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+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/auxdisplay/hit,hd44780.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Hitachi HD44780 Character LCD Controller
+
+maintainers:
+ - Geert Uytterhoeven <geert@linux-m68k.org>
+
+description:
+ The Hitachi HD44780 Character LCD Controller is commonly used on character
+ LCDs that can display one or more lines of text. It exposes an M6800 bus
+ interface, which can be used in either 4-bit or 8-bit mode. By using a
+ GPIO expander it is possible to use the driver with one of the popular I2C
+ expander boards based on the PCF8574 available for these displays. For
+ an example see below.
+
+properties:
+ compatible:
+ const: hit,hd44780
+
+ data-gpios:
+ description:
+ GPIO pins connected to the data signal lines DB0-DB7 (8-bit mode) or
+ DB4-DB7 (4-bit mode) of the LCD Controller's bus interface.
+ oneOf:
+ - maxItems: 4
+ - maxItems: 8
+
+ enable-gpios:
+ description:
+ GPIO pin connected to the "E" (Enable) signal line of the LCD
+ Controller's bus interface.
+ maxItems: 1
+
+ rs-gpios:
+ description:
+ GPIO pin connected to the "RS" (Register Select) signal line of the LCD
+ Controller's bus interface.
+ maxItems: 1
+
+ rw-gpios:
+ description:
+ GPIO pin connected to the "RW" (Read/Write) signal line of the LCD
+ Controller's bus interface.
+ maxItems: 1
+
+ backlight-gpios:
+ description: GPIO pin used for enabling the LCD's backlight.
+ 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
+ - data-gpios
+ - enable-gpios
+ - rs-gpios
+ - display-height-chars
+ - display-width-chars
+
+additionalProperties: false
+
+examples:
+ - |
+ #include <dt-bindings/gpio/gpio.h>
+ auxdisplay {
+ compatible = "hit,hd44780";
+
+ data-gpios = <&hc595 0 GPIO_ACTIVE_HIGH>,
+ <&hc595 1 GPIO_ACTIVE_HIGH>,
+ <&hc595 2 GPIO_ACTIVE_HIGH>,
+ <&hc595 3 GPIO_ACTIVE_HIGH>;
+ enable-gpios = <&hc595 4 GPIO_ACTIVE_HIGH>;
+ rs-gpios = <&hc595 5 GPIO_ACTIVE_HIGH>;
+
+ display-height-chars = <2>;
+ display-width-chars = <16>;
+ };
+ - |
+ #include <dt-bindings/gpio/gpio.h>
+ i2c {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ pcf8574: pcf8574@27 {
+ compatible = "nxp,pcf8574";
+ reg = <0x27>;
+ gpio-controller;
+ #gpio-cells = <2>;
+ };
+ };
+ hd44780 {
+ compatible = "hit,hd44780";
+ display-height-chars = <2>;
+ display-width-chars = <16>;
+ data-gpios = <&pcf8574 4 0>,
+ <&pcf8574 5 0>,
+ <&pcf8574 6 0>,
+ <&pcf8574 7 0>;
+ enable-gpios = <&pcf8574 2 0>;
+ rs-gpios = <&pcf8574 0 0>;
+ rw-gpios = <&pcf8574 1 0>;
+ backlight-gpios = <&pcf8574 3 0>;
+ };