[PATCH 3/4] clk: kirkwood: Add CLK_IGNORE_UNUSED to ethernet ge0 and ge1 clocks

Jason Cooper jason at lakedaemon.net
Tue Oct 1 11:36:31 EDT 2013


On Tue, Oct 01, 2013 at 05:33:58PM +0200, Thomas Petazzoni wrote:
> Dear Jason Cooper,
> 
> On Tue, 1 Oct 2013 11:15:28 -0400, Jason Cooper wrote:
> 
> > > Sorry for jumping into the discussion, but how does that solve the case
> > > when the driver is loaded as a module, and therefore unused clocks are
> > > disabled before the driver ->probe() function gets called?
> > 
> > Sorry, I wrote the reply to JasonG just moments before and assumed a
> > little knowledge of that in this reply.
> > 
> > We would use Ezequiel's patch to ensure CLK_IGNORE_UNUSED is set for the
> > clock during boot, then, after boot, mv643xx_eth's probe would look for
> > the mac address in the DT.  If it's there, it would unset the flag
> > knowing that it can recover the mac address from the DT.  Then we could
> > get the power savings from suspend/unload.
> 
> Ah, ok. What was wrong with the idea of getting the MAC address from
> the hardware early at boot time, and adjust the in-memory Device Tree
> with this information, so that the mv643xx_eth driver can find them
> whenever it gets loaded, and regardless of whether clocks have been
> disabled or not?

I'm personally not opposed to that at all.  iirc, there was some
opposition (from Grant?) to modifying the DT from within the kernel.
Sorry, I can't put my finger on the objection atm.

thx,

Jason.



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