Messages in this thread | | | From | Geert Uytterhoeven <> | Date | Mon, 20 Mar 2017 16:27:01 +0100 | Subject | Re: [PATCH v2 4/5] dt-bindings: auxdisplay: Add bindings for Hitachi HD44780 |
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Hi Rob, Greg,
On Mon, Mar 20, 2017 at 4:15 PM, Rob Herring <robh@kernel.org> wrote: > On Fri, Mar 10, 2017 at 03:15:20PM +0100, Geert Uytterhoeven wrote: >> 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>
>> --- /dev/null >> +++ b/Documentation/devicetree/bindings/auxdisplay/hit,hd44780.txt
>> +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. > > display-{width,height}-chars
Makes sense.
Greg: As this is already in char-misc-next, shall I send an update for the bindings and the driver?
>> +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, > > Active state?
That's typically handled via the last cell of the GPIO specifier, cfr. GPIO_ACTIVE_HIGH / GPIO_ACTIVE_LOW in <dt-bindings/gpio/gpio.h>.
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
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