Re: [PATCH v2 1/7] iio: backend: add API for interface get

[David Lechner <dlechner@baylibre.com>]

On 10/4/24 9:07 AM, Antoniu Miclaus wrote:
> Add backend support for obtaining the interface type used.
> 
> Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
> ---
> changes in v2:
>  - add IIO_BACKEND_INTERFACE_COUNT in enum.
>  - add trailing commas where applies.
>  drivers/iio/industrialio-backend.c | 24 ++++++++++++++++++++++++
>  include/linux/iio/backend.h        | 11 +++++++++++
>  2 files changed, 35 insertions(+)
> 
> diff --git a/drivers/iio/industrialio-backend.c b/drivers/iio/industrialio-backend.c
> index efe05be284b6..a322b0be7b2c 100644
> --- a/drivers/iio/industrialio-backend.c
> +++ b/drivers/iio/industrialio-backend.c
> @@ -449,6 +449,30 @@ ssize_t iio_backend_ext_info_set(struct iio_dev *indio_dev, uintptr_t private,
>  }
>  EXPORT_SYMBOL_NS_GPL(iio_backend_ext_info_set, IIO_BACKEND);
>  
> +/**
> + * iio_backend_interface_type_get - get the interace type used.

spelling: s/interace/interface

> + * @back: Backend device
> + * @type: Interface type
> + *
> + * RETURNS:
> + * 0 on success, negative error number on failure.
> + */
> +int iio_backend_interface_type_get(struct iio_backend *back,
> +				   enum iio_backend_interface_type *type)
> +{
> +	int ret;
> +
> +	ret = iio_backend_op_call(back, interface_type_get, type);
> +	if (ret)
> +		return ret;
> +
> +	if (*type >= IIO_BACKEND_INTERFACE_COUNT)
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_NS_GPL(iio_backend_interface_type_get, IIO_BACKEND);
> +
>  /**
>   * iio_backend_extend_chan_spec - Extend an IIO channel
>   * @indio_dev: IIO device
> diff --git a/include/linux/iio/backend.h b/include/linux/iio/backend.h
> index 8099759d7242..34fc76c99d8a 100644
> --- a/include/linux/iio/backend.h
> +++ b/include/linux/iio/backend.h
> @@ -63,6 +63,12 @@ enum iio_backend_sample_trigger {
>  	IIO_BACKEND_SAMPLE_TRIGGER_MAX
>  };
>  
> +enum iio_backend_interface_type {
> +	IIO_BACKEND_INTERFACE_LVDS,
> +	IIO_BACKEND_INTERFACE_CMOS,

There are some chips that can do both serial and parallel, so I
think these qualifiers should be included in the enum as well.

	IIO_BACKEND_INTERFACE_SERIAL_LVDS,
	IIO_BACKEND_INTERFACE_SERIAL_CMOS,

> +	IIO_BACKEND_INTERFACE_COUNT,

No comma here, and add a comment that this should always be last
since it is a count and not an interface type descriptor.

> +};
> +
>  /**
>   * struct iio_backend_ops - operations structure for an iio_backend
>   * @enable: Enable backend.
> @@ -81,6 +87,7 @@ enum iio_backend_sample_trigger {
>   * @extend_chan_spec: Extend an IIO channel.
>   * @ext_info_set: Extended info setter.
>   * @ext_info_get: Extended info getter.
> + * @interface_type_get: Interface type.
>   **/
>  struct iio_backend_ops {
>  	int (*enable)(struct iio_backend *back);
> @@ -113,6 +120,8 @@ struct iio_backend_ops {
>  			    const char *buf, size_t len);
>  	int (*ext_info_get)(struct iio_backend *back, uintptr_t private,
>  			    const struct iio_chan_spec *chan, char *buf);
> +	int (*interface_type_get)(struct iio_backend *back,
> +				  enum iio_backend_interface_type *type);
>  };
>  
>  int iio_backend_chan_enable(struct iio_backend *back, unsigned int chan);
> @@ -142,6 +151,8 @@ ssize_t iio_backend_ext_info_set(struct iio_dev *indio_dev, uintptr_t private,
>  ssize_t iio_backend_ext_info_get(struct iio_dev *indio_dev, uintptr_t private,
>  				 const struct iio_chan_spec *chan, char *buf);
>  
> +int iio_backend_interface_type_get(struct iio_backend *back,
> +				   enum iio_backend_interface_type *type);
>  int iio_backend_extend_chan_spec(struct iio_dev *indio_dev,
>  				 struct iio_backend *back,
>  				 struct iio_chan_spec *chan);