Re: [PATCH v1 2/6] thermal: cpu_cooling: Support passing driver private data.

[Eduardo Valentin <edubezval@gmail.com>]

On Mon, Jun 02, 2014 at 02:54:04PM +0530, Amit Kachhap wrote:
> On 5/29/14, Javi Merino <javi.merino@arm.com> wrote:
> > Hi Amit,
> >
> > One minor comment.
> >
> > On Thu, May 29, 2014 at 09:15:30AM +0100, Amit Daniel Kachhap wrote:
> >> This patch allows the caller of cpufreq cooling APIs to register along
> >> with their driver data which will be useful while receiving any cooling
> >> states
> >> notifications.
> >> This patch is in preparation to add notfication support for cpufrequency
> >> cooling changes. This change also removes the unnecessary exposing of
> >> internal housekeeping structure via thermal_cooling_device->devdata to
> >> the
> >> users of cpufreq cooling APIs. As part of this implmentation, this private
> >> local
> >> structure (cpufreq_dev) is now stored in a list and scanned for each call
> >> to
> >> cpu cooling interfaces.
> >>
> >> Signed-off-by: Amit Daniel Kachhap <amit.daniel@samsung.com>
> >> ---
> >>  Documentation/thermal/cpu-cooling-api.txt          |    3 +-
> >>  drivers/thermal/cpu_cooling.c                      |   89
> >> ++++++++++++++++----
> >>  drivers/thermal/db8500_cpufreq_cooling.c           |    2 +-
> >>  drivers/thermal/samsung/exynos_thermal_common.c    |    2 +-
> >>  drivers/thermal/ti-soc-thermal/ti-thermal-common.c |    2 +-
> >>  include/linux/cpu_cooling.h                        |    5 +-
> >>  6 files changed, 80 insertions(+), 23 deletions(-)
> >>
> >> diff --git a/Documentation/thermal/cpu-cooling-api.txt
> >> b/Documentation/thermal/cpu-cooling-api.txt
> >> index fca24c9..aaa07c6 100644
> >> --- a/Documentation/thermal/cpu-cooling-api.txt
> >> +++ b/Documentation/thermal/cpu-cooling-api.txt
> >> @@ -17,13 +17,14 @@ the user. The registration APIs returns the cooling
> >> device pointer.
> >>
> >>  1.1 cpufreq registration/unregistration APIs
> >>  1.1.1 struct thermal_cooling_device *cpufreq_cooling_register(
> >> -       struct cpumask *clip_cpus)
> >> +       struct cpumask *clip_cpus, void *devdata)
> >>
> >>      This interface function registers the cpufreq cooling device with the
> >> name
> >>      "thermal-cpufreq-%x". This api can support multiple instances of
> >> cpufreq
> >>      cooling devices.
> >>
> >>     clip_cpus: cpumask of cpus where the frequency constraints will
> >> happen.
> >> +   devdata: driver private data pointer.
> >>
> >>  1.1.2 void cpufreq_cooling_unregister(struct thermal_cooling_device
> >> *cdev)
> >>
> >> diff --git a/drivers/thermal/cpu_cooling.c
> >> b/drivers/thermal/cpu_cooling.c
> >> index 16388b0..6d145d5 100644
> >> --- a/drivers/thermal/cpu_cooling.c
> >> +++ b/drivers/thermal/cpu_cooling.c
> >> @@ -50,16 +50,18 @@ struct cpufreq_cooling_device {
> >>         unsigned int cpufreq_state;
> >>         unsigned int cpufreq_val;
> >>         struct cpumask allowed_cpus;
> >> +       struct list_head node;
> >>  };
> >>  static DEFINE_IDR(cpufreq_idr);
> >>  static DEFINE_MUTEX(cooling_cpufreq_lock);
> >>
> >> -static unsigned int cpufreq_dev_count;
> >> -
> >>  /* notify_table passes value to the CPUFREQ_ADJUST callback function. */
> >>  #define NOTIFY_INVALID NULL
> >>  static DEFINE_PER_CPU(struct cpufreq_cooling_device *, notify_device);
> >>
> >> +/* A list to hold all the cpufreq cooling devices registered */
> >> +static LIST_HEAD(cpufreq_cooling_list);
> >> +
> >>  /**
> >>   * get_idr - function to get a unique id.
> >>   * @idr: struct idr * handle used to create a id.
> >> @@ -98,6 +100,26 @@ static void release_idr(struct idr *idr, int id)
> >>
> >>  /* Below code defines functions to be used for cpufreq as cooling device
> >> */
> >>
> >> +/**
> >> + * cpufreq_cooling_get_info - function to cpufreq_dev for the
> >> corresponding cdev
> >> + * @cdev: pointer of the cooling device
> >> + *
> >> + * This function will loop through the cpufreq_cooling_device list and
> >> + * return the matching device
> >> + *
> >
> > You should add a "Locking:" section here which documents that this
> > function must be called with cooling_cpufreq_lock held.
> Yes agreed. Will update in the next version.

One good practice is to check the output of scripts/kerneldoc on your
changed file.

Cheers

> 
> Thanks,
> Amit
> >
> > Cheers,
> > Javi
> >
> >> + * Return: cpufreq_cooling_device if matched with the cdev or NULL if
> >> not
> >> + * matched.
> >> + */
> >> +static inline struct cpufreq_cooling_device *
> >> +cpufreq_cooling_get_info(struct thermal_cooling_device *cdev)
> >> +{
> >> +       struct cpufreq_cooling_device *cpufreq_dev = NULL;
> >> +       list_for_each_entry(cpufreq_dev, &cpufreq_cooling_list, node)
> >> +               if (cpufreq_dev->cool_dev == cdev)
> >> +                       break;
> >> +       return cpufreq_dev;
> >> +}
> >> +
> >
> >
> >