Re: [PATCH v2 3/5] iio: backend: add support for data source get

[Jonathan Cameron <jic23@kernel.org>]

On Mon, 31 Mar 2025 21:02:46 +0200
Angelo Dureghello <adureghello@baylibre.com> wrote:

> From: Angelo Dureghello <adureghello@baylibre.com>
> 
> Add backend support for getting the data source used.
> 
> The ad3552r HDL implements an internal ramp generator, so adding the
> getter to allow data source get/set by debugfs.
> 
> Signed-off-by: Angelo Dureghello <adureghello@baylibre.com>

Looking for a Nuno Ack on this one.


> ---
>  drivers/iio/industrialio-backend.c | 28 ++++++++++++++++++++++++++++
>  include/linux/iio/backend.h        |  5 +++++
>  2 files changed, 33 insertions(+)
> 
> diff --git a/drivers/iio/industrialio-backend.c b/drivers/iio/industrialio-backend.c
> index a43c8d1bb3d0f4dda4277cac94b0ea9232c071e4..c1eb9ef9db08aec8437d0d00cf77914ad6611b72 100644
> --- a/drivers/iio/industrialio-backend.c
> +++ b/drivers/iio/industrialio-backend.c
> @@ -380,6 +380,34 @@ int iio_backend_data_source_set(struct iio_backend *back, unsigned int chan,
>  }
>  EXPORT_SYMBOL_NS_GPL(iio_backend_data_source_set, "IIO_BACKEND");
>  
> +/**
> + * iio_backend_data_source_get - Get current data source
> + * @back: Backend device
> + * @chan: Channel number
> + * @data: Pointer to receive the current source value
> + *
> + * A given backend may have different sources to stream/sync data. This allows
> + * to know what source is in use.
> + *
> + * RETURNS:
> + * 0 on success, negative error number on failure.
> + */
> +int iio_backend_data_source_get(struct iio_backend *back, unsigned int chan,
> +				enum iio_backend_data_source *data)
> +{
> +	int ret;
> +
> +	ret = iio_backend_op_call(back, data_source_get, chan, data);
> +	if (ret)
> +		return ret;
> +
> +	if (*data >= IIO_BACKEND_DATA_SOURCE_MAX)
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_NS_GPL(iio_backend_data_source_get, "IIO_BACKEND");
> +
>  /**
>   * iio_backend_set_sampling_freq - Set channel sampling rate
>   * @back: Backend device
> diff --git a/include/linux/iio/backend.h b/include/linux/iio/backend.h
> index e45b7dfbec35c094942a3034fc6057a7960b9772..e59d909cb65924b4872cadd4b7e5e894c13c189f 100644
> --- a/include/linux/iio/backend.h
> +++ b/include/linux/iio/backend.h
> @@ -84,6 +84,7 @@ enum iio_backend_interface_type {
>   * @chan_disable: Disable one channel.
>   * @data_format_set: Configure the data format for a specific channel.
>   * @data_source_set: Configure the data source for a specific channel.
> + * @data_source_get: Data source getter for a specific channel.
>   * @set_sample_rate: Configure the sampling rate for a specific channel.
>   * @test_pattern_set: Configure a test pattern.
>   * @chan_status: Get the channel status.
> @@ -115,6 +116,8 @@ struct iio_backend_ops {
>  			       const struct iio_backend_data_fmt *data);
>  	int (*data_source_set)(struct iio_backend *back, unsigned int chan,
>  			       enum iio_backend_data_source data);
> +	int (*data_source_get)(struct iio_backend *back, unsigned int chan,
> +			       enum iio_backend_data_source *data);
>  	int (*set_sample_rate)(struct iio_backend *back, unsigned int chan,
>  			       u64 sample_rate_hz);
>  	int (*test_pattern_set)(struct iio_backend *back,
> @@ -176,6 +179,8 @@ int iio_backend_data_format_set(struct iio_backend *back, unsigned int chan,
>  				const struct iio_backend_data_fmt *data);
>  int iio_backend_data_source_set(struct iio_backend *back, unsigned int chan,
>  				enum iio_backend_data_source data);
> +int iio_backend_data_source_get(struct iio_backend *back, unsigned int chan,
> +				enum iio_backend_data_source *data);
>  int iio_backend_set_sampling_freq(struct iio_backend *back, unsigned int chan,
>  				  u64 sample_rate_hz);
>  int iio_backend_test_pattern_set(struct iio_backend *back,
>