gpio-mt7621 offset fix for 5.10 kernel series

[Sergio Paracuellos]

On Wed, Oct 19, 2022 at 6:02 AM Sergio Paracuellos
<sergio.paracuellos at gmail.com> wrote:
>
> On Wed, Oct 19, 2022 at 1:10 AM Rosen Penev <rosenp at gmail.com> wrote:
> >
> > On Tue, Oct 18, 2022 at 3:50 PM Peter Naulls <peter at chocky.org> wrote:
> > >
> > > On 10/18/22 17:10, Lukas Zeller wrote:
> > > .
> > > >
> > > > Just not any more - the mt7621 had this too. I currently patch it back into
> > > > 22.03's gpio-mt7621.c for my builds and set base in the DTS, see [3]
> > > >
> > > > I can follow the rationale to get rid of legacy GPIOs, but in the context
> > > > of experimenting platforms, where GPIOs are a thing to work with in
> > > > user space, there's just no real replacement yet (see details in [1],[2]).
> > >
> > > Yes, I see.
> > >
> > > I have a mix of C and scripted GPIO access in my setup, and certainly I can
> > > move to libgpiod for that - or just just access them as files with
> > > named GPIOs as setup per the DTS.
> > Let's CC Sergio, who upstreamed this driver.
>
> For kernel developers, setting base in GPIOs is a no go. You have to
> let the kernel to assign its numbers so you can handle different GPIO
> layouts with multiple chips.
> This is the reason we have 'gpio-line-names' property so you can set
> up names for your pins and use it together with actual user space
> tools libgpiod and gpiod. Any other gpio user space library is
> considered deprecated in these days.

See Linus comments about base in review:
https://marc.info/?l=linux-gpio&m=152845919029921&w=1

Thanks,
    Sergio Paracuellos
>
> Best regards,
>     Sergio Paracuellos
>
> > >
> > > I do see the GPIO shell examples in the OpenWrt wiki, but the code needs
> > > more work to deal with multiple banks, and it just makes figuring out
> > > the GPIO number to use more clunky without any good cause.
> > >
> > > Now, the numbered GPIOs really are just for debug in my system, the
> > > actual code will use the named ones, but still.
> > >
> > > Is the long-term intent for shell scripting to instead use the libgpiod
> > > tools?
> > >
> > > https://openwrt.org/docs/techref/hardware/port.gpio
> > >
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