Re: [PATCH v10 2/8] iio: backend: add support for data size set

["Nuno Sá" <noname.nuno@gmail.com>]

On Fri, 2025-01-17 at 15:06 +0200, Antoniu Miclaus wrote:
> Add backend support for setting the data size used.
> This setting can be adjusted within the IP cores interfacing devices.
> 
> Reviewed-by: David Lechner <dlechner@baylibre.com>
> Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
> ---

Reviewed-by: Nuno Sa <nuno.sa@analog.com>

> no changes in v10.
>  drivers/iio/industrialio-backend.c | 21 +++++++++++++++++++++
>  include/linux/iio/backend.h        |  3 +++
>  2 files changed, 24 insertions(+)
> 
> diff --git a/drivers/iio/industrialio-backend.c b/drivers/iio/industrialio-
> backend.c
> index 8bf3d570da1b..2088afa7a55c 100644
> --- a/drivers/iio/industrialio-backend.c
> +++ b/drivers/iio/industrialio-backend.c
> @@ -660,6 +660,27 @@ int iio_backend_interface_type_get(struct iio_backend
> *back,
>  }
>  EXPORT_SYMBOL_NS_GPL(iio_backend_interface_type_get, "IIO_BACKEND");
>  
> +/**
> + * iio_backend_data_size_set - set the data width/size in the data bus.
> + * @back: Backend device
> + * @size: Size in bits
> + *
> + * Some frontend devices can dynamically control the word/data size on the
> + * interface/data bus. Hence, the backend device needs to be aware of it so
> + * data can be correctly transferred.
> + *
> + * Return:
> + * 0 on success, negative error number on failure.
> + */
> +int iio_backend_data_size_set(struct iio_backend *back, unsigned int size)
> +{
> +	if (!size)
> +		return -EINVAL;
> +
> +	return iio_backend_op_call(back, data_size_set, size);
> +}
> +EXPORT_SYMBOL_NS_GPL(iio_backend_data_size_set, "IIO_BACKEND");
> +
>  /**
>   * iio_backend_extend_chan_spec - Extend an IIO channel
>   * @back: Backend device
> diff --git a/include/linux/iio/backend.h b/include/linux/iio/backend.h
> index a0ea6c29d7ba..9ae861a21472 100644
> --- a/include/linux/iio/backend.h
> +++ b/include/linux/iio/backend.h
> @@ -95,6 +95,7 @@ enum iio_backend_interface_type {
>   * @ext_info_set: Extended info setter.
>   * @ext_info_get: Extended info getter.
>   * @interface_type_get: Interface type.
> + * @data_size_set: Data size.
>   * @read_raw: Read a channel attribute from a backend device
>   * @debugfs_print_chan_status: Print channel status into a buffer.
>   * @debugfs_reg_access: Read or write register value of backend.
> @@ -137,6 +138,7 @@ struct iio_backend_ops {
>  			    const struct iio_chan_spec *chan, char *buf);
>  	int (*interface_type_get)(struct iio_backend *back,
>  				  enum iio_backend_interface_type *type);
> +	int (*data_size_set)(struct iio_backend *back, unsigned int size);
>  	int (*read_raw)(struct iio_backend *back,
>  			struct iio_chan_spec const *chan, int *val, int
> *val2,
>  			long mask);
> @@ -197,6 +199,7 @@ 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_data_size_set(struct iio_backend *back, unsigned int size);
>  int iio_backend_read_raw(struct iio_backend *back,
>  			 struct iio_chan_spec const *chan, int *val, int
> *val2,
>  			 long mask);