aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/devfreq/devfreq.c (follow)
AgeCommit message (Collapse)AuthorFilesLines
2013-11-07Merge branch 'pm-devfreq'Rafael J. Wysocki1-2/+2
* pm-devfreq: PM / devfreq: create_freezable_workqueue() doesn't return an ERR_PTR PM / devfreq: Remove duplicate header file inclusion in exynos5_bus.c PM / devfreq: Use devm_* APIs in exynos5_bus.c PM / devfreq: Remove redundant platform_set_drvdata() in exynos5_bus.c PM / devfreq: Fix incorrect usage of IS_ERR_OR_NULL in exynos5_bus.c
2013-10-28PM / devfreq: create_freezable_workqueue() doesn't return an ERR_PTRDan Carpenter1-2/+2
The create_freezable_workqueue() function returns a NULL on error and not an ERR_PTR. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
2013-10-25PM / OPP: rename header to linux/pm_opp.hNishanth Menon1-1/+1
Since Operating Performance Points (OPP) functions are specific to device specific power management, be specific and rename opp.h to pm_opp.h Reported-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Nishanth Menon <nm@ti.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-10-25PM / OPP: rename data structures to dev_pm equivalentsNishanth Menon1-4/+5
Since Operating Performance Points (OPP) data structures are specific to device specific power management, be specific and rename opp_* data structures in OPP library with dev_pm_opp_* equivalent. Affected structures are: struct opp enum opp_event Minor checkpatch warning resulting of this change was fixed as well. Reported-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Nishanth Menon <nm@ti.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-10-25PM / OPP: rename functions to dev_pm_opp*Nishanth Menon1-7/+7
Since Operating Performance Points (OPP) functions are specific to device specific power management, be specific and rename opp_* accessors in OPP library with dev_pm_opp_* equivalent. Affected functions are: opp_get_voltage opp_get_freq opp_get_opp_count opp_find_freq_exact opp_find_freq_floor opp_find_freq_ceil opp_add opp_enable opp_disable opp_get_notifier opp_init_cpufreq_table opp_free_cpufreq_table Reported-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Nishanth Menon <nm@ti.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-08-19devfreq: convert devfreq_class to use dev_groupsGreg Kroah-Hartman1-34/+44
The dev_attrs field of struct class is going away soon, dev_groups should be used instead. This converts the devfreq_class code to use the correct field. Cc: MyungJoo Ham <myungjoo.ham@samsung.com> Cc: Kyungmin Park <kyungmin.park@samsung.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-03Merge branch 'akpm' (updates from Andrew Morton)Linus Torvalds1-1/+1
Merge first patch-bomb from Andrew Morton: - various misc bits - I'm been patchmonkeying ocfs2 for a while, as Joel and Mark have been distracted. There has been quite a bit of activity. - About half the MM queue - Some backlight bits - Various lib/ updates - checkpatch updates - zillions more little rtc patches - ptrace - signals - exec - procfs - rapidio - nbd - aoe - pps - memstick - tools/testing/selftests updates * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (445 commits) tools/testing/selftests: don't assume the x bit is set on scripts selftests: add .gitignore for kcmp selftests: fix clean target in kcmp Makefile selftests: add .gitignore for vm selftests: add hugetlbfstest self-test: fix make clean selftests: exit 1 on failure kernel/resource.c: remove the unneeded assignment in function __find_resource aio: fix wrong comment in aio_complete() drivers/w1/slaves/w1_ds2408.c: add magic sequence to disable P0 test mode drivers/memstick/host/r592.c: convert to module_pci_driver drivers/memstick/host/jmb38x_ms: convert to module_pci_driver pps-gpio: add device-tree binding and support drivers/pps/clients/pps-gpio.c: convert to module_platform_driver drivers/pps/clients/pps-gpio.c: convert to devm_* helpers drivers/parport/share.c: use kzalloc Documentation/accounting/getdelays.c: avoid strncpy in accounting tool aoe: update internal version number to v83 aoe: update copyright date aoe: perform I/O completions in parallel ...
2013-07-03drivers: avoid format string in dev_set_nameKees Cook1-1/+1
Calling dev_set_name with a single paramter causes it to be handled as a format string. Many callers are passing potentially dynamic string content, so use "%s" in those cases to avoid any potential accidents, including wrappers like device_create*() and bdi_register(). Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-06-03PM / devfreq: add comments and DocumentationMyungJoo Ham1-0/+10
- Added missing ABI documents - Added comments to clarify the objectives of functions Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com> Acked-by: Nishanth Menon <nm@ti.com> Acked-by: Rajagopal Venkat <rajagopal.venkat@linaro.org>
2013-06-03PM / devfreq: account suspend/resume for statsRajagopal Venkat1-3/+12
devfreq stats is not taking device suspend and resume into account. Fix it. Signed-off-by: Rajagopal Venkat <rajagopal.venkat@linaro.org> Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com>
2013-01-22PM / devfreq: add locking documentation for recommended_oppNishanth Menon1-0/+5
OPP pointers are protected by RCU locks, the pointer validity is permissible only under the section of rcu_read_lock to rcu_read_unlock Add documentation to the effect. Signed-off-by: Nishanth Menon <nm@ti.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2012-12-07Merge branch 'pm-devfreq'Rafael J. Wysocki1-277/+640
* pm-devfreq: (23 commits) PM / devfreq: remove compiler error with module governors (2) PM / devfreq: Fix return value in devfreq_remove_governor() PM / devfreq: Fix incorrect argument in error message PM / devfreq: missing rcu_read_lock() added for find_device_opp() PM / devfreq: remove compiler error when a governor is module PM / devfreq: exynos4_bus.c: Fixed an alignment of the func call args. PM / devfreq: Add sysfs node to expose available governors PM / devfreq: allow sysfs governor node to switch governor PM / devfreq: governors: add GPL module license and allow module build PM / devfreq: map devfreq drivers to governor using name PM / devfreq: register governors with devfreq framework PM / devfreq: provide hooks for governors to be registered PM / devfreq: export update_devfreq PM / devfreq: Add sysfs node for representing frequency transition information. PM / devfreq: Add sysfs node to expose available frequencies PM / devfreq: documentation cleanups for devfreq header PM / devfreq: Use devm_* functions in exynos4_bus.c PM / devfreq: make devfreq_class static PM / devfreq: fix sscanf handling for writable sysfs entries PM / devfreq: kernel-doc typo corrections ...
2012-11-28PM / devfreq: remove compiler error with module governors (2)MyungJoo Ham1-0/+5
Governors compiled as modules may use these functions. Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2012-11-26PM / devfreq: Fix return value in devfreq_remove_governor()Sachin Kamat1-1/+1
Use the value obtained from the function instead of -EINVAL. Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org> Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
2012-11-26PM / devfreq: Fix incorrect argument in error messageSachin Kamat1-1/+1
'g' is cast to the error return code. Hence gives the following error which is fixed by this patch. drivers/devfreq/devfreq.c:645 devfreq_remove_governor() error: 'g' dereferencing possible ERR_PTR() Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org> Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
2012-11-26PM / devfreq: missing rcu_read_lock() added for find_device_opp()MyungJoo Ham1-6/+20
opp_get_notifier() uses find_device_opp(), which requires to held rcu_read_lock. In order to keep the notifier-header valid, we have added rcu_read_lock(). Reported-by: Kees Cook <keescook@chromium.org> Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
2012-11-20PM / devfreq: Add sysfs node to expose available governorsNishanth Menon1-0/+22
Now that governor list can be variable, knowing the available governors is useful to be able to select a governor using relevant sysfs node. Cc: Rajagopal Venkat <rajagopal.venkat@linaro.org> Cc: MyungJoo Ham <myungjoo.ham@samsung.com> Cc: Kyungmin Park <kyungmin.park@samsung.com> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Kevin Hilman <khilman@ti.com> Cc: linux-pm@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Nishanth Menon <nm@ti.com> Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
2012-11-20PM / devfreq: allow sysfs governor node to switch governorNishanth Menon1-1/+44
This allows us to select governor runtime from the default configuration without having to rebuild kernel or the devfreq driver using the sysfs node: /sys/class/devfreq/.../governor cat of the governor will return valid governor and an echo 'governor_name'>governor will switch governor Cc: Rajagopal Venkat <rajagopal.venkat@linaro.org> Cc: MyungJoo Ham <myungjoo.ham@samsung.com> Cc: Kyungmin Park <kyungmin.park@samsung.com> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Kevin Hilman <khilman@ti.com> Cc: linux-pm@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Nishanth Menon <nm@ti.com> Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com> Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
2012-11-20PM / devfreq: map devfreq drivers to governor using nameNishanth Menon1-8/+87
Allow devfreq drivers to register a preferred governor name and when the devfreq governor loads itself at a later point required drivers are managed appropriately, at the time of unload of a devfreq governor, stop managing those drivers as well. Since the governor structures do not need to be exposed anymore, remove the definitions and make them static NOTE: devfreq_list_lock is now used to protect governor start and stop - as this allows us to protect governors and devfreq with the proper dependencies as needed. As part of this change, change the registration of exynos bus driver to request for ondemand using the governor name. Cc: Rajagopal Venkat <rajagopal.venkat@linaro.org> Cc: MyungJoo Ham <myungjoo.ham@samsung.com> Cc: Kyungmin Park <kyungmin.park@samsung.com> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Kevin Hilman <khilman@ti.com> Cc: linux-pm@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Nishanth Menon <nm@ti.com> [Merge conflict resolved by MyungJoo Ham] Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
2012-11-20PM / devfreq: provide hooks for governors to be registeredNishanth Menon1-0/+91
Add devfreq_add_governor and devfreq_remove_governor which can be invoked by governors to register with devfreq. This sets up the stage to dynamically switch governors and allow governors to be dynamically loaded as well. Cc: Rajagopal Venkat <rajagopal.venkat@linaro.org> Cc: MyungJoo Ham <myungjoo.ham@samsung.com> Cc: Kyungmin Park <kyungmin.park@samsung.com> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Kevin Hilman <khilman@ti.com> Cc: linux-pm@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Nishanth Menon <nm@ti.com> Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com>
2012-11-20PM / devfreq: export update_devfreqNishanth Menon1-0/+1
Allow update_devfreq to be used by devfreq governor built as modules Cc: Rajagopal Venkat <rajagopal.venkat@linaro.org> Cc: MyungJoo Ham <myungjoo.ham@samsung.com> Cc: Kyungmin Park <kyungmin.park@samsung.com> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Kevin Hilman <khilman@ti.com> Cc: linux-pm@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Nishanth Menon <nm@ti.com> Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com> Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
2012-11-20PM / devfreq: Add sysfs node for representing frequency transition information.Jonghwa Lee1-0/+101
This patch adds sysfs node which can be used to get information of frequency transition. It represents transition table which contains total number of transition of each freqeuncy state and time spent. It is inspired CPUFREQ's status driver. Signed-off-by: Jonghwa Lee <jonghwa3.lee@samsung.com> [Added Documentation/ABI entry, updated kernel-doc, and resolved merge conflict] Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
2012-11-20PM / devfreq: Add sysfs node to expose available frequenciesNishanth Menon1-0/+32
devfreq governors such as ondemand are controlled by a min and max frequency, while governors like userspace governor allow us to set a specific frequency. However, for the same specific device, depending on the SoC, the available frequencies can vary. So expose the available frequencies as a snapshot over sysfs to allow informed decisions. This was inspired by cpufreq framework's equivalent for similar usage sysfs node: scaling_available_frequencies. Cc: Rajagopal Venkat <rajagopal.venkat@linaro.org> Cc: MyungJoo Ham <myungjoo.ham@samsung.com> Cc: Kyungmin Park <kyungmin.park@samsung.com> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Kevin Hilman <khilman@ti.com> Cc: linux-pm@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Nishanth Menon <nm@ti.com> Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
2012-11-15PM / OPP: predictable fail results for opp_find* functions, v2Nishanth Menon1-2/+2
Currently the opp_find* functions return -ENODEV when: a) it cant find a device (e.g. request for an OPP search on device which was not registered) b) When it cant find a match for the search strategy used This makes life a little in-efficient for users such as devfreq to make reasonable judgement before switching search strategies. So, standardize the return results as following: -EINVAL for bad pointer parameters -ENODEV when device cannot be found -ERANGE when search fails This has the following benefit for devfreq implementation: The search fails when an unregistered device pointer is provided. This is a trigger to change the search direction and search for a better fit, however, if we cannot differentiate between a valid search range failure Vs an unregistered device, second search goes through the same fail return condition. This can be avoided by appropriate handling of error return code. With this change, we also fix devfreq for the improved search strategy with updated error code. Signed-off-by: Nishanth Menon <nm@ti.com> Reviewed-by: Kevin Hilman <khilman@ti.com> Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2012-11-15PM / devfreq: make devfreq_class staticNishanth Menon1-1/+1
devfreq_class is used internally by devfreq and has no need to be globally available. This also fixes the following sparse warning: drivers/devfreq/devfreq.c:30:14: warning: symbol 'devfreq_class' was not declared. Should it be static? Signed-off-by: Nishanth Menon <nm@ti.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2012-11-15PM / devfreq: fix sscanf handling for writable sysfs entriesNishanth Menon1-6/+3
sscanf returns 0 when an invalid parameter like: echo -n "a">min_freq is attempted. Returning back the return result(0) will cause the command not to return back to command prompt. Instead, just return -EINVAL when sscanf does not return 1. This is done for min_freq, max_freq and polling_interval Signed-off-by: Nishanth Menon <nm@ti.com> Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2012-11-15PM / devfreq: kernel-doc typo correctionsNishanth Menon1-11/+11
Parameter documentation needs a ':' for scripts/kernel-doc to parse properly. Minor fixes for ones warned by: ./scripts/kernel-doc -text drivers/devfreq/devfreq.c>/dev/null Signed-off-by: Nishanth Menon <nm@ti.com> Acked-by: Randy Dunlap <rdunlap@xenotime.net> Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2012-11-15PM / devfreq: Add current freq callback in device profileRajagopal Venkat1-0/+14
Devfreq returns governor predicted frequency as current frequency via sysfs interface. But device may not support all frequencies that governor predicts. So add a callback in device profile to get current freq from driver. Also add a new sysfs node to expose governor predicted next target frequency. Signed-off-by: Rajagopal Venkat <rajagopal.venkat@linaro.org> Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2012-11-15PM / devfreq: Add suspend and resume apisRajagopal Venkat1-0/+28
Add devfreq suspend/resume apis for devfreq users. This patch supports suspend and resume of devfreq load monitoring, required for devices which can idle. Signed-off-by: Rajagopal Venkat <rajagopal.venkat@linaro.org> Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2012-11-15PM / devfreq: Core updates to support devices which can idleRajagopal Venkat1-253/+189
Prepare devfreq core framework to support devices which can idle. When device idleness is detected perhaps through runtime-pm, need some mechanism to suspend devfreq load monitoring and resume back when device is online. Present code continues monitoring unless device is removed from devfreq core. This patch introduces following design changes, - use per device work instead of global work to monitor device load. This enables suspend/resume of device devfreq and reduces monitoring code complexity. - decouple delayed work based load monitoring logic from core by introducing helpers functions to be used by governors. This provides flexibility for governors either to use delayed work based monitoring functions or to implement their own mechanism. - devfreq core interacts with governors via events to perform specific actions. These events include start/stop devfreq. This sets ground for adding suspend/resume events. The devfreq apis are not modified and are kept intact. Signed-off-by: Rajagopal Venkat <rajagopal.venkat@linaro.org> Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2012-08-21workqueue: make deferrable delayed_work initializer names consistentTejun Heo1-1/+1
Initalizers for deferrable delayed_work are confused. * __DEFERRED_WORK_INITIALIZER() * DECLARE_DEFERRED_WORK() * INIT_DELAYED_WORK_DEFERRABLE() Rename them to * __DEFERRABLE_WORK_INITIALIZER() * DECLARE_DEFERRABLE_WORK() * INIT_DEFERRABLE_WORK() This patch doesn't cause any functional changes. Signed-off-by: Tejun Heo <tj@kernel.org>
2012-03-17PM / devfreq: add relation of recommended frequency.MyungJoo Ham1-4/+38
The semantics of "target frequency" given to devfreq driver from devfreq framework has always been interpretted as "at least" or GLB (greatest lower bound). However, the framework might want the device driver to limit its max frequency (LUB: least upper bound), especially if it is given by thermal framework (it's too hot). Thus, the target fuction should have another parameter to express whether the framework wants GLB or LUB. And, the additional parameter, "u32 flags", does it. With the update, devfreq_recommended_opp() is also updated. Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Reviewed-by: Mike Turquette <mturquette@ti.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2012-01-20PM / devfreq: add min/max_freq limit requested by users.MyungJoo Ham1-0/+70
The frequency requested to devfreq device driver from devfreq governors is restricted by min_freq and max_freq input. Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
2011-11-23PM / devfreq: separate error paths from successful pathAxel Lin1-8/+7
I think this change improves code readability. Signed-off-by: Axel Lin <axel.lin@gmail.com> Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-11-14PM / devfreq: fix use after free in devfreq_remove_deviceAxel Lin1-2/+6
In devfreq_remove_device, calling _remove_devfreq will also free devfreq. Don't dereference devfreq->governor->no_central_polling after _remove_devfreq. Signed-off-by: Axel Lin <axel.lin@gmail.com> Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-11-10PM / devfreq: Remove compiler error after irq.h updateMyungJoo Ham1-0/+2
Added <linux/module.h> and <linux/stat.h> to avoid a compiler error because linux/irq.h no longer includes linux/module.h after Linux 3.2. Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-10-02PM / devfreq: Add common sysfs interfacesMyungJoo Ham1-0/+69
Device specific sysfs interface /sys/devices/.../power/devfreq_* - governor R: name of governor - cur_freq R: current frequency - polling_interval R: polling interval in ms given with devfreq profile W: update polling interval. - central_polling R: 1 if polling is managed by devfreq framework Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Reviewed-by: Mike Turquette <mturquette@ti.com> Acked-by: Kevin Hilman <khilman@ti.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> -- Documentation/ABI/testing/sysfs-class-devfreq | 44 ++++++++++++++++ drivers/devfreq/devfreq.c | 69 ++++++++++++++++++++++++++ 2 files changed, 113 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-class-devfreq
2011-10-02PM: Introduce devfreq: generic DVFS framework with device-specific OPPsMyungJoo Ham1-0/+532
With OPPs, a device may have multiple operable frequency and voltage sets. However, there can be multiple possible operable sets and a system will need to choose one from them. In order to reduce the power consumption (by reducing frequency and voltage) without affecting the performance too much, a Dynamic Voltage and Frequency Scaling (DVFS) scheme may be used. This patch introduces the DVFS capability to non-CPU devices with OPPs. DVFS is a techique whereby the frequency and supplied voltage of a device is adjusted on-the-fly. DVFS usually sets the frequency as low as possible with given conditions (such as QoS assurance) and adjusts voltage according to the chosen frequency in order to reduce power consumption and heat dissipation. The generic DVFS for devices, devfreq, may appear quite similar with /drivers/cpufreq. However, cpufreq does not allow to have multiple devices registered and is not suitable to have multiple heterogenous devices with different (but simple) governors. Normally, DVFS mechanism controls frequency based on the demand for the device, and then, chooses voltage based on the chosen frequency. devfreq also controls the frequency based on the governor's frequency recommendation and let OPP pick up the pair of frequency and voltage based on the recommended frequency. Then, the chosen OPP is passed to device driver's "target" callback. When PM QoS is going to be used with the devfreq device, the device driver should enable OPPs that are appropriate with the current PM QoS requests. In order to do so, the device driver may call opp_enable and opp_disable at the notifier callback of PM QoS so that PM QoS's update_target() call enables the appropriate OPPs. Note that at least one of OPPs should be enabled at any time; be careful when there is a transition. Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Reviewed-by: Mike Turquette <mturquette@ti.com> Acked-by: Kevin Hilman <khilman@ti.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.