On Thu, Jan 8, 2026 at 9:41 AM Geert Uytterhoeven <[email protected]> wrote:
> > > What is the rationale behind using brcm,bcm6345-gpio?
> > > Given brcm,bcm6345-gpio has 32-bit registers, while opencores,gpio
> > > has 8-bit registers, I doubt the latter is compatible with the former...
Yeah this needs to be fixed/reverted pronto :/
> > I switch the size from 32-bit to 8-bit using the reg = <* 0x1>, <* 0x1>
> > setting.
> > Also the reg addresses of "dat" and "dirout" are different for the real
> > brcm,bcm6345-gpio.
> >
> > brcm,bcm6345-gpio. Example:
> >
> > /* GPIOs 192 .. 223 */
> > gpio6: gpio@518 {
> > compatible = "brcm,bcm6345-gpio";
> > reg = <0x518 0x04>, <0x538 0x04>;
> > reg-names = "dirout", "dat";
> > gpio-controller;
> > #gpio-cells = <2>;
> > };
> >
> > vs opencores,gpio Example:
> >
> > gpio0: gpio@91000000 {
> > compatible = "opencores,gpio", "brcm,bcm6345-gpio";
> > reg = <0x91000000 0x1>, <0x91000001 0x1>;
> > reg-names = "dat", "dirout";
> > gpio-controller;
> > #gpio-cells = <2>;
> > };
>
> Exactly, the register space and register widths are different
...as proved here.
Stafford can you send a fixup or revert patch?
(Only need to revert if you can't make a fix quick enough, which I
think you can.)
> > The opencores,gpio setup does work.
> >
> > Now that I think about it, would it have been better to just add
> > opencores,gpio
> > to gpio-mmio.c compatible list?
>
> I think that would be better.
Yes this is better.
I should have seen this, I guess I was sloppy :(
> > If so I will can revise this patch and add patch to gpio-mmio.c.
>
> DT maintainers: Given gpio-mmio is that generic/simple, is there a
> specific reason there is no generic "gpio-mmio" compatible value that
> can be used as a fallback, avoiding the need to keep on adding new
> entries to gpio_mmio_of_match[]?
I think "gpio-mmio" combined with compulsory property of
bus-width = <nn> (as used by multiple bindings) would be
generic enough. So a schema that accepts "gpio-mmio" if and
only if bus-width = 8|16|32|64 would be acceptable.
Yours,
Linus Walleij
