On 9/16/20 11:23 AM, Alexandru Ardelean wrote: > From: Sergiu Cuciurean <sergiu.cuciurean@xxxxxxxxxx> > > 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@xxxxxxxxxxxxxx/ > > Signed-off-by: Sergiu Cuciurean <sergiu.cuciurean@xxxxxxxxxx> > Signed-off-by: Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx> > --- > drivers/iio/dac/stm32-dac.c | 13 +++++++++---- > 1 file changed, 9 insertions(+), 4 deletions(-) Hi Alexandru, Many thanks for this updated patch, Reviewed-by: Fabrice Gasnier <fabrice.gasnier@xxxxxx> Best regards, Fabrice > > 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; >
