dt-bindings: phy: Convert mixel,mipi-dsi-phy to json-schema

This patch converts the mixel,mipi-dsi-phy binding to
DT schema format using json-schema.

Comparing to the plain text version, the new binding adds
the 'assigned-clocks', 'assigned-clock-parents' and
'assigned-clock-rates' properites, otherwise 'make dtbs_check'
would complain that there are mis-matches.  Also, the new
binding requires the 'power-domains' property since all potential
SoCs that embed this PHY would provide a power domain for it.
The example of the new binding takes reference to the latest
dphy node in imx8mq.dtsi.

Cc: Guido Günther <agx@sigxcpu.org>
Cc: Kishon Vijay Abraham I <kishon@ti.com>
Cc: Vinod Koul <vkoul@kernel.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: NXP Linux Team <linux-imx@nxp.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Guido Günther <agx@sigxcpu.org>
Signed-off-by: Liu Ying <victor.liu@nxp.com>
Link: https://lore.kernel.org/r/20220419010852.452169-4-victor.liu@nxp.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

Documentation/devicetree/bindings/phy/mixel,mipi-dsi-phy.yaml

@@ -0,0 +1,72 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/phy/mixel,mipi-dsi-phy.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Mixel DSI PHY for i.MX8
+
+maintainers:
+  - Guido Günther <agx@sigxcpu.org>
+
+description: |
+  The Mixel MIPI-DSI PHY IP block is e.g. found on i.MX8 platforms (along the
+  MIPI-DSI IP from Northwest Logic). It represents the physical layer for the
+  electrical signals for DSI.
+
+properties:
+  compatible:
+    enum:
+      - fsl,imx8mq-mipi-dphy
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  clock-names:
+    const: phy_ref
+
+  assigned-clocks:
+    maxItems: 1
+
+  assigned-clock-parents:
+    maxItems: 1
+
+  assigned-clock-rates:
+    maxItems: 1
+
+  "#phy-cells":
+    const: 0
+
+  power-domains:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - clock-names
+  - assigned-clocks
+  - assigned-clock-parents
+  - assigned-clock-rates
+  - "#phy-cells"
+  - power-domains
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/imx8mq-clock.h>
+    dphy: dphy@30a0030 {
+        compatible = "fsl,imx8mq-mipi-dphy";
+        reg = <0x30a00300 0x100>;
+        clocks = <&clk IMX8MQ_CLK_DSI_PHY_REF>;
+        clock-names = "phy_ref";
+        assigned-clocks = <&clk IMX8MQ_CLK_DSI_PHY_REF>;
+        assigned-clock-parents = <&clk IMX8MQ_VIDEO_PLL1_OUT>;
+        assigned-clock-rates = <24000000>;
+        #phy-cells = <0>;
+        power-domains = <&pgc_mipi>;
+    };