SHMobile Compatibility String Inconsistencies

[Guennadi Liakhovetski]

Hi Laurent,

On Tue, 27 Aug 2013, Laurent Pinchart wrote:

> Hi Guennadi,
> 
> On Monday 26 August 2013 18:08:52 Guennadi Liakhovetski wrote:
> > On Sat, 24 Aug 2013, Simon Horman wrote:
> > > On Fri, Aug 23, 2013 at 01:31:31PM +0200, Laurent Pinchart wrote:
> > > > On Friday 23 August 2013 12:11:11 David Gibson wrote:
> > > > > On Thu, Aug 22, 2013 at 02:46:40PM +0900, Simon Horman wrote:
> > > > > > Hi Laurent, Hi Guennadi, Hi All,
> > > > > > 
> > > > > > Olof has brought to my attention that there is some inconsistency
> > > > > > in the way that compatibility strings for SHMobile are named and he
> > > > > > has asked us to clean things up for v3.12.
> > > > > > 
> > > > > > Looking through arch/arm/boot/dts/ I see that we have:
> > > > > > 
> > > > > > 1. {gpio,pfc}-r8aXXXX and;
> > 
> > Add shdma-<soc> to the above
> > 
> > > > > > 2. r8aXXXX-sdhi
> > > > > > 
> > > > > > The inconsistency that Olof has asked us to resolve is that we
> > > > > > should either use r8aXXXX- or -r8aXXXX. Not both.
> > 
> > Given the 3:1 score the choice seems rather simple to me. So, if we do
> > have to make those consistent, let's change SDHI.
> 
> Agreed.
> 
> > > > > > It seems to me that neither option is inherently better than the
> > > > > > other so we should just choose the path of least resistance to make
> > > > > > things consistent.
> > > > > > 
> > > > > > Laurent, Guennadi, do you have any opinions on if it would
> > > > > > be easier to change the GPIO and PFC compatibility strings;
> > > > > > or to change the SDHI compatibility strings?
> > > > > > 
> > > > > > Ideally I would like you to come to some sort of consensus and send
> > > > > > patches.
> > > > > 
> > > > > So, by all means clean this up in the dts.
> > > > > 
> > > > > BUT, in keeping with the recent discussions on improving the DT
> > > > > process, the corresponding drivers must continue to recognize both
> > > > > forms, so that old DTs will still work correctly.
> > > > 
> > > > Given the early state of DT support in arm/mach-shmobile, I'm pretty
> > > > sure we have no DT-based systems in the wild. The old compatibility
> > > > string could in my opinion just be dropped.
> > > 
> > > I tend to agree, though I don't mind either way.
> > 
> > So, what path should we choose? I see 2 SDHI users in your current "devel"
> > brunch: sh73a0 (kzm9g) and r8a73a4 (ape6evm). Should we make a single
> > patch, changing the driver and both users and push it via ARM with Chris'
> > ack or shall we add new compats, switch .dtsi's, remove old compats - over
> > 2 kernel versions?
> 
> I'm fine with both, but in the latter case I don't see a need to spread it 
> over two kernel versions.

The latter only makes sense if we want to push patches via separate trees, 
i.e.
DMA
ARM
DMA
and doing this within 1 kernel release would be difficult. Whereas if we 
want to push all 3 patches via 1 tree, then I'd say just doing 1 patch 
would be easier.

Thanks
Guennadi

> > Can we still get anything for this into 3.12 or is it too late? Would it be
> > a "fix" enough for -rc2 / late -rc1?
> 
> -- 
> Regards,
> 
> Laurent Pinchart

---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/