On Mon, Sep 23, 2024 at 12:15 PM Antoniu Miclaus
<antoniu.miclaus@xxxxxxxxxx> wrote:
>
> Add backend support for obtaining the interface type used.
>
> Signed-off-by: Antoniu Miclaus <antoniu.miclaus@xxxxxxxxxx>
> ---
> drivers/iio/industrialio-backend.c | 24 ++++++++++++++++++++++++
> include/linux/iio/backend.h | 10 ++++++++++
> 2 files changed, 34 insertions(+)
>
> diff --git a/drivers/iio/industrialio-backend.c b/drivers/iio/industrialio-backend.c
> index efe05be284b6..53ab6bc86a50 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.
> + * @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_CMOS)
> + 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..ba8ad30ac9ba 100644
> --- a/include/linux/iio/backend.h
> +++ b/include/linux/iio/backend.h
> @@ -63,6 +63,11 @@ enum iio_backend_sample_trigger {
> IIO_BACKEND_SAMPLE_TRIGGER_MAX
> };
>
> +enum iio_backend_interface_type {
> + IIO_BACKEND_INTERFACE_LVDS,
> + IIO_BACKEND_INTERFACE_CMOS
> +};
> +
> /**
> * struct iio_backend_ops - operations structure for an iio_backend
> * @enable: Enable backend.
> @@ -81,6 +86,7 @@ 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 +119,8 @@ 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 +150,8 @@ 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);
> --
> 2.46.0
>
This seems very specific to the AD485x chips and the AXI ADC backend.
Since it is describing how the chip is wired to the AXI DAC IP block,
I would be tempted to use the devicetree for this info instead of
adding a new backend function.
