arm64: dts: imx8mm-evk: Add supports-clkreq property to PCIe M.2 port

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#.

imx8mm-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>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

diff --git a/arch/arm64/boot/dts/freescale/imx8mm-evk.dtsi b/arch/arm64/boot/dts/freescale/imx8mm-evk.dtsi
index ff7ca20752309a6e8c62c09c19d9e7c17f8c26b0..6eab8a6001dbf9d88f1de93709faa3d82dc56da6 100644 (file)
--- a/arch/arm64/boot/dts/freescale/imx8mm-evk.dtsi
+++ b/arch/arm64/boot/dts/freescale/imx8mm-evk.dtsi
@@ -542,6 +542,7 @@
        assigned-clock-parents = <&clk IMX8MM_SYS_PLL2_50M>,
                                 <&clk IMX8MM_SYS_PLL2_250M>;
        vpcie-supply = <&reg_pcie0>;
+       supports-clkreq;
        status = "okay";
 };