arm64: dts: qcom: msm8916: Add device tree for Huawei Ascend G7

The Huawei Ascend G7 is a smartphone from Huawei based on MSM8916.
It's fairly similar to the other MSM8916 devices, the only notable
exception are the "cd-gpios" for detecting if a SD card was inserted:
It looks like Huawei forgot to re-route this to gpio38, so the correct
GPIO seems to be gpio56 on this device.

Note: The original firmware from Huawei can only boot 32-bit kernels.
To boot arm64 kernels it is necessary to flash 64-bit TZ/HYP firmware
with EDL, e.g. taken from the DragonBoard 410c. This works because Huawei
forgot to set up (firmware) secure boot for some reason.

Also note that Huawei no longer provides bootloader unlock codes.
This can be bypassed by patching the bootloader from a custom HYP firmware,
making it think the bootloader is unlocked. I use a modified version of
qhypstub [1], that patches a single instruction in the Huawei bootloader.

The device tree contains initial support for the Huawei Ascend G7 with:
  - UART (untested, probably available via some test points)
  - eMMC/SD card
  - Buttons
  - Notification LED (combination of 3 GPIO LEDs)
  - Vibrator
  - WiFi/Bluetooth (WCNSS)
  - USB

[1]: https://github.com/msm8916-mainline/qhypstubSigned-off-by: Stephan Gerhold <stephan@gerhold.net>
Link: https://lore.kernel.org/r/20210514104328.18756-1-stephan@gerhold.netSigned-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

arch/arm64/boot/dts/qcom/Makefile

@@ -9,6 +9,7 @@ dtb-$(CONFIG_ARCH_QCOM)	+= ipq8074-hk10-c1.dtb
 dtb-$(CONFIG_ARCH_QCOM)	+= ipq8074-hk10-c2.dtb
 dtb-$(CONFIG_ARCH_QCOM)	+= msm8916-alcatel-idol347.dtb
 dtb-$(CONFIG_ARCH_QCOM)	+= msm8916-asus-z00l.dtb
+dtb-$(CONFIG_ARCH_QCOM)	+= msm8916-huawei-g7.dtb
 dtb-$(CONFIG_ARCH_QCOM)	+= msm8916-longcheer-l8150.dtb
 dtb-$(CONFIG_ARCH_QCOM)	+= msm8916-longcheer-l8910.dtb
 dtb-$(CONFIG_ARCH_QCOM)	+= msm8916-mtp.dtb

arch/arm64/boot/dts/qcom/msm8916-huawei-g7.dts

+// SPDX-License-Identifier: GPL-2.0-only
+// Copyright (C) 2021 Stephan Gerhold
+
+/dts-v1/;
+
+#include "msm8916-pm8916.dtsi"
+#include <dt-bindings/gpio/gpio.h>
+#include <dt-bindings/input/input.h>
+#include <dt-bindings/leds/common.h>
+
+/*
+ * Note: The original firmware from Huawei can only boot 32-bit kernels.
+ * To boot arm64 kernels it is necessary to flash 64-bit TZ/HYP firmware
+ * with EDL, e.g. taken from the DragonBoard 410c. This works because Huawei
+ * forgot to set up (firmware) secure boot for some reason.
+ *
+ * Also note that Huawei no longer provides bootloader unlock codes.
+ * This can be bypassed by patching the bootloader from a custom HYP firmware,
+ * making it think the bootloader is unlocked.
+ *
+ * See: https://wiki.postmarketos.org/wiki/Huawei_Ascend_G7_(huawei-g7)
+ */
+
+/ {
+	model = "Huawei Ascend G7";
+	compatible = "huawei,g7", "qcom,msm8916";
+
+	aliases {
+		serial0 = &blsp1_uart2;
+	};
+
+	chosen {
+		stdout-path = "serial0";
+	};
+
+	gpio-keys {
+		compatible = "gpio-keys";
+
+		pinctrl-names = "default";
+		pinctrl-0 = <&gpio_keys_default>;
+
+		label = "GPIO Buttons";
+
+		volume-up {
+			label = "Volume Up";
+			gpios = <&msmgpio 107 GPIO_ACTIVE_LOW>;
+			linux,code = <KEY_VOLUMEUP>;
+		};
+	};
+
+	leds {
+		compatible = "gpio-leds";
+
+		pinctrl-names = "default";
+		pinctrl-0 = <&gpio_leds_default>;
+
+		led-0 {
+			gpios = <&msmgpio 8 GPIO_ACTIVE_HIGH>;
+			color = <LED_COLOR_ID_RED>;
+			default-state = "off";
+			function = LED_FUNCTION_INDICATOR;
+		};
+
+		led-1 {
+			gpios = <&msmgpio 9 GPIO_ACTIVE_HIGH>;
+			color = <LED_COLOR_ID_GREEN>;
+			default-state = "off";
+			function = LED_FUNCTION_INDICATOR;
+		};
+
+		led-2 {
+			gpios = <&msmgpio 10 GPIO_ACTIVE_HIGH>;
+			color = <LED_COLOR_ID_BLUE>;
+			default-state = "off";
+			function = LED_FUNCTION_INDICATOR;
+		};
+	};
+
+	usb_id: usb-id {
+		compatible = "linux,extcon-usb-gpio";
+		id-gpio = <&msmgpio 117 GPIO_ACTIVE_HIGH>;
+		pinctrl-names = "default";
+		pinctrl-0 = <&usb_id_default>;
+	};
+};
+
+&blsp1_uart2 {
+	status = "okay";
+};
+
+&pm8916_resin {
+	status = "okay";
+	linux,code = <KEY_VOLUMEDOWN>;
+};
+
+&pm8916_vib {
+	status = "okay";
+};
+
+&pronto {
+	status = "okay";
+};
+
+&sdhc_1 {
+	status = "okay";
+
+	pinctrl-names = "default", "sleep";
+	pinctrl-0 = <&sdc1_clk_on &sdc1_cmd_on &sdc1_data_on>;
+	pinctrl-1 = <&sdc1_clk_off &sdc1_cmd_off &sdc1_data_off>;
+};
+
+&sdhc_2 {
+	status = "okay";
+
+	pinctrl-names = "default", "sleep";
+	pinctrl-0 = <&sdc2_clk_on &sdc2_cmd_on &sdc2_data_on &sdhc2_cd_default>;
+	pinctrl-1 = <&sdc2_clk_off &sdc2_cmd_off &sdc2_data_off &sdhc2_cd_default>;
+
+	/*
+	 * The Huawei device tree sets cd-gpios = <&msmgpio 38 GPIO_ACTIVE_HIGH>.
+	 * However, gpio38 does not change its state when inserting/removing the
+	 * SD card, it's just low all the time. The Huawei kernel seems to use
+	 * polling for SD card detection instead.
+	 *
+	 * However, looking closer at the GPIO debug output it turns out that
+	 * gpio56 switches its state when inserting/removing the SD card.
+	 * It behaves just like gpio38 normally does. Usually GPIO56 is used as
+	 * "UIM2_PRESENT", i.e. to check if a second SIM card is inserted.
+	 * Maybe Huawei decided to replace the second SIM card slot with the
+	 * SD card slot and forgot to re-route to gpio38.
+	 */
+	cd-gpios = <&msmgpio 56 GPIO_ACTIVE_LOW>;
+};
+
+&usb {
+	status = "okay";
+	extcon = <&usb_id>, <&usb_id>;
+};
+
+&usb_hs_phy {
+	extcon = <&usb_id>;
+};
+
+&smd_rpm_regulators {
+	vdd_l1_l2_l3-supply = <&pm8916_s3>;
+	vdd_l4_l5_l6-supply = <&pm8916_s4>;
+	vdd_l7-supply = <&pm8916_s4>;
+
+	s3 {
+		regulator-min-microvolt = <1200000>;
+		regulator-max-microvolt = <1300000>;
+	};
+
+	s4 {
+		regulator-min-microvolt = <1800000>;
+		regulator-max-microvolt = <2100000>;
+	};
+
+	l1 {
+		regulator-min-microvolt = <1225000>;
+		regulator-max-microvolt = <1225000>;
+	};
+
+	l2 {
+		regulator-min-microvolt = <1200000>;
+		regulator-max-microvolt = <1200000>;
+	};
+
+	l4 {
+		regulator-min-microvolt = <2050000>;
+		regulator-max-microvolt = <2050000>;
+	};
+
+	l5 {
+		regulator-min-microvolt = <1800000>;
+		regulator-max-microvolt = <1800000>;
+	};
+
+	l6 {
+		regulator-min-microvolt = <1800000>;
+		regulator-max-microvolt = <1800000>;
+	};
+
+	l7 {
+		regulator-min-microvolt = <1800000>;
+		regulator-max-microvolt = <1800000>;
+	};
+
+	l8 {
+		regulator-min-microvolt = <2950000>;
+		regulator-max-microvolt = <2950000>;
+	};
+
+	l9 {
+		regulator-min-microvolt = <3300000>;
+		regulator-max-microvolt = <3300000>;
+	};
+
+	l10 {
+		regulator-min-microvolt = <2700000>;
+		regulator-max-microvolt = <2800000>;
+	};
+
+	l11 {
+		regulator-min-microvolt = <1800000>;
+		regulator-max-microvolt = <2950000>;
+		regulator-allow-set-load;
+		regulator-system-load = <200000>;
+	};
+
+	l12 {
+		regulator-min-microvolt = <1800000>;
+		regulator-max-microvolt = <2950000>;
+	};
+
+	l13 {
+		regulator-min-microvolt = <3075000>;
+		regulator-max-microvolt = <3075000>;
+	};
+
+	l14 {
+		regulator-min-microvolt = <1800000>;
+		regulator-max-microvolt = <3300000>;
+	};
+
+	l15 {
+		regulator-min-microvolt = <1800000>;
+		regulator-max-microvolt = <3300000>;
+	};
+
+	l16 {
+		regulator-min-microvolt = <1800000>;
+		regulator-max-microvolt = <3300000>;
+	};
+
+	l17 {
+		regulator-min-microvolt = <2850000>;
+		regulator-max-microvolt = <2850000>;
+	};
+
+	l18 {
+		regulator-min-microvolt = <2700000>;
+		regulator-max-microvolt = <2700000>;
+	};
+};
+
+&msmgpio {
+	gpio_keys_default: gpio-keys-default {
+		pins = "gpio107";
+		function = "gpio";
+
+		drive-strength = <2>;
+		bias-pull-up;
+	};
+
+	gpio_leds_default: gpio-leds-default {
+		pins = "gpio8", "gpio9", "gpio10";
+		function = "gpio";
+
+		drive-strength = <2>;
+		bias-disable;
+	};
+
+	sdhc2_cd_default: sdhc2-cd-default {
+		pins = "gpio56";
+		function = "gpio";
+
+		drive-strength = <2>;
+		bias-disable;
+	};
+
+	usb_id_default: usb-id-default {
+		pins = "gpio117";
+		function = "gpio";
+
+		drive-strength = <8>;
+		bias-pull-up;
+	};
+};