Commit Graph

34 Commits

Author SHA1 Message Date
Heiner Kallweit 9534cc31dd leds: core: add managed version of led_trigger_register
Complementing devm_led_classdev_register add a managed version of
led_trigger_register.

I omit a managed version of led_classdev_unregister as the equivalent
devm_led_classdev_unregister isn't used in the kernel as of today.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>
2016-01-04 09:57:40 +01:00
Jacek Anaszewski acd899e4f3 leds: implement sysfs interface locking mechanism
Add a mechanism for locking LED subsystem sysfs interface.
This patch prepares ground for addition of LED Flash Class
extension, whose API will be integrated with V4L2 Flash API.
Such a fusion enforces introducing a locking scheme, which
will secure consistent access to the LED Flash Class device.

The mechanism being introduced allows for disabling LED
subsystem sysfs interface by calling led_sysfs_disable function
and enabling it by calling led_sysfs_enable. The functions
alter the LED_SYSFS_DISABLE flag state and must be called
under mutex lock. The state of the lock is checked with use
of led_sysfs_is_disabled function. Such a design allows for
providing immediate feedback to the user space on whether
the LED Flash Class device is available or is under V4L2 Flash
sub-device control.

Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Bryan Wu <cooloney@gmail.com>
2014-11-14 14:29:35 -08:00
Sasha Levin 14f5716bc2 leds: make sure we unregister a trigger only once
Currently, we may attempt to unregister a trigger more than once, for
example when we receive two consecutive reboot notifications, or when
we do a regular unregistration plus reboot notification.

This leads to the following error since we try to delete the list node
twice:

[ 2780.254922] WARNING: CPU: 0 PID: 13764 at lib/list_debug.c:53 __list_del_entry+0x3e/0xe0()
[ 2780.265559] list_del corruption, ffffffffa5eb6470->next is LIST_POISON1 (dead000000100100)
[ 2780.271710] Modules linked in:
[ 2780.274156] CPU: 0 PID: 13764 Comm: kworker/0:2 Tainted: G        W     3.14.0-next-20140403-sasha-00012-gef5fa7d-dirty #373
[ 2780.283063] Workqueue: events do_poweroff
[ 2780.285644]  0000000000000009 ffff8800330dbb38 ffffffffa34bfa33 0000000000002fe0
[ 2780.291571]  ffff8800330dbb88 ffff8800330dbb78 ffffffffa015a37c ffff8800330dbb68
[ 2780.296670]  ffffffffa5eb6470 0000000000000000 ffffffffa5eb6400 ffffffffa5ad7430
[ 2780.299756] Call Trace:
[ 2780.301530] dump_stack (lib/dump_stack.c:52)
[ 2780.303802] warn_slowpath_common (kernel/panic.c:418)
[ 2780.306151] warn_slowpath_fmt (kernel/panic.c:433)
[ 2780.308156] __list_del_entry (lib/list_debug.c:51 (discriminator 1))
[ 2780.310800] list_del (lib/list_debug.c:78)
[ 2780.313175] led_trigger_unregister (drivers/leds/led-triggers.c:225)
[ 2780.315599] heartbeat_reboot_notifier (drivers/leds/trigger/ledtrig-heartbeat.c:119)
[ 2780.317247] notifier_call_chain (kernel/notifier.c:95)
[ 2780.320014] __blocking_notifier_call_chain (kernel/notifier.c:316)
[ 2780.323263] blocking_notifier_call_chain (kernel/notifier.c:326)
[ 2780.326096] kernel_power_off (include/linux/kmod.h:95 kernel/reboot.c:153 kernel/reboot.c:179)
[ 2780.327883] do_poweroff (kernel/power/poweroff.c:23)
[ 2780.330748] process_one_work (kernel/workqueue.c:2221 include/linux/jump_label.h:105 include/trace/events/workqueue.h:111 kernel/workqueue.c:2226)
[ 2780.333027] ? process_one_work (include/linux/workqueue.h:186 kernel/workqueue.c:611 kernel/workqueue.c:638 kernel/workqueue.c:2214)
[ 2780.335487] process_scheduled_works (include/linux/list.h:188 kernel/workqueue.c:2277)
[ 2780.337101] worker_thread (kernel/workqueue.c:2352)
[ 2780.338712] ? rescuer_thread (kernel/workqueue.c:2297)
[ 2780.341326] kthread (kernel/kthread.c:219)
[ 2780.343446] ? kthread_create_on_node (kernel/kthread.c:185)
[ 2780.345733] ret_from_fork (arch/x86/kernel/entry_64.S:555)
[ 2780.347168] ? kthread_create_on_node (kernel/kthread.c:185)

Prevent it by making sure we don't attempt to unregister a trigger that
is not in the triggers list.

Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Bryan Wu <cooloney@gmail.com>
2014-04-07 14:47:25 -07:00
Paul Gortmaker 7c7d2a26db drivers/leds: delete non-required instances of include <linux/init.h>
None of these files are actually using any __init type directives
and hence don't need to include <linux/init.h>.  Most are just a
left over from __devinit and __cpuinit removal, or simply due to
code getting copied from one driver to the next.

Cc: Bryan Wu <cooloney@gmail.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: linux-leds@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Bryan Wu <cooloney@gmail.com>
2014-02-27 09:56:56 -08:00
ZHAO Gang 11e043b53c leds: replace list_for_each with list_for_each_entry
Use the more convenient macro.

Signed-off-by: ZHAO Gang <gamerh2o@gmail.com>
Signed-off-by: Bryan Wu <cooloney@gmail.com>
2014-01-27 17:28:52 -08:00
Sachin Kamat 09f5fe7563 leds: led-triggers: Fix checkpatch warnings
Fixes the following type of warnings:
WARNING: Prefer netdev_warn(netdev, ... then dev_warn(dev, ...
then pr_warn(...  to printk(KERN_WARNING ...
WARNING: quoted string split across lines

While at it also fix a coding style issue w.r.t braces.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Bryan Wu <cooloney@gmail.com>
2012-11-27 14:49:30 -08:00
Fabio Baltieri a8df7b1ab7 leds: add led_trigger_rename function
Implements a "led_trigger_rename" function to rename a trigger with
proper locking.

This assumes that led name was originally allocated in non-constant
storage.

Signed-off-by: Fabio Baltieri <fabio.baltieri@gmail.com>
Cc: Kurt Van Dijck <kurt.van.dijck@eia.be>
Signed-off-by: Bryan Wu <cooloney@gmail.com>
2012-11-26 14:28:50 -08:00
Colin Cross 52c47742f7 leds: triggers: send uevent when changing triggers
Some triggers create sysfs files when they are enabled. Send a uevent
"change" notification whenever the trigger is changed to allow userspace
processes such as udev to modify permissions on the new files.

A change notification will also be sent during registration of led class
devices or led triggers if the default trigger of an led class device
is found.

(bryan.wu@canonical.com: rename trigger to trig to fix the build error)

Signed-off-by: Colin Cross <ccross@android.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Signed-off-by: Bryan Wu <bryan.wu@canonical.com>
2012-09-11 18:32:41 +08:00
Fabio Baltieri d23a22a74f leds: delay led_set_brightness if stopping soft-blink
Delay execution of led_set_brightness() if need to stop soft-blink
timer.

This allows led_set_brightness to be called in hard-irq context even if
soft-blink was activated on that LED.

Signed-off-by: Fabio Baltieri <fabio.baltieri@gmail.com>
Cc: Pawel Moll <pawel.moll@arm.com>
Signed-off-by: Bryan Wu <bryan.wu@canonical.com>
2012-09-11 18:32:40 +08:00
Fabio Baltieri 86e99d23d0 Revert "leds: use led_set_brightness in led_trigger_event"
This reverts commit a0193cbee0.

The problem with the original commit was that it caused a warning with
the MMC trigger calling del_timer_sync from hard-irq context.

Signed-off-by: Fabio Baltieri <fabio.baltieri@gmail.com>
Reported-by: Pawel Moll <pawel.moll@arm.com>
Signed-off-by: Bryan Wu <bryan.wu@canonical.com>
2012-08-13 14:33:02 +08:00
Bryan Wu 20c0e6b878 leds: fix sparse warnings due to missing static
drivers/leds/led-core.c:56:6: sparse: symbol 'led_blink_setup' was not declared. Should it be static?
drivers/leds/led-triggers.c:233:6: sparse: symbol 'led_trigger_blink_setup' was not declared. Should it be static?

Reported-by: Fengguang Wu <wfg@linux.intel.com>
Signed-off-by: Bryan Wu <bryan.wu@canonical.com>
2012-07-24 07:52:35 +08:00
Fabio Baltieri a0193cbee0 leds: use led_set_brightness in led_trigger_event
Fix led_trigger_event() to use led_set_brightness() instead of
__led_set_brightness(), so that any pending blink timer is stopped before
setting the new brightness value.  Without this fix LED status may be
overridden by a pending timer.

This allows a trigger to use a mix of led_trigger_event(),
led_trigger_blink() and led_trigger_blink_oneshot() without races.

(applied over: leds: Rename led_brightness_set() to led_set_brightness())

Signed-off-by: Fabio Baltieri <fabio.baltieri@gmail.com>
Cc: Shuah Khan <shuahkhan@gmail.com>
Signed-off-by: Bryan Wu <bryan.wu@canonical.com>
2012-07-24 07:52:34 +08:00
Shuah Khan 19cd67e2d5 leds: Rename led_brightness_set() to led_set_brightness()
Rename leds external interface led_brightness_set() to led_set_brightness().
This is the second phase of the change to reduce confusion between the
leds internal and external interfaces that set brightness. With this change,
now the external interface is led_set_brightness(). The first phase renamed
the internal interface led_set_brightness() to __led_set_brightness().
There are no changes to the interface implementations.

Signed-off-by: Shuah Khan <shuahkhan@gmail.com>
Signed-off-by: Bryan Wu <bryan.wu@canonical.com>
2012-07-24 07:52:34 +08:00
Shuah Khan 0da3e65ba8 leds: Rename led_set_brightness() to __led_set_brightness()
Rename leds internal interface led_set_brightness() to __led_set_brightness()
to reduce confusion between led_set_brightness() and the external interface
led_brightness_set(). led_brightness_set() cancels the timer and then calls
led_set_brightness().

Signed-off-by: Shuah Khan <shuahkhan@gmail.com>
Signed-off-by: Bryan Wu <bryan.wu@canonical.com>
2012-07-24 07:52:34 +08:00
Fabio Baltieri 5bb629c504 leds: add oneshot blink functions
Add two new functions, led_blink_set_oneshot and
led_trigger_blink_oneshot, to be used by triggers for one-shot blink of
led devices.

This is implemented extending the existing software-blink code, and uses
the same timer and handler function.

The behavior of the code is to do a blink-on, blink-off sequence when
the function is called, ignoring other calls until the sequence is
completed so that the leds keep blinking at constant rate if the
functions are called repeatedly.

This is meant to be used by drivers which needs to trigger on sporadic
event, but doesn't have clear busy/idle trigger points.

After the blink sequence the led remains off. This behavior can be
inverted setting the "invert" argument, which blink the led off, than on
and leave the led on after the sequence.

(bryan.wu@canonical.com: rebase to commit 'leds: don't disable blinking
when writing the same value to delay_on or delay_off')

Signed-off-by: Fabio Baltieri <fabio.baltieri@gmail.com>
Acked-by: Shuah Khan <shuahkhan@gmail.com>
Signed-off-by: Bryan Wu <bryan.wu@canonical.com>
2012-07-24 07:52:34 +08:00
Bryan Wu eb202621f8 led-triggers: rename *trigger to *trig for unified naming scheme
No functional change.

Signed-off-by: Bryan Wu <bryan.wu@canonical.com>
2012-07-24 07:52:33 +08:00
Kay Sievers edbaa603eb driver-core: remove sysdev.h usage.
The sysdev.h file should not be needed by any in-kernel code, so remove
the .h file from these random files that seem to still want to include
it.

The sysdev code will be going away soon, so this include needs to be
removed no matter what.

Cc: Jiandong Zheng <jdzheng@broadcom.com>
Cc: Scott Branden <sbranden@broadcom.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Kukjin Kim <kgene.kim@samsung.com>
Cc: David Brown <davidb@codeaurora.org>
Cc: Daniel Walker <dwalker@fifo99.com>
Cc: Bryan Huntsman <bryanh@codeaurora.org>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Wan ZongShun <mcuos.com@gmail.com>
Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: "Venkatesh Pallipadi
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
2011-12-21 16:26:03 -08:00
Masakazu Mokuno cba4c2ac08 drivers/leds/led-triggers.c: fix memory leak
The memory for struct led_trigger should be kfreed in the
led_trigger_register() error path.  Also this function should return NULL
on error.

Signed-off-by: Masakazu Mokuno <mokuno@sm.sony.co.jp>
Cc: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-10-31 17:30:55 -07:00
Vasily Khoruzhick 0b9536c957 leds: Add ability to blink via simple trigger
As blink API is now available, it's possible to add ability to blink via
simple trigger.

Signed-off-by: Vasily Khoruzhick <anarsoul@gmail.com>
Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>
2011-01-31 16:30:24 +03:00
Johannes Berg 5ada28bf76 led-class: always implement blinking
Currently, blinking LEDs can be awkward because it is not guaranteed that
all LEDs implement blinking.  The trigger that wants it to blink then
needs to implement its own timer solution.

Rather than require that, add led_blink_set() API that triggers can use.
This function will attempt to use hw blinking, but if that fails
implements a timer for it.  To stop blinking again, brightness_set() also
needs to be wrapped into API that will stop the software blink.

As a result of this, the timer trigger becomes a very trivial one, and
hopefully we can finally see triggers using blinking as well because it's
always easy to use.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-by: Richard Purdie <rpurdie@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-11-12 07:55:32 -08:00
Tejun Heo 5a0e3ad6af include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-30 22:02:32 +09:00
Adam Nielsen 700c6ea224 leds: Prevent multiple LED triggers with the same name
Signed-off-by: Adam Nielsen <a.nielsen@shikadi.net>
Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>
2009-04-06 16:06:26 +01:00
Dmitry Baryshkov fe3025b55c leds: Ensure led->trigger is set earlier
Make sure led->trigger is valid before calling trigger->activate

Signed-off-by: Dmitry Baryshkov <dbaryshkov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
2008-07-23 09:49:56 +01:00
Németh Márton 4d404fd5c5 leds: Cleanup various whitespace and code style issues
Break the lines which were more than 80 characters into more
lines; replace SPACEs with TABs; correct ident at switch-case;
change character encoding from ISO-8859-2 to UTF-8.

The order of the functions in led-triggers.c changed in order
the similar functions can still be together under titles
"Used by LED Class", "LED Trigger Interface" and "Simple
LED Tigger Interface" as was grouped before when exported
with EXPORT_SYMBOL.

Signed-off-by: Márton Németh <nm127@freemail.hu>
Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
2008-04-24 23:37:42 +01:00
Németh Márton 0013b23d66 leds: disable triggers on brightness set
Disable any active triggers when the brightness attribute is
set to zero.

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Signed-off-by: Márton Németh <nm127@freemail.hu>
Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
2008-04-24 23:34:18 +01:00
Richard Purdie 72f8da329e leds: Fix leds_list_lock locking issues
Covert leds_list_lock to a rw_sempahore to match previous LED trigger
locking fixes, fixing lock ordering.

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
2007-12-31 23:09:44 +00:00
Richard Purdie dc47206e55 leds: Fix led trigger locking bugs
Convert part of the led trigger core from rw spinlocks to rw
semaphores. We're calling functions which can sleep from invalid
contexts otherwise. Fixes bug #9264.

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
2007-12-07 09:06:53 +00:00
Richard Purdie f8a7c6fe14 leds: Convert from struct class_device to struct device
Convert the LEDs class from struct class_device to struct device
since class_device is scheduled for removal.

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-16 01:15:51 +01:00
Richard Purdie e3986f6380 leds: Add warning printks in error paths
Add warning printks if led_trigger_register_simple() fails.

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
2007-07-16 01:15:51 +01:00
Richard Purdie 3593a6d64d leds: Fix trigger unregister_simple if register_simple fails
Fix led_trigger_unregister_simple to handle the case where
led_trigger_register_simple fails, avoiding a NULL pointer
dereference.

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
2007-07-16 01:15:50 +01:00
Paul Collins e3e5fc91d9 [PATCH] leds: turn LED off when changing triggers
I was playing with LED triggers when I noticed that changing from heartbeat
(or ide-disk) to "none" at the right moment would leave the LED stuck on.
This is easy to reproduce by doing "find / >/dev/null" with the ide-disk
trigger enabled and then switching to "none".

Here is a patch that fixes the problem by explicitly turning the LED off
after removing the existing trigger.

Signed-off-by: Paul Collins <paul@ondioline.org>
Acked-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-01 00:39:21 -07:00
Jörn Engel 6ab3d5624e Remove obsolete #include <linux/config.h>
Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
2006-06-30 19:25:36 +02:00
Ingo Molnar 34af946a22 [PATCH] spin/rwlock init cleanups
locking init cleanups:

 - convert " = SPIN_LOCK_UNLOCKED" to spin_lock_init() or DEFINE_SPINLOCK()
 - convert rwlocks in a similar manner

this patch was generated automatically.

Motivation:

 - cleanliness
 - lockdep needs control of lock initialization, which the open-coded
   variants do not give
 - it's also useful for -rt and for lock debugging in general

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-27 17:32:39 -07:00
Richard Purdie c3bc9956ec [PATCH] LED: add LED trigger tupport
Add support for LED triggers to the LED subsystem.  "Triggers" are events
which change the state of an LED.  Two kinds of trigger are available, simple
ones which can be added to exising code with minimum disruption and complex
ones for implementing new or more complex functionality.

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-31 12:18:56 -08:00