arm64: dts: exynos: gs101-pixel-common: add Maxim MAX77759 PMIC

On Pixel 6 (and Pro), a MAX77759 companion PMIC for USB Type-C
applications is used, which contains four functional blocks (at
distinct I2C addresses):
  * top (including GPIO & NVMEM)
  * charger
  * fuel gauge
  * TCPCi

This change adds the PMIC and the subnodes for the GPIO expander and
NVMEM, and defines the NVMEM layout.

The NVMEM layout is declared such that it matches downstream's
open-coded configuration [1].

Note:
The pinctrl nodes are kept sorted by the 'samsung,pins' property rather
than node name, as I think that makes it easier to look at and to add
new nodes unambiguously in the future. Its label is prefixed with 'if'
(for interface), because there are three PMICs in total in use on
Pixel 6 (Pro).

Link: https://android.googlesource.com/kernel/google-modules/bms/+/96e729a83817/max77759_maxq.c#67 [1]
Signed-off-by: André Draszik <[email protected]>
Reviewed-by: Peter Griffin <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Krzysztof Kozlowski <[email protected]>

Author: andred

arch/arm64/boot/dts/exynos/google/gs101-pixel-common.dtsi

@@ -188,6 +188,60 @@
 			};
 		};
 	};
+
+	pmic@66 {
+		compatible = "maxim,max77759";
+		reg = <0x66>;
+
+		pinctrl-0 = <&if_pmic_int>;
+		pinctrl-names = "default";
+		interrupts-extended = <&gpa8 3 IRQ_TYPE_LEVEL_LOW>;
+
+		interrupt-controller;
+		#interrupt-cells = <2>;
+
+		gpio {
+			compatible = "maxim,max77759-gpio";
+
+			gpio-controller;
+			#gpio-cells = <2>;
+			/*
+			 * "Human-readable name [SIGNAL_LABEL]" where the
+			 * latter comes from the schematic
+			 */
+			gpio-line-names = "OTG boost [OTG_BOOST_EN]",
+					  "max20339 IRQ [MW_OVP_INT_L]";
+
+			interrupt-controller;
+			#interrupt-cells = <2>;
+		};
+
+		nvmem-0 {
+			compatible = "maxim,max77759-nvmem";
+
+			nvmem-layout {
+				compatible = "fixed-layout";
+				#address-cells = <1>;
+				#size-cells = <1>;
+
+				reboot-mode@0 {
+					reg = <0x0 0x4>;
+				};
+
+				boot-reason@4 {
+					reg = <0x4 0x4>;
+				};
+
+				shutdown-user-flag@8 {
+					reg = <0x8 0x1>;
+				};
+
+				rsoc@a {
+					reg = <0xa 0x2>;
+				};
+			};
+		};
+	};
 };
 
 &pinctrl_far_alive {
@@ -211,6 +265,13 @@
 		samsung,pin-pud = <GS101_PIN_PULL_UP>;
 		samsung,pin-drv = <GS101_PIN_DRV_2_5_MA>;
 	};
+
+	if_pmic_int: if-pmic-int-pins {
+		samsung,pins = "gpa8-3";
+		samsung,pin-function = <GS101_PIN_FUNC_EINT>;
+		samsung,pin-pud = <GS101_PIN_PULL_UP>;
+		samsung,pin-drv = <GS101_PIN_DRV_2_5_MA>;
+	};
 };
 
 &pinctrl_gpio_alive {