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

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Date:	Mon, 2 Jun 2014 14:54:04 +0530
From:	Amit Kachhap <amit.kachhap@...il.com>
To:	Javi Merino <javi.merino@....com>
Cc:	"linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
	"linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>,
	"rjw@...ysocki.net" <rjw@...ysocki.net>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"edubezval@...il.com" <edubezval@...il.com>,
	Zhang Rui <rui.zhang@...el.com>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"lenb@...nel.org" <lenb@...nel.org>
Subject: Re: [PATCH v1 2/6] thermal: cpu_cooling: Support passing driver
 private data.

On 5/29/14, Javi Merino <javi.merino@....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@...sung.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.

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;
>> +}
>> +
>
>
>
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