linux-kernel - Re: [PATCH 2/2] [RFC] cpufreq: omap: scale regulator from clk notifier

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Date:	Tue, 17 Jul 2012 08:42:54 -0700
From:	Mike Turquette <mturquette@...com>
To:	Prashant Gaikwad <pgaikwad@...dia.com>
Cc:	Mike Turquette <mturquette@...aro.org>,
	"paul@...an.com" <paul@...an.com>,
	"broonie@...nsource.wolfsonmicro.com" 
	<broonie@...nsource.wolfsonmicro.com>,
	"viresh.kumar@...aro.org" <viresh.kumar@...aro.org>,
	Peter De Schrijver <pdeschrijver@...dia.com>,
	"rnayak@...com" <rnayak@...com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"rob.herring@...xeda.com" <rob.herring@...xeda.com>,
	"ccross@...roid.com" <ccross@...roid.com>,
	"tglx@...utronix.de" <tglx@...utronix.de>,
	"shawn.guo@...aro.org" <shawn.guo@...aro.org>,
	"linus.walleij@...aro.org" <linus.walleij@...aro.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH 2/2] [RFC] cpufreq: omap: scale regulator from clk
 notifier

On 20120717-10:50, Prashant Gaikwad wrote:
> On Saturday 14 July 2012 05:46 AM, Mike Turquette wrote:
> >+	/* scaling up?  scale voltage before frequency */
> >+	if (cnd->new_rate>  cnd->old_rate) {
> >+		dev_dbg(mpu_dev, "cpufreq-omap: %d mV -->  %d mV\n",
> >+				volt_old, volt_new);
> >+
> >+		ret = regulator_set_voltage(mpu_reg, volt_new - tol, volt_new + tol);
> >+
> >+		if (ret<  0) {
> >+			dev_warn(mpu_dev, "%s: unable to scale voltage up.\n",
> >+				 __func__);
> >+			return NOTIFY_BAD;
> >+		}
> >+	}
> >+
> >+	/* scaling down?  scale voltage after frequency */
> >+	if (cnd->new_rate<  cnd->old_rate) {
> >+		dev_dbg(mpu_dev, "cpufreq-omap: %d mV -->  %d mV\n",
> >+				volt_old, volt_new);
> >+
> >+		ret = regulator_set_voltage(mpu_reg, volt_new - tol, volt_new + tol);
> >+
> >+		if (ret<  0) {
> >+			dev_warn(mpu_dev, "%s: unable to scale voltage down.\n",
> >+				 __func__);
> >+			return NOTIFY_BAD;
> >+		}
> >  	}
> 
> How are you checking pre and post rate change condition here? Need
> switch case for event?
>

Oops.  This version of the patch is missing that.  I previously had a
version of the patch which did pre/post checking but all of this code
was in arch/arm/mach-omap2/.  It looks like when I moved things around I
accidentally dropped that bit.

Anyways that is trivial to do and simply changes like the following:

if (cnd->new_rate > cnd->old_rate && flags & CLK_PRE_RATE_CHANGE)
	...

if (cnd->new_rate < cnd->old_rate && flags & CLK_POST_RATE_CHANGE)
	...

Regards,
Mike
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