Re: [PATCH] video: hd44780: Add hd44780 lcd display driver
From: Lars Poeschel
Date: Thu Dec 07 2017 - 03:33:54 EST
On Wed, Dec 6, 2017 at 16:04:10 CET Geert Uytterhoeven wrote:
> Hi Lars,
>
> On Wed, Dec 6, 2017 at 2:52 PM, Lars Poeschel <poeschel@xxxxxxxxxxx> wrote:
> > This adds a console driver for hd44780 based character lcd displays and
> > clones. The driver currently supports 20x4 character displays with
> > character ROMs A00 and A02.
> > The hardware wirings to the display have to be supplied to the kernel in
> > the devicetree. The binding doc has the necessary information.
> > There are also tons of these cheap displays sold with a serial
> > interface. Many of them use a simple pcf8574 gpio expanders. An example
> > for using that kind of display is also in the binding doc.
> >
> > Signed-off-by: Lars Poeschel <poeschel@xxxxxxxxxxx>
>
> Thanks for your patch!
>
> > ---
> >
> > .../bindings/video/console/hd44780con.txt | 42 ++
> > drivers/video/console/Kconfig | 13 +
> > drivers/video/console/Makefile | 1 +
> > drivers/video/console/hd44780con.c | 676
> > +++++++++++++++++++++
> I'm wondering if you could implement this on top of the existing charlcd
> framework:
>
> drivers/auxdisplay/charlcd.c
> include/misc/charlcd.h
>
> which can use the existing hd44780 backend:
>
> Documentation/devicetree/bindings/auxdisplay/hit,hd44780.txt
> drivers/auxdisplay/hd44780.c
>
> That way it can be used on other character LCDs, like the one supported by
> drivers/auxdisplay/panel.c.
Oh! Yes, this is a very interesting idea! This would involve multiple steps
until this would be useful for me, but I will definitely have a look at this!
So, please drop my patch for now. If for some reason in the future I find,
that it should go upstream, I will submit it again.
BTW thanks for the hint about the hd44780 charlcd backend. I did not know
about this. My hd44780 console driver is quite a bit old. I just found time to
clean up, rebase, test and submit it now.
Regards,
Lars