linux-kernel - [PATCH v3 0/4] PM / devfreq: Add cpu based scaling support to passive governor

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Date:   Mon,  9 May 2022 21:03:33 +0900
From:   Chanwoo Choi <cwchoi00@...il.com>
To:     linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     johnson.wang@...iatek.com, mka@...omium.org, wenst@...omium.org,
        jia-wei.chang@...iatek.com, andrew-sh.cheng@...iatek.com,
        hsinyi@...omium.org, saravanak@...gle.com, cw00.choi@...sung.com,
        myungjoo.ham@...sung.com, kyungmin.park@...sung.com
Subject: [PATCH v3 0/4] PM / devfreq: Add cpu based scaling support to passive governor

The devfreq passive governor has already supported the devfreq parent device
for coupling the frequency change if some hardware have the constraints
such as power sharing and so on.

Add cpu based scaling support to passive governor with required-opp property.
It uses the cpufreq notifier to catch the frequency change timing of cpufreq
and get the next frequency according to new cpu frequency by using required-opp
property. It is based on patch[1] and then just code clean-up by myself.

Make the common code for both passive_devfreq and passive_cpufreq
parent type to remove the duplicate code.

[1] [RFC,v2] PM / devfreq: Add cpu based scaling support to passive_governor
- https://lore.kernel.org/patchwork/patch/1101049/

Changes from v2:
: https://patchwork.kernel.org/project/linux-pm/cover/20220507150145.531864-1-cw00.choi@samsung.com/
- Drop the following patch ("PM / devfreq: passive: Update frequency when start governor")
- Move p_data->this initialization into cpufreq_passive_regiser_notifier()

Changes from v1:
: https://patchwork.kernel.org/project/linux-pm/cover/20210617060546.26933-1-cw00.choi@samsung.com/
- Rename cpu_data variable to parent_cpu_data to avoid build fail
- Use for_each_possible_cpu macro when register cpufreq transition notifier
- Add missing exception handling when cpufreq_passive_register_notifier is failed
- Keep cpufreq_policy for posible cpus instead of NR_CPU in order to avoid
  the memory waste when NR_CPU is too high.
- Add reviewed-by tag of Matthias Kaehlcke for patch1


Chanwoo Choi (3):
  PM / devfreq: Export devfreq_get_freq_range symbol within devfreq
  PM / devfreq: passive: Reduce duplicate code when passive_devfreq case
  PM / devfreq: passive: Keep cpufreq_policy for possible cpus

Saravana Kannan (1):
  PM / devfreq: Add cpu based scaling support to passive governor

 drivers/devfreq/devfreq.c          |  20 +-
 drivers/devfreq/governor.h         |  27 ++
 drivers/devfreq/governor_passive.c | 400 ++++++++++++++++++++++++-----
 include/linux/devfreq.h            |  17 +-
 4 files changed, 387 insertions(+), 77 deletions(-)

-- 
2.25.1