dt-bindings: Add schemas for simple-framebuffer

The simple framebuffer is a binding that allows the bootloader to setup a
framebuffer, describe it in the Device Tree for the OS to pick it up and
use it as is.

Replace the current binding by a schema to allow the validation tools to
check those nodes.

Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Chen-Yu Tsai <wens@csie.org>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Maxime Jourdan <mjourdan@baylibre.com>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Signed-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/display/amlogic,simple-framebuffer.txt

-Meson specific Simple Framebuffer bindings
-
-This binding documents meson specific extensions to the simple-framebuffer
-bindings. The meson simplefb u-boot code relies on the devicetree containing
-pre-populated simplefb nodes.
-
-These extensions are intended so that u-boot can select the right node based
-on which pipeline is being used. As such they are solely intended for
-firmware / bootloader use, and the OS should ignore them.
-
-Required properties:
-- compatible: "amlogic,simple-framebuffer", "simple-framebuffer"
-- amlogic,pipeline, one of:
-  "vpu-cvbs"
-  "vpu-hdmi"
-
-Example:
-
-chosen {
-	#address-cells = <2>;
-	#size-cells = <2>;
-	ranges;
-
-	simplefb_hdmi: framebuffer-hdmi {
-		compatible = "amlogic,simple-framebuffer",
-			     "simple-framebuffer";
-		amlogic,pipeline = "vpu-hdmi";
-		clocks = <&clkc CLKID_HDMI_PCLK>,
-			 <&clkc CLKID_CLK81>,
-			 <&clkc CLKID_GCLK_VENCI_INT0>;
-		power-domains = <&pwrc_vpu>;
-	};
-};

Documentation/devicetree/bindings/display/simple-framebuffer-sunxi.txt

-Sunxi specific Simple Framebuffer bindings
-
-This binding documents sunxi specific extensions to the simple-framebuffer
-bindings. The sunxi simplefb u-boot code relies on the devicetree containing
-pre-populated simplefb nodes.
-
-These extensions are intended so that u-boot can select the right node based
-on which pipeline is being used. As such they are solely intended for
-firmware / bootloader use, and the OS should ignore them.
-
-Required properties:
-- compatible: "allwinner,simple-framebuffer"
-- allwinner,pipeline, one of:
-  "de_be0-lcd0"
-  "de_be1-lcd1"
-  "de_be0-lcd0-hdmi"
-  "de_be1-lcd1-hdmi"
-  "mixer0-lcd0"
-  "mixer0-lcd0-hdmi"
-  "mixer1-lcd1-hdmi"
-  "mixer1-lcd1-tve"
-
-Example:
-
-chosen {
-	#address-cells = <1>;
-	#size-cells = <1>;
-	ranges;
-
-	framebuffer@0 {
-		compatible = "allwinner,simple-framebuffer", "simple-framebuffer";
-		allwinner,pipeline = "de_be0-lcd0-hdmi";
-		clocks = <&pll5 1>, <&ahb_gates 36>, <&ahb_gates 43>,
-			 <&ahb_gates 44>;
-	};
-};

Documentation/devicetree/bindings/display/simple-framebuffer.txt

-Simple Framebuffer
-
-A simple frame-buffer describes a frame-buffer setup by firmware or
-the bootloader, with the assumption that the display hardware has already
-been set up to scan out from the memory pointed to by the reg property.
-
-Since simplefb nodes represent runtime information they must be sub-nodes of
-the chosen node (*). Simplefb nodes must be named "framebuffer@<address>".
-
-If the devicetree contains nodes for the display hardware used by a simplefb,
-then the simplefb node must contain a property called "display", which
-contains a phandle pointing to the primary display hw node, so that the OS
-knows which simplefb to disable when handing over control to a driver for the
-real hardware. The bindings for the hw nodes must specify which node is
-considered the primary node.
-
-It is advised to add display# aliases to help the OS determine how to number
-things. If display# aliases are used, then if the simplefb node contains a
-"display" property then the /aliases/display# path must point to the display
-hw node the "display" property points to, otherwise it must point directly
-to the simplefb node.
-
-If a simplefb node represents the preferred console for user interaction,
-then the chosen node's stdout-path property should point to it, or to the
-primary display hw node, as with display# aliases. If display aliases are
-used then it should be set to the alias instead.
-
-It is advised that devicetree files contain pre-filled, disabled framebuffer
-nodes, so that the firmware only needs to update the mode information and
-enable them. This way if e.g. later on support for more display clocks get
-added, the simplefb nodes will already contain this info and the firmware
-does not need to be updated.
-
-If pre-filled framebuffer nodes are used, the firmware may need extra
-information to find the right node. In that case an extra platform specific
-compatible and platform specific properties should be used and documented,
-see e.g. simple-framebuffer-sunxi.txt .
-
-Required properties:
-- compatible: "simple-framebuffer"
-- reg: Should contain the location and size of the framebuffer memory.
-- width: The width of the framebuffer in pixels.
-- height: The height of the framebuffer in pixels.
-- stride: The number of bytes in each line of the framebuffer.
-- format: The format of the framebuffer surface. Valid values are:
-  - r5g6b5 (16-bit pixels, d[15:11]=r, d[10:5]=g, d[4:0]=b).
-  - a8b8g8r8 (32-bit pixels, d[31:24]=a, d[23:16]=b, d[15:8]=g, d[7:0]=r).
-
-Optional properties:
-- clocks : List of clocks used by the framebuffer.
-- *-supply : Any number of regulators used by the framebuffer. These should
-	     be named according to the names in the device's design.
-
-  The above resources are expected to already be configured correctly.
-  The OS must ensure they are not modified or disabled while the simple
-  framebuffer remains active.
-
-- display : phandle pointing to the primary display hardware node
-
-Example:
-
-aliases {
-	display0 = &lcdc0;
-}
-
-chosen {
-	framebuffer0: framebuffer@1d385000 {
-		compatible = "simple-framebuffer";
-		reg = <0x1d385000 (1600 * 1200 * 2)>;
-		width = <1600>;
-		height = <1200>;
-		stride = <(1600 * 2)>;
-		format = "r5g6b5";
-		clocks = <&ahb_gates 36>, <&ahb_gates 43>, <&ahb_gates 44>;
-		lcd-supply = <&reg_dc1sw>;
-		display = <&lcdc0>;
-	};
-	stdout-path = "display0";
-};
-
-soc@1c00000 {
-	lcdc0: lcdc@1c0c000 {
-		compatible = "allwinner,sun4i-a10-lcdc";
-		...
-	};
-};
-
-
-*) Older devicetree files may have a compatible = "simple-framebuffer" node
-in a different place, operating systems must first enumerate any compatible
-nodes found under chosen and then check for other compatible nodes.

Documentation/devicetree/bindings/display/simple-framebuffer.yaml

+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/simple-framebuffer.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Simple Framebuffer Device Tree Bindings
+
+maintainers:
+  - Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
+  - Hans de Goede <hdegoede@redhat.com>
+
+description: |+
+  A simple frame-buffer describes a frame-buffer setup by firmware or
+  the bootloader, with the assumption that the display hardware has
+  already been set up to scan out from the memory pointed to by the
+  reg property.
+
+  Since simplefb nodes represent runtime information they must be
+  sub-nodes of the chosen node (*). Simplefb nodes must be named
+  framebuffer@<address>.
+
+  If the devicetree contains nodes for the display hardware used by a
+  simplefb, then the simplefb node must contain a property called
+  display, which contains a phandle pointing to the primary display
+  hw node, so that the OS knows which simplefb to disable when handing
+  over control to a driver for the real hardware. The bindings for the
+  hw nodes must specify which node is considered the primary node.
+
+  It is advised to add display# aliases to help the OS determine how
+  to number things. If display# aliases are used, then if the simplefb
+  node contains a display property then the /aliases/display# path
+  must point to the display hw node the display property points to,
+  otherwise it must point directly to the simplefb node.
+
+  If a simplefb node represents the preferred console for user
+  interaction, then the chosen node stdout-path property should point
+  to it, or to the primary display hw node, as with display#
+  aliases. If display aliases are used then it should be set to the
+  alias instead.
+
+  It is advised that devicetree files contain pre-filled, disabled
+  framebuffer nodes, so that the firmware only needs to update the
+  mode information and enable them. This way if e.g. later on support
+  for more display clocks get added, the simplefb nodes will already
+  contain this info and the firmware does not need to be updated.
+
+  If pre-filled framebuffer nodes are used, the firmware may need
+  extra information to find the right node. In that case an extra
+  platform specific compatible and platform specific properties should
+  be used and documented.
+
+properties:
+  compatible:
+    items:
+      - enum:
+          - allwinner,simple-framebuffer
+          - amlogic,simple-framebuffer
+      - const: simple-framebuffer
+
+  reg:
+    description: Location and size of the framebuffer memory
+
+  clocks:
+    description: List of clocks used by the framebuffer.
+
+  power-domains:
+    description: List of power domains used by the framebuffer.
+
+  width:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Width of the framebuffer in pixels
+
+  height:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Height of the framebuffer in pixels
+
+  stride:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Number of bytes of a line in the framebuffer
+
+  format:
+    description: >
+      Format of the framebuffer:
+        * `a8b8g8r8` - 32-bit pixels, d[31:24]=a, d[23:16]=b, d[15:8]=g, d[7:0]=r
+        * `r5g6b5` - 16-bit pixels, d[15:11]=r, d[10:5]=g, d[4:0]=b
+    enum:
+      - a8b8g8r8
+      - r5g6b5
+
+  display:
+    $ref: /schemas/types.yaml#/definitions/phandle
+    description: Primary display hardware node
+
+  allwinner,pipeline:
+    description: Pipeline used by the framebuffer on Allwinner SoCs
+    enum:
+      - de_be0-lcd0
+      - de_be0-lcd0-hdmi
+      - de_be0-lcd0-tve0
+      - de_be1-lcd0
+      - de_be1-lcd1-hdmi
+      - de_fe0-de_be0-lcd0
+      - de_fe0-de_be0-lcd0-hdmi
+      - de_fe0-de_be0-lcd0-tve0
+      - mixer0-lcd0
+      - mixer0-lcd0-hdmi
+      - mixer1-lcd1-hdmi
+      - mixer1-lcd1-tve
+
+  amlogic,pipeline:
+    description: Pipeline used by the framebuffer on Amlogic SoCs
+    enum:
+      - vpu-cvbs
+      - vpu-hdmi
+
+patternProperties:
+  "^[a-zA-Z0-9-]+-supply$":
+    $ref: /schemas/types.yaml#/definitions/phandle
+    description:
+      Regulators used by the framebuffer. These should be named
+      according to the names in the device design.
+
+required:
+  # The binding requires also reg, width, height, stride and format,
+  # but usually they will be filled by the bootloader.
+  - compatible
+
+additionalProperties: false
+
+examples:
+  - |
+    aliases {
+      display0 = &lcdc0;
+    };
+
+    chosen {
+      #address-cells = <1>;
+      #size-cells = <1>;
+      stdout-path = "display0";
+      framebuffer0: framebuffer@1d385000 {
+        compatible = "simple-framebuffer";
+        reg = <0x1d385000 3840000>;
+        width = <1600>;
+        height = <1200>;
+        stride = <3200>;
+        format = "r5g6b5";
+        clocks = <&ahb_gates 36>, <&ahb_gates 43>, <&ahb_gates 44>;
+        lcd-supply = <&reg_dc1sw>;
+        display = <&lcdc0>;
+      };
+    };
+
+    soc@1c00000 {
+      lcdc0: lcdc@1c0c000 {
+        compatible = "allwinner,sun4i-a10-lcdc";
+      };
+    };
+
+...