rockchip: backport upstream fix R76S SD suspend power loss

This patch is a full backport of Linux upstream commit a9c1acebfe0484343a443d082e039ca77186ed22
for rk3576-nanopi-r76s.dts device tree, resolving SD card power dropout in runtime suspend.

When runtime suspend is active, the SD power domain is shut down, wiping power control
registers and cutting card power. I/O recovery relies on mmc_blk_mq_rw_recovery(),
which results in poor performance and unstable card detection.

Implement GPIO-controlled vcc3v3_sd regulator and attach vmmc-supply to sdmmc node
to maintain SD power during suspend. Also add cd-gpios to guarantee working hotplug
when system enters idle/suspend state.

Modifications in DTS:
- vcc3v3_sd fixed regulator + sdmmc_pwren pinctrl
- vmmc-supply & vqmmc-supply for sdmmc bus power retention
- cd-gpios for SD card presence detection

Signed-off-by: xiao bo <peterwillcn@gmail.com>
Link: https://github.com/openwrt/openwrt/pull/23924
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>

diff --git a/target/linux/rockchip/patches-6.18/053-v6.19-arm64-dts-rockchip-Fix-SD-card-support-for-RK3576-Na.patch b/target/linux/rockchip/patches-6.18/053-v6.19-arm64-dts-rockchip-Fix-SD-card-support-for-RK3576-Na.patch
new file mode 100644 (file)
index 0000000..0d4a4a5
--- /dev/null
+++ b/target/linux/rockchip/patches-6.18/053-v6.19-arm64-dts-rockchip-Fix-SD-card-support-for-RK3576-Na.patch
@@ -0,0 +1,77 @@
+From 3256c25e6c833e11e2a574b69f4ba30e86049846 Mon Sep 17 00:00:00 2001
+From: Shawn Lin <shawn.lin@rock-chips.com>
+Date: Fri, 16 Jan 2026 08:55:32 +0800
+Subject: [PATCH] arm64: dts: rockchip: Fix SD card support for RK3576 Nanopi
+ R76s
+
+[ Upstream commit a9c1acebfe0484343a443d082e039ca77186ed22 ]
+
+When runtime suspend is enabled, the associated power domain is powered
+off, which resets the registers, including the power control bit. As a result,
+the card loses power during runtime suspend. The card should still be able
+to process I/O with the help of mmc_blk_mq_rw_recovery(), which is suboptimal.
+To address this issue, we must use vmmc-supply with a GPIO based method to
+maintain power to the card and store valid tuning phases. Also, add cd-gpios
+method to make hot-plug work correctly during idle periods.
+
+Fixes: 7fee88882704 ("arm64: dts: rockchip: Add devicetree for the FriendlyElec NanoPi R76S")
+Cc: stable@vger.kernel.org
+Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
+Tested-by: Marco Schirrmeister <mschirrmeister@gmail.com>
+Link: https://patch.msgid.link/1768524932-163929-6-git-send-email-shawn.lin@rock-chips.com
+Signed-off-by: Heiko Stuebner <heiko@sntech.de>
+Signed-off-by: Sasha Levin <sashal@kernel.org>
+---
+ .../boot/dts/rockchip/rk3576-nanopi-r76s.dts  | 23 ++++++++++++++++++-
+ 1 file changed, 22 insertions(+), 1 deletion(-)
+
+--- a/arch/arm64/boot/dts/rockchip/rk3576-nanopi-r76s.dts
++++ b/arch/arm64/boot/dts/rockchip/rk3576-nanopi-r76s.dts
+@@ -192,6 +192,18 @@
+               regulator-name = "vcc_3v3_s0";
+               vin-supply = <&vcc_3v3_s3>;
+       };
++
++      vcc3v3_sd: regulator-vcc-3v3-sd {
++              compatible = "regulator-fixed";
++              enable-active-high;
++              gpios = <&gpio0 RK_PB6 GPIO_ACTIVE_HIGH>;
++              pinctrl-names = "default";
++              pinctrl-0 = <&sdmmc_pwren>;
++              regulator-name = "vcc3v3_sd";
++              regulator-min-microvolt = <3300000>;
++              regulator-max-microvolt = <3300000>;
++              vin-supply = <&vcc_3v3_s0>;
++      };
+ };
+ 
+ &combphy0_ps {
+@@ -726,6 +738,12 @@
+               };
+       };
+ 
++      sdmmc {
++              sdmmc_pwren: sdmmc-pwren {
++                      rockchip,pins = <0 RK_PB6 RK_FUNC_GPIO &pcfg_pull_none>;
++              };
++      };
++
+       usb {
+               usb_otg0_pwren_h: usb-otg0-pwren-h {
+                       rockchip,pins = <0 RK_PD1 RK_FUNC_GPIO &pcfg_pull_none>;
+@@ -751,11 +769,14 @@
+       bus-width = <4>;
+       cap-mmc-highspeed;
+       cap-sd-highspeed;
++      cd-gpios = <&gpio0 RK_PA7 GPIO_ACTIVE_LOW>;
+       disable-wp;
+       no-mmc;
+       no-sdio;
++      pinctrl-names = "default";
++      pinctrl-0 = <&sdmmc0_clk &sdmmc0_cmd &sdmmc0_det &sdmmc0_bus4>;
+       sd-uhs-sdr104;
+-      vmmc-supply = <&vcc_3v3_s3>;
++      vmmc-supply = <&vcc3v3_sd>;
+       vqmmc-supply = <&vccio_sd_s0>;
+       status = "okay";
+ };