[PATCH 2/3] arm64: dts: rockchip: Enable M.2 B-key WWAN slot on Radxa ROCK 3B

[Adam Wermuth <adam@wermuth.pl>]

The M.2 B-key slot on the ROCK 3B is controlled by three GPIOs:

 - GPIO0_C6 (4G_PWREN_H) enables the 3.3V supply of the slot, which
   is generated from vcc5v0_sys by a dedicated buck converter,
 - GPIO0_D6 (4G_RESET) drives the RESET# signal of the slot,
 - GPIO1_B0 (4G_DISABLE) drives W_DISABLE1#.

Unless the supply is enabled and both active-low signals are
deasserted, the module never enumerates on USB. Describe the supply
as an always-on fixed regulator and hog RESET# and W_DISABLE1# in
their inactive state.

Tested with a SIMCom SIM7600G-H module.

Signed-off-by: Adam Wermuth <adam@wermuth.pl>
---
 .../boot/dts/rockchip/rk3568-rock-3b.dts      | 38 +++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/arch/arm64/boot/dts/rockchip/rk3568-rock-3b.dts b/arch/arm64/boot/dts/rockchip/rk3568-rock-3b.dts
index ad9a91c0d0d0..908bb4425e81 100644
--- a/arch/arm64/boot/dts/rockchip/rk3568-rock-3b.dts
+++ b/arch/arm64/boot/dts/rockchip/rk3568-rock-3b.dts
@@ -98,6 +98,20 @@ vcc3v3_sys2: regulator-3v3-vcc-sys2 {
 		vin-supply = <&vcc5v0_sys>;
 	};
 
+	vcc3v3_wwan: regulator-3v3-vcc-wwan {
+		compatible = "regulator-fixed";
+		enable-active-high;
+		gpios = <&gpio0 RK_PC6 GPIO_ACTIVE_HIGH>;
+		pinctrl-names = "default";
+		pinctrl-0 = <&wwan_pwren_h>;
+		regulator-name = "vcc3v3_wwan";
+		regulator-always-on;
+		regulator-boot-on;
+		regulator-min-microvolt = <3300000>;
+		regulator-max-microvolt = <3300000>;
+		vin-supply = <&vcc5v0_sys>;
+	};
+
 	vcc5v0_sys: regulator-5v0-vcc-sys {
 		compatible = "regulator-fixed";
 		regulator-name = "vcc5v0_sys";
@@ -220,6 +234,24 @@ &gmac1m1_rgmii_bus
 	status = "okay";
 };
 
+&gpio0 {
+	wwan-reset-hog {
+		gpio-hog;
+		gpios = <RK_PD6 GPIO_ACTIVE_LOW>;
+		output-low;
+		line-name = "wwan-reset";
+	};
+};
+
+&gpio1 {
+	wwan-disable-hog {
+		gpio-hog;
+		gpios = <RK_PB0 GPIO_ACTIVE_LOW>;
+		output-low;
+		line-name = "wwan-w-disable";
+	};
+};
+
 &gpu {
 	mali-supply = <&vdd_gpu>;
 	status = "okay";
@@ -655,6 +687,12 @@ wifi_wake_host_h: wifi-wake-host-h {
 			rockchip,pins = <3 RK_PD5 RK_FUNC_GPIO &pcfg_pull_none>;
 		};
 	};
+
+	wwan {
+		wwan_pwren_h: wwan-pwren-h {
+			rockchip,pins = <0 RK_PC6 RK_FUNC_GPIO &pcfg_pull_none>;
+		};
+	};
 };
 
 &pmu_io_domains {
-- 
2.43.0