Re: [PATCH v3 7/7] ARM: shmobile: kzm9g-reference: require ZB clock for Ethernet controller

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Geert,

On Thursday 30 October 2014 19:03:37 Geert Uytterhoeven wrote:
> On Thu, Oct 30, 2014 at 6:41 PM, Ulrich Hecht wrote:
> > On Wed, Oct 29, 2014 at 1:21 AM, Simon Horman <horms@verge.net.au> wrote:
> >> On Tue, Oct 28, 2014 at 06:02:16PM +0100, Ulrich Hecht wrote:
> >>> Unlike the legacy stuff, CCF disables the ethernet controller's clock
> >>> unless it is used somewhere.
> >> 
> >> This feels like it should come earlier in the series to avoid
> >> breaking then fixing ethernet support for kzm9g-reference.
> > 
> > The CCF support, not being used yet, doesn't actually break anything.
> > The reason this patch is separated from the rest is that it works, but
> > it's not completely clear (to me) how.
> > 
> > As Laurent has pointed out before, the LAN controller is not
> > (directly) hooked up to this clock, but to an external oscillator.
> > Nonetheless Ethernet won't work unless ZB is on, which I have
> > determined by trial and error. Maybe that should have been pointed out
> > in the description...
> 
> I don't have the schematics for kzm9g, but I guess the LAN controller
> is hooked up to the BSC (Bus State Controller).

Yes it is. We should probably model the BSC in DT, and add the LAN controller 
as a child of the BSC node. With automatic clock management in runtime PM, 
could we do without a BSC driver entirely ?

> According to the sh73a0 datasheet, ZBø is the clock for the BSC.

-- 
Regards,

Laurent Pinchart