Re: [PATCH 3/4] arm64: dts: rockchip: Add base DT for rk3528 SoC

Dragan Simic
2024-08-05T19:13:58Z

Hello Yao,

On 2024-08-05 18:22, Yao Zi wrote:
> On Mon, Aug 05, 2024 at 01:47:45PM +0200, Heiko Stübner wrote:
>> Am Montag, 5. August 2024, 13:37:11 CEST schrieb Dragan Simic:
>> > On 2024-08-05 12:59, Yao Zi wrote:
>> > > On Sun, Aug 04, 2024 at 04:05:24PM +0200, Krzysztof Kozlowski wrote:
>> > >> On 04/08/2024 15:20, Yao Zi wrote:
>> > >> >>
>> > >> >>> + compatible = "fixed-clock";
>> > >> >>> + #clock-cells = <0>;
>> > >> >>> + clock-frequency = <24000000>;
>> > >> >>> + clock-output-names = "xin24m";
>> > >> >>> + };
>> > >> >>> +
>> > >> >>> + gic: interrupt-controller@fed01000 {
>> > >> >>
>> > >> >> Why this all is outside of SoC?
>> > >> >
>> > >> > Just as Heiko says, device tree for all other Rockchip SoCs don't have
>> > >> > a "soc" node. I didn't know why before but just follow the style.
>> > >> >
>> > >> > If you prefer add a soc node, I am willing to.
>> > >>
>> > >> Surprising as usually we expect MMIO nodes being part of SoC to be
>> > >> under
>> > >> soc@, but if that's Rockchip preference then fine.
>> > >>
>> > >
>> > > Okay, then I would leave it as is.
>> > >
>> > > For the fixed-clock node, I think "xin24m: clock-24m { }" is okay and
>> > > follows the new rule?
>> >
>> > I find "xin24m: clock-xin24m { }" better, because keeping the "xin24m"
>> > part in /sys listing(s), for example, can only be helpful.
>>
>> I would second that :-) . Like on a number of boards we have for
>> example
>> 125MHz gmac clock generators ... with 2 gmacs, there are 2 of them.
>>
>> I'm not sure the preferred name accounts for that?
>>
>> Similarly we also keep the naming in the regulator node,
>> it's regulator-vcc3v3-somename {} instead of just regulator-3v3 {}.
>
> "clock-xin24m" wouldn't be more descriptive than "clock-24m" and there
> are usually only a few fixed clocks in dt, thus finding corresponding
> definition isn't a problem I think.

Well, using "clock-xin24m" comes with another benefit, which is using
the same "xin24m" as in the actual clock name. That way, the same clock
name gets used in various /sys listings and in the debug clock summary
in /sys. Having that kind of consistency can only be beneficial.

> For the gmac case, Krzysztof, do you think something like
> "clock-125m-gmac1" is acceptable, just like what has been done for
> regulators?