dt-bindings: display: Add Sharp Memory LCD bindings

Add device tree bindings for the monochrome Sharp Memory LCD

Co-developed-by: Mehdi Djait <[e-mail]>
Signed-off-by: Mehdi Djait <[e-mail]>
Signed-off-by: Alex Lanzano <[e-mail]>
Reviewed-by: Krzysztof Kozlowski <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]
Signed-off-by: Dmitry Baryshkov <[e-mail]>

Documentation/devicetree/bindings/display/sharp,ls010b7dh04.yaml

···
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/sharp,ls010b7dh04.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Sharp Memory LCD panels
+
+maintainers:
+  - Alex Lanzano <[e-mail]>
+
+description:
+  Sharp Memory LCDs are a series of monochrome displays that operate over
+  a SPI bus. The displays require a signal (VCOM) to be generated to prevent
+  DC bias build up resulting in pixels being unable to change. Three modes
+  can be used to provide the VCOM signal ("software", "external", "pwm").
+
+properties:
+  compatible:
+    enum:
+      - sharp,ls010b7dh04
+      - sharp,ls011b7dh03
+      - sharp,ls012b7dd01
+      - sharp,ls013b7dh03
+      - sharp,ls013b7dh05
+      - sharp,ls018b7dh02
+      - sharp,ls027b7dh01
+      - sharp,ls027b7dh01a
+      - sharp,ls032b7dd02
+      - sharp,ls044q7dh01
+
+  reg:
+    maxItems: 1
+
+  spi-max-frequency:
+    maximum: 2000000
+
+  sharp,vcom-mode:
+    $ref: /schemas/types.yaml#/definitions/string
+    description: |
+      software - This mode relies on a software operation to send a
+      "maintain display" message to the display, toggling the vcom
+      bit on and off with each message
+
+      external - This mode relies on an external clock to generate
+      the signal on the EXTCOMM pin
+
+      pwm - This mode relies on a pwm device to generate the signal
+      on the EXTCOMM pin
+
+    enum: [software, external, pwm]
+
+  enable-gpios: true
+
+  pwms:
+    maxItems: 1
+    description: External VCOM signal
+
+required:
+  - compatible
+  - reg
+  - sharp,vcom-mode
+
+allOf:
+  - $ref: panel/panel-common.yaml#
+  - $ref: /schemas/spi/spi-peripheral-props.yaml#
+
+  - if:
+      properties:
+        sharp,vcom-mode:
+          const: pwm
+    then:
+      required:
+        - pwms
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    spi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        display@0 {
+            compatible = "sharp,ls013b7dh03";
+            reg = <0>;
+            spi-cs-high;
+            spi-max-frequency = <1000000>;
+            sharp,vcom-mode = "software";
+        };
+    };
+...