Messages in this thread | | | From | Geert Uytterhoeven <> | Date | Mon, 20 Jan 2020 11:10:37 +0100 | Subject | Re: [PATCH v1 2/5] pardata: new bus for parallel data access |
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Hi Sam,
(stumbled on this accidentally)
On Thu, Aug 2, 2018 at 9:46 PM Sam Ravnborg <sam@ravnborg.org> wrote: > The pardata supports implement a simple bus for devices > that are connected using a parallel bus driven by GPIOs. > The is often used in combination with simple displays > that is often seen in older embedded designs. > There is a demand for this support also in the linux > kernel for HW designs that uses these kind of displays. > > The pardata bus uses a platfrom_driver that when probed > creates devices for all child nodes in the DT, > which are then supposed to be handled by pardata_drivers. > > Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
> --- /dev/null > +++ b/Documentation/driver-api/pardata.rst > @@ -0,0 +1,60 @@ > +.. SPDX-License-Identifier: GPL-2.0 > + > +========================= > +Parallel Data Bus/Drivers > +========================= > + > +Displays may be connected using a simple parallel bus. > +This is often seen in embedded systems with a simple MCU, but is also > +used in Linux based systems to a small extent. > + > +The bus looks like this: > + > +.. code-block:: none > + > + ----+ > + | DB0-DB7 or DB4-DB7 +---- > + ===/======================== > + | E - enable | D > + ---------------------------- I > + C | Reset | S > + P ---------------------------- P > + U | Read/Write (one or two) | L > + ---------------------------- A > + | RS - instruction/data | Y > + ---------------------------- > + | +---- > + ----+
Oh, cool! Looks like this can be used by the hd44780 driver.
Documentation/devicetree/bindings/auxdisplay/hit,hd44780.txt drivers/auxdisplay/hd44780.c
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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