dt-bindings: mmc: Convert MMC Card binding to a schema

MMC Cards can have an optional Device Tree binding to add
non-discoverable properties.

Now that we have the DT validation in place, let's convert the device
tree bindings for that driver over to a YAML schema.

Some of these properties were already described in the MMC controller
binding, even though they are not generic and do not apply to any
device, so we took the occasion to fix this.

Cc: [e-mail]
Cc: Ulf Hansson <[e-mail]>
Signed-off-by: Maxime Ripard <[e-mail]>
Reviewed-by: Rob Herring <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Ulf Hansson <[e-mail]>

Documentation/devicetree/bindings/mmc/mmc-card.txt

···
-mmc-card / eMMC bindings
-------------------------
-
-This documents describes the devicetree bindings for a mmc-host controller
-child node describing a mmc-card / an eMMC, see "Use of Function subnodes"
-in mmc.txt
-
-Required properties:
--compatible : Must be "mmc-card"
--reg        : Must be <0>
-
-Optional properties:
--broken-hpi : Use this to indicate that the mmc-card has a broken hpi
-              implementation, and that hpi should not be used
-
-Example:
-
-&mmc2 {
-	pinctrl-names = "default";
-	pinctrl-0 = <&mmc2_pins_a>;
-	vmmc-supply = <&reg_vcc3v3>;
-	bus-width = <8>;
-	non-removable;
-
-	mmccard: mmccard@0 {
-		reg = <0>;
-		compatible = "mmc-card";
-		broken-hpi;
-	};
-};

Documentation/devicetree/bindings/mmc/mmc-card.yaml

···
+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mmc/mmc-card.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: MMC Card / eMMC Generic Device Tree Bindings
+
+maintainers:
+  - Ulf Hansson <[e-mail]>
+
+description: |
+  This documents describes the devicetree bindings for a mmc-host controller
+  child node describing a mmc-card / an eMMC.
+
+properties:
+  compatible:
+    const: mmc-card
+
+  reg:
+    const: 0
+
+  broken-hpi:
+    $ref: /schemas/types.yaml#/definitions/flag
+    description:
+      Use this to indicate that the mmc-card has a broken hpi
+      implementation, and that hpi should not be used.
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    mmc {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        card@0 {
+            compatible = "mmc-card";
+            reg = <0>;
+            broken-hpi;
+        };
+    };
+
+...

Documentation/devicetree/bindings/mmc/mmc-controller.yaml

···
               subnode describes. A value of 0 denotes the memory SD
               function, values from 1 to 7 denote the SDIO functions.
 
-      broken-hpi:
-        $ref: /schemas/types.yaml#/definitions/flag
-        description:
-          Use this to indicate that the mmc-card has a broken hpi
-          implementation, and that hpi should not be used.
-
     required:
       - reg