Re: [Lcd-linux] lcd over gpio

[Claudio <cla...@gm...>]

Hello Mattia,
did you have some news on this topic?
I took a couple of hitachi compatible LCD and a linux gpio enabled board.

2011/1/18 Mattia Jona-Lasinio <mat...@gm...>:
> On Tue, Jan 18, 2011 at 1:12 PM, Claudio <cla...@gm...> wrote:
>> Dear mattia,
>> let me introduce a different scenario.
>>
>> The USB device are really different each other and support for its
>> could be difficult and inefficient, beside on embedded devices
>> generally you want to use the USB port for something more useful.
>
> Hmmmm, quite a lot of people might disagree with you as USB is now
> considered THE universal and preferred way to connect external devices
> to computers. Anyway, I see your point.
>
>> The gpio implementaion instread allow you to support a huge range of
>> embedded devices like router, develop board as well some routerboard
>> or industial board; moreover you can use a USB to GPIO adapter (like
>> ftdi) and then connect any kind of lcd also on you modern laptop/pc
>> (that typically don't have parport or gpio).
>
> I agree and this should in principle be very easy. If the GPIO
> implementation in the kernel is at a usable level then I'm more than
> happy to try to use it. In any case it will provide a sort of standard
> way to access the display. If this is the case then it is very easy as
> the only two functions in the HD44780 driver that need a rewrite are
> the two lowlevel read and write functions. If I write a patch, will
> you be able to test it and report on it?
>
>> The parport implementation is hacky and should be mainained just for
>> history but it is de facto obsolete(how many device you can found with
>> parport today in your home?).
>
> I agree and that's why I wanted to move to something newer. LCD-Linux
> was intended at the beginning to provide a cheap display output to old
> and obsolete hardware. These days this goal does not make any sense as
> an embedded device can run as a router much more efficiently than an
> old computer.
>
>> In this scenario the GPIO support is priority and such version of
>> lcd-linux is, in imho, also more acceptable by mainline kernel.
>
> LCD-Linux was already proposed for inclusion in the kernel mainline
> but some issues prevented this. The main reason being that LCD-Linux
> duplicates in some sense the console emulation and kernel developers
> don't like duplicate code (why reinventing the wheel?). To make a long
> story short LCD-Linux wasn't rejected but it was asked to merge some
> parts of it with the existing kernel code, which is not always easy.
> There was some traffic about this on the main linux kernel maling list
> in july 2010.
>
> Best
>
> Mattia
>
>
>>
>>