linux-kernel - Re: [PATCH v3 01/12] PM / devfreq: Init user limits from OPP limits, not viceversa

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Message-ID: <20180615210619.GA249892@rodete-desktop-imager.corp.google.com>
Date:   Fri, 15 Jun 2018 14:06:21 -0700
From:   Brian Norris <briannorris@...omium.org>
To:     Matthias Kaehlcke <mka@...omium.org>
Cc:     MyungJoo Ham <myungjoo.ham@...sung.com>,
        Kyungmin Park <kyungmin.park@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>, linux-pm@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        Douglas Anderson <dianders@...omium.org>,
        Enric Balletbo i Serra <enric.balletbo@...labora.com>,
        "Rafael J . Wysocki" <rjw@...ysocki.net>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        Lee Jones <lee.jones@...aro.org>
Subject: Re: [PATCH v3 01/12] PM / devfreq: Init user limits from OPP limits,
 not viceversa

Hi,

On Thu, Jun 14, 2018 at 12:47:01PM -0700, Matthias Kaehlcke wrote:
> Commit ab8f58ad72c4 ("PM / devfreq: Set min/max_freq when adding
> the devfreq device") introduced the initialization of the user
> limits min/max_freq from the lowest/highest available OPPs. Later
> commit f1d981eaecf8 ("PM / devfreq: Use the available min/max
> frequency") added scaling_min/max_freq, which actually represent
> the frequencies of the lowest/highest available OPP. scaling_min/
> max_freq are initialized with the values from min/max_freq, which
> is totally correct in the context, but a bit awkward to read.
> 
> Swap the initialization and assign scaling_min/max_freq with the
> OPP freqs and then the user limts min/max_freq with scaling_min/
> max_freq.
> 
> Needless to say that this change is a NOP, intended to improve
> readability.
> ---

BTW, putting the '---' here means that stuff below it usually gets
dropped when applied (e.g., with git-am). So it'll drop your
Signed-off-by and Reviewed-by. Not a huge problem if the maintainers
look out for that.

> Signed-off-by: Matthias Kaehlcke <mka@...omium.org>
> Reviewed-by: Chanwoo Choi <cw00.choi@...sung.com>

Reviewed-by: Brian Norris <briannorris@...omium.org>

> 
> Changes in v3:
> - none
> 
> Changes in v2:
> - added 'Reviewed-by: Chanwoo Choi <cw00.choi@...sung.com>' tag
> 
>  drivers/devfreq/devfreq.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
> index fe2af6aa88fc..0057ef5b0a98 100644
> --- a/drivers/devfreq/devfreq.c
> +++ b/drivers/devfreq/devfreq.c
> @@ -604,21 +604,21 @@ struct devfreq *devfreq_add_device(struct device *dev,
>  		mutex_lock(&devfreq->lock);
>  	}
>  
> -	devfreq->min_freq = find_available_min_freq(devfreq);
> -	if (!devfreq->min_freq) {
> +	devfreq->scaling_min_freq = find_available_min_freq(devfreq);
> +	if (!devfreq->scaling_min_freq) {
>  		mutex_unlock(&devfreq->lock);
>  		err = -EINVAL;
>  		goto err_dev;
>  	}
> -	devfreq->scaling_min_freq = devfreq->min_freq;
> +	devfreq->min_freq = devfreq->scaling_min_freq;
>  
> -	devfreq->max_freq = find_available_max_freq(devfreq);
> -	if (!devfreq->max_freq) {
> +	devfreq->scaling_max_freq = find_available_max_freq(devfreq);
> +	if (!devfreq->scaling_max_freq) {
>  		mutex_unlock(&devfreq->lock);
>  		err = -EINVAL;
>  		goto err_dev;
>  	}
> -	devfreq->scaling_max_freq = devfreq->max_freq;
> +	devfreq->max_freq = devfreq->scaling_max_freq;
>  
>  	dev_set_name(&devfreq->dev, "devfreq%d",
>  				atomic_inc_return(&devfreq_no));
> -- 
> 2.18.0.rc1.242.g61856ae69a-goog
>