RE: [PATCH v3 8/9] arm64: dts: imx8mm-evk: add the pcie support on imx8mm evk board

[Richard Zhu <hongxing.zhu@nxp.com>]

> -----Original Message-----
> From: Lucas Stach <l.stach@pengutronix.de>
> Sent: Saturday, October 16, 2021 3:04 AM
> To: Richard Zhu <hongxing.zhu@nxp.com>; tharvey@gateworks.com;
> kishon@ti.com; vkoul@kernel.org; robh@kernel.org;
> galak@kernel.crashing.org; shawnguo@kernel.org
> Cc: linux-phy@lists.infradead.org; devicetree@vger.kernel.org;
> linux-arm-kernel@lists.infradead.org; linux-kernel@vger.kernel.org;
> kernel@pengutronix.de; dl-linux-imx <linux-imx@nxp.com>
> Subject: Re: [PATCH v3 8/9] arm64: dts: imx8mm-evk: add the pcie support on
> imx8mm evk board
> 
> Am Dienstag, dem 12.10.2021 um 16:41 +0800 schrieb Richard Zhu:
> > Add the PCIe support on i.MX8MM EVK board.
> >
> > Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
> > ---
> >  arch/arm64/boot/dts/freescale/imx8mm-evk.dtsi | 46
> > +++++++++++++++++++
> >  1 file changed, 46 insertions(+)
> >
> > diff --git a/arch/arm64/boot/dts/freescale/imx8mm-evk.dtsi
> > b/arch/arm64/boot/dts/freescale/imx8mm-evk.dtsi
> > index 2d0684ac82f6..5ce43daa0c8b 100644
> > --- a/arch/arm64/boot/dts/freescale/imx8mm-evk.dtsi
> > +++ b/arch/arm64/boot/dts/freescale/imx8mm-evk.dtsi
> > @@ -31,6 +31,23 @@ status {
> >  		};
> >  	};
> >
> > +	pcie0_refclk: pcie0-refclk {
> > +		compatible = "fixed-clock";
> > +			#clock-cells = <0>;
> > +			clock-frequency = <100000000>;
> > +	};
> 
> This is both the PHY reference and bus clock. I guess you could just squash
> Patch 4/9 into this one, as they are both required to get PCIe on the EVK
> board.
> 
[Richard Zhu] Okay, agree with that. Would squash #4 with #8 together.
Thanks.

> > +
> > +	reg_pcie0_gpio: regulator-pcie-gpio {
> 
> Drop the gpio suffix.
[Richard Zhu] Okay, would be dropped.

> 
> > +		compatible = "regulator-fixed";
> > +		pinctrl-names = "default";
> > +		pinctrl-0 = <&pinctrl_pcie0_reg>;
> > +		regulator-name = "MPCIE_3V3";
> > +		regulator-min-microvolt = <3300000>;
> > +		regulator-max-microvolt = <3300000>;
> > +		gpio = <&gpio1 5 GPIO_ACTIVE_HIGH>;
> > +		enable-active-high;
> > +	};
> > +
> >  	reg_usdhc2_vmmc: regulator-usdhc2 {
> >  		compatible = "regulator-fixed";
> >  		pinctrl-names = "default";
> > @@ -296,6 +313,22 @@ &pcie_phy {
> >  	status = "okay";
> >  };
> >
> > +&pcie0 {
> > +	pinctrl-names = "default";
> > +	pinctrl-0 = <&pinctrl_pcie0>;
> > +	reset-gpio = <&gpio4 21 GPIO_ACTIVE_LOW>;
> > +	clocks = <&clk IMX8MM_CLK_PCIE1_ROOT>, <&clk
> IMX8MM_CLK_PCIE1_AUX>,
> > +		 <&clk IMX8MM_CLK_DUMMY>, <&pcie0_refclk>;
> 
> The i.MX8MM PCIe driver should not request the pcie_phy clock. Please add
> a change in the driver, so we don't need to hook up a useless dummy clock to
> this node.
[Richard Zhu] Okay, thanks.

> 
> Regards,
> Lucas
> 
> > +	clock-names = "pcie", "pcie_aux", "pcie_phy", "pcie_bus";
> > +	assigned-clocks = <&clk IMX8MM_CLK_PCIE1_AUX>,
> > +			  <&clk IMX8MM_CLK_PCIE1_CTRL>;
> > +	assigned-clock-rates = <10000000>, <250000000>;
> > +	assigned-clock-parents = <&clk IMX8MM_SYS_PLL2_50M>,
> > +				 <&clk IMX8MM_SYS_PLL2_250M>;
> > +	vpcie-supply = <&reg_pcie0_gpio>;
> > +	status = "okay";
> > +};
> > +
> >  &sai3 {
> >  	pinctrl-names = "default";
> >  	pinctrl-0 = <&pinctrl_sai3>;
> > @@ -413,6 +446,19 @@ MX8MM_IOMUXC_I2C3_SDA_I2C3_SDA
> 	0x400001c3
> >  		>;
> >  	};
> >
> > +	pinctrl_pcie0: pcie0grp {
> > +		fsl,pins = <
> > +			MX8MM_IOMUXC_I2C4_SCL_PCIE1_CLKREQ_B    0x61
> > +			MX8MM_IOMUXC_SAI2_RXFS_GPIO4_IO21       0x41
> > +		>;
> > +	};
> > +
> > +	pinctrl_pcie0_reg: pcie0reggrp {
> > +		fsl,pins = <
> > +			MX8MM_IOMUXC_GPIO1_IO05_GPIO1_IO5       0x41
> > +		>;
> > +	};
> > +
> >  	pinctrl_pmic: pmicirqgrp {
> >  		fsl,pins = <
> >  			MX8MM_IOMUXC_GPIO1_IO03_GPIO1_IO3		0x141
>