Add Richtek RTQ2208 SubPMIC support

Merge series from Alina Yu <alina_yu@richtek.com>:

This patch series adds support for RTQ2208 SubPMIC regulators.
The RTQ2208 is a multi-phase, programmable power management IC that
integrate with dual multi-configurable, synchronous buck converters
and two ldos. The bucks features wide output voltage range from 0.4V to 2.05V
and the capability to configure the corresponding power stages.

Documentation/devicetree/bindings/regulator/richtek,rtq2208.yaml

+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/regulator/richtek,rtq2208.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Richtek RTQ2208 SubPMIC Regulator
+
+maintainers:
+  - Alina Yu <alina_yu@richtek.com>
+
+description: |
+  RTQ2208 is a highly integrated power converter that offers functional safety dual
+  multi-configurable synchronous buck converters and two LDOs.
+
+  Bucks support "regulator-allowed-modes" and "regulator-mode". The former defines the permitted
+  switching operation in normal mode; the latter defines the operation in suspend to RAM mode.
+
+  No matter the RTQ2208 is configured to normal or suspend to RAM mode, there are two switching
+  operation modes for all buck rails, automatic power saving mode (Auto mode) and forced continuous
+  conduction mode (FCCM).
+
+  The definition of modes is in the datasheet which is available in below link
+  and their meaning is::
+    0 - Auto mode for power saving, which reducing the switching frequency at light load condition
+    to maintain high frequency.
+    1 - FCCM to meet the strict voltage regulation accuracy, which keeping constant switching frequency.
+
+  Datasheet will be available soon at
+  https://www.richtek.com/assets/Products
+
+properties:
+  compatible:
+    enum:
+      - richtek,rtq2208
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+    
+  richtek,mtp-sel-high:
+    type: boolean
+    description:
+      vout register selection based on this boolean value.
+      false - Using DVS0 register setting to adjust vout
+      true - Using DVS1 register setting to adjust vout
+
+  regulators:
+    type: object
+    additionalProperties: false
+
+    patternProperties:
+      "^buck-[a-h]$":
+        type: object
+        $ref: regulator.yaml#
+        unevaluatedProperties: false
+        description:
+          description for buck-[a-h] regulator.
+
+        properties:
+          regulator-allowed-modes:
+            description:
+              two buck modes in different switching accuracy.
+              0 - Auto mode
+              1 - FCCM
+            items:
+              enum: [0, 1]
+
+      "^ldo[1-2]$":
+        type: object
+        $ref: regulator.yaml#
+        unevaluatedProperties: false
+        description:
+          regulator description for ldo[1-2].
+
+required:
+  - compatible
+  - reg
+  - regulators
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+    i2c {
+      #address-cells = <1>;
+      #size-cells = <0>;
+
+      pmic@10 {
+        compatible = "richtek,rtq2208";
+        reg = <0x10>;
+        interrupts-extended = <&gpio26 0 IRQ_TYPE_LEVEL_LOW>;
+        richtek,mtp-sel-high;
+
+        regulators {
+          buck-a {
+            regulator-min-microvolt = <400000>;
+            regulator-max-microvolt = <2050000>;
+            regulator-allowed-modes = <0 1>;
+            regulator-always-on;
+            regulator-state-mem {
+              regulator-on-in-suspend;
+              regulator-mode = <1>;
+            };
+          };
+          buck-b {
+            regulator-min-microvolt = <400000>;
+            regulator-max-microvolt = <2050000>;
+            regulator-allowed-modes = <0 1>;
+            regulator-always-on;
+            regulator-state-mem {
+              regulator-on-in-suspend;
+              regulator-mode = <1>;
+            };
+          };
+          buck-c {
+            regulator-min-microvolt = <400000>;
+            regulator-max-microvolt = <2050000>;
+            regulator-allowed-modes = <0 1>;
+            regulator-always-on;
+            regulator-state-mem {
+              regulator-on-in-suspend;
+              regulator-mode = <1>;
+            };
+          };
+          buck-d {
+            regulator-min-microvolt = <400000>;
+            regulator-max-microvolt = <2050000>;
+            regulator-allowed-modes = <0 1>;
+            regulator-always-on;
+            regulator-state-mem {
+              regulator-on-in-suspend;
+              regulator-mode = <1>;
+            };
+          };
+          buck-e {
+            regulator-min-microvolt = <400000>;
+            regulator-max-microvolt = <2050000>;
+            regulator-allowed-modes = <0 1>;
+            regulator-always-on;
+            regulator-state-mem {
+              regulator-on-in-suspend;
+              regulator-mode = <1>;
+            };
+          };
+          buck-f {
+            regulator-min-microvolt = <400000>;
+            regulator-max-microvolt = <2050000>;
+            regulator-allowed-modes = <0 1>;
+            regulator-always-on;
+            regulator-state-mem {
+              regulator-on-in-suspend;
+              regulator-mode = <1>;
+            };
+          };
+          buck-g {
+            regulator-min-microvolt = <400000>;
+            regulator-max-microvolt = <2050000>;
+            regulator-allowed-modes = <0 1>;
+            regulator-always-on;
+            regulator-state-mem {
+              regulator-on-in-suspend;
+              regulator-mode = <1>;
+            };
+          };
+          buck-h {
+            regulator-min-microvolt = <400000>;
+            regulator-max-microvolt = <2050000>;
+            regulator-allowed-modes = <0 1>;
+            regulator-always-on;
+            regulator-state-mem {
+              regulator-on-in-suspend;
+              regulator-mode = <1>;
+            };
+          };
+          ldo1 {
+            regulator-min-microvolt = <1200000>;
+            regulator-max-microvolt = <1200000>;
+            regulator-always-on;
+            regulator-state-mem {
+              regulator-on-in-suspend;
+            };
+          };
+          ldo2 {
+            regulator-min-microvolt = <3300000>;
+            regulator-max-microvolt = <3300000>;
+            regulator-always-on;
+            regulator-state-mem {
+              regulator-on-in-suspend;
+            };
+          };
+        };
+      };
+    };

drivers/regulator/Kconfig

@@ -1254,6 +1254,17 @@ config REGULATOR_RTQ6752
 	  synchronous boost converters for PAVDD, and one synchronous NAVDD
 	  buck-boost. This device is suitable for automotive TFT-LCD panel.
 
+config REGULATOR_RTQ2208
+	tristate "Richtek RTQ2208 SubPMIC Regulator"
+	depends on I2C
+	select REGMAP_I2C
+	help
+	  This driver adds support for RTQ2208 SubPMIC regulators.
+	  The RTQ2208 is a multi-phase, programmable power management IC that
+	  integrate with dual multi-configurable, synchronous buck converters
+	  and two ldos. It features wide output voltage range from 0.4V to 2.05V
+	  and the capability to configure the corresponding power stages.
+
 config REGULATOR_S2MPA01
 	tristate "Samsung S2MPA01 voltage regulator"
 	depends on MFD_SEC_CORE || COMPILE_TEST

drivers/regulator/Makefile

@@ -147,6 +147,7 @@ obj-$(CONFIG_REGULATOR_RT6245)	+= rt6245-regulator.o
 obj-$(CONFIG_REGULATOR_RTMV20)	+= rtmv20-regulator.o
 obj-$(CONFIG_REGULATOR_RTQ2134) += rtq2134-regulator.o
 obj-$(CONFIG_REGULATOR_RTQ6752)	+= rtq6752-regulator.o
+obj-$(CONFIG_REGULATOR_RTQ2208) += rtq2208-regulator.o
 obj-$(CONFIG_REGULATOR_S2MPA01) += s2mpa01.o
 obj-$(CONFIG_REGULATOR_S2MPS11) += s2mps11.o
 obj-$(CONFIG_REGULATOR_S5M8767) += s5m8767.o