ARM: dts: amlogic: meson8-fernsehfee3: Describe regulators

The fernsehfee3 board uses a Ricoh RN5T618 PMIC to generate various
voltages. Board schematics are not available, but the regulator voltages
found in /sys/kernel/debug/regulator/regulator_summary match those in
meson8m2-mxiii-plus.dts:

 DCDC1               0    0      0 unknown  1100mV     0mA     0mV     0mV
 DCDC2               0    0      0 unknown  1150mV     0mA     0mV     0mV
 DCDC3               0    0      0 unknown  1500mV     0mA     0mV     0mV
 LDO1                0    0      0 unknown  2900mV     0mA     0mV     0mV
 LDO2                0    0      0 unknown  1800mV     0mA     0mV     0mV
 LDO3                0    0      0 unknown  1800mV     0mA     0mV     0mV
 LDO4                0    0      0 unknown  2850mV     0mA     0mV     0mV
 LDO5                0    0      0 unknown  1800mV     0mA     0mV     0mV
 LDORTC1             0    0      0 unknown  2700mV     0mA     0mV     0mV
 LDORTC2             0    0      0 unknown   900mV     0mA     0mV     0mV

This patch takes the following approach:

 - Copy RN5T618 regulator nodes from meson8m2-mxiii-plus.dts
 - Remove some of the regulator names, which do not seem to apply
 - Verify regulator supply relations by starting without any relations
   (and without regulator-always-on) and seeing what breaks when the
   kernel turns off "unused" regulators.

This results in the following observations:

 - When LDO1 is turned off, the board resets
 - When DCDC1, DCDC2, DCDC3, LDO2, or LDO5 are turned off, the board (as
   observed through the serial port) stops running, so these must stay on
   at all times.
 - LDO4 (VCC2V8) appears to be unused on this board.
 - LDO3 (VCC1V8_USB) must stay on in order for USB to work, both the
   external USB ports and the internal USB wifi module.

The cpu-supply and mali-supply relations are also copied from
meson8m2-mxiii-plus.dts

Signed-off-by: J. Neuschäfer <j.ne@posteo.net>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Link: https://lore.kernel.org/r/20250428-fernsehfee-v2-4-293b98a43a91@posteo.net
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>

1 files changed, 91 insertions, 0 deletions

diff --git a/arch/arm/boot/dts/amlogic/meson8-fernsehfee3.dts b/arch/arm/boot/dts/amlogic/meson8-fernsehfee3.dts
index 3f9e2e5d8d5b..4e52447d51bd 100644
--- a/arch/arm/boot/dts/amlogic/meson8-fernsehfee3.dts
+++ b/arch/arm/boot/dts/amlogic/meson8-fernsehfee3.dts
@@ -85,6 +85,10 @@
 	};
 };
 
+&cpu0 {
+	cpu-supply = <&vcck>;
+};
+
 &ethmac {
 	status = "okay";
 	pinctrl-0 = <&eth_pins>;
@@ -117,6 +121,87 @@
 		compatible = "ricoh,rn5t618";
 		reg = <0x32>;
 		system-power-controller;
+
+		regulators {
+			vcck: DCDC1 {
+				regulator-name = "VCCK";
+				regulator-min-microvolt = <825000>;
+				regulator-max-microvolt = <1150000>;
+				regulator-boot-on;
+				regulator-always-on;
+			};
+
+			vddee: DCDC2 {
+				/* the output is also used as VDDAO */
+				regulator-name = "VDD_EE";
+				regulator-min-microvolt = <950000>;
+				regulator-max-microvolt = <1150000>;
+				regulator-boot-on;
+				regulator-always-on;
+			};
+
+			DCDC3 {
+				regulator-name = "VDD_DDR";
+				regulator-min-microvolt = <1500000>;
+				regulator-max-microvolt = <1500000>;
+				regulator-boot-on;
+				regulator-always-on;
+			};
+
+			LDO1 {
+				regulator-name = "VDDIO_AO28";
+				regulator-min-microvolt = <2900000>;
+				regulator-max-microvolt = <2900000>;
+				regulator-boot-on;
+				regulator-always-on;
+			};
+
+			LDO2 {
+				regulator-name = "VDDIO_AO18";
+				regulator-min-microvolt = <1800000>;
+				regulator-max-microvolt = <1800000>;
+				regulator-boot-on;
+				regulator-always-on;
+			};
+
+			vcc1v8_usb: LDO3 {
+				regulator-name = "VCC1V8_USB";
+				regulator-min-microvolt = <1800000>;
+				regulator-max-microvolt = <1800000>;
+				regulator-boot-on;
+			};
+
+			LDO4 {
+				/* This one appears to be unused */
+				regulator-name = "VCC2V8";
+				regulator-min-microvolt = <2850000>;
+				regulator-max-microvolt = <2850000>;
+			};
+
+			LDO5 {
+				regulator-name = "AVDD1V8";
+				regulator-min-microvolt = <1800000>;
+				regulator-max-microvolt = <1800000>;
+				regulator-boot-on;
+				regulator-always-on;
+			};
+
+			LDORTC1 {
+				regulator-name = "VDD_LDO";
+				regulator-min-microvolt = <2700000>;
+				regulator-max-microvolt = <2700000>;
+				regulator-boot-on;
+				regulator-always-on;
+			};
+
+			LDORTC2 {
+				regulator-name = "RTC_0V9";
+				regulator-min-microvolt = <900000>;
+				regulator-max-microvolt = <900000>;
+				regulator-boot-on;
+				regulator-always-on;
+			};
+		};
 	};
 
 	eeprom@50 {
@@ -137,6 +222,10 @@
 	/* TODO: SiI9293 HDMI receiver @ 0x39 */
 };
 
+&mali {
+	mali-supply = <&vddee>;
+};
+
 &sdhc {
 	status = "okay";
 	pinctrl-0 = <&sdxc_c_pins>;
@@ -188,6 +277,7 @@
 
 &usb0_phy {
 	status = "okay";
+	phy-supply = <&vcc1v8_usb>;
 };
 
 &usb1 {
@@ -206,6 +296,7 @@
 
 &usb1_phy {
 	status = "okay";
+	phy-supply = <&vcc1v8_usb>;
 };
 
 &ir_receiver {