Re: [PATCH v4 02/10] arm64: dts: qcom: qcs6490-rb3gen2: Add TC956x PCIe switch node

[Krishna Chaitanya Chundru]

On 2/25/2025 5:19 PM, Dmitry Baryshkov wrote:
> On Tue, Feb 25, 2025 at 03:03:59PM +0530, Krishna Chaitanya Chundru wrote:
> > Add a node for the TC956x PCIe switch, which has three downstream ports.
> > Two embedded Ethernet devices are present on one of the downstream ports.
> >
> > Power to the TC956x is supplied through two LDO regulators, controlled by
> > two GPIOs, which are added as fixed regulators. Configure the TC956x
> > through I2C.
> >
> > Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@xxxxxxxxxxxxxxxx>
> > Reviewed-by: Bjorn Andersson <andersson@xxxxxxxxxx>
> > Acked-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
> > ---
> >   arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts | 116 +++++++++++++++++++++++++++
> >   arch/arm64/boot/dts/qcom/sc7280.dtsi         |   2 +-
> >   2 files changed, 117 insertions(+), 1 deletion(-)
> >
> > diff --git a/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts b/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts
> > index 7a36c90ad4ec..13dbb24a3179 100644
> > --- a/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts
> > +++ b/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts
> > @@ -218,6 +218,31 @@ vph_pwr: vph-pwr-regulator {
> >   		regulator-min-microvolt = <3700000>;
> >   		regulator-max-microvolt = <3700000>;
> >   	};
> > +
> > +	vdd_ntn_0p9: regulator-vdd-ntn-0p9 {
> > +		compatible = "regulator-fixed";
> > +		regulator-name = "VDD_NTN_0P9";
> > +		gpio = <&pm8350c_gpios 2 GPIO_ACTIVE_HIGH>;
> > +		regulator-min-microvolt = <899400>;
> > +		regulator-max-microvolt = <899400>;
> > +		enable-active-high;
> > +		pinctrl-0 = <&ntn_0p9_en>;
> > +		pinctrl-names = "default";
> > +		regulator-enable-ramp-delay = <4300>;
> > +	};
> > +
> > +	vdd_ntn_1p8: regulator-vdd-ntn-1p8 {
> > +		compatible = "regulator-fixed";
> > +		regulator-name = "VDD_NTN_1P8";
> > +		gpio = <&pm8350c_gpios 3 GPIO_ACTIVE_HIGH>;
> > +		regulator-min-microvolt = <1800000>;
> > +		regulator-max-microvolt = <1800000>;
> > +		enable-active-high;
> > +		pinctrl-0 = <&ntn_1p8_en>;
> > +		pinctrl-names = "default";
> > +		regulator-enable-ramp-delay = <10000>;
> > +	};
> > +
> >   };
> >   
> >   &apps_rsc {
> > @@ -735,6 +760,75 @@ &pcie1_phy {
> >   	status = "okay";
> >   };
> >   
> > +&pcie1_port {
> > +	pcie@0,0 {
> > +		compatible = "pci1179,0623", "pciclass,0604";
> > +		reg = <0x10000 0x0 0x0 0x0 0x0>;
> > +		#address-cells = <3>;
> > +		#size-cells = <2>;
> > +
> > +		device_type = "pci";
> > +		ranges;
> > +		bus-range = <0x2 0xff>;
> > +
> > +		vddc-supply = <&vdd_ntn_0p9>;
> > +		vdd18-supply = <&vdd_ntn_1p8>;
> > +		vdd09-supply = <&vdd_ntn_0p9>;
> > +		vddio1-supply = <&vdd_ntn_1p8>;
> > +		vddio2-supply = <&vdd_ntn_1p8>;
> > +		vddio18-supply = <&vdd_ntn_1p8>;
> > +
> > +		i2c-parent = <&i2c0 0x77>;
> > +
> > +		reset-gpios = <&pm8350c_gpios 1 GPIO_ACTIVE_LOW>;
> > +
> > +		pcie@1,0 {
>
> PCIe bus can be autodetected. Is there a reason for describing all the
> ports and a full topology? If so, it should be stated in the commit
> message.
As these ports are fixed we are defining them here, I will mention this
in the commit message. It is similar to how we added pcieport for all
the platforms, I tried to add full topology here. And if we want to
configure any ports like l0s entry delay, l1 entry delay etc in future
we need these full topology to be present.

- Krishna Chaitanya.
> > +			reg = <0x20800 0x0 0x0 0x0 0x0>;
> > +			#address-cells = <3>;
> > +			#size-cells = <2>;
> > +
> > +			device_type = "pci";
> > +			ranges;
> > +			bus-range = <0x3 0xff>;
> > +		};
> > +
> > +		pcie@2,0 {
> > +			reg = <0x21000 0x0 0x0 0x0 0x0>;
> > +			#address-cells = <3>;
> > +			#size-cells = <2>;
> > +
> > +			device_type = "pci";
> > +			ranges;
> > +			bus-range = <0x4 0xff>;
> > +		};
> > +
> > +		pcie@3,0 {