linux-kernel - Re: [PATCH v2 2/9] cpufreq: Auto-register the driver as a thermal cooling device if asked

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Date:   Wed, 23 Jan 2019 11:39:29 +0100
From:   "Rafael J. Wysocki" <rafael@...nel.org>
To:     Viresh Kumar <viresh.kumar@...aro.org>
Cc:     Amit Kucheria <amit.kucheria@...aro.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-arm-msm <linux-arm-msm@...r.kernel.org>,
        Eduardo Valentin <edubezval@...il.com>,
        Stephen Boyd <swboyd@...omium.org>,
        Doug Anderson <dianders@...omium.org>,
        Matthias Kaehlcke <mka@...omium.org>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Ingo Molnar <mingo@...nel.org>,
        Sudeep Holla <sudeep.holla@....com>,
        Tao Wang <kevin.wangtao@...ilicon.com>,
        Linux PM <linux-pm@...r.kernel.org>
Subject: Re: [PATCH v2 2/9] cpufreq: Auto-register the driver as a thermal
 cooling device if asked

On Wed, Jan 23, 2019 at 11:36 AM Viresh Kumar <viresh.kumar@...aro.org> wrote:
>
> On 21-01-19, 21:10, Amit Kucheria wrote:
> > @@ -151,6 +152,11 @@ struct cpufreq_policy {
> >
> >       /* For cpufreq driver's internal use */
> >       void                    *driver_data;
> > +
> > +#ifdef CONFIG_CPU_THERMAL
> > +     /* Pointer to the cooling device if used for thermal mitigation */
> > +     struct thermal_cooling_device *cdev;
> > +#endif
> >  };
> >
> >  /* Only for ACPI */
> > @@ -386,6 +392,12 @@ struct cpufreq_driver {
> >   */
> >  #define CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING    BIT(6)
> >
> > +/*
> > + * Set by drivers that want the core to automatically register the cpufreq
> > + * driver as a thermal cooling device.
> > + */
> > +#define CPUFREQ_AUTO_REGISTER_COOLING_DEV    BIT(7)
> > +
> >  int cpufreq_register_driver(struct cpufreq_driver *driver_data);
> >  int cpufreq_unregister_driver(struct cpufreq_driver *driver_data);
> >
> > @@ -415,6 +427,19 @@ cpufreq_verify_within_cpu_limits(struct cpufreq_policy *policy)
> >                       policy->cpuinfo.max_freq);
> >  }
> >
> > +#ifdef CONFIG_CPU_THERMAL
> > +static inline void register_cooling_device(struct cpufreq_policy *policy) {
> > +     policy->cdev = of_cpufreq_cooling_register(policy);
> > +}
> > +
> > +static inline void unregister_cooling_device(struct cpufreq_policy *policy) {
> > +     cpufreq_cooling_unregister(policy->cdev);
> > +     policy->cdev = NULL;
> > +}
> > +#else
> > +static inline void register_cooling_device(struct cpufreq_policy *policy) {}
> > +static inline void unregister_cooling_device(struct cpufreq_policy *policy) {}
> > +#endif
>
> The whole ifdef hackery here saves space for a pointer per policy.
> Just get rid of it, it isn't worth it.

Is struct thermal_cooling_device defined if CONFIG_THERMAL is unset?