Re: [PATCH V2 1/3] firmware: zynqmp: Add MMIO read and write support for PS_MODE pin

[Arnd Bergmann <arnd@xxxxxxxx>]

On Wed, Aug 11, 2021 at 3:08 PM Linus Walleij <linus.walleij@xxxxxxxxxx> wrote:
>
> On Thu, Aug 5, 2021 at 7:42 PM Piyush Mehta <piyush.mehta@xxxxxxxxxx> wrote:
>
> > Add Xilinx ZynqMP firmware MMIO APIs support to set and get PS_MODE
> > pins value and status. These APIs create an interface path between
> > mode pin controller driver and low-level API to access GPIO pins.
> >
> > Signed-off-by: Piyush Mehta <piyush.mehta@xxxxxxxxxx>
> > ---
> > Changes in v2:
> > - Added Xilinx ZynqMP firmware MMIO API support to set and get pin
> >   value and status.
>
> I doubt this is "GPIO".
> General Purpose? I think not. It seems to be about boot mode.

Agreed.

> If you need a userspace ABI, then add sysfs files to this firmware
> driver instead of bridging it to the GPIO subsystem.

I don't really want custom user interfaces in firmware drivers either.

What is the high-level description of the 'PS_MODE' here? Is
this perhaps something we already have a user interface for?

       Arnd