linux.git/drivers/leds/led-class.c, branch v3.19

leds: Add support for setting brightness in a synchronous way

2014-11-14T22:29:35+00:00

There are use cases when setting a LED brightness has to
have immediate effect (e.g. setting a torch LED brightness).
This patch extends LED subsystem to support such operations.
The LED subsystem internal API __led_set_brightness is changed
to led_set_brightness_async and new led_set_brightness_sync API
is added.

Signed-off-by: Jacek Anaszewski 
Acked-by: Kyungmin Park 
Cc: Richard Purdie 
Signed-off-by: Bryan Wu

leds: implement sysfs interface locking mechanism

2014-11-14T22:29:35+00:00

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 
Acked-by: Kyungmin Park 
Cc: Richard Purdie 
Signed-off-by: Bryan Wu

leds: Improve and export led_update_brightness

2014-09-12T21:01:54+00:00

led_update_brightness helper function used to be exploited only locally
in the led-class.c module, where its result was being passed to the
brightness_show sysfs callback. With the introduction of v4l2-flash
subdevice the same functionality becomes required for reading current
brightness from a LED device. This patch adds checking of return value
of the brightness_get callback and moves the led_update_brightness()
function to the LED subsystem public API.

Signed-off-by: Jacek Anaszewski 
Acked-by: Kyungmin Park 
Cc: Richard Purdie 
Signed-off-by: Bryan Wu

leds: avoid using DEVICE_ATTR macro for max_brightness attribute

2014-09-11T23:55:26+00:00

Make definition of the brightness related sysfs attributes
consistent. The modification entails change of the function
name: led_max_brightness_show -> max_brightness_show

Signed-off-by: Jacek Anaszewski 
Acked-by: Sakari Ailus 
Acked-by: Kyungmin Park 
Cc: Richard Purdie 
Signed-off-by: Bryan Wu

leds: Reorder include directives

2014-09-11T23:55:25+00:00

Reorder include directives so that they are arranged
in alphabetical order.

Signed-off-by: Jacek Anaszewski 
Acked-by: Kyungmin Park 
Cc: Richard Purdie 
Signed-off-by: Bryan Wu

Revert "leds: convert blink timer to workqueue"

2014-09-02T17:02:13+00:00

This reverts commit 8b37e1bef5a6b60e949e28a4db3006e4b00bd758.

It's broken as it changes led_blink_set() in a way that it can now sleep
(while synchronously waiting for workqueue to be cancelled). That's a
problem, because it's possible that this function gets called from atomic
context (tpt_trig_timer() takes a readlock and thus disables preemption).

This has been brought up 3 weeks ago already [1] but no proper fix has
materialized, and I keep seeing the problem since 3.17-rc1.

[1] https://lkml.org/lkml/2014/8/16/128

 BUG: sleeping function called from invalid context at kernel/workqueue.c:2650
 in_atomic(): 1, irqs_disabled(): 0, pid: 2335, name: wpa_supplicant
 5 locks held by wpa_supplicant/2335:
  #0:  (rtnl_mutex){+.+.+.}, at: [] rtnl_lock+0x12/0x20
  #1:  (&wdev->mtx){+.+.+.}, at: [] cfg80211_mgd_wext_siwessid+0x5c/0x180 [cfg80211]
  #2:  (&local->mtx){+.+.+.}, at: [] ieee80211_prep_connection+0x17a/0x9a0 [mac80211]
  #3:  (&local->chanctx_mtx){+.+.+.}, at: [] ieee80211_vif_use_channel+0x5d/0x2a0 [mac80211]
  #4:  (&trig->leddev_list_lock){.+.+..}, at: [] tpt_trig_timer+0xec/0x170 [mac80211]
 CPU: 0 PID: 2335 Comm: wpa_supplicant Not tainted 3.17.0-rc3 #1
 Hardware name: LENOVO 7470BN2/7470BN2, BIOS 6DET38WW (2.02 ) 12/19/2008
  ffff8800360b5a50 ffff8800751f76d8 ffffffff8159e97f ffff8800360b5a30
  ffff8800751f76e8 ffffffff810739a5 ffff8800751f77b0 ffffffff8106862f
  ffffffff810685d0 0aa2209200000000 ffff880000000004 ffff8800361c59d0
 Call Trace:
  [] dump_stack+0x4d/0x66
  [] __might_sleep+0xe5/0x120
  [] flush_work+0x5f/0x270
  [] ? mod_delayed_work_on+0x80/0x80
  [] ? mark_held_locks+0x6a/0x90
  [] ? __cancel_work_timer+0x6f/0x100
  [] ? trace_hardirqs_on_caller+0xfd/0x1c0
  [] __cancel_work_timer+0x7b/0x100
  [] cancel_delayed_work_sync+0xe/0x10
  [] led_blink_set+0x1b/0x40
  [] tpt_trig_timer+0x110/0x170 [mac80211]
  [] ieee80211_mod_tpt_led_trig+0x9d/0x160 [mac80211]
  [] __ieee80211_recalc_idle+0x98/0x140 [mac80211]
  [] ieee80211_idle_off+0xe/0x10 [mac80211]
  [] ieee80211_add_chanctx+0x3b/0x220 [mac80211]
  [] ieee80211_new_chanctx+0x44/0xf0 [mac80211]
  [] ieee80211_vif_use_channel+0x1fa/0x2a0 [mac80211]
  [] ieee80211_prep_connection+0x188/0x9a0 [mac80211]
  [] ieee80211_mgd_auth+0x256/0x2e0 [mac80211]
  [] ieee80211_auth+0x13/0x20 [mac80211]
  [] cfg80211_mlme_auth+0x106/0x270 [cfg80211]
  [] cfg80211_conn_do_work+0x155/0x3b0 [cfg80211]
  [] cfg80211_connect+0x3f0/0x540 [cfg80211]
  [] cfg80211_mgd_wext_connect+0x158/0x1f0 [cfg80211]
  [] cfg80211_mgd_wext_siwessid+0xde/0x180 [cfg80211]
  [] ? cfg80211_wext_giwessid+0x50/0x50 [cfg80211]
  [] cfg80211_wext_siwessid+0x1d/0x40 [cfg80211]
  [] ioctl_standard_iw_point+0x14c/0x3e0
  [] ? trace_hardirqs_on_caller+0xfd/0x1c0
  [] ioctl_standard_call+0x8a/0xd0
  [] ? ioctl_standard_iw_point+0x3e0/0x3e0
  [] wireless_process_ioctl.constprop.10+0xb6/0x100
  [] wext_handle_ioctl+0x5d/0xb0
  [] dev_ioctl+0x329/0x620
  [] ? trace_hardirqs_on_caller+0xfd/0x1c0
  [] sock_ioctl+0x142/0x2e0
  [] do_vfs_ioctl+0x300/0x520
  [] ? sysret_check+0x1b/0x56
  [] ? trace_hardirqs_on_caller+0xfd/0x1c0
  [] SyS_ioctl+0x81/0xa0
  [] system_call_fastpath+0x1a/0x1f
 wlan0: send auth to 00:0b:6b:3c:8c:e4 (try 1/3)
 wlan0: authenticated
 wlan0: associate with 00:0b:6b:3c:8c:e4 (try 1/3)
 wlan0: RX AssocResp from 00:0b:6b:3c:8c:e4 (capab=0x431 status=0 aid=2)
 wlan0: associated
 IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
 cfg80211: Calling CRDA for country: NA
 wlan0: Limiting TX power to 27 (27 - 0) dBm as advertised by 00:0b:6b:3c:8c:e4

 =================================
 [ INFO: inconsistent lock state ]
 3.17.0-rc3 #1 Not tainted
 ---------------------------------
 inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
 swapper/0/0 [HC0[0]:SC1[1]:HE1:SE0] takes:
  ((&(&led_cdev->blink_work)->work)){+.?...}, at: [] flush_work+0x0/0x270
 {SOFTIRQ-ON-W} state was registered at:
   [] __lock_acquire+0x30e/0x1a30
   [] lock_acquire+0x91/0x110
   [] flush_work+0x38/0x270
   [] __cancel_work_timer+0x7b/0x100
   [] cancel_delayed_work_sync+0xe/0x10
   [] led_blink_set+0x1b/0x40
   [] tpt_trig_timer+0x110/0x170 [mac80211]
   [] ieee80211_mod_tpt_led_trig+0x9d/0x160 [mac80211]
   [] __ieee80211_recalc_idle+0x98/0x140 [mac80211]
   [] ieee80211_idle_off+0xe/0x10 [mac80211]
   [] ieee80211_add_chanctx+0x3b/0x220 [mac80211]
   [] ieee80211_new_chanctx+0x44/0xf0 [mac80211]
   [] ieee80211_vif_use_channel+0x1fa/0x2a0 [mac80211]
   [] ieee80211_prep_connection+0x188/0x9a0 [mac80211]
   [] ieee80211_mgd_auth+0x256/0x2e0 [mac80211]
   [] ieee80211_auth+0x13/0x20 [mac80211]
   [] cfg80211_mlme_auth+0x106/0x270 [cfg80211]
   [] cfg80211_conn_do_work+0x155/0x3b0 [cfg80211]
   [] cfg80211_connect+0x3f0/0x540 [cfg80211]
   [] cfg80211_mgd_wext_connect+0x158/0x1f0 [cfg80211]
   [] cfg80211_mgd_wext_siwessid+0xde/0x180 [cfg80211]
   [] cfg80211_wext_siwessid+0x1d/0x40 [cfg80211]
   [] ioctl_standard_iw_point+0x14c/0x3e0
   [] ioctl_standard_call+0x8a/0xd0
   [] wireless_process_ioctl.constprop.10+0xb6/0x100
   [] wext_handle_ioctl+0x5d/0xb0
   [] dev_ioctl+0x329/0x620
   [] sock_ioctl+0x142/0x2e0
   [] do_vfs_ioctl+0x300/0x520
   [] SyS_ioctl+0x81/0xa0
   [] system_call_fastpath+0x1a/0x1f
 irq event stamp: 493416
 hardirqs last  enabled at (493416): [] __cancel_work_timer+0x6f/0x100
 hardirqs last disabled at (493415): [] try_to_grab_pending+0x1f/0x160
 softirqs last  enabled at (493408): [] _local_bh_enable+0x1d/0x50
 softirqs last disabled at (493409): [] irq_exit+0xa5/0xb0

 other info that might help us debug this:
  Possible unsafe locking scenario:

        CPU0
        ----
   lock((&(&led_cdev->blink_work)->work));
   
     lock((&(&led_cdev->blink_work)->work));

  *** DEADLOCK ***

 2 locks held by swapper/0/0:
  #0:  (((&tpt_trig->timer))){+.-...}, at: [] call_timer_fn+0x0/0x180
  #1:  (&trig->leddev_list_lock){.+.?..}, at: [] tpt_trig_timer+0xec/0x170 [mac80211]

 stack backtrace:
 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.17.0-rc3 #1
 Hardware name: LENOVO 7470BN2/7470BN2, BIOS 6DET38WW (2.02 ) 12/19/2008
  ffffffff8246eb30 ffff88007c203b00 ffffffff8159e97f ffffffff81a194c0
  ffff88007c203b50 ffffffff81599c29 0000000000000001 ffffffff00000001
  ffff880000000000 0000000000000006 ffffffff81a194c0 ffffffff81093ad0
 Call Trace:
    [] dump_stack+0x4d/0x66
  [] print_usage_bug+0x1f4/0x205
  [] ? check_usage_backwards+0x140/0x140
  [] mark_lock+0x223/0x2b0
  [] __lock_acquire+0x2b0/0x1a30
  [] lock_acquire+0x91/0x110
  [] ? mod_delayed_work_on+0x80/0x80
  [] ? __ieee80211_get_rx_led_name+0x10/0x10 [mac80211]
  [] flush_work+0x38/0x270
  [] ? mod_delayed_work_on+0x80/0x80
  [] ? mark_held_locks+0x6a/0x90
  [] ? __cancel_work_timer+0x6f/0x100
  [] ? __ieee80211_get_rx_led_name+0x10/0x10 [mac80211]
  [] ? trace_hardirqs_on_caller+0xad/0x1c0
  [] ? __ieee80211_get_rx_led_name+0x10/0x10 [mac80211]
  [] __cancel_work_timer+0x7b/0x100
  [] cancel_delayed_work_sync+0xe/0x10
  [] led_blink_set+0x1b/0x40
  [] tpt_trig_timer+0x110/0x170 [mac80211]
  [] call_timer_fn+0x75/0x180
  [] ? process_timeout+0x10/0x10
  [] ? __ieee80211_get_rx_led_name+0x10/0x10 [mac80211]
  [] run_timer_softirq+0x1fc/0x2f0
  [] __do_softirq+0x115/0x2e0
  [] irq_exit+0xa5/0xb0
  [] do_IRQ+0x53/0xf0
  [] common_interrupt+0x6f/0x6f
    [] ? cpuidle_enter_state+0x6e/0x180
  [] cpuidle_enter+0x12/0x20
  [] cpu_startup_entry+0x330/0x360
  [] rest_init+0xc1/0xd0
  [] ? csum_partial_copy_generic+0x170/0x170
  [] start_kernel+0x44f/0x45a
  [] ? set_init_arg+0x53/0x53
  [] x86_64_start_reservations+0x2a/0x2c
  [] x86_64_start_kernel+0xf1/0xf4

Cc: Vincent Donnefort 
Cc: Hugh Dickins 
Cc: Tejun Heo 
Signed-off-by: Jiri Kosina 
Signed-off-by: Bryan Wu

leds: convert blink timer to workqueue

2014-07-03T19:02:14+00:00

This patch converts the blink timer from led-core to workqueue which is more
suitable for this kind of non-priority operations. Moreover, timer may lead to
errors when a LED setting function use a scheduling function such as pinctrl
which is using mutex.

Signed-off-by: Vincent Donnefort 
Signed-off-by: Bryan Wu

leds: add led-class attribute-group support

2014-06-25T21:55:03+00:00

Allow led-class devices to be created with optional attribute groups.

This is needed in order to allow led drivers to create custom device
attributes in a race-free manner.

Signed-off-by: Johan Hovold 
Signed-off-by: Bryan Wu

leds: convert class code to use dev_groups

2013-07-27T01:05:17+00:00

The dev_attrs field of struct class is going away soon, dev_groups
should be used instead.  This converts the led class code to use the
correct field.

Acked-by: Bryan Wu 
Cc: Richard Purdie 
Signed-off-by: Greg Kroah-Hartman

leds: Convert led class driver from legacy pm ops to dev_pm_ops

2013-06-21T00:36:45+00:00

Convert drivers/leds/led-class to use dev_pm_ops for power management and
remove Legacy PM ops hooks. With this change, led class registers
suspend/resume callbacks via class->pm (dev_pm_ops) instead of Legacy
class->suspend/resume. When __device_suspend() runs call-backs, it will
find class->pm ops for the led class.

Signed-off-by: Shuah Khan 
Signed-off-by: Bryan Wu