Re: [PATCH v2 08/16] iio: adc: sc27xx_adc: do not use internal iio_dev lock

Jonathan Cameron
2022-10-09T12:06:11Z

On Tue, 4 Oct 2022 15:49:01 +0200
Nuno Sá <nuno.sa@analog.com> wrote:

> The iio_device lock is only meant for internal use. Hence define a
> device local lock to protect against concurrent accesses.
>
> While at it, properly include "mutex.h" for mutex related APIs.
>
> Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Applied. Pushed out as testing for now, will rebase after rc1.

Thanks,

J
> ---
> drivers/iio/adc/sc27xx_adc.c | 14 ++++++++++----
> 1 file changed, 10 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/iio/adc/sc27xx_adc.c b/drivers/iio/adc/sc27xx_adc.c
> index f8421cbba8fa..ff1fc329bb9b 100644
> --- a/drivers/iio/adc/sc27xx_adc.c
> +++ b/drivers/iio/adc/sc27xx_adc.c
> @@ -4,6 +4,7 @@
> #include <linux/hwspinlock.h>
> #include <linux/iio/iio.h>
> #include <linux/module.h>
> +#include <linux/mutex.h>
> #include <linux/nvmem-consumer.h>
> #include <linux/of.h>
> #include <linux/of_device.h>
> @@ -83,6 +84,8 @@ struct sc27xx_adc_data {
> struct device *dev;
> struct regulator *volref;
> struct regmap *regmap;
> + /* lock to protect against multiple access to the device */
> + struct mutex lock;
> /*
> * One hardware spinlock to synchronize between the multiple
> * subsystems which will access the unique ADC controller.
> @@ -664,9 +667,9 @@ static int sc27xx_adc_read_raw(struct iio_dev *indio_dev,
>
> switch (mask) {
> case IIO_CHAN_INFO_RAW:
> - mutex_lock(&indio_dev->mlock);
> + mutex_lock(&data->lock);
> ret = sc27xx_adc_read(data, chan->channel, scale, &tmp);
> - mutex_unlock(&indio_dev->mlock);
> + mutex_unlock(&data->lock);
>
> if (ret)
> return ret;
> @@ -675,10 +678,10 @@ static int sc27xx_adc_read_raw(struct iio_dev *indio_dev,
> return IIO_VAL_INT;
>
> case IIO_CHAN_INFO_PROCESSED:
> - mutex_lock(&indio_dev->mlock);
> + mutex_lock(&data->lock);
> ret = sc27xx_adc_read_processed(data, chan->channel, scale,
> &tmp);
> - mutex_unlock(&indio_dev->mlock);
> + mutex_unlock(&data->lock);
>
> if (ret)
> return ret;
> @@ -934,6 +937,9 @@ static int sc27xx_adc_probe(struct platform_device *pdev)
> indio_dev->info = &sc27xx_info;
> indio_dev->channels = sc27xx_channels;
> indio_dev->num_channels = ARRAY_SIZE(sc27xx_channels);
> +
> + mutex_init(&sc27xx_data->lock);
> +
> ret = devm_iio_device_register(dev, indio_dev);
> if (ret)
> dev_err(dev, "could not register iio (ADC)");