Re: [PATCH v5 03/21] dt-bindings: pinctrl: Add starfive,jhb100-sys0-pinctrl

[Linus Walleij]

On Fri, Aug 14, 2026 at 1:22 PM Changhuang Liang
<changhuang.liang@xxxxxxxxxxxxxxxx> wrote:

> > You still did not explain the cells - neither in reply nor in commit - thus start
> > with that. Why do you need it? Multiple controllers have groupped pins or
> > GPIOs in registers, so explanation "every 32 GPIOs correspond to one register"
> > tells me nothing. Why would that matter how many GPIOs is in one register?
>
> Since every 32 GPIOs correspond to one register, Linus suggested at the time that I could try using:
> gpios = <&gpio [instance] offset flags>;
> gpio-ranges = <&pinctrl [gpio_instance] gpio_offset pin_offset count>;
>
> The advantage of using this is that in a GPIO controller with more than 32 GPIOs, every 32 GPIOs
> can be treated as one GPIO bank. This way, in the driver, converting pin_offset to gpio_offset does
> not require a large number of /32 and %32 operations.
>
> the following is Linus's original suggestion at the time
> https://lore.kernel.org/all/CAD++jL=tvDBWJHRGGJw4nnox_kcJKn5hwvwz9zxadMRedyvRhw@xxxxxxxxxxxxxx/

Just copy this explanation into the commit so it is clear why you
need three cells for this.

Yours,
Linus Walleij