Re: [PATCHv3 0/7] gpio: extend basic_mmio_gpio for differentcontrollers

From: Jamie Iles
Date: Wed May 04 2011 - 10:57:39 EST


Hi Alan,

On Wed, May 04, 2011 at 03:44:40PM +0100, Alan Cox wrote:
> > OK, so here's what I've got so far (patches attached). I've updated the
> > basic_mmio_gpio library with your initial lkml patch and updated it to
> > allow bgpio_chip to be embedded in another structure. I've also
> > attempted to convert over the bt8xx and langwell drivers but they're a
> > little rough around the edges in places (and untested as I don't have
> > the hardware).
>
> Looking at the Langwell driver you replace 130 lines of code that do the
> job, with 126 lines of code that do setup for a whole extra module which
> makes it bigger and slower as well as much harder to maintain.
>
> That sounds to me like for Langwell at least it is not worth doing
> because all you've done is added complexity, indirection and overhead. So
> NAK the Langwell one.

I picked that one because I thought it might convert nicely, but it
didn't! I posted it anyway in case I'm missing a better way to do it
and to give a fair representation.

With regards to the ARM drivers, lots of these aren't currently devices
(in the driver model) so converting many of these would be net code
increase but I suspect that it's probably worth it in these cases
(providing that's the only complexity).

> The bt8xx looks a nice example of one of the cases where it will help
> however.

Yes, and I suspect there are a few others too.

Jamie
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