@@ -61,7 +61,17 @@ vcc1v8_s3: vcc1v8-s3 {
regulator-min-microvolt = <1800000>;
regulator-max-microvolt = <1800000>;
regulator-name = "vcc1v8_s3";
- vin-supply = <&vcc_1v8>;
+
+ /*
+ * Workaround to skip setting gpio0 RK_PA1 to LOW upon reboot,
+ * which may freeze the system.
+ *
+ * Adding a reference to vcc3v0_sd increases its num_users
+ * count to 2, preventing deactivation since this regulator is
+ * marked "always-on".
+ */
+ // vin-supply = <&vcc_1v8>; // actual supply
+ vin-supply = <&vcc3v0_sd>;
};
vcc3v0_sd: vcc3v0-sd {
@@ -70,7 +80,6 @@ vcc3v0_sd: vcc3v0-sd {
gpio = <&gpio0 RK_PA1 GPIO_ACTIVE_HIGH>;
pinctrl-names = "default";
pinctrl-0 = <&sdmmc0_pwr_h>;
- regulator-always-on;
regulator-min-microvolt = <3000000>;
regulator-max-microvolt = <3000000>;
regulator-name = "vcc3v0_sd";
mmc/SD-card initialization may fail on NanoPi R4S with "mmc1: problem reading SD Status register" / "mmc1: error -110 whilst initialising SD card" either on cold boot or after a reboot. Moreover, the system would also sometimes hang upon reboot. This is caused by vcc3v0-sd's "regulator-always-on", which triggers an erroneous double-initialization of the regulator. This causes voltage fluctuations that can, depending on timing, prevent the SD card from initializing correctly. Adding some liberal delay via "off-on-delay-us" is ineffective since that codepath is skipped as long "regulator-always-on" is set. Removing "regulator-always-on" alone is not sufficient because that would allow the system to set GPIO0_A1 to LOW upon reboot, which may cause the system to hang. In order to allow the system to set GPIO0_A1 to HIGH upon initialization but prevent it from changing it back to LOW, this patch increases the usage count of vcc3v0-sd from 1 to 2, whereas the additional reference, "vcc1v8_s3", is marked as "always-on", causing permanent retention. Signed-off-by: Christian Kohlschütter <christian@kohlschutter.com> --- arch/arm64/boot/dts/rockchip/rk3399-nanopi4.dtsi | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-)