dt-bindings: reset: st,sti-picophyreset: Convert to yaml

Convert the device tree bindings for the STMicroelectronics STi
SoftReset controller to YAML schema to allow participating in DT
validation.
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Cc: Peter Griffin <peter.griffin@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220407154338.4190674-12-p.zabel@pengutronix.de

Documentation/devicetree/bindings/reset/st,sti-picophyreset.txt

-STMicroelectronics STi family Sysconfig Picophy SoftReset Controller
-=============================================================================
-
-This binding describes a reset controller device that is used to enable and
-disable on-chip PicoPHY USB2 phy(s) using "softreset" control bits found in
-the STi family SoC system configuration registers.
-
-The actual action taken when softreset is asserted is hardware dependent.
-However, when asserted it may not be possible to access the hardware's
-registers and after an assert/deassert sequence the hardware's previous state
-may no longer be valid.
-
-Please refer to Documentation/devicetree/bindings/reset/reset.txt
-for common reset controller binding usage.
-
-Required properties:
-- compatible: Should be "st,stih407-picophyreset"
-- #reset-cells: 1, see below
-
-Example:
-
-	picophyreset: picophyreset-controller {
-		compatible = "st,stih407-picophyreset";
-		#reset-cells = <1>;
-	};
-
-Specifying picophyreset control of devices
-=======================================
-
-Device nodes should specify the reset channel required in their "resets"
-property, containing a phandle to the picophyreset device node and an
-index specifying which channel to use, as described in
-Documentation/devicetree/bindings/reset/reset.txt.
-
-Example:
-
-	usb2_picophy0: usbpicophy@0 {
-		resets = <&picophyreset STIH407_PICOPHY0_RESET>;
-	};
-
-Macro definitions for the supported reset channels can be found in:
-include/dt-bindings/reset/stih407-resets.h

Documentation/devicetree/bindings/reset/st,stih407-picophyreset.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/reset/st,stih407-picophyreset.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: STMicroelectronics STi family Sysconfig Picophy SoftReset Controller
+
+maintainers:
+  - Peter Griffin <peter.griffin@linaro.org>
+
+description: |
+  This binding describes a reset controller device that is used to enable and
+  disable on-chip PicoPHY USB2 phy(s) using "softreset" control bits found in
+  the STi family SoC system configuration registers.
+
+  The actual action taken when softreset is asserted is hardware dependent.
+  However, when asserted it may not be possible to access the hardware's
+  registers and after an assert/deassert sequence the hardware's previous state
+  may no longer be valid.
+
+properties:
+  compatible:
+    const: st,stih407-picophyreset
+
+  '#reset-cells':
+    const: 1
+
+required:
+  - compatible
+  - '#reset-cells'
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/reset/stih407-resets.h>
+
+    picophyreset: picophyreset-controller {
+        compatible = "st,stih407-picophyreset";
+        #reset-cells = <1>;
+    };
+
+    // Specifying picophyreset control of devices
+    usb2_picophy0: usbpicophy {
+        resets = <&picophyreset STIH407_PICOPHY0_RESET>;
+    };