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authorGeert Uytterhoeven <geert@linux-m68k.org>2017-03-10 17:15:20 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-03-17 09:10:49 +0300
commitdd9502a9e9156dd854dd0bec0dd385b4662bab3e (patch)
treed1d0b8d3ba8de569dedca418cd7f937452883440 /Documentation/devicetree/bindings/auxdisplay
parent1d3b2af213902059d9f4b35eb15b53f8062dc3b3 (diff)
downloadlinux-dd9502a9e9156dd854dd0bec0dd385b4662bab3e.tar.xz
dt-bindings: auxdisplay: Add bindings for Hitachi HD44780
Add DT bindings for an Hitachi HD44780 Character LCD Controller where its M6800 bus interface is connected to GPIOs. Memory-mapped configurations are not yet supported. Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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+DT bindings for the Hitachi HD44780 Character LCD Controller
+
+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.
+
+Required properties:
+ - compatible: Must contain "hit,hd44780",
+ - data-gpios: Must contain an array of either 4 or 8 GPIO specifiers,
+ referring to the 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,
+ - enable-gpios: Must contain a GPIO specifier, referring to the GPIO pin
+ connected to the "E" (Enable) signal line of the LCD Controller's bus
+ interface,
+ - rs-gpios: Must contain a GPIO specifier, referring to the GPIO pin
+ connected to the "RS" (Register Select) signal line of the LCD Controller's
+ bus interface,
+ - display-height: Height of the display, in character cells,
+ - display-width: Width of the display, in character cells.
+
+Optional properties:
+ - rw-gpios: Must contain a GPIO specifier, referring to the GPIO pin
+ connected to the "RW" (Read/Write) signal line of the LCD Controller's bus
+ interface,
+ - backlight-gpios: Must contain a GPIO specifier, referring to the GPIO pin
+ used for enabling the LCD's backlight,
+ - internal-buffer-width: Internal buffer width (default is 40 for displays
+ with 1 or 2 lines, and display-width for displays with more than 2 lines).
+
+Example:
+
+ 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 = <2>;
+ display-width = <16>;
+ };