Re: [PATCH v2 04/16] iio: adc: lpc32xx_adc: do not use internal iio_dev lock

Jonathan Cameron
2022-10-09T11:58:45Z

On Tue, 4 Oct 2022 15:48:57 +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.

Thanks,

J

> ---
> drivers/iio/adc/lpc32xx_adc.c | 11 ++++++++---
> 1 file changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/iio/adc/lpc32xx_adc.c b/drivers/iio/adc/lpc32xx_adc.c
> index b56ce15255cf..732c924a976d 100644
> --- a/drivers/iio/adc/lpc32xx_adc.c
> +++ b/drivers/iio/adc/lpc32xx_adc.c
> @@ -15,6 +15,7 @@
> #include <linux/io.h>
> #include <linux/module.h>
> #include <linux/mod_devicetable.h>
> +#include <linux/mutex.h>
> #include <linux/platform_device.h>
> #include <linux/regulator/consumer.h>
>
> @@ -49,6 +50,8 @@ struct lpc32xx_adc_state {
> struct clk *clk;
> struct completion completion;
> struct regulator *vref;
> + /* lock to protect against multiple access to the device */
> + struct mutex lock;
>
> u32 value;
> };
> @@ -64,10 +67,10 @@ static int lpc32xx_read_raw(struct iio_dev *indio_dev,
>
> switch (mask) {
> case IIO_CHAN_INFO_RAW:
> - mutex_lock(&indio_dev->mlock);
> + mutex_lock(&st->lock);
> ret = clk_prepare_enable(st->clk);
> if (ret) {
> - mutex_unlock(&indio_dev->mlock);
> + mutex_unlock(&st->lock);
> return ret;
> }
> /* Measurement setup */
> @@ -80,7 +83,7 @@ static int lpc32xx_read_raw(struct iio_dev *indio_dev,
> wait_for_completion(&st->completion); /* set by ISR */
> clk_disable_unprepare(st->clk);
> *val = st->value;
> - mutex_unlock(&indio_dev->mlock);
> + mutex_unlock(&st->lock);
>
> return IIO_VAL_INT;
>
> @@ -201,6 +204,8 @@ static int lpc32xx_adc_probe(struct platform_device *pdev)
> iodev->modes = INDIO_DIRECT_MODE;
> iodev->num_channels = ARRAY_SIZE(lpc32xx_adc_iio_channels);
>
> + mutex_init(&st->lock);
> +
> retval = devm_iio_device_register(&pdev->dev, iodev);
> if (retval)
> return retval;