df->governor is being dereferenced before it is null checked,
hence there is a potential null pointer dereference.

Notice that df->governor is being null checked at line 1004:
if (df->governor) {, which implies it might be null.

Fix this by null checking df->governor before dereferencing it.

Addresses-Coverity-ID: 1401988 ("Dereference before null check")
Fixes: bcf23c79 ("PM / devfreq: Fix available_governor sysfs")
Signed-off-by: NGustavo A. R. Silva <garsilva@embeddedor.com>
Reviewed-by: NChanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>

Propagate the error of devfreq_add_device() in devm_devfreq_add_device()
rather than statically returning ENOMEM. This makes it slightly faster
to pinpoint the cause of a returned error.

Fixes: 8cd84092 ("PM / devfreq: Add resource-managed function for devfreq device")
Cc: stable@vger.kernel.org
Acked-by: NChanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: NBjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>

The freq_table array of each devfreq device is always not NULL.
In result, it is unneeded to check whether profile->freq_table
is NULL or not.
Signed-off-by: NChanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>

The commit a76caf55 ("thermal: Add devfreq cooling") allows
the devfreq device to use the cooling device. When the cooling down
are required, the devfreq_cooling.c disables the OPP entry with
the dev_pm_opp_disable(). In result, 'available_frequencies'[1]
sysfs node never came to show the all available frequencies.
[1] /sys/class/devfreq/.../available_frequencies

So, this patch uses the 'freq_table' in the 'struct devfreq_dev_profile'
in order to show the all available frequencies.
- If 'freq_table' is NULL, devfreq core initializes them by using OPP values.
- If 'freq_table' is initialized, devfreq core just uses the 'freq_table'.

And this patch adds some comment about the sort way of 'freq_table'.
Signed-off-by: NChanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>

This patch changes the return type of devfreq_set_freq_table()
from 'void' to 'int' in order to check whether it fails or not.

And This patch just removes the 'devfreq' prefix and the description
of function. Because the helper functions are only used by the devfreq.
Signed-off-by: NChanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>

The commit a76caf55 ("thermal: Add devfreq cooling") is able
to disable OPP as a cooling device. In result, both update_devfreq()
and {min|max}_freq_show() have to consider the 'opp->available'
status of each OPP.

So, this patch adds the 'scaling_{min|max}_freq' to struct devfreq
in order to indicate the available mininum and maximum frequency
by adjusting OPP interface such as dev_pm_opp_{disable|enable}().
The 'scaling_{min|max}_freq' are used for on both update_devfreq()
and {min|max}_freq_show().
Signed-off-by: NChanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>

This reverts commit 3104fa30.

The {min|max}_freq_show() show the stored value of the struct devfreq.
But, if the drivers/thermal/devfreq_cooling.c disables the specific
frequency value, {min|max}_freq_show() have to check this situation
before showing the stored value. So, this patch revert the macro
in order to add the additional codes.
Signed-off-by: NChanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>

Prior to that, the min/max_freq of the devfreq device are always zero
before the user changes the min/max_freq through sysfs entries.
It might make the confusion for the min/max_freq.

This patch initializes the available min/max_freq by using the OPP
during adding the devfreq device.
Signed-off-by: NChanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>

When the devfreq_add_device fails to register deivce, the memory
leak of devfreq instance happen. So, this patch fix the memory
leak issue. Before freeing the devfreq instance checks whether
devfreq instance is NULL or not because the device_unregister()
frees the devfreq instance when jumping to the 'err_init'.
It is to prevent the duplicate the kfee(devfreq).

Cc: stable@vger.kernel.org
Fixes: ac4b2811 ("PM / devfreq: fix duplicated kfree on devfreq pointer")
Signed-off-by: NChanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>

Fix typos and add the following to the scripts/spelling.txt:

  followings||following

While we are here, add a missing colon in the boilerplate in DT binding
documents.  The "you SoC" in allwinner,sunxi-pinctrl.txt was fixed as
well.

I reworded "as the followings:" to "as follows:" for
drivers/usb/gadget/udc/renesas_usb3.c.

Link: http://lkml.kernel.org/r/1481573103-11329-32-git-send-email-yamada.masahiro@socionext.comSigned-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch modifies the device name as devfreq(X) for sysfs by using the 'devfreq'
prefix word instead of separate device name. On user-space aspect, user would
find the some devfreq drvier with 'devfreq(X)' pattern. So, this patch modify the
device name as following:
- /sys/class/devfreq/[non-standard device name] -> /sys/class/devfreq/devfreq(X)
Signed-off-by: NChanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>

The _remove_devfreq() releases the all resources of the devfreq
device. This function is only called in the devfreq_dev_release().
For that reason, the devfreq core doesn't need to leave the
_remove_devfreq() separately. This patch releases the all
resources in the devfreq_dev_release() and then removes the
_remove_devfreq().
Signed-off-by: NChanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>

Until now, the trans_stat information of passive devfreq is not updated.
This patch updates the trans_stat information after setting the target
frequency of passive devfreq device.

Fixes: 99613311 ("PM / devfreq: Add new passive governor")
Cc: stable@vger.kernel.org
Signed-off-by: NChanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>

The devfreq using passive governor is not able to change the governor.
So, the user can not change the governor through 'available_governor' sysfs
entry. Also, the devfreq which don't use the passive governor is not able to
change to 'passive' governor on the fly.

Fixes: 99613311 ("PM / devfreq: Add new passive governor")
Cc: stable@vger.kernel.org
Signed-off-by: NChanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>

This patch just fixes the checkpatch warnings.
Signed-off-by: NChanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>

This patch updates dev_pm_opp_find_freq_*() routines to get a reference
to the OPPs returned by them.

Also updates the users of dev_pm_opp_find_freq_*() routines to call
dev_pm_opp_put() after they are done using the OPPs.

As it is guaranteed the that OPPs wouldn't get freed while being used,
the RCU read side locking present with the users isn't required anymore.
Drop it as well.

This patch also updates all users of devfreq_recommended_opp() which was
returning an OPP received from the OPP core.

Note that some of the OPP core routines have gained
rcu_read_{lock|unlock}() calls, as those still use RCU specific APIs
within them.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com> [Devfreq]
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Let the OPP core provide helpers to register notifiers for any device,
instead of exposing srcu_head outside of the core.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Acked-by: NMyungJoo Ham <myungjoo.ham@samsung.com>
Reviewed-by: NStephen Boyd <sboyd@codeaurora.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

This patch fixes the bug of devfreq_add_device(). The devfreq device must
have the default governor. If find_devfreq_governor() returns error,
devfreq_add_device() fail to add the devfreq instance.

Fixes: 1b5c1be2 (PM / devfreq: map devfreq drivers to governor using name)
Signed-off-by: NChanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The function name in the comment was incorrect.
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>
Reviewed-by: NChanwoo Choi <cw00.choi@samsung.com>

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>