[PATCH v3 1/4] iio: core: introduce iio_device_{claim|release}_buffer_mode() APIs

[Andy Shevchenko]

On Wed, Oct 12, 2022 at 6:15 PM Nuno Sá <nuno.sa at analog.com> wrote:
>
> These APIs are analogous to iio_device_claim_direct_mode() and
> iio_device_release_direct_mode() but, as the name suggests, with the
> logic flipped. While this looks odd enough, it will have at least two
> users (in following changes) and it will be important to move the iio
> mlock to the private struct.

IIO

> Signed-off-by: Nuno Sá <nuno.sa at analog.com>
> ---
>  drivers/iio/industrialio-core.c | 38 +++++++++++++++++++++++++++++++++
>  include/linux/iio/iio.h         |  2 ++
>  2 files changed, 40 insertions(+)
>
> diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
> index 151ff3993354..cf80f81e4665 100644
> --- a/drivers/iio/industrialio-core.c
> +++ b/drivers/iio/industrialio-core.c
> @@ -2083,6 +2083,44 @@ void iio_device_release_direct_mode(struct iio_dev *indio_dev)
>  }
>  EXPORT_SYMBOL_GPL(iio_device_release_direct_mode);
>
> +/**
> + * iio_device_claim_buffer_mode - Keep device in buffer mode
> + * @indio_dev: the iio_dev associated with the device
> + *
> + * If the device is in buffer mode it is guaranteed to stay
> + * that way until iio_device_release_buffer_mode() is called.
> + *
> + * Use with iio_device_release_buffer_mode()

Missed trailing period.

> + *
> + * Returns: 0 on success, -EBUSY on failure

Ditto.

> + */
> +int iio_device_claim_buffer_mode(struct iio_dev *indio_dev)
> +{
> +       mutex_lock(&indio_dev->mlock);
> +
> +       if (iio_buffer_enabled(indio_dev))
> +               return 0;
> +
> +       mutex_unlock(&indio_dev->mlock);
> +       return -EBUSY;
> +}
> +EXPORT_SYMBOL_GPL(iio_device_claim_buffer_mode);
> +
> +/**
> + * iio_device_release_buffer_mode - releases claim on buffer mode
> + * @indio_dev: the iio_dev associated with the device
> + *
> + * Release the claim. Device is no longer guaranteed to stay
> + * in buffer mode.
> + *
> + * Use with iio_device_claim_buffer_mode()

Ditto.

> + */
> +void iio_device_release_buffer_mode(struct iio_dev *indio_dev)
> +{
> +       mutex_unlock(&indio_dev->mlock);
> +}
> +EXPORT_SYMBOL_GPL(iio_device_release_buffer_mode);
> +
>  /**
>   * iio_device_get_current_mode() - helper function providing read-only access to
>   *                                the opaque @currentmode variable
> diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
> index f0ec8a5e5a7a..9d3bd6379eb8 100644
> --- a/include/linux/iio/iio.h
> +++ b/include/linux/iio/iio.h
> @@ -629,6 +629,8 @@ int __devm_iio_device_register(struct device *dev, struct iio_dev *indio_dev,
>  int iio_push_event(struct iio_dev *indio_dev, u64 ev_code, s64 timestamp);
>  int iio_device_claim_direct_mode(struct iio_dev *indio_dev);
>  void iio_device_release_direct_mode(struct iio_dev *indio_dev);
> +int iio_device_claim_buffer_mode(struct iio_dev *indio_dev);
> +void iio_device_release_buffer_mode(struct iio_dev *indio_dev);
>
>  extern struct bus_type iio_bus_type;
>
> --
> 2.38.0
>


-- 
With Best Regards,
Andy Shevchenko