On Wed, 16 Sep 2020 12:18:02 +0200 Fabrice Gasnier <fabrice.gasnier@xxxxxx> wrote: > 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> Applied to the togreg branch of iio.git and pushed out as testing for the autobuilders to poke at it. Thanks, Jonathan > > 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; > >
