Hi Miquel,
On Wed, Feb 23, 2022 at 4:49 PM Miquel Raynal <miquel.raynal@xxxxxxxxxxx> wrote:
> geert@xxxxxxxxxxxxxx wrote on Wed, 23 Feb 2022 13:21:47 +0100:
> > On Tue, Feb 22, 2022 at 11:35 AM Miquel Raynal
> > <miquel.raynal@xxxxxxxxxxx> wrote:
> > > Just like for the NAND controller that is also on this SoC, let's
> > > provide a SoC generic and a more specific couple of compatibles for the
> > > DMA controller.
> > >
> > > Signed-off-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
> >
> > > +++ b/Documentation/devicetree/bindings/dma/snps,dma-spear1340.yaml
> >
> > Perhaps you want to add the power-domains property?
> > The RZ/N1 clock driver is also a clock-domain provider.
>
> I haven't looked at the power domains yet, but I don't plan to invest
> time on it right now. Unless I don't understand your request, and you
> are telling me that someone else added the description and we should
> now point to the right domain from each new node?
The RZ/N1 System Controller is a clock-domain provider. This means
it can automatically manage the module clocks of devices that are
part of the clock domain, assuming device drivers are using Runtime PM.
The upstream RZ/N1 DTS doesn't have many devices enabled yet.
Most of them are (variants of) Synopsis IP cores, and their drivers
manage clocks explicitly, instead of relying on Runtime PM.
BTW, I have just noticed the system-controller node[1] even lacks
the #power-domain-cells property, while the example[2] does have it.
When that is added, device nodes can gain "power-domains = <&sysctrl>",
and module clocks can be managed from Runtime PM. Perhaps the NAND
driver would be a good target for conversion to Runtime PM, as its
driver is not shared with SoCs from other vendors yet?
Note this is not mandatory, and drivers can keep on using explicit
clock handling (until the IP core is reused on an SoC that not only
has a clock-domain, but also real power-domains).
[1] arch/arm/boot/dts/r9a06g032.dtsi
[2] Documentation/devicetree/bindings/clock/renesas,r9a06g032-sysctrl.yaml
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
