Re: gpio: dwapb: Synopsys Designware GPIO

[Jamie Iles <jamie-wmLquQDDieKakBO8gow8eQ@public.gmane.org>]

Hi Steffen,

On Thu, Oct 31, 2013 at 04:58:03PM +0100, Steffen Trumtrar wrote:
> Hi Alan,
> 
> On Thu, Oct 31, 2013 at 10:34:50AM -0500, delicious quinoa wrote:
> > On Thu, Oct 31, 2013 at 10:18 AM, Dinh Nguyen <dinh.linux-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> > > Yes, we'll post a patch up on rocketboards-next and maybe we can post them
> > > to the mailing list too?
> > >
> > Hi Steffen,
> > 
> > I've posted a branch on rocketboards.orgs' linux-socfpga-next.git.
> > The branch name is dwapb-gpio-3.11.
> > 
> 
> good. I will have a look.
> 
> > The top five patches are:
> > 1. Remove the Altera gpio-dw.c driver
> > 2 & 3.  Cherrypick Jamie's stuff from his git repo
> > 4. Enable gpio-dwapb in our defconfig and dts
> > 5. This is the main patch here: use irq_domain_add_linear for
> > gpio-dwapb.c plus a few bug fixes.
> > 
> > If you'd rather see that last patch on the mailing list, I can post it
> > there for review.
> > 
> 
> I wonder if we want to really keep the binding as it is proposed by
> Jamie. Do we really win anything by having to specify the banks in the
> DT? In my version I get the number of ports, width etc. from the config registers
> of the device. I think everything that the device knows itself and can be read
> out at runtime shouldn't be specified in the DT.
> And it seems that the binding was never merged, so I guess we can change it.

The reason for having it split into banks is that for hardware that has 
a mixture of bank sizes (odd hardware admittedly, but that includes 
hardware that I was writing the driver for), we had a setup like 16 pins 
on bank A, 16 on B, 1 on C and 16 on D where each bank could have a 
maximum of 32, so converting from a data sheet to GPIO number is not 
obvious.  Grant Likely suggested representing the banks as different 
devices, so that's how I created the binding.

Jamie
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