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

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

Hi Geert,

On Wednesday 05 November 2014 22:06:38 Geert Uytterhoeven wrote:
> On Wed, Nov 5, 2014 at 4:43 PM, Laurent Pinchart wrote:
> >> > 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 ?
> 
> I'm afraid we're gonna need a bus driver to handle that correctly.
> Especially when considering the BSC is in a PM domain (A4S).
> 
> Fortunately A4S is always powered when the CPU is talking to Ethernet,
> as A4S contains the CPU cores, too.

If the BSC DT node references the MSTP clock and the power domain, do you 
think it would be possible to let core code handle them without requiring a 
custom driver (obviously with extensions to core code) ?

-- 
Regards,

Laurent Pinchart