From: Sergiu Cuciurean <sergiu.cuciur...@analog.com> 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+efnpgfdjk5zeqecegkqjxxcvehlw...@mail.gmail.com/ Signed-off-by: Sergiu Cuciurean <sergiu.cuciur...@analog.com> Signed-off-by: Alexandru Ardelean <alexandru.ardel...@analog.com> --- drivers/iio/dac/stm32-dac.c | 13 +++++++++---- 1 file 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; -- 2.17.1
