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dt-bindings: auxdisplay: Add bindings for Hitachi HD44780

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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>
This commit is contained in:
Geert Uytterhoeven 2017-03-10 15:15:20 +01:00 • committed by Greg Kroah-Hartman
parent 1d3b2af213
commit dd9502a9e9
1 changed files with 44 additions and 0 deletions
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Documentation/devicetree/bindings/auxdisplay/hit,hd44780.txt Normal file
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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>;
};