In case devfreq->previous_freq is still uninitialized in
devfreq_update_status(), i.e. it has value '0', the lookups in
that function fail, eventually leading to some error message:
[    3.041292] devfreq bus_dmc: Couldn't update frequency transition information.

Just skip the statup update in this situation.
Signed-off-by: NTobias Jakobi <tjakobi@math.uni-bielefeld.de>
Acked-by: NMyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Use devfreq_list_lock around list_del() to prevent list corruption.
Signed-off-by: NAxel Lin <axel.lin@ingics.com>
Acked-by: NMyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

of_node_put needs to be called when the device node which is got
from of_parse_phandle has finished using.

Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: NPeter Chen <peter.chen@nxp.com>
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>

The Kconfig currently controlling compilation of this code is:

menuconfig PM_DEVFREQ
      bool "Generic Dynamic Voltage and Frequency Scaling (DVFS) support"

...meaning that it currently is not being built as a module by anyone.

Lets remove the modular code that is essentially orphaned, so that
when reading the driver there is no doubt it is builtin-only.

This code wasn't using module_init, so we don't need to be concerned
with altering the initcall level here.

We also delete the MODULE_LICENSE tag etc. since all that information
is already contained at the top of the file in the comments.

We don't replace module.h with init.h since the file already has that.
But we do add export.h since this file does export some symbols.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
Reviewed-by: NChanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>

This patch sends the DEVFREQ_POSTCHANGE notification when
devfreq->profile->targer() is failed. The PRECHANGE/POSTCHANGE
should be paired.

Fixes: 0fe3a664 (PM / devfreq: Add new DEVFREQ_TRANSITION_NOTIFIER notifier)
Reported-by: NLin Huang <hl@rock-chips.com>
Signed-off-by: NChanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Some systems need current frequency from last_status for calculation
but it is zeroed during initialization. When the device starts there is
no history, but we can assume that the last frequency was the
same as the initial frequency (which is also used in 'previous_freq').
The log shows the result of this misinterpreted value.
[    2.042847] ... Failed to get voltage for frequency 0: -34
Signed-off-by: NLukasz Luba <lukasz.luba@arm.com>
Reviewed-by: NJavi Merino <javi.merino@arm.com>
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>

When device_register() returns with error, it has already
done put_device() on the input device pointer.
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>

1295  */
1296 void device_unregister(struct device *dev)
1297 {
1298         pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
1299         device_del(dev);
1300         put_device(dev);
1301 }
1302 EXPORT_SYMBOL_GPL(device_unregister);
1303

device_unregister is called put_device, there is no need to call
put_device(&devfreq->dev) again.
Signed-off-by: NCai Zhiyong <caizhiyong@huawei.com>
Reviewed-by: NChanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>

device_unregister() calls kfree already.
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>

devm_kzalloc of devfreq's statistics data structure has been
using its parent device as the dev allocated for.
If a device's devfreq is disabled in run-time,
such allocated memory won't be freed.

Desginating more precisely with the devfreq device
pointer fixes the issue.
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>

This patch adds the new DEVFREQ_TRANSITION_NOTIFIER notifier to send
the notification when the frequency of device is changed.
This notifier has two state as following:
- DEVFREQ_PRECHANGE  : Notify it before chaning the frequency of device
- DEVFREQ_POSTCHANGE : Notify it after changed the frequency of device

And this patch adds the resourced-managed function to release the resource
automatically when error happen.
Signed-off-by: NChanwoo Choi <cw00.choi@samsung.com>
[m.reichl and linux.amoon: Tested it on exynos4412-odroidu3 board]
Tested-by: NMarkus Reichl <m.reichl@fivetechno.de>
Tested-by: NAnand Moon <linux.amoon@gmail.com>
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>
Acked-by: NKrzysztof Kozlowski <k.kozlowski@samsung.com>

This patch adds the new devfreq_get_devfreq_by_phandle() OF helper function
which can find the instance of devfreq device by using phandle ("devfreq").
Signed-off-by: NChanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>
[m.reichl and linux.amoon: Tested it on exynos4412-odroidu3 board]
Tested-by: NMarkus Reichl <m.reichl@fivetechno.de>
Tested-by: NAnand Moon <linux.amoon@gmail.com>
Acked-by: NKrzysztof Kozlowski <k.kozlowski@samsung.com>

Before this patch for a device without statistics support,

$ cat trans_stat
    From  :   To
          :   time(ms)
Total transitions : 0
$

After this patch applied for such a device,

$ cat trans_stat
Not Supported.
$
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>

This patch modifies the indentation of 'trans_stat' sysfs to improve readability.
The 1GHz is 1000,000,000. So it needs the least 10 position to show the GHz unit.

- Before apply this patch,
-sh-3.2# cat trans_stat
   From  :   To
         :50000000100000000133000000200000000400000000   time(ms)
*50000000:       0       0       0       0       7   1817635
 100000000:       4       0       0       0       4      1590
 133000000:       1       4       0       0       7       975
 200000000:       2       2       7       0       1      2655
 400000000:       0       2       5      12       0      1860
Total transition : 58

- After apply this patch,
-sh-3.2# cat trans_stat
     From  :   To
           :  50000000 100000000 133000000 200000000 400000000   time(ms)
*  50000000:         0         0         0         0         7     14405
  100000000:         4         0         0         0         3      2015
  133000000:         2         3         0         0         7      1020
  200000000:         1         2         7         0         0      2970
  400000000:         0         2         5        10         0      1575
Total transition : 53
Signed-off-by: NChanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>

This patch initialize the freq_table array of each devfreq device by using
the devfreq_set_freq_table(). If freq_table is NULL, the devfreq framework
is not able to support the frequency transtion information through sysfs.

The OPP core uses the integer type for the number of opps in the opp list
and uses the 'unsigned long' type for each frequency. So, this patch
modifies the type of some variable as following:
- the type of freq_table : unsigned int -> unsigned long
- the type of max_state  : unsigned int -> int

- Corrected types, format strings, mutex usages by MyungJoo
Signed-off-by: NChanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>

This patch adds the 'show_one' macro to simplify the duplicate code
of both max_freq_show() and min_freq_show().
Signed-off-by: NChanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>

When device_register() fails, kfree(devfreq) is called already in
devfreq_dev_release(), hence there is no need to call kfree(devfreq)
in err_dev again.
Signed-off-by: NGeliang Tang <geliangtang@163.com>
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>

Writing the currently set governor into sysfs currently
seems to fail.
Fix this by setting the return code to zero before
leaving governor_store().
Signed-off-by: NTobias Jakobi <tjakobi@math.uni-bielefeld.de>
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>

time_in_state in struct devfreq is defined as unsigned long, so
devm_kzalloc should use sizeof(unsigned long) as argument instead
of sizeof(unsigned int), otherwise it will cause unexpected result
in 64bit system.
Signed-off-by: NXiaolong Ye <yexl@marvell.com>
Signed-off-by: NKevin Liu <kliu5@marvell.com>
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>

The thermal infrastructure should use the devfreq cooling device, which
uses the OPP library to disable OPPs as necessary.

Fix a couple of typos in the same comment while we are at it.
Signed-off-by: NJavi Merino <javi.merino@arm.com>
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>

IS_ERR(_OR_NULL) already contain an 'unlikely' compiler flag and there
is no need to do that again from its callers. Drop it.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>

_remove_devfreq() does not have @skip anymore after 3.16.
The comment for _remove_devfreq() has been updated correspondingly.
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>

These functions are indended for use by drivers and should be available
also when the driver is built as a module.

Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: NÃrjan Eide <orjan.eide@arm.com>
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>

This patch add resource-managed function for devfreq opp as following
functions. The devm_devfreq_register_opp_notifier() manages automatically
the registration of devfreq opp using device resource management.
- devm_devfreq_register_opp_notifier
- devm_devfreq_unregister_opp_notifier()
Signed-off-by: NChanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>

This patch add resource-managed function for devfreq device as following
functions. The devm_devfreq_add_device() manages automatically the memory
of devfreq device using device resource management.
- devm_devfreq_add_device()
- devm_devfreq_remove_device()
Signed-off-by: NChanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>

This patch modify devfreq_remove_device() to improve the sequence of resource
free. If executing existing devfreq_remove_device(), this function always
executes _remove_devfreq() twice. In result, second _remove_devfreq() always
return error value. So, This patch resolves complicated function sequence
as following:

[Flow sequence before modification]
devfreq_remove_device()
   _remove_devfreq(devfreq, false)
      kfree(devfreq);  /* Free devfreq */
      if (!skip ...) { /* skip is false */
         device_unregister(&devfreq->dev)
         put_device(&devfreq->dev);
            ...
            dev->release()
               devfreq_dev_release()
                  _remove_devfreq(devfreq, true) <- Recall to free devfreq
                  /*
		   * Always return error without freeing resource because
		   * already _remove_devfreq() frees the memory of devfreq.
		   */
   }

[Flow sequence after modification]
devfreq_remove_device
   device_unregister(&devfreq->dev)
   put_device(&devfreq->dev);
      ..
      dev->release()
         devfreq_dev_release()
            _remove_devfreq()
               kfree(devfreq); /* Free devfreq */
Signed-off-by: NChanwoo Choi <cw00.choi@samsung.com>
[Merge conflict resolved by MyungJoo]
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>

The current devfreq_update_status() has the following bugs:
- If previous frequency doesn't have a valid level, it does an out of bounds
  access into the trans_table and causes memory corruption.
- When the new frequency doesn't have a valid level, the time spent in the
  new frequency is counted towards the next valid frequency switch instead of
  being ignored.
- The time spent on the previous frequency is added to the new frequency's
  stats instead of the previous frequency's stats.

This patch fixes all of this.
Signed-off-by: NSaravana Kannan <skannan@codeaurora.org>
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>

The create_freezable_workqueue() function returns a NULL on error and
not an ERR_PTR.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>

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: NRandy Dunlap <rdunlap@infradead.org>
Signed-off-by: NNishanth Menon <nm@ti.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

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: NRandy Dunlap <rdunlap@infradead.org>
Signed-off-by: NNishanth Menon <nm@ti.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

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: NRandy Dunlap <rdunlap@infradead.org>
Signed-off-by: NNishanth Menon <nm@ti.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

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: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

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: NKees Cook <keescook@chromium.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

- Added missing ABI documents
- Added comments to clarify the objectives of functions
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>
Acked-by: NNishanth Menon <nm@ti.com>
Acked-by: NRajagopal Venkat <rajagopal.venkat@linaro.org>

devfreq stats is not taking device suspend and resume into
account. Fix it.
Signed-off-by: NRajagopal Venkat <rajagopal.venkat@linaro.org>
Acked-by: NMyungJoo Ham <myungjoo.ham@samsung.com>

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: NNishanth Menon <nm@ti.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Governors compiled as modules may use these functions.
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Use the value obtained from the function instead of -EINVAL.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>

'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: NSachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>

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: NKees Cook <keescook@chromium.org>
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>