Re: [PATCH v4 4/4] arm64: dts: qcom: Add CMN PLL node for IPQ9574 SoC

[Dmitry Baryshkov <dmitry.baryshkov@linaro.org>]

On Fri, 18 Oct 2024 at 09:55, Jie Luo <quic_luoj@quicinc.com> wrote:
>
>
>
> On 10/18/2024 6:32 AM, Dmitry Baryshkov wrote:
> > On Tue, Oct 15, 2024 at 10:16:54PM +0800, Luo Jie wrote:
> >> The CMN PLL clock controller allows selection of an input
> >> clock rate from a defined set of input clock rates. It in-turn
> >> supplies fixed rate output clocks to the hardware blocks that
> >> provide ethernet functions such as PPE (Packet Process Engine)
> >> and connected switch or PHY, and to GCC.
> >>
> >> Signed-off-by: Luo Jie <quic_luoj@quicinc.com>
> >> ---
> >>   arch/arm64/boot/dts/qcom/ipq9574-rdp-common.dtsi |  6 +++++-
> >>   arch/arm64/boot/dts/qcom/ipq9574.dtsi            | 20 +++++++++++++++++++-
> >>   2 files changed, 24 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/arch/arm64/boot/dts/qcom/ipq9574-rdp-common.dtsi b/arch/arm64/boot/dts/qcom/ipq9574-rdp-common.dtsi
> >> index 91e104b0f865..77e1e42083f3 100644
> >> --- a/arch/arm64/boot/dts/qcom/ipq9574-rdp-common.dtsi
> >> +++ b/arch/arm64/boot/dts/qcom/ipq9574-rdp-common.dtsi
> >> @@ -3,7 +3,7 @@
> >>    * IPQ9574 RDP board common device tree source
> >>    *
> >>    * Copyright (c) 2020-2021 The Linux Foundation. All rights reserved.
> >> - * Copyright (c) 2023, Qualcomm Innovation Center, Inc. All rights reserved.
> >> + * Copyright (c) 2023-2024, Qualcomm Innovation Center, Inc. All rights reserved.
> >>    */
> >>
> >>   /dts-v1/;
> >> @@ -164,6 +164,10 @@ &usb3 {
> >>      status = "okay";
> >>   };
> >>
> >> +&cmn_pll_ref_clk {
> >> +    clock-frequency = <48000000>;
> >> +};
> >> +
> >>   &xo_board_clk {
> >>      clock-frequency = <24000000>;
> >>   };
> >> diff --git a/arch/arm64/boot/dts/qcom/ipq9574.dtsi b/arch/arm64/boot/dts/qcom/ipq9574.dtsi
> >> index 14c7b3a78442..93f66bb83c5a 100644
> >> --- a/arch/arm64/boot/dts/qcom/ipq9574.dtsi
> >> +++ b/arch/arm64/boot/dts/qcom/ipq9574.dtsi
> >> @@ -3,10 +3,11 @@
> >>    * IPQ9574 SoC device tree source
> >>    *
> >>    * Copyright (c) 2020-2021 The Linux Foundation. All rights reserved.
> >> - * Copyright (c) 2023, Qualcomm Innovation Center, Inc. All rights reserved.
> >> + * Copyright (c) 2023-2024, Qualcomm Innovation Center, Inc. All rights reserved.
> >>    */
> >>
> >>   #include <dt-bindings/clock/qcom,apss-ipq.h>
> >> +#include <dt-bindings/clock/qcom,ipq-cmn-pll.h>
> >>   #include <dt-bindings/clock/qcom,ipq9574-gcc.h>
> >>   #include <dt-bindings/interconnect/qcom,ipq9574.h>
> >>   #include <dt-bindings/interrupt-controller/arm-gic.h>
> >> @@ -19,6 +20,11 @@ / {
> >>      #size-cells = <2>;
> >>
> >>      clocks {
> >> +            cmn_pll_ref_clk: cmn-pll-ref-clk {
> >> +                    compatible = "fixed-clock";
> >> +                    #clock-cells = <0>;
> >> +            };
> >
> > Which block provides this clock? If it is provided by the external XO
> > then it should not be a part of the SoC dtsi.
>
> The on-chip WiFi block supplies this reference clock. So keeping it in
> the SoC DTSI is perhaps appropriate.

Then maybe it should be provided by the WiFi device node? At least you
should document your design decisions in the commit message.

Also, I don't think this node passes DT schema validation. Did you check it?

>
> >
> >> +
> >>              sleep_clk: sleep-clk {
> >>                      compatible = "fixed-clock";
> >>                      #clock-cells = <0>;
> >> @@ -243,6 +249,18 @@ mdio: mdio@90000 {
> >>                      status = "disabled";
> >>              };
> >>
> >> +            cmn_pll: clock-controller@9b000 {
> >> +                    compatible = "qcom,ipq9574-cmn-pll";
> >> +                    reg = <0x0009b000 0x800>;
> >> +                    clocks = <&cmn_pll_ref_clk>,
> >> +                             <&gcc GCC_CMN_12GPLL_AHB_CLK>,
> >> +                             <&gcc GCC_CMN_12GPLL_SYS_CLK>;
> >> +                    clock-names = "ref", "ahb", "sys";
> >> +                    #clock-cells = <1>;
> >> +                    assigned-clocks = <&cmn_pll CMN_PLL_CLK>;
> >> +                    assigned-clock-rates-u64 = /bits/ 64 <12000000000>;
> >> +            };
> >> +
> >>              qfprom: efuse@a4000 {
> >>                      compatible = "qcom,ipq9574-qfprom", "qcom,qfprom";
> >>                      reg = <0x000a4000 0x5a1>;
> >>
> >> --
> >> 2.34.1
> >>
> >
>


-- 
With best wishes
Dmitry