dt-bindings: mfd: Document ROHM BD71828 bindings

ROHM BD71828 Power management IC integrates 7 buck converters, 7 LDOs,
a real-time clock (RTC), 3 GPO/regulator control pins, HALL input
and a 32.768 kHz clock gate.

Document the dt bindings drivers are using.
Signed-off-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

Documentation/devicetree/bindings/mfd/rohm,bd71828-pmic.yaml

+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mfd/rohm,bd71828-pmic.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: ROHM BD71828 Power Management Integrated Circuit bindings
+
+maintainers:
+  - Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
+
+description: |
+  BD71828GW is a single-chip power management IC for battery-powered portable
+  devices. The IC integrates 7 buck converters, 7 LDOs, and a 1500 mA
+  single-cell linear charger. Also included is a Coulomb counter, a real-time
+  clock (RTC), and a 32.768 kHz clock gate.
+
+properties:
+  compatible:
+    const: rohm,bd71828
+
+  reg:
+    description:
+      I2C slave address.
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  gpio-controller: true
+
+  "#gpio-cells":
+    const: 2
+    description: |
+      The first cell is the pin number and the second cell is used to specify
+      flags. See ../gpio/gpio.txt for more information.
+
+  clocks:
+    maxItems: 1
+
+  "#clock-cells":
+    const: 0
+
+  rohm,charger-sense-resistor-ohms:
+    minimum: 10000000
+    maximum: 50000000
+    description: |
+      BD71827 and BD71828 have SAR ADC for measuring charging currents.
+      External sense resistor (RSENSE in data sheet) should be used. If some
+      other but 30MOhm resistor is used the resistance value should be given
+      here in Ohms.
+
+  regulators:
+    $ref: ../regulator/rohm,bd71828-regulator.yaml
+    description:
+      List of child nodes that specify the regulators.
+
+  leds:
+    $ref: ../leds/rohm,bd71828-leds.yaml
+
+  gpio-reserved-ranges:
+    description: |
+      Usage of BD71828 GPIO pins can be changed via OTP. This property can be
+      used to mark the pins which should not be configured for GPIO. Please see
+      the ../gpio/gpio.txt for more information.
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+  - "#clock-cells"
+  - regulators
+  - gpio-controller
+  - "#gpio-cells"
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+    #include <dt-bindings/leds/common.h>
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+        pmic: pmic@4b {
+            compatible = "rohm,bd71828";
+            reg = <0x4b>;
+
+            interrupt-parent = <&gpio1>;
+            interrupts = <29 IRQ_TYPE_LEVEL_LOW>;
+
+            clocks = <&osc 0>;
+            #clock-cells = <0>;
+            clock-output-names = "bd71828-32k-out";
+
+            gpio-controller;
+            #gpio-cells = <2>;
+            gpio-reserved-ranges = <0 1>, <2 1>;
+
+            rohm,charger-sense-resistor-ohms = <10000000>;
+
+            regulators {
+                buck1: BUCK1 {
+                    regulator-name = "buck1";
+                    regulator-min-microvolt = <500000>;
+                    regulator-max-microvolt = <2000000>;
+                    regulator-ramp-delay = <2500>;
+                };
+                buck2: BUCK2 {
+                    regulator-name = "buck2";
+                    regulator-min-microvolt = <500000>;
+                    regulator-max-microvolt = <2000000>;
+                    regulator-ramp-delay = <2500>;
+                };
+                buck3: BUCK3 {
+                    regulator-name = "buck3";
+                    regulator-min-microvolt = <1200000>;
+                    regulator-max-microvolt = <2000000>;
+                };
+                buck4: BUCK4 {
+                    regulator-name = "buck4";
+                    regulator-min-microvolt = <1000000>;
+                    regulator-max-microvolt = <1800000>;
+                };
+                buck5: BUCK5 {
+                    regulator-name = "buck5";
+                    regulator-min-microvolt = <2500000>;
+                    regulator-max-microvolt = <3300000>;
+                };
+                buck6: BUCK6 {
+                    regulator-name = "buck6";
+                    regulator-min-microvolt = <500000>;
+                    regulator-max-microvolt = <2000000>;
+                    regulator-ramp-delay = <2500>;
+                };
+                buck7: BUCK7 {
+                    regulator-name = "buck7";
+                    regulator-min-microvolt = <500000>;
+                    regulator-max-microvolt = <2000000>;
+                    regulator-ramp-delay = <2500>;
+                };
+                ldo1: LDO1 {
+                    regulator-name = "ldo1";
+                    regulator-min-microvolt = <800000>;
+                    regulator-max-microvolt = <3300000>;
+                };
+                ldo2: LDO2 {
+                    regulator-name = "ldo2";
+                    regulator-min-microvolt = <800000>;
+                    regulator-max-microvolt = <3300000>;
+                };
+                ldo3: LDO3 {
+                    regulator-name = "ldo3";
+                    regulator-min-microvolt = <800000>;
+                    regulator-max-microvolt = <3300000>;
+                };
+                ldo4: LDO4 {
+                    regulator-name = "ldo4";
+                    regulator-min-microvolt = <800000>;
+                    regulator-max-microvolt = <3300000>;
+                };
+                ldo5: LDO5 {
+                    regulator-name = "ldo5";
+                    regulator-min-microvolt = <800000>;
+                    regulator-max-microvolt = <3300000>;
+                };
+                ldo6: LDO6 {
+                    regulator-name = "ldo6";
+                    regulator-min-microvolt = <1800000>;
+                    regulator-max-microvolt = <1800000>;
+                };
+                ldo7_reg: LDO7 {
+                    regulator-name = "ldo7";
+                    regulator-min-microvolt = <800000>;
+                    regulator-max-microvolt = <3300000>;
+                };
+            };
+
+            leds {
+                compatible = "rohm,bd71828-leds";
+
+                led-1 {
+                    rohm,led-compatible = "bd71828-grnled";
+                    function = LED_FUNCTION_INDICATOR;
+                    color = <LED_COLOR_ID_GREEN>;
+                };
+                led-2 {
+                    rohm,led-compatible = "bd71828-ambled";
+                    function = LED_FUNCTION_CHARGING;
+                    color = <LED_COLOR_ID_AMBER>;
+                };
+            };
+        };
+    };