Re: [PATCH 2/3] arm64: dts: qcom: sc7280: Add PCIe and PHY related nodes

[Prasad Malisetty <pmaliset@codeaurora.org>]

On 2021-05-08 01:36, Stephen Boyd wrote:
> Quoting Prasad Malisetty (2021-05-07 03:17:27)
>> Add PCIe controller and PHY nodes for sc7280 SOC.
>> 
>> Signed-off-by: Prasad Malisetty <pmaliset@codeaurora.org>
>> ---
>>  arch/arm64/boot/dts/qcom/sc7280.dtsi | 138 
>> +++++++++++++++++++++++++++++++++++
>>  1 file changed, 138 insertions(+)
>> 
>> diff --git a/arch/arm64/boot/dts/qcom/sc7280.dtsi 
>> b/arch/arm64/boot/dts/qcom/sc7280.dtsi
>> index 2cc4785..a9f25fc1 100644
>> --- a/arch/arm64/boot/dts/qcom/sc7280.dtsi
>> +++ b/arch/arm64/boot/dts/qcom/sc7280.dtsi
>> @@ -12,6 +12,7 @@
>>  #include <dt-bindings/power/qcom-aoss-qmp.h>
>>  #include <dt-bindings/power/qcom-rpmpd.h>
>>  #include <dt-bindings/soc/qcom,rpmh-rsc.h>
>> +#include <dt-bindings/gpio/gpio.h>
>> 
>>  / {
>>         interrupt-parent = <&intc>;
>> @@ -316,6 +317,118 @@
>>                         };
>>                 };
>> 
> [...]
>> +
>> +               pcie1_phy: phy@1c0e000 {
>> +                       compatible = 
>> "qcom,sm8250-qmp-gen3x2-pcie-phy";
>> +                       reg = <0 0x01c0e000 0 0x1c0>;
>> +                       #address-cells = <2>;
>> +                       #size-cells = <2>;
>> +                       ranges;
>> +                       clocks = <&gcc GCC_PCIE_1_AUX_CLK>,
>> +                                <&gcc GCC_PCIE_1_CFG_AHB_CLK>,
>> +                                <&gcc GCC_PCIE_CLKREF_EN>,
>> +                                <&gcc GCC_PCIE1_PHY_RCHNG_CLK>;
>> +                       clock-names = "aux", "cfg_ahb", "ref", 
>> "refgen";
>> +
>> +                       resets = <&gcc GCC_PCIE_1_PHY_BCR>;
>> +                       reset-names = "phy";
>> +
>> +                       assigned-clocks = <&gcc 
>> GCC_PCIE1_PHY_RCHNG_CLK>;
>> +                       assigned-clock-rates = <100000000>;
>> +
>> +                       status = "disabled";
> 
> I think the style is to put status disabled close to the compatible?

Generally I have added status disabled in end as like many nodes. just 
curious to ask is there any specific reason to put close to compatible.
> 
>> +
>> +                       pcie1_lane: lanes@1c0e200 {
>> +                               reg = <0 0x1c0e200 0 0x170>, /* tx0 */
> 
> Please pad reg addresses to 8 characters.

Done
> 
>> +                                     <0 0x1c0e400 0 0x200>, /* rx0 */
>> +                                     <0 0x1c0ea00 0 0x1f0>, /* pcs */
>> +                                     <0 0x1c0e600 0 0x170>, /* tx1 */
>> +                                     <0 0x1c0e800 0 0x200>, /* rx1 */
>> +                                     <0 0x1c0ee00 0 0xf4>; /* 
>> "pcs_com" same as pcs_misc? */
> 
> Is this a TODO? I'd prefer all the comments on the reg properties to be
> removed.
> 
Done
>> +                               clocks = <&rpmhcc RPMH_CXO_CLK>;
>> +                               clock-names = "pipe0";
>> +
>> +                               #phy-cells = <0>;
>> +                               #clock-cells = <1>;
>> +                               clock-output-names = 
>> "pcie_1_pipe_clk";
>> +                       };
>> +               };
>> +
>>                 stm@6002000 {
>>                         compatible = "arm,coresight-stm", 
>> "arm,primecell";
>>                         reg = <0 0x06002000 0 0x1000>,
>> @@ -871,6 +984,31 @@
>>                                 pins = "gpio46", "gpio47";
>>                                 function = "qup13";
>>                         };
>> +
>> +                       pcie1_default_state: pcie1-default {
>> +                               clkreq {
>> +                                       pins = "gpio79";
>> +                                       function = "pcie1_clkreqn";
>> +                                       bias-pull-up;
> 
> Move this bias-pull-up to the idp file?

Done
> 
>> +                               };
>> +
>> +                               reset-n {
>> +                                       pins = "gpio2";
>> +                                       function = "gpio";
>> +
>> +                                       drive-strength = <16>;
>> +                                       output-low;
>> +                                       bias-disable;
>> +                               };
>> +
>> +                               wake-n {
>> +                                       pins = "gpio3";
>> +                                       function = "gpio";
>> +
>> +                                       drive-strength = <2>;
>> +                                       bias-pull-up;
>> +                               };
> 
> These last two nodes with the pull-up and drive-strength settings 
> should
> be in the board files, like the idp one, instead of here in the SoC
> file. That way board designers can take the SoC and connect the pcie to
> an external device using these pins and set the configuration they want
> on these pins, or choose not to connect them to the SoC at all and use
> those pins for something else.
> 
> In addition, it looks like the reset could be a reset-gpios property
> instead of an output-low config.
> 
we are using reset property as perst gpio in pcie node.
>> +                       };
>>                 };
>>