Re: [PATCH v6 05/11] arm64: dts: imx8mq-evk: Add supports-clkreq property to PCIe M.2 port

Frank Li
2025-10-31T19:38:54Z

On Wed, Oct 15, 2025 at 11:04:22AM +0800, Richard Zhu wrote:
> According to PCIe r6.1, sec 5.5.1.
>
> The following rules define how the L1.1 and L1.2 substates are entered:
> Both the Upstream and Downstream Ports must monitor the logical state of
> the CLKREQ# signal.
>
> Typical implement is using open drain, which connect RC's clkreq# to
> EP's clkreq# together and pull up clkreq#.
>
> imx8mq-evk matches this requirement, so add supports-clkreq to allow
> PCIe device enter ASPM L1 Sub-State.
>
> Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
> ---

Reviewed-by: Frank Li <Frank.Li@nxp.com>

> arch/arm64/boot/dts/freescale/imx8mq-evk.dts | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/arch/arm64/boot/dts/freescale/imx8mq-evk.dts b/arch/arm64/boot/dts/freescale/imx8mq-evk.dts
> index a88bc90346636..852992b915a39 100644
> --- a/arch/arm64/boot/dts/freescale/imx8mq-evk.dts
> +++ b/arch/arm64/boot/dts/freescale/imx8mq-evk.dts
> @@ -375,6 +375,7 @@ &pcie0 {
> <&clk IMX8MQ_CLK_PCIE1_PHY>,
> <&clk IMX8MQ_CLK_PCIE1_AUX>;
> vph-supply = <&vgen5_reg>;
> + supports-clkreq;
> status = "okay";
> };
>
> @@ -398,6 +399,7 @@ &pcie1 {
> <&clk IMX8MQ_CLK_PCIE2_AUX>;
> vpcie-supply = <&reg_pcie1>;
> vph-supply = <&vgen5_reg>;
> + supports-clkreq;
> status = "okay";
> };
>
> --
> 2.37.1
>