linux-kernel - Re: [PATCH v4 3/3] thermal: mediatek: Add cpu dynamic power cooling model.

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Message-ID: <1448875581.29031.14.camel@mtksdaap41>
Date:	Mon, 30 Nov 2015 17:26:21 +0800
From:	dawei chien <dawei.chien@...iatek.com>
To:	Viresh Kumar <viresh.kumar@...aro.org>
CC:	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Rob Herring <robh+dt@...nel.org>,
	Pawel Moll <pawel.moll@....com>,
	Mark Rutland <mark.rutland@....com>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	"Kumar Gala" <galak@...eaurora.org>,
	Matthias Brugger <matthias.bgg@...il.com>,
	Daniel Kurtz <djkurtz@...omium.org>,
	Sascha Hauer <s.hauer@...gutronix.de>,
	Daniel Lezcano <daniel.lezcano@...aro.org>,
	<devicetree@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>,
	<linux-kernel@...r.kernel.org>, <linux-pm@...r.kernel.org>,
	<linux-mediatek@...ts.infradead.org>,
	<srv_heupstream@...iatek.com>,
	Sascha Hauer <kernel@...gutronix.de>,
	"Punit Agrawal" <punit.agrawal@....com>
Subject: Re: [PATCH v4 3/3] thermal: mediatek: Add cpu dynamic power cooling
 model.

On Mon, 2015-11-30 at 11:08 +0530, Viresh Kumar wrote:
> On 27-11-15, 17:32, Dawei Chien wrote:
> > MT8173 cpufreq driver use of_cpufreq_power_cooling_register registering
> > cooling devices with dynamic power coefficient.
> > 
> > Signed-off-by: Dawei Chien <dawei.chien@...iatek.com>
> > ---
> > This patch is base on patchset:
> > https://lkml.org/lkml/2015/11/17/251
> > ---
> >  drivers/cpufreq/mt8173-cpufreq.c |   28 ++++++++++++++++++++--------
> >  1 file changed, 20 insertions(+), 8 deletions(-)
> > 
> > diff --git a/drivers/cpufreq/mt8173-cpufreq.c b/drivers/cpufreq/mt8173-cpufreq.c
> > index 83001dc..4d39468 100644
> > --- a/drivers/cpufreq/mt8173-cpufreq.c
> > +++ b/drivers/cpufreq/mt8173-cpufreq.c
> > @@ -263,24 +263,34 @@ static int mtk_cpufreq_set_target(struct cpufreq_policy *policy,
> >  	return 0;
> >  }
> >  
> > +#define DYNAMIC_POWER "dynamic-power-coefficient"
> > +
> >  static void mtk_cpufreq_ready(struct cpufreq_policy *policy)
> >  {
> >  	struct mtk_cpu_dvfs_info *info = policy->driver_data;
> >  	struct device_node *np = of_node_get(info->cpu_dev->of_node);
> > +	u32 capacitance;
> >  
> >  	if (WARN_ON(!np))
> >  		return;
> >  
> >  	if (of_find_property(np, "#cooling-cells", NULL)) {
> > -		info->cdev = of_cpufreq_cooling_register(np,
> > -							 policy->related_cpus);
> > +		if (!info->cdev) {
> 
> Why will info->cdev be non-NULL here ?

This is a error-checking to avoid user or any script by command line hotplug CPU
more than two times, we don't need to register cooling device on this case.

I will remove it if you don't agree it.

> > +			of_property_read_u32(np, DYNAMIC_POWER, &capacitance);
> 
> This can fail, in which case capacitance will be used uninitialized.
> Fix that by initializing it with 0 at the beginning of this routine.

Thank you, I will follow your comment to fix it on next version.

> > +			info->cdev = of_cpufreq_power_cooling_register(np,
> > +							policy->related_cpus,
> > +							capacitance,
> > +							NULL);
> >  
> > -		if (IS_ERR(info->cdev)) {
> > -			dev_err(info->cpu_dev,
> > -				"running cpufreq without cooling device: %ld\n",
> > -				PTR_ERR(info->cdev));
> > +			if (IS_ERR(info->cdev)) {
> > +				dev_err(info->cpu_dev,
> > +					"running cpufreq without cooling device: %ld\n",
> > +					PTR_ERR(info->cdev));
> >  
> > -			info->cdev = NULL;
> > +				info->cdev = NULL;
> > +			}
> >  		}
> >  	}
> >  
> > @@ -460,7 +470,9 @@ static int mtk_cpufreq_exit(struct cpufreq_policy *policy)
> >  {
> >  	struct mtk_cpu_dvfs_info *info = policy->driver_data;
> >  
> > -	cpufreq_cooling_unregister(info->cdev);
> > +	if (info->cdev)
> > +		cpufreq_cooling_unregister(info->cdev);
> > +
> 
> Why do you need to update this?

This is a error-checking to avoid user or any script by command line
unplug CPU more than two times, we don't need to unregister cooling
device on this case.

I will remove it if you don't agree it.

> >  	dev_pm_opp_free_cpufreq_table(info->cpu_dev, &policy->freq_table);
> >  	mtk_cpu_dvfs_info_release(info);
> >  	kfree(info);
> > -- 
> > 1.7.9.5
> 


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