Re: Freescale unified driver

[Gary Thomas <gary at mlbassoc dot com>]

Gerster Jochen-B01096 wrote:
> Hi
>
> I don't think it's a good idee to make one unified driver for many archs in one source directory!
> The problem is the pheripheral from the freescale archs may have some little difference
> which makes it necessary to do some changes on the unified driver!
> Also someone want to use other features or an other concept in the driver ....
>
> I think it would be better to copy a similar driver to its own source dir
> and then adjust it to the new arch(I think this is the normal process).
> So it is ensured running ecos code stay running and not crashs due to a ecos source update
> because the new unified driver gets a bug for archX while it was modified for archY by an other developer!
> And the porting/adjusting process becomes shorter/easier because the developer of the new port hasn't to
> dicuss every change in the mailing list and hasn't to pay attention on the other archs.
>
> The problem is that the developers don't seat in the same office where the can have a short meeting and test the unified
> driver on the different archs it's used for.
> So easy sourcecode "care"(?) isn't the main goal.

Actually, we try to do this all the time, whenever it's possible.
The basic idea is to have a driver "template" where the platform
(and architecture) details are filled in by macros, etc, in separate
platform files.

Look at how the generic (16x5x) serial drivers work for example.
There is a basic structure in .../devs/serial/generic/16x5x
To use the driver, you need the platform details, e.g. for the
ARM PID board in .../devs/serial/arm/pid or a Super-H platform
in .../devs/serial/sh/se77x9, etc.  Thus, one very generic driver
can work on many platforms and multiple architectures.

All it takes is a bit of care in how the driver is written :-)

> Best regards
> Jochen
>
>
>
>
>
>
> -----Original Message-----
> From: ecos-patches-owner@ecos.sourceware.org [mailto:ecos-patches-owner@ecos.sourceware.org] On Behalf Of Ilija Koco
> Sent: Donnerstag, 3. August 2006 20:02
> To: Uwe Kindler
> Cc: ecos-patches@ecos.sourceware.org
> Subject: Re: kernel dsr handling new option
>
> Hi Uwe
>
> I placed eSCI driver in devs/serial/freescale/esci (I created freescale dir for freescale's serial devices employed on various fs architecture chips).
>
> There is a possibility for us to get a job that will need can. In that case I'll look for your driver and do same for can (devs/can/flexcan).
> I'll send you a note.
>
> Regards
> Ilija
>
> Uwe Kindler wrote:
> > Hello Ilija,
> >
> > > Making multiple drivers for same device is not a good practice.
> > The FlexCAN device driver is part of the official eCos CVS since may 
> > 2005. It is in the devs/can/m68k/mcf52xx directory. I know that the 
> > FlexCAN module is not only part of the Coldfire family but it also 
> > implemented in other Freescale microcontrollers. It should be no 
> > proplem for another developer to port this driver for other Freescale 
> > processors. If someone will do a port for another Freescale product 
> > then maybe we should think about moving the driver into a separate 
> > directory and make it common for all Freescale products that use 
> > FlexCAN module.
> >
> >
> > Best Regards
> >
> >
> > Uwe Kindler
> > Software Engineering
> >
> > --
> >
> > cetoni GmbH
> > Am Wiesenring 6
> > D-07554 Korbussen
> >
> > Tel.: +49 (0) 36602 338 28
> > Fax:  +49 (0) 36602 338 11
> > uwe.kindler@cetoni.de
> > www.cetoni.de


--
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Gary Thomas                 |  Consulting for the
MLB Associates              |    Embedded world
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