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

Thomas Petazzoni thomas.petazzoni at free-electrons.com
Tue Oct 1 11:33:58 EDT 2013

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?

Thomas Petazzoni, Free Electrons
Embedded Linux, Kernel and Android engineering

More information about the linux-arm-kernel mailing list