Re: [PATCH 9/9] arm64: dts: renesas: rzg3s-smarc-som: Enable I3C

[Claudiu Beznea]

Hi, Wolfram,

On 5/22/26 15:29, Wolfram Sang wrote:
> Hi Claudiu,
>
> > +	i3c_pins: i3c {
> > +		pins = "I3C_SDA", "I3C_SCL";
> > +#if SW_CONFIG4 == SW_ON
> > +		power-source = <1200>;
> > +#else
> > +		power-source = <1800>;
> > +#endif
> > +		input-enable;
> > +		renesas,i3c-standby = <0>;
> > +	};
> > +
> > +	i3c_standby_pins: i3c-standby {
> > +		pins = "I3C_SDA", "I3C_SCL";
> > +#if SW_CONFIG4 == SW_ON
> > +		power-source = <1200>;
> > +#else
> > +		power-source = <1800>;
> > +#endif
> > +		renesas,i3c-standby = <1>;
> > +	};
>
> That doesn't look like HW description to me because the pins are the
> same for regular and standby mode.

Yes, same pins, different states. Isn't that the role of different pinctrl 
entries in DT for the same node? E.g., for SHDI we use the same approach, same 
pins but different states. Bellow is an example from RZ/G3S but same approach is 
used for other Renesas SoCs as well:

https://elixir.bootlin.com/linux/v7.1-rc4/source/arch/arm64/boot/dts/renesas/rzg3s-smarc-som.dtsi#L305

https://elixir.bootlin.com/linux/v7.1-rc4/source/arch/arm64/boot/dts/renesas/rzg3s-smarc-som.dtsi#L321

> Their state is changed when powering
> down, but that should not need DT encoding, I'd think. The driver should
> know what to do, or?

Through different pinctrl states different pinctrl settings are applied in the 
pin controller HW by calling well known pinctrl APIs from the consumer drivers 
(e.g. pinctrl_pm_select_sleep_state() in case of the I3C driver as proposed in [1]).

Is there another way the I3C driver (or any pinctrl driver consumer) could apply 
pinctrl settings?

[1] https://lore.kernel.org/all/20260522101815.1722909-18-claudiu.beznea@xxxxxxxxxx

--
Thank you,
Claudiu