Re: [PATCH v2 2/4] leds: simatic-ipc-leds: add new driver for Siemens Industial PCs

Henning Schild
2021-03-23T17:46:23Z

Am Thu, 18 Mar 2021 13:40:58 +0100
schrieb Alexander Dahl <ada@thorsis.com>:

> Hei hei,
>
> > Enrico Weigelt, metux IT consult <lkml@metux.net> hat am 18.03.2021
> > 11:27 geschrieben:
> >
> >
> > On 15.03.21 11:48, Andy Shevchenko wrote:
> >
> > Hi,
> >
> > > I have a question, why we can't provide a GPIO driver which is
> > > already in the kernel and, with use of the patch series I sent,
> > > to convert this all magic to GPIO LEDs as it's done for all
> > > normal cases?
> >
> > Do we alread have a generic led driver that for cases that just
> > set/clear bits in some mem/io location ? If not, that would be
> > really great to have.
>
> Yes, there is. Look out for compatible "register-bit-led" in device
> tree. That's from driver in drivers/leds/leds-syscon.c and you can
> use it inside a syscon node in dts.
>
> It assumes one bit per LED.

Sorry guys, i am lost here. Is there a driver i can base mine on, if so
which one? Maybe you can point me to a good example that is
conceptually similar.

As i already wrote in the reviews of v1, the ACPI tables will not
change on the machines in question. So there is a need for a driver.
Either one like i did propose or maybe something that patches ACPI or
loads device-tree snippets, again please point me to good examples.

We are talking about x86-only here.

Henning

> Greets
> Alex