dt-bindings: power: reset: Convert syscon-reboot-mode to DT schema

Modern device tree bindings are supposed to be created as YAML-files
in accordance with dt-schema. This commit replaces SYSCON reboot-mode
legacy bare text bindings with YAML file. As before the bindings file
states that the corresponding dts node is supposed to be compatible
"syscon-reboot-mode" device and necessarily have an offset property
to determine which register from the regmap is supposed to keep the
mode on reboot.

Signed-off-by: Serge Semin <[e-mail]>
Reviewed-by: Rob Herring <[e-mail]>
Signed-off-by: Sebastian Reichel <[e-mail]>

Documentation/devicetree/bindings/power/reset/syscon-reboot-mode.txt

···
-SYSCON reboot mode driver
-
-This driver gets reboot mode magic value form reboot-mode driver
-and stores it in a SYSCON mapped register. Then the bootloader
-can read it and take different action according to the magic
-value stored.
-
-This DT node should be represented as a sub-node of a "syscon", "simple-mfd"
-node.
-
-Required properties:
-- compatible: should be "syscon-reboot-mode"
-- offset: offset in the register map for the storage register (in bytes)
-
-Optional property:
-- mask: bits mask of the bits in the register to store the reboot mode magic value,
-  default set to 0xffffffff if missing.
-
-The rest of the properties should follow the generic reboot-mode description
-found in reboot-mode.txt
-
-Example:
-	pmu: pmu@20004000 {
-		compatible = "rockchip,rk3066-pmu", "syscon", "simple-mfd";
-		reg = <0x20004000 0x100>;
-
-		reboot-mode {
-			compatible = "syscon-reboot-mode";
-			offset = <0x40>;
-			mode-normal = <BOOT_NORMAL>;
-			mode-recovery = <BOOT_RECOVERY>;
-			mode-bootloader = <BOOT_FASTBOOT>;
-			mode-loader = <BOOT_BL_DOWNLOAD>;
-		};
-	};

Documentation/devicetree/bindings/power/reset/syscon-reboot-mode.yaml

···
+# SPDX-License-Identifier: GPL-2.0-only
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/power/reset/syscon-reboot-mode.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Generic SYSCON reboot mode driver
+
+maintainers:
+  - Sebastian Reichel <[e-mail]>
+
+description: |
+  This driver gets reboot mode magic value from reboot-mode driver
+  and stores it in a SYSCON mapped register. Then the bootloader
+  can read it and take different action according to the magic
+  value stored. The SYSCON mapped register is retrieved from the
+  parental dt-node plus the offset. So the SYSCON reboot-mode node
+  should be represented as a sub-node of a "syscon", "simple-mfd" node.
+
+properties:
+  compatible:
+    const: syscon-reboot-mode
+
+  mask:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Update only the register bits defined by the mask (32 bit)
+
+  offset:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Offset in the register map for the mode register (in bytes)
+
+patternProperties:
+  "^mode-.+":
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Vendor-specific mode value written to the mode register
+
+additionalProperties: false
+
+required:
+  - compatible
+  - offset
+
+examples:
+  - |
+    #include <dt-bindings/soc/rockchip,boot-mode.h>
+
+    reboot-mode {
+      compatible = "syscon-reboot-mode";
+      offset = <0x40>;
+      mode-normal = <BOOT_NORMAL>;
+      mode-recovery = <BOOT_RECOVERY>;
+      mode-bootloader = <BOOT_FASTBOOT>;
+      mode-loader = <BOOT_BL_DOWNLOAD>;
+    };
+...