Re: [PATCH v6 6/7] iio: ABI: Add custom data type

From: Andy Shevchenko

Date: Wed Feb 25 2026 - 06:45:47 EST


On Wed, Feb 25, 2026 at 11:18:06AM +0100, Francesco Lavra wrote:
> This type is used when the data received from or sent to a device cannot be
> identified with a standard type and must be processed by custom userspace.
> Any driver using the custom type must provide a driver-specific document
> that explains what the data represents and how it is to be interpreted by
> userspace.

This rises the same Q as for other firmware-hidden algos, et cetera: How
can we prevent the kernel from being just a simple proxy between HW and
the userspace? What would be the point of having the "driver" in the kernel
space?

...

> static const char * const iio_chan_type_name_spec[] = {

> [IIO_CHROMATICITY] = "chromaticity",
> [IIO_ATTENTION] = "attention",
> [IIO_ALTCURRENT] = "altcurrent",
> + [IIO_CUSTOM] = "custom"

No more channel types after this? Why?

> };

...

> enum iio_chan_type {

> IIO_CHROMATICITY,
> IIO_ATTENTION,
> IIO_ALTCURRENT,
> + IIO_CUSTOM

Ditto.

> };

--
With Best Regards,
Andy Shevchenko