On 11/28/2012 09:17 AM, Shawn Guo wrote:

On Wed, Nov 28, 2012 at 10:58:02PM +0800, Shawn Guo wrote:

quoted

On Wed, Nov 28, 2012 at 07:16:12AM -0600, Mark Langsdorf wrote:

quoted

I'd
have to move most of the logic of hb_set_target() into
clk_highbank.c:clk_pll_set_rate() and then add extra logic for when
cpufreq is not enabled/loaded.

You only need to move hb_voltage_change() into cpu clock's .set_rate()
hook with no need of checking if cpufreq is enabled or not.

Need to also check whether frequency or voltage should be changed first
in .set_rate() though.

Yes, that's entirely what I meant when I said that I would need to move
most of the hb_set_target() logic into .set_rate(). I would also need to
account for retries if the voltage set operation fails, which it
sometimes does.

The ECME handles changing the voltage but doesn't look like a voltage
regulator. Amongst other things, by design it doesn't export meaningful
voltage information to Linux. I tried to get cpufreq-clk0 to work with
the Highbank design and it ended up being much easier and more sane to
create a separate driver.

--Mark Langsdorf
Calxeda, Inc.