[Lcd4linux-devel] Switch to new architecture

[Michael R. <re...@eu...>]

It has happened: I decided to start with the new driver architecture, 
which will use the Evaluator, and will support widgets.

I've been worrying for a long time how to start, and I had some other 
wishes which I didn't know how to do: for example, how to get a better 
naming convention into the source files (I want to keep them in one 
directory as long as possible). Anybode has an idea how to rename files 
when using CVS?

Now I'm goint the following way: I will introduce some new files, while 
keeping the old ones up and running. As far as the new architecture has 
at least the same level of functionality as the old one, I will start to 
drop the old files. At least I hope this works...

I started with drv.c and drv.h, which is the framework for all display 
drivers, and will someday replace 'display.c'.

Next I created an almost empty 'drv_MatrixOrbital.c'. You see, all 
drivers will have this 'drv_' from now on.

The new architecture has a seperation of drivers and models, where the 
old one only knew models (a model is what you specified in the config 
file as "Display")

A new driver has far less functions than the old ones, to be exactly, 
three as of now:

list() lists all supported models of this driver (for the output of 
lcd4linux -l)

init() initializes the driver
if it has to know what exact type of display it should serve, it's the 
driver's task to ask in the config file

quit() deinitializes the driver

There are no more put(), bar() and so on functions anymore, but the 
driver will register the widgets he offers. Every driver has to register 
a "text" or "label" widget, but nothing more. Think of a text-only 
display without user-defineable chars: there are no bars and no icons. A 
fully-graphics display can offer a lot of differet widgets, OTOH.


This is how the config file will look like:

Display "TheBigOne" {
    Driver MatrixOrbital
    Model  LK204-25
    Port   /dev/usb/tts/0
}

Display "TheSmallOne" {
    Driver HD44780
    Port   /dev/parport/0
    Size 16x1
    Wire {
       EX INIT
    }
}

Display "TheBigOne"


Note that you don't have to uncomment all the displays you don't have. 
Just select a "section"!


Stay tuned!


bye, Michael

-- 
Michael Reinelt                                   Tel: +43 676 3079941
Geisslergasse 4                                   Fax: +43 316  692343
A-8045 Graz, Austria                          e-mail: re...@eu...