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![Jiri Kosina](/assets/img/avatar_default.png)
This reverts commit 8b37e1bef5
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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: [<ffffffff814c7c92>] rtnl_lock+0x12/0x20
#1: (&wdev->mtx){+.+.+.}, at: [<ffffffffc06e649c>] cfg80211_mgd_wext_siwessid+0x5c/0x180 [cfg80211]
#2: (&local->mtx){+.+.+.}, at: [<ffffffffc0817dea>] ieee80211_prep_connection+0x17a/0x9a0 [mac80211]
#3: (&local->chanctx_mtx){+.+.+.}, at: [<ffffffffc08081ed>] ieee80211_vif_use_channel+0x5d/0x2a0 [mac80211]
#4: (&trig->leddev_list_lock){.+.+..}, at: [<ffffffffc081e68c>] 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:
[<ffffffff8159e97f>] dump_stack+0x4d/0x66
[<ffffffff810739a5>] __might_sleep+0xe5/0x120
[<ffffffff8106862f>] flush_work+0x5f/0x270
[<ffffffff810685d0>] ? mod_delayed_work_on+0x80/0x80
[<ffffffff810945ca>] ? mark_held_locks+0x6a/0x90
[<ffffffff81068a5f>] ? __cancel_work_timer+0x6f/0x100
[<ffffffff810946ed>] ? trace_hardirqs_on_caller+0xfd/0x1c0
[<ffffffff81068a6b>] __cancel_work_timer+0x7b/0x100
[<ffffffff81068b0e>] cancel_delayed_work_sync+0xe/0x10
[<ffffffff8147cf3b>] led_blink_set+0x1b/0x40
[<ffffffffc081e6b0>] tpt_trig_timer+0x110/0x170 [mac80211]
[<ffffffffc081ecdd>] ieee80211_mod_tpt_led_trig+0x9d/0x160 [mac80211]
[<ffffffffc07e4278>] __ieee80211_recalc_idle+0x98/0x140 [mac80211]
[<ffffffffc07e59ce>] ieee80211_idle_off+0xe/0x10 [mac80211]
[<ffffffffc0804e5b>] ieee80211_add_chanctx+0x3b/0x220 [mac80211]
[<ffffffffc08062e4>] ieee80211_new_chanctx+0x44/0xf0 [mac80211]
[<ffffffffc080838a>] ieee80211_vif_use_channel+0x1fa/0x2a0 [mac80211]
[<ffffffffc0817df8>] ieee80211_prep_connection+0x188/0x9a0 [mac80211]
[<ffffffffc081c246>] ieee80211_mgd_auth+0x256/0x2e0 [mac80211]
[<ffffffffc07eab33>] ieee80211_auth+0x13/0x20 [mac80211]
[<ffffffffc06cb006>] cfg80211_mlme_auth+0x106/0x270 [cfg80211]
[<ffffffffc06ce085>] cfg80211_conn_do_work+0x155/0x3b0 [cfg80211]
[<ffffffffc06cf670>] cfg80211_connect+0x3f0/0x540 [cfg80211]
[<ffffffffc06e6148>] cfg80211_mgd_wext_connect+0x158/0x1f0 [cfg80211]
[<ffffffffc06e651e>] cfg80211_mgd_wext_siwessid+0xde/0x180 [cfg80211]
[<ffffffffc06e36c0>] ? cfg80211_wext_giwessid+0x50/0x50 [cfg80211]
[<ffffffffc06e36dd>] cfg80211_wext_siwessid+0x1d/0x40 [cfg80211]
[<ffffffff81584d0c>] ioctl_standard_iw_point+0x14c/0x3e0
[<ffffffff810946ed>] ? trace_hardirqs_on_caller+0xfd/0x1c0
[<ffffffff8158502a>] ioctl_standard_call+0x8a/0xd0
[<ffffffff81584fa0>] ? ioctl_standard_iw_point+0x3e0/0x3e0
[<ffffffff81584b76>] wireless_process_ioctl.constprop.10+0xb6/0x100
[<ffffffff8158521d>] wext_handle_ioctl+0x5d/0xb0
[<ffffffff814cfb29>] dev_ioctl+0x329/0x620
[<ffffffff810946ed>] ? trace_hardirqs_on_caller+0xfd/0x1c0
[<ffffffff8149c7f2>] sock_ioctl+0x142/0x2e0
[<ffffffff811b0140>] do_vfs_ioctl+0x300/0x520
[<ffffffff815a67fb>] ? sysret_check+0x1b/0x56
[<ffffffff810946ed>] ? trace_hardirqs_on_caller+0xfd/0x1c0
[<ffffffff811b03e1>] SyS_ioctl+0x81/0xa0
[<ffffffff815a67d6>] 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: [<ffffffff810685d0>] flush_work+0x0/0x270
{SOFTIRQ-ON-W} state was registered at:
[<ffffffff81094dbe>] __lock_acquire+0x30e/0x1a30
[<ffffffff81096c81>] lock_acquire+0x91/0x110
[<ffffffff81068608>] flush_work+0x38/0x270
[<ffffffff81068a6b>] __cancel_work_timer+0x7b/0x100
[<ffffffff81068b0e>] cancel_delayed_work_sync+0xe/0x10
[<ffffffff8147cf3b>] led_blink_set+0x1b/0x40
[<ffffffffc081e6b0>] tpt_trig_timer+0x110/0x170 [mac80211]
[<ffffffffc081ecdd>] ieee80211_mod_tpt_led_trig+0x9d/0x160 [mac80211]
[<ffffffffc07e4278>] __ieee80211_recalc_idle+0x98/0x140 [mac80211]
[<ffffffffc07e59ce>] ieee80211_idle_off+0xe/0x10 [mac80211]
[<ffffffffc0804e5b>] ieee80211_add_chanctx+0x3b/0x220 [mac80211]
[<ffffffffc08062e4>] ieee80211_new_chanctx+0x44/0xf0 [mac80211]
[<ffffffffc080838a>] ieee80211_vif_use_channel+0x1fa/0x2a0 [mac80211]
[<ffffffffc0817df8>] ieee80211_prep_connection+0x188/0x9a0 [mac80211]
[<ffffffffc081c246>] ieee80211_mgd_auth+0x256/0x2e0 [mac80211]
[<ffffffffc07eab33>] ieee80211_auth+0x13/0x20 [mac80211]
[<ffffffffc06cb006>] cfg80211_mlme_auth+0x106/0x270 [cfg80211]
[<ffffffffc06ce085>] cfg80211_conn_do_work+0x155/0x3b0 [cfg80211]
[<ffffffffc06cf670>] cfg80211_connect+0x3f0/0x540 [cfg80211]
[<ffffffffc06e6148>] cfg80211_mgd_wext_connect+0x158/0x1f0 [cfg80211]
[<ffffffffc06e651e>] cfg80211_mgd_wext_siwessid+0xde/0x180 [cfg80211]
[<ffffffffc06e36dd>] cfg80211_wext_siwessid+0x1d/0x40 [cfg80211]
[<ffffffff81584d0c>] ioctl_standard_iw_point+0x14c/0x3e0
[<ffffffff8158502a>] ioctl_standard_call+0x8a/0xd0
[<ffffffff81584b76>] wireless_process_ioctl.constprop.10+0xb6/0x100
[<ffffffff8158521d>] wext_handle_ioctl+0x5d/0xb0
[<ffffffff814cfb29>] dev_ioctl+0x329/0x620
[<ffffffff8149c7f2>] sock_ioctl+0x142/0x2e0
[<ffffffff811b0140>] do_vfs_ioctl+0x300/0x520
[<ffffffff811b03e1>] SyS_ioctl+0x81/0xa0
[<ffffffff815a67d6>] system_call_fastpath+0x1a/0x1f
irq event stamp: 493416
hardirqs last enabled at (493416): [<ffffffff81068a5f>] __cancel_work_timer+0x6f/0x100
hardirqs last disabled at (493415): [<ffffffff81067e9f>] try_to_grab_pending+0x1f/0x160
softirqs last enabled at (493408): [<ffffffff81053ced>] _local_bh_enable+0x1d/0x50
softirqs last disabled at (493409): [<ffffffff81054c75>] irq_exit+0xa5/0xb0
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock((&(&led_cdev->blink_work)->work));
<Interrupt>
lock((&(&led_cdev->blink_work)->work));
*** DEADLOCK ***
2 locks held by swapper/0/0:
#0: (((&tpt_trig->timer))){+.-...}, at: [<ffffffff810b4c50>] call_timer_fn+0x0/0x180
#1: (&trig->leddev_list_lock){.+.?..}, at: [<ffffffffc081e68c>] 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:
<IRQ> [<ffffffff8159e97f>] dump_stack+0x4d/0x66
[<ffffffff81599c29>] print_usage_bug+0x1f4/0x205
[<ffffffff81093ad0>] ? check_usage_backwards+0x140/0x140
[<ffffffff810944d3>] mark_lock+0x223/0x2b0
[<ffffffff81094d60>] __lock_acquire+0x2b0/0x1a30
[<ffffffff81096c81>] lock_acquire+0x91/0x110
[<ffffffff810685d0>] ? mod_delayed_work_on+0x80/0x80
[<ffffffffc081e5a0>] ? __ieee80211_get_rx_led_name+0x10/0x10 [mac80211]
[<ffffffff81068608>] flush_work+0x38/0x270
[<ffffffff810685d0>] ? mod_delayed_work_on+0x80/0x80
[<ffffffff810945ca>] ? mark_held_locks+0x6a/0x90
[<ffffffff81068a5f>] ? __cancel_work_timer+0x6f/0x100
[<ffffffffc081e5a0>] ? __ieee80211_get_rx_led_name+0x10/0x10 [mac80211]
[<ffffffff8109469d>] ? trace_hardirqs_on_caller+0xad/0x1c0
[<ffffffffc081e5a0>] ? __ieee80211_get_rx_led_name+0x10/0x10 [mac80211]
[<ffffffff81068a6b>] __cancel_work_timer+0x7b/0x100
[<ffffffff81068b0e>] cancel_delayed_work_sync+0xe/0x10
[<ffffffff8147cf3b>] led_blink_set+0x1b/0x40
[<ffffffffc081e6b0>] tpt_trig_timer+0x110/0x170 [mac80211]
[<ffffffff810b4cc5>] call_timer_fn+0x75/0x180
[<ffffffff810b4c50>] ? process_timeout+0x10/0x10
[<ffffffffc081e5a0>] ? __ieee80211_get_rx_led_name+0x10/0x10 [mac80211]
[<ffffffff810b50ac>] run_timer_softirq+0x1fc/0x2f0
[<ffffffff81054805>] __do_softirq+0x115/0x2e0
[<ffffffff81054c75>] irq_exit+0xa5/0xb0
[<ffffffff810049b3>] do_IRQ+0x53/0xf0
[<ffffffff815a74af>] common_interrupt+0x6f/0x6f
<EOI> [<ffffffff8147b56e>] ? cpuidle_enter_state+0x6e/0x180
[<ffffffff8147b732>] cpuidle_enter+0x12/0x20
[<ffffffff8108bba0>] cpu_startup_entry+0x330/0x360
[<ffffffff8158fb51>] rest_init+0xc1/0xd0
[<ffffffff8158fa90>] ? csum_partial_copy_generic+0x170/0x170
[<ffffffff81af3ff2>] start_kernel+0x44f/0x45a
[<ffffffff81af399c>] ? set_init_arg+0x53/0x53
[<ffffffff81af35ad>] x86_64_start_reservations+0x2a/0x2c
[<ffffffff81af36a0>] x86_64_start_kernel+0xf1/0xf4
Cc: Vincent Donnefort <vdonnefort@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Bryan Wu <cooloney@gmail.com>
298 lines
7.3 KiB
C
298 lines
7.3 KiB
C
/*
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* LED Class Core
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*
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* Copyright (C) 2005 John Lenz <lenz@cs.wisc.edu>
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* Copyright (C) 2005-2007 Richard Purdie <rpurdie@openedhand.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/list.h>
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#include <linux/spinlock.h>
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#include <linux/device.h>
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#include <linux/timer.h>
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#include <linux/err.h>
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#include <linux/ctype.h>
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#include <linux/leds.h>
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#include "leds.h"
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static struct class *leds_class;
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static void led_update_brightness(struct led_classdev *led_cdev)
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{
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if (led_cdev->brightness_get)
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led_cdev->brightness = led_cdev->brightness_get(led_cdev);
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}
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static ssize_t brightness_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct led_classdev *led_cdev = dev_get_drvdata(dev);
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/* no lock needed for this */
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led_update_brightness(led_cdev);
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return sprintf(buf, "%u\n", led_cdev->brightness);
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}
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static ssize_t brightness_store(struct device *dev,
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struct device_attribute *attr, const char *buf, size_t size)
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{
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struct led_classdev *led_cdev = dev_get_drvdata(dev);
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unsigned long state;
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ssize_t ret = -EINVAL;
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ret = kstrtoul(buf, 10, &state);
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if (ret)
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return ret;
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if (state == LED_OFF)
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led_trigger_remove(led_cdev);
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__led_set_brightness(led_cdev, state);
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return size;
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}
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static DEVICE_ATTR_RW(brightness);
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static ssize_t led_max_brightness_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct led_classdev *led_cdev = dev_get_drvdata(dev);
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return sprintf(buf, "%u\n", led_cdev->max_brightness);
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}
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static DEVICE_ATTR(max_brightness, 0444, led_max_brightness_show, NULL);
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#ifdef CONFIG_LEDS_TRIGGERS
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static DEVICE_ATTR(trigger, 0644, led_trigger_show, led_trigger_store);
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static struct attribute *led_trigger_attrs[] = {
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&dev_attr_trigger.attr,
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NULL,
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};
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static const struct attribute_group led_trigger_group = {
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.attrs = led_trigger_attrs,
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};
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#endif
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static struct attribute *led_class_attrs[] = {
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&dev_attr_brightness.attr,
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&dev_attr_max_brightness.attr,
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NULL,
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};
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static const struct attribute_group led_group = {
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.attrs = led_class_attrs,
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};
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static const struct attribute_group *led_groups[] = {
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&led_group,
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#ifdef CONFIG_LEDS_TRIGGERS
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&led_trigger_group,
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#endif
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NULL,
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};
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static void led_timer_function(unsigned long data)
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{
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struct led_classdev *led_cdev = (void *)data;
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unsigned long brightness;
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unsigned long delay;
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if (!led_cdev->blink_delay_on || !led_cdev->blink_delay_off) {
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__led_set_brightness(led_cdev, LED_OFF);
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return;
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}
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if (led_cdev->flags & LED_BLINK_ONESHOT_STOP) {
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led_cdev->flags &= ~LED_BLINK_ONESHOT_STOP;
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return;
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}
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brightness = led_get_brightness(led_cdev);
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if (!brightness) {
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/* Time to switch the LED on. */
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brightness = led_cdev->blink_brightness;
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delay = led_cdev->blink_delay_on;
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} else {
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/* Store the current brightness value to be able
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* to restore it when the delay_off period is over.
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*/
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led_cdev->blink_brightness = brightness;
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brightness = LED_OFF;
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delay = led_cdev->blink_delay_off;
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}
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__led_set_brightness(led_cdev, brightness);
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/* Return in next iteration if led is in one-shot mode and we are in
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* the final blink state so that the led is toggled each delay_on +
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* delay_off milliseconds in worst case.
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*/
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if (led_cdev->flags & LED_BLINK_ONESHOT) {
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if (led_cdev->flags & LED_BLINK_INVERT) {
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if (brightness)
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led_cdev->flags |= LED_BLINK_ONESHOT_STOP;
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} else {
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if (!brightness)
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led_cdev->flags |= LED_BLINK_ONESHOT_STOP;
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}
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}
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mod_timer(&led_cdev->blink_timer, jiffies + msecs_to_jiffies(delay));
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}
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static void set_brightness_delayed(struct work_struct *ws)
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{
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struct led_classdev *led_cdev =
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container_of(ws, struct led_classdev, set_brightness_work);
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led_stop_software_blink(led_cdev);
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__led_set_brightness(led_cdev, led_cdev->delayed_set_value);
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}
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/**
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* led_classdev_suspend - suspend an led_classdev.
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* @led_cdev: the led_classdev to suspend.
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*/
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void led_classdev_suspend(struct led_classdev *led_cdev)
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{
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led_cdev->flags |= LED_SUSPENDED;
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led_cdev->brightness_set(led_cdev, 0);
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}
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EXPORT_SYMBOL_GPL(led_classdev_suspend);
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/**
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* led_classdev_resume - resume an led_classdev.
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* @led_cdev: the led_classdev to resume.
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*/
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void led_classdev_resume(struct led_classdev *led_cdev)
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{
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led_cdev->brightness_set(led_cdev, led_cdev->brightness);
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led_cdev->flags &= ~LED_SUSPENDED;
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}
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EXPORT_SYMBOL_GPL(led_classdev_resume);
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static int led_suspend(struct device *dev)
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{
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struct led_classdev *led_cdev = dev_get_drvdata(dev);
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if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
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led_classdev_suspend(led_cdev);
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return 0;
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}
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static int led_resume(struct device *dev)
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{
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struct led_classdev *led_cdev = dev_get_drvdata(dev);
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if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
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led_classdev_resume(led_cdev);
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return 0;
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}
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static const struct dev_pm_ops leds_class_dev_pm_ops = {
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.suspend = led_suspend,
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.resume = led_resume,
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};
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/**
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* led_classdev_register - register a new object of led_classdev class.
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* @parent: The device to register.
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* @led_cdev: the led_classdev structure for this device.
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*/
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int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)
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{
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led_cdev->dev = device_create_with_groups(leds_class, parent, 0,
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led_cdev, led_cdev->groups,
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"%s", led_cdev->name);
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if (IS_ERR(led_cdev->dev))
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return PTR_ERR(led_cdev->dev);
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#ifdef CONFIG_LEDS_TRIGGERS
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init_rwsem(&led_cdev->trigger_lock);
|
|
#endif
|
|
/* add to the list of leds */
|
|
down_write(&leds_list_lock);
|
|
list_add_tail(&led_cdev->node, &leds_list);
|
|
up_write(&leds_list_lock);
|
|
|
|
if (!led_cdev->max_brightness)
|
|
led_cdev->max_brightness = LED_FULL;
|
|
|
|
led_update_brightness(led_cdev);
|
|
|
|
INIT_WORK(&led_cdev->set_brightness_work, set_brightness_delayed);
|
|
|
|
init_timer(&led_cdev->blink_timer);
|
|
led_cdev->blink_timer.function = led_timer_function;
|
|
led_cdev->blink_timer.data = (unsigned long)led_cdev;
|
|
|
|
#ifdef CONFIG_LEDS_TRIGGERS
|
|
led_trigger_set_default(led_cdev);
|
|
#endif
|
|
|
|
dev_dbg(parent, "Registered led device: %s\n",
|
|
led_cdev->name);
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(led_classdev_register);
|
|
|
|
/**
|
|
* led_classdev_unregister - unregisters a object of led_properties class.
|
|
* @led_cdev: the led device to unregister
|
|
*
|
|
* Unregisters a previously registered via led_classdev_register object.
|
|
*/
|
|
void led_classdev_unregister(struct led_classdev *led_cdev)
|
|
{
|
|
#ifdef CONFIG_LEDS_TRIGGERS
|
|
down_write(&led_cdev->trigger_lock);
|
|
if (led_cdev->trigger)
|
|
led_trigger_set(led_cdev, NULL);
|
|
up_write(&led_cdev->trigger_lock);
|
|
#endif
|
|
|
|
cancel_work_sync(&led_cdev->set_brightness_work);
|
|
|
|
/* Stop blinking */
|
|
led_stop_software_blink(led_cdev);
|
|
led_set_brightness(led_cdev, LED_OFF);
|
|
|
|
device_unregister(led_cdev->dev);
|
|
|
|
down_write(&leds_list_lock);
|
|
list_del(&led_cdev->node);
|
|
up_write(&leds_list_lock);
|
|
}
|
|
EXPORT_SYMBOL_GPL(led_classdev_unregister);
|
|
|
|
static int __init leds_init(void)
|
|
{
|
|
leds_class = class_create(THIS_MODULE, "leds");
|
|
if (IS_ERR(leds_class))
|
|
return PTR_ERR(leds_class);
|
|
leds_class->pm = &leds_class_dev_pm_ops;
|
|
leds_class->dev_groups = led_groups;
|
|
return 0;
|
|
}
|
|
|
|
static void __exit leds_exit(void)
|
|
{
|
|
class_destroy(leds_class);
|
|
}
|
|
|
|
subsys_initcall(leds_init);
|
|
module_exit(leds_exit);
|
|
|
|
MODULE_AUTHOR("John Lenz, Richard Purdie");
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_DESCRIPTION("LED Class Interface");
|