Messages in this thread | | | Date | Wed, 28 Nov 2012 09:01:15 -0600 | From | Mark Langsdorf <> | Subject | Re: [PATCH 6/6 v6] cpufreq, highbank: add support for highbank cpufreq |
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On 11/28/2012 09:17 AM, Shawn Guo wrote: > On Wed, Nov 28, 2012 at 10:58:02PM +0800, Shawn Guo wrote: >> On Wed, Nov 28, 2012 at 07:16:12AM -0600, Mark Langsdorf wrote: >>> 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.
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