Re: [PATCH] arm64: dts: rockchip: Explicitly set pclk_pmu_src on rk3399

Brian Norris
2016-08-29T18:18:42Z

On Mon, Aug 29, 2016 at 11:11:24AM -0700, Doug Anderson wrote:
> On rk3399 we explicitly set ppll in the device tree to 676000000. The
> ppll has one major child, pclk_pmu_src, that is the parent of lots of
> other clocks. Right now nobody is setting that clock rate and we're
> relying on the divider to just happen to be something sane. Let's be
> explicit in our request so we're not relying on the firmware.
>
> With the current firmware I tested with this patch has no expected
> impact but it's probably good to do anyway.
>
> Signed-off-by: Douglas Anderson <dianders-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
> ---
> arch/arm64/boot/dts/rockchip/rk3399.dtsi | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm64/boot/dts/rockchip/rk3399.dtsi b/arch/arm64/boot/dts/rockchip/rk3399.dtsi
> index 62d450935a57..ffb3faa8c176 100644
> --- a/arch/arm64/boot/dts/rockchip/rk3399.dtsi
> +++ b/arch/arm64/boot/dts/rockchip/rk3399.dtsi
> @@ -908,8 +908,8 @@
> reg = <0x0 0xff750000 0x0 0x1000>;
> #clock-cells = <1>;
> #reset-cells = <1>;
> - assigned-clocks = <&pmucru PLL_PPLL>;
> - assigned-clock-rates = <676000000>;
> + assigned-clocks = <&pmucru PLL_PPLL>, <&pmucru PCLK_SRC_PMU>;
> + assigned-clock-rates = <676000000>, <112666667>;

I think this makes sense and is a good idea. One alternative would be to
have the various children actually set a rate that they expect, but
several of them don't have a separate driver at all, and that would be
of dubious value anyway I think.

Reviewed-by: Brian Norris <briannorris-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>

> };
>
> cru: clock-controller@ff760000 {
> --
> 2.8.0.rc3.226.g39d4020