_dev, int ch,
ret = pm_runtime_get_sync(dev);
if (ret < 0) {
pm_runtime_put_noidle(dev);
- mutex_unlock(&indio_dev->mlock);
+ mutex_unlock(&dac->lock);
return ret;
}
}
ret = regmap_update_bits(dac->common->regmap, STM32_DAC_CR, msk, en);
- mutex_unlock(&indio_dev->mlock);
+ mutex_unlock(&dac->lock);
if (ret < 0) {
dev_err(&indio_dev->dev, "%s failed\n", en ?
"Enable" : "Disable");
@@ -327,6 +330,8 @@ static int stm32_dac_probe(struct platform_device *pdev)
indio_dev->info = &stm32_dac_iio_info;
indio_dev->modes = INDIO_DIRECT_MODE;
+ mutex_init(&dac->lock);
+
ret = stm32_dac_chan_of_init(indio_dev);
if (ret < 0)
return ret;