linux-toradex.git/drivers/base/power/sysfs.c, branch v5.5-rc7

PM / wakeup: Register wakeup class kobj after device is added

2019-08-20T22:25:16+00:00

The device_set_wakeup_enable() function can be called on a device that
hasn't been registered with device_add() yet. This allows the device to
be in a state where wakeup is enabled for it but the device isn't
published to userspace in sysfs yet.

After commit c8377adfa781 ("PM / wakeup: Show wakeup sources stats in
sysfs"), calling device_set_wakeup_enable() will fail for a device that
hasn't been registered with the driver core via device_add(). This is
because we try to create sysfs entries for the device and associate a
wakeup class kobject with it before the device has been registered.
Let's follow a similar approach that device_set_wakeup_capable() takes
here and register the wakeup class either from
device_set_wakeup_enable() when the device is already registered, or
from dpm_sysfs_add() when the device is being registered with the driver
core via device_add().

Fixes: c8377adfa781 ("PM / wakeup: Show wakeup sources stats in sysfs")
Reported-by: Qian Cai 
Reviewed-by: Tri Vo 
Signed-off-by: Stephen Boyd 
Signed-off-by: Rafael J. Wysocki

drivers: base: power: add proper SPDX identifiers on files that did not have them.

2019-04-04T18:03:40+00:00

There were a few files in the driver core power code that did not have
SPDX identifiers on them, so fix that up.  At the same time, remove the
"free form" text that specified the license of the file, as that is
impossible for any tool to properly parse.

Cc: "Rafael J. Wysocki" 
Signed-off-by: Greg Kroah-Hartman

PM-runtime: Call pm_runtime_active|suspended_time() from sysfs

2019-03-07T10:23:17+00:00

Avoid the open-coding of the accounted time acquisition in
runtime_active|suspend_time_show() and make them call
pm_runtime_active|suspended_time() instead.

Note that this change also indirectly avoids holding dev->power.lock
around the do_div() computation and the sprintf() call which is an
additional improvement.

Signed-off-by: Ulf Hansson 
[ rjw: Changelog ]
Signed-off-by: Rafael J. Wysocki

PM / core: Add support to skip power management in device/driver model

2019-02-19T09:42:43+00:00

All device objects in the driver model contain fields that control the
handling of various power management activities. However, it's not
always useful. There are few instances where pseudo devices are added
to the model just to take advantage of many other features like
kobjects, udev events, and so on. One such example is cpu devices and
their caches.

The sysfs for the cpu caches are managed by adding devices with cpu
as the parent in cpu_device_create() when secondary cpu is brought
online. Generally when the secondary CPUs are hotplugged back in as part
of resume from suspend-to-ram, we call cpu_device_create() from the cpu
hotplug state machine while the cpu device associated with that CPU is
not yet ready to be resumed as the device_resume() call happens bit
later. It's not really needed to set the flag is_prepared for cpu
devices as they are mostly pseudo device and hotplug framework deals
with state machine and not managed through the cpu device.

This often results in annoying warning when resuming:
Enabling non-boot CPUs ...
CPU1: Booted secondary processor
 cache: parent cpu1 should not be sleeping
CPU1 is up
CPU2: Booted secondary processor
 cache: parent cpu2 should not be sleeping
CPU2 is up
.... and so on.

So in order to fix these kind of errors, we could just completely avoid
doing any power management related initialisations and operations if
they are not used by these devices.

Add no_pm flags to indicate that the device doesn't require any sort of
PM activities and all of them can be completely skipped. We can use the
same flag to also avoid adding not used *power* sysfs entries for these
devices. For now, lets use this for cpu cache devices.

Reviewed-by: Ulf Hansson 
Signed-off-by: Sudeep Holla 
Tested-by: Eugeniu Rosca 
Signed-off-by: Rafael J. Wysocki

PM-runtime: Replace jiffies-based accounting with ktime-based accounting

2019-01-31T09:45:10+00:00

Replace jiffies-based accounting for runtime_active_time and
runtime_suspended_time with ktime-based accounting. This makes the
runtime debug counters inline with genpd and other PM subsytems which
use ktime-based accounting.

Timekeeping is initialized before driver_init(). It's only at that time
that PM-runtime can be enabled.

Signed-off-by: Thara Gopinath 
[switch from ktime to raw nsec]
Signed-off-by: Vincent Guittot 
Reviewed-by: Ulf Hansson 
Signed-off-by: Rafael J. Wysocki

PM / wakeup: Export wakeup_count instead of event_count via sysfs

2018-06-06T07:23:36+00:00

Currently we export event_count instead of wakeup_count via the
per-device wakeup_count sysfs attribute. Change it to wakeup_count
to make it more meaningful.

wakeup_count increments only when events_check_enabled is set,
that is whenever writes the current wakeup count to
/sys/power/wakeup_count.  Also events_check_enabled is cleared on
every resume. User space is expected to write to this just before
suspend.  This way pm_wakeup_event(), when called from IRQs handles,
will increment wakeup_count only if we are in system-wide
suspend-resume cycle and should give a fair approximation of how many
times a device may have triggered a wakeup from system suspend.

event_count on the other hand will increment every time
pm_wakeup_event() is called irrespective of whether we are in a
suspend-resume cycle and some drivers call it on every interrupt
which makes it less useful for system wakeup tracking.

Signed-off-by: Ravi Chandra Sadineni 
Acked-by: Pavel Machek 
[ rjw: Subject & changelog ]
Signed-off-by: Rafael J. Wysocki

PM / sysfs: Convert to use DEVICE_ATTR_RO / DEVICE_ATTR_RW

2017-12-05T00:59:57+00:00

Use DEVICE_ATTR_RO() and DEVICE_ATTR_RW() macros instead of
open coding them.

No functional change intended.

Signed-off-by: Andy Shevchenko 
Acked-by: Pavel Machek 
Signed-off-by: Rafael J. Wysocki

PM / sysfs: Remove redundant 'else' keyword.

2017-12-05T00:59:57+00:00

There is no need to use 'else' if in main branch 'return' is present.

No functional change intended.

Signed-off-by: Andy Shevchenko 
Acked-by: Pavel Machek 
Signed-off-by: Rafael J. Wysocki

PM / sysfs: Convert to use sysfs_streq()

2017-12-05T00:59:56+00:00

...instead of custom approach.

Signed-off-by: Andy Shevchenko 
Acked-by: Pavel Machek 
Signed-off-by: Rafael J. Wysocki

PM / QoS: Fix device resume latency framework

2017-11-08T11:14:51+00:00

The special value of 0 for device resume latency PM QoS means
"no restriction", but there are two problems with that.

First, device resume latency PM QoS requests with 0 as the
value are always put in front of requests with positive
values in the priority lists used internally by the PM QoS
framework, causing 0 to be chosen as an effective constraint
value.  However, that 0 is then interpreted as "no restriction"
effectively overriding the other requests with specific
restrictions which is incorrect.

Second, the users of device resume latency PM QoS have no
way to specify that *any* resume latency at all should be
avoided, which is an artificial limitation in general.

To address these issues, modify device resume latency PM QoS to
use S32_MAX as the "no constraint" value and 0 as the "no
latency at all" one and rework its users (the cpuidle menu
governor, the genpd QoS governor and the runtime PM framework)
to follow these changes.

Also add a special "n/a" value to the corresponding user space I/F
to allow user space to indicate that it cannot accept any resume
latencies at all for the given device.

Fixes: 85dc0b8a4019 (PM / QoS: Make it possible to expose PM QoS latency constraints)
Link: https://bugzilla.kernel.org/show_bug.cgi?id=197323
Reported-by: Reinette Chatre 
Signed-off-by: Rafael J. Wysocki 
Tested-by: Reinette Chatre 
Tested-by: Geert Uytterhoeven 
Tested-by: Tero Kristo 
Reviewed-by: Ramesh Thomas