linux-kernel - Re: [PATCH 2/6 v4] clk, highbank: Prevent glitches in non-bypass reset mode

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Date:	Mon, 12 Nov 2012 15:35:30 -0600
From:	Mark Langsdorf <mark.langsdorf@...xeda.com>
To:	Mike Turquette <mturquette@...aro.org>
CC:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"cpufreq@...r.kernel.org" <cpufreq@...r.kernel.org>,
	"linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
	Rob Herring <rob.herring@...xeda.com>
Subject: Re: [PATCH 2/6 v4] clk, highbank: Prevent glitches in non-bypass
 reset mode

On 11/12/2012 03:24 PM, Mike Turquette wrote:
> Quoting Mark Langsdorf (2012-11-07 10:32:42)
>> The highbank clock will glitch with the current code if the
>> clock rate is reset without relocking the PLL. Program the PLL
>> correctly to preven glitches.
>>
>> Signed-off-by: Mark Langsdorf <mark.langsdorf@...xeda.com>
>> Signed-off-by: Rob Herring <rob.herring@...xeda.com>
>> Cc: mturquette@...aro.org
> 
> Hi Mark,
> 
> Looks fine to me.
> 
> I seem to be missing the rest of this series in my mail.  Did you want
> me to take only this patch (2/6) into clk-next or were you only looking
> for my ACK?

The entire series enables highbank cpufreq. Would you normally take this
patch through cpufreq-next with an ACK or directly through clk-next?

--Mark Langsdorf
Calxeda, Inc.

>> ---
>> Changes from v3
>>         Changelog text and patch name now correspond to the actual patch
>>         was clk, highbank: remove non-bypass reset mode
>> Changes from v2
>>         None
>> Changes from v1:
>>         Removed erroneous reformating.
>>
>>  drivers/clk/clk-highbank.c | 2 ++
>>  1 file changed, 2 insertions(+)
>>
>> diff --git a/drivers/clk/clk-highbank.c b/drivers/clk/clk-highbank.c
>> index 52fecad..3a0b723 100644
>> --- a/drivers/clk/clk-highbank.c
>> +++ b/drivers/clk/clk-highbank.c
>> @@ -182,8 +182,10 @@ static int clk_pll_set_rate(struct clk_hw *hwclk, unsigned long rate,
>>                 reg |= HB_PLL_EXT_ENA;
>>                 reg &= ~HB_PLL_EXT_BYPASS;
>>         } else {
>> +               writel(reg | HB_PLL_EXT_BYPASS, hbclk->reg);
>>                 reg &= ~HB_PLL_DIVQ_MASK;
>>                 reg |= divq << HB_PLL_DIVQ_SHIFT;
>> +               writel(reg | HB_PLL_EXT_BYPASS, hbclk->reg);
>>         }
>>         writel(reg, hbclk->reg);
>>  
>> -- 
>> 1.7.11.7

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