* Trent Piepho <tpiepho@xxxxxxxxx> [200930 09:34]:
> On Wed, Sep 30, 2020 at 2:15 AM Tony Lindgren <tony@xxxxxxxxxxx> wrote:
> >
> > * Trent Piepho <tpiepho@xxxxxxxxx> [200930 08:35]:
> > > The closest thing would be the generic pin config type bindings, which
> > > go in the pinctrl driver's nodes, and look like this:
> > > &am335x_pinmux {
> > > pinctrl_yoyo_reset: yoyogrp {
> > > pins = "foo";
> > > function = "gpio";
> > > bias-pull-up;
> > > };
> > > };
> >
> > There's a bit of a dtb size and boot time issue for adding properties
> > for each pin where that needs to be done for several hundred pins :)
>
> pins is list, multiple pins can be specified at once. Otherwise the
> property name would be "pin" and not "pins" There's also a groups
> property to refer to multiple pins at once, e.g.
>
> arch/mips/boot/dts/ingenic/ci20.dts- pins_mmc1: mmc1 {
> arch/mips/boot/dts/ingenic/ci20.dts- function = "mmc1";
> arch/mips/boot/dts/ingenic/ci20.dts: groups =
> "mmc1-1bit-d", "mmc1-4bit-d";
> arch/mips/boot/dts/ingenic/ci20.dts- bias-disable;
> arch/mips/boot/dts/ingenic/ci20.dts- };
>
> arch/mips/boot/dts/pic32/pic32mzda_sk.dts- user_leds_s0: user_leds_s0 {
> arch/mips/boot/dts/pic32/pic32mzda_sk.dts: pins = "H0", "H1", "H2";
> arch/mips/boot/dts/pic32/pic32mzda_sk.dts- output-low;
> arch/mips/boot/dts/pic32/pic32mzda_sk.dts- microchip,digital;
> arch/mips/boot/dts/pic32/pic32mzda_sk.dts- };
Right.
> > > Is "some additional property for specifying generic conf flags"
> > > different from the existing pinctrl-single,bias-pullup, etc.
> > > properties? Because splitting the data cell into two parts doesn't
> > > make any difference to those.
> >
> > So with an interrupt style binding with generic pinconf flags we can
> > leave out the parsing of multiple properties for each pin. Sure the
> > pin is only referenced by the controller like you pointed out but the
> > pinconf flags could be generic.
>
> Where do these flags go? In pinctrl-single,pins? Like:
>
> pinctrl-single,pins = <AM335X_PIN_MDC MUX_MODE7 PIN_INPUT_PULLUP>;
>
> But PIN_INPUT_PULLUP is a generic flag? Which is translated into the
> proper value by??
Yes that's what I was thinking, something like this with generic flags:
pinctrl-single,pins = <AM335X_PIN_MDC (PIN_INPUT | PIN_PULLUP) MUX_MODE7>;
> Or are you talking about replacing the existing pinctrl-0,
> pinctrl-names properties with a totally different system that looks
> more like gpio and interrupt handles?
That would be even better :) Might be just too much to deal with..
In any case the parser code could already be generic if we had generic
flags based on #pinctrl-cells.
Regards,
Tony
