linux-kernel - Re: [PATCH 13/13] auxdisplay: Add HD44780 Character LCD support

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Date:   Wed, 8 Feb 2017 18:19:03 +0100
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     Andy Shevchenko <andy.shevchenko@...il.com>
Cc:     Miguel Ojeda Sandonis <miguel.ojeda.sandonis@...il.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Willy Tarreau <willy@...roxy.com>,
        Ksenija Stanojevic <ksenija.stanojevic@...il.com>,
        Arnd Bergmann <arnd@...db.de>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        devicetree <devicetree@...r.kernel.org>
Subject: Re: [PATCH 13/13] auxdisplay: Add HD44780 Character LCD support

Hi Andy,

On Wed, Feb 8, 2017 at 5:27 PM, Andy Shevchenko
<andy.shevchenko@...il.com> wrote:
> On Wed, Feb 8, 2017 at 3:41 PM, Geert Uytterhoeven <geert@...ux-m68k.org> wrote:
>> On Wed, Feb 8, 2017 at 2:38 PM, Andy Shevchenko
>> <andy.shevchenko@...il.com> wrote:
>>> Btw, have you any plans to make an order among spreaded LCD drivers in
>>> kernel? Perhaps we may gather them under auxdisplay hood?
>>
>> I have no such plan. I just had a long-standing personal interest in hd44780.
>
> I have one too regarding to I2C/SPI interfaced hardware.
> If you remember it was an attempt for lcd-linux to be upstreamed,
> which provides (besides i2c/spi bus drivers) those LCDs as tty
> devices.
> Also interesting feature to have.

I'm actually driving mine from SPI, using a 74HCT595 shift register and
the 74x164 GPIO driver.  Should work with i2c and a PCF8574 GPIO
expander too, except that my SoC has 3.3V I/Os, while my display
needs 5V, which is taken care of by the HCT shift register.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-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