Re: [PATCH v9 3/4] clk: meson: add DT documentation for emmc clock controller

[Martin Blumenstingl]

Hi Liang,

On Fri, Jan 14, 2022 at 4:06 AM Liang Yang <liang.yang@xxxxxxxxxxx> wrote:
[...]
> >> +properties:
> >> +  compatible:
> >> +    enum:
> >> +      - "amlogic,axg-mmc-clkc", "syscon"
> >
> > Why is it a syscon?
>
> The register documented by reg is shared with SD/eMMC controller port C,
> and it need to be ops on NFC driver.
Can you please share an example how the .dts would look like in the
end for two example cases:
1) using the sd_emmc_c MMC interface
2) not using the MMC interface of sd_emmc_c but only using it's clocks
for the NFC

Initially I wanted to suggest the usage of a sub-node with compatible
= "mmc-slot" (see
Documentation/devicetree/bindings/mmc/amlogic,meson-mx-sdio.txt for an
example) to decide whether the MMC controller is registered or whether
just the clock controller is registered.
However, the mmc-slot compatible string is not documented in
Documentation/devicetree/bindings/mmc/mmc-controller.yaml currently.
Maybe the MMC maintainers have any suggestions if other IPs have
similar requirements (for IPs with shared parts).


Best regards,
Martin