iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

iio: stm32-dac: Replace indio_dev->mlock with own device lock

Browse Source 
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>
This commit is contained in:
Sergiu Cuciurean 2020-09-16 12:23:49 +03:00 committed by Jonathan Cameron
parent d3e0e14d65
commit 2544ea7bd0
1 changed files with 9 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
drivers/iio/dac/stm32-dac.c
View File

@ -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;