On Mon, 23 Sep 2024 13:10:19 +0300
Antoniu Miclaus <antoniu.miclaus@xxxxxxxxxx> wrote:
> Add backend support for setting the data size used.
Say 'why' a device might do this. I assume in general
it's because you haven't wired all the pins, but is there a
reason it might be dynamic?
Jonathan
>
> Signed-off-by: Antoniu Miclaus <antoniu.miclaus@xxxxxxxxxx>
> ---
> 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 53ab6bc86a50..a6a6bedce7f1 100644
> --- a/drivers/iio/industrialio-backend.c
> +++ b/drivers/iio/industrialio-backend.c
> @@ -473,6 +473,27 @@ 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.
> + *
> + * RETURNS:
> + * 0 on success, negative error number on failure.
> + */
> +ssize_t iio_backend_data_size_set(struct iio_backend *back, ssize_t 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
> * @indio_dev: IIO device
> diff --git a/include/linux/iio/backend.h b/include/linux/iio/backend.h
> index ba8ad30ac9ba..85b33ed69cc0 100644
> --- a/include/linux/iio/backend.h
> +++ b/include/linux/iio/backend.h
> @@ -87,6 +87,7 @@ 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.
> **/
> struct iio_backend_ops {
> int (*enable)(struct iio_backend *back);
> @@ -121,6 +122,7 @@ 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, ssize_t size);
> };
>
> int iio_backend_chan_enable(struct iio_backend *back, unsigned int chan);
> @@ -152,6 +154,7 @@ ssize_t iio_backend_ext_info_get(struct iio_dev *indio_dev, uintptr_t private,
>
> int iio_backend_interface_type_get(struct iio_backend *back,
> enum iio_backend_interface_type *type);
> +ssize_t iio_backend_data_size_set(struct iio_backend *back, ssize_t size);
> int iio_backend_extend_chan_spec(struct iio_dev *indio_dev,
> struct iio_backend *back,
> struct iio_chan_spec *chan);
