[PATCH 2/2] auxdisplay: devicetree doc for HD44780/PCF8574

[Ralf Schlatterbeck <rsc@runtux.com>]

Add devicetree documentation with example.

Signed-off-by: Ralf Schlatterbeck <rsc@runtux.com>
---
 .../auxdisplay/hit,hd44780+nxp,pcf8575.yaml   | 65 +++++++++++++++++++
 1 file changed, 65 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/auxdisplay/hit,hd44780+nxp,pcf8575.yaml

diff --git a/Documentation/devicetree/bindings/auxdisplay/hit,hd44780+nxp,pcf8575.yaml b/Documentation/devicetree/bindings/auxdisplay/hit,hd44780+nxp,pcf8575.yaml
new file mode 100644
index 000000000000..c8e822c43b10
--- /dev/null
+++ b/Documentation/devicetree/bindings/auxdisplay/hit,hd44780+nxp,pcf8575.yaml
@@ -0,0 +1,65 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/auxdisplay/hit,hd44780+nxp,pcf8575.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Hitachi HD44780 Character LCD Controller attached to I2C via PCF8575
+
+maintainers:
+  - Ralf Schlatterbeck <rsc@runtux.com>
+
+description:
+  The Hitachi HD44780 Character LCD Controller is commonly used on character
+  LCDs that can display one or more lines of text. The display itself
+  exposes a parallel connection but they're often used with a PCF8575
+  I/O expander to connect them to an I2C bus.
+
+properties:
+  compatible:
+    const: hit,hd44780+nxp,pcf8575
+
+  reg:
+    description: I2C-bus address
+    maxItems: 1
+
+  display-height-chars:
+    description: Height of the display, in character cells,
+    $ref: /schemas/types.yaml#/definitions/uint32
+    minimum: 1
+    maximum: 4
+
+  display-width-chars:
+    description: Width of the display, in character cells.
+    $ref: /schemas/types.yaml#/definitions/uint32
+    minimum: 1
+    maximum: 64
+
+  internal-buffer-width:
+    description:
+      Internal buffer width (default is 40 for displays with 1 or 2 lines, and
+      display-width-chars for displays with more than 2 lines).
+    $ref: /schemas/types.yaml#/definitions/uint32
+    minimum: 1
+    maximum: 64
+
+required:
+  - compatible
+  - display-height-chars
+  - display-width-chars
+
+additionalProperties: false
+
+examples:
+  - |
+    i2c@2000 {
+      #address-cells = <1>;
+      #size-cells = <0>;
+
+      auxdisplay: hd44780@27 {
+        compatible = "hit,hd44780+nxp,pcf8575";
+        reg = <0x27>;
+        display-height-chars = <2>;
+        display-width-chars = <16>;
+      };
+    };
-- 
2.20.1