Re: [PATCH] ARM: dts: db600c: add support to pcie refclk

[Srinivas Kandagatla]

Thanks Bjorn for the review comments,

On 21/03/18 11:35, Bjorn Andersson wrote:
> On Tue 20 Mar 17:28 HKT 2018, Srinivas Kandagatla wrote:
>
> > From: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
> >
> > This patch adds support to external pcie refclk.
> >
> > Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
> > ---
> >   arch/arm/boot/dts/qcom-apq8064-db600c.dts | 27 +++++++++++++++++++++++++++
> >   1 file changed, 27 insertions(+)
> >
> > diff --git a/arch/arm/boot/dts/qcom-apq8064-db600c.dts b/arch/arm/boot/dts/qcom-apq8064-db600c.dts
> > index 50151ef6e912..7587088c122f 100644
> > --- a/arch/arm/boot/dts/qcom-apq8064-db600c.dts
> > +++ b/arch/arm/boot/dts/qcom-apq8064-db600c.dts
> > @@ -45,6 +45,18 @@
> >   
> >   	};
> >   
> > +	clocks {
> > +		compatible = "simple-bus";
> > +		pcie_refclk: pcie-refclk {
>
> As the si53154 is used to acquire 3 different clocks (2 pcie and 1 sata)
> it would be nice to accurately represent this in the DT. That said,
> exposing this as a clock allow us to change the representation here
> later. (Both pcie_core_clk and pcie_eth_clk use the same gpio pin as
> enable pin, so I don't know how to represent this...)
This is a refclk, which should be always same for both PCIe Controllers 
and connected PCIe endpoints.

For sata we should have one more refclk entry of its own.

> So for now, please name this "pcie_core_clk", per the schematics.

This is pcie refclk, if you follow the line in the schematics should see 
that it terminates to pcie refclk.

> > +			pinctrl-0 = <&pcie_pins>;
> > +			pinctrl-names = "default";
> > +			compatible = "gpio-gate-clock";
> > +	                clocks = <&rpmcc 27>;
> > +			#clock-cells = <0>;
> > +			enable-gpios = <&pm8921_gpio 22 GPIO_ACTIVE_HIGH>;
> > +		};
> > +	};
> > +
> >   	hdmi-out {
> >   		compatible = "hdmi-connector";
> >   		type = "a";
> > @@ -140,6 +152,16 @@
> >   
> >   		qcom,ssbi@500000 {
> >   			pmic@0 {
> > +				gpio@150 {
> > +					pcie_pins: pcie_pins {
>
> Please label this "pcie_clk_en_pin" and don't use '_' in the name of the
> node.
I agree, Will fix it.
> > +						pios {
>
> You can omit this level and just put the properties in directly in the
> pcie-clk-en node.
Okay.

thanks,
srini
> > +							pins = "gpio22";
> > +							function = "normal";
> > +							power-source = <PM8921_GPIO_VPH>;
> > +						};
> > +					};
> > +				};
> > +
>
> Regards,
> Bjorn