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

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On 08/30/2016 02:18 AM, Brian Norris wrote:
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@xxxxxxxxxxxx>
---
  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.

I agree with you. This clk default div is set in the uboot or coreboot.
And if is need to set in kernel ,I hope the freq is 50M(<48285714>).
This freq can meet the performance,and the power consumption is not too much.

Reviewed-by: Brian Norris <briannorris@xxxxxxxxxxxx>

  	};

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





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