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SubjectRe: [PATCH v5 04/12] PM / devfreq: Add struct devfreq_policy
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Hi Matthias,

On 2018년 07월 07일 02:07, Matthias Kaehlcke wrote:
> Hi,
>
> On Wed, Jul 04, 2018 at 11:51:30AM +0900, Chanwoo Choi wrote:
>> Hi,
>>
>> On 2018년 07월 04일 08:46, Matthias Kaehlcke wrote:
>>> Move variables related with devfreq policy changes from struct devfreq
>>> to the new struct devfreq_policy and add a policy field to struct devfreq.
>>>
>>> The following variables are moved:
>>>
>>> df->min/max_freq => p->user.min/max_freq
>>> df->scaling_min/max_freq => p->devinfo.min/max_freq
>>> df->governor => p->governor
>>> df->governor_name => p->governor_name
>>>
>>> Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
>>> Reviewed-by: Brian Norris <briannorris@chromium.org>
>>> ---
>>> Changes in v5:
>>> - none
>>>
>>> Changes in v4:
>>> - added 'Reviewed-by: Brian Norris <briannorris@chromium.org>' tag
>>>
>>> Changes in v3:
>>> - none
>>>
>>> Changes in v2:
>>> - performance, powersave and simpleondemand governors don't need changes
>>> with "PM / devfreq: Don't adjust to user limits in governors"
>>> - formatting fixes
>>> ---
>>> drivers/devfreq/devfreq.c | 137 ++++++++++++++++-------------
>>> drivers/devfreq/governor_passive.c | 4 +-
>>> include/linux/devfreq.h | 38 +++++---
>
>
>>> 3 files changed, 103 insertions(+), 76 deletions(-)
>>>
>>
>> (skip)
>>
>>>
>>> diff --git a/drivers/devfreq/governor_passive.c b/drivers/devfreq/governor_passive.c
>>> index 3bc29acbd54e..e0987c749ec2 100644
>>> --- a/drivers/devfreq/governor_passive.c
>>> +++ b/drivers/devfreq/governor_passive.c
>>> @@ -99,12 +99,12 @@ static int update_devfreq_passive(struct devfreq *devfreq, unsigned long freq)
>>> {
>>> int ret;
>>>
>>> - if (!devfreq->governor)
>>> + if (!devfreq->policy.governor)
>>> return -EINVAL;
>>>
>>> mutex_lock_nested(&devfreq->lock, SINGLE_DEPTH_NESTING);
>>>
>>> - ret = devfreq->governor->get_target_freq(devfreq, &freq);
>>> + ret = devfreq->policy.governor->get_target_freq(devfreq, &freq);
>>> if (ret < 0)
>>> goto out;
>>>
>>> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
>>> index 3aae5b3af87c..9bf23b976f4d 100644
>>> --- a/include/linux/devfreq.h
>>> +++ b/include/linux/devfreq.h
>>> @@ -109,6 +109,30 @@ struct devfreq_dev_profile {
>>> unsigned int max_state;
>>> };
>>>
>>> +/**
>>> + * struct devfreq_freq_limits - Devfreq frequency limits
>>> + * @min_freq: minimum frequency
>>> + * @max_freq: maximum frequency
>>> + */
>>> +struct devfreq_freq_limits {
>>> + unsigned long min_freq;
>>> + unsigned long max_freq;
>>> +};
>>> +
>>> +/**
>>> + * struct devfreq_policy - Devfreq policy
>>> + * @user: frequency limits requested by the user
>>> + * @devinfo: frequency limits of the device (available OPPs)
>>> + * @governor: method how to choose frequency based on the usage.
>>
>> nitpick. remove '.' on the end of line.
>
> Ok
>
>>> + * @governor_name: devfreq governor name for use with this devfreq
>>> + */
>>> +struct devfreq_policy {
>>> + struct devfreq_freq_limits user;
>>> + struct devfreq_freq_limits devinfo;
>>> + const struct devfreq_governor *governor;
>>> + char governor_name[DEVFREQ_NAME_LEN];
>>> +};
>>> +
>>> /**
>>> * struct devfreq - Device devfreq structure
>>> * @node: list node - contains the devices with devfreq that have been
>>> @@ -117,8 +141,6 @@ struct devfreq_dev_profile {
>>> * @dev: device registered by devfreq class. dev.parent is the device
>>> * using devfreq.
>>> * @profile: device-specific devfreq profile
>>> - * @governor: method how to choose frequency based on the usage.
>>> - * @governor_name: devfreq governor name for use with this devfreq
>>> * @nb: notifier block used to notify devfreq object that it should
>>> * reevaluate operable frequencies. Devfreq users may use
>>> * devfreq.nb to the corresponding register notifier call chain.
>>> @@ -126,10 +148,7 @@ struct devfreq_dev_profile {
>>> * @previous_freq: previously configured frequency value.
>>> * @data: Private data of the governor. The devfreq framework does not
>>> * touch this.
>>> - * @min_freq: Limit minimum frequency requested by user (0: none)
>>> - * @max_freq: Limit maximum frequency requested by user (0: none)
>>> - * @scaling_min_freq: Limit minimum frequency requested by OPP interface
>>> - * @scaling_max_freq: Limit maximum frequency requested by OPP interface
>>> + * @policy: Policy for frequency adjustments
>>
>> The devfreq_policy contains the range of frequency and governor information.
>> But, this description focus on the frequency. You need to explain the more
>> correct description of 'policy'.
>
> I wouldn't say that the focus is on 'frequency', but on 'frequency
> adjustments', and the governor is an integral part of them.

OK. I agree your original description.

>
> I can change it to "Policy for frequency adjustments, including
> frequency limits and the governor" if you prefer. I'm open to other
> suggestions.

(snip)

--
Best Regards,
Chanwoo Choi
Samsung Electronics
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