leds: triggers: Flush pending brightness before activating trigger

The race fixed in timer_trig_activate() between a blocking
set_brightness() call and trigger->activate() can affect any trigger.
So

leds: triggers: Flush pending brightness before activating trigger

The race fixed in timer_trig_activate() between a blocking
set_brightness() call and trigger->activate() can affect any trigger.
So move the call to flush_work() into led_trigger_set() where it can
avoid the race for all triggers.

Fixes: 0db37915d912 ("leds: avoid races with workqueue")
Fixes: 8c0f693c6eff ("leds: avoid flush_work in atomic context")
Cc: stable@vger.kernel.org
Tested-by: Dustin L. Howett <dustin@howett.net>
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/r/20240613-led-trigger-flush-v2-1-f4f970799d77@weissschuh.net
Signed-off-by: Lee Jones <lee@kernel.org>

show more ...

leds: trigger: Call synchronize_rcu() before calling trig->activate()

Some triggers call led_trigger_event() from their activate() callback
to initialize the brightness of the LED for which the trig

leds: trigger: Call synchronize_rcu() before calling trig->activate()

Some triggers call led_trigger_event() from their activate() callback
to initialize the brightness of the LED for which the trigger is being
activated.

In order for the LED's initial state to be set correctly this requires that
the led_trigger_event() call uses the new version of trigger->led_cdevs,
which has the new LED.

AFAICT led_trigger_event() will always use the new version when it is
running on the same CPU as where the list_add_tail_rcu() call was made,
which is why the missing synchronize_rcu() has not lead to bug reports.
But if activate() is pre-empted, sleeps or uses a worker then
the led_trigger_event() call may run on another CPU which may still use
the old trigger->led_cdevs list.

Add a synchronize_rcu() call to ensure that any led_trigger_event() calls
done from activate() always use the new list.

Triggers using led_trigger_event() from their activate() callback are:
net/bluetooth/leds.c, net/rfkill/core.c and drivers/tty/vt/keyboard.c.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20240531120124.75662-1-hdegoede@redhat.com
Signed-off-by: Lee Jones <lee@kernel.org>

show more ...

leds: trigger: Unregister sysfs attributes before calling deactivate()

Triggers which have trigger specific sysfs attributes typically store
related data in trigger-data allocated by the activate()

leds: trigger: Unregister sysfs attributes before calling deactivate()

Triggers which have trigger specific sysfs attributes typically store
related data in trigger-data allocated by the activate() callback and
freed by the deactivate() callback.

Calling device_remove_groups() after calling deactivate() leaves a window
where the sysfs attributes show/store functions could be called after
deactivation and then operate on the just freed trigger-data.

Move the device_remove_groups() call to before deactivate() to close
this race window.

This also makes the deactivation path properly do things in reverse order
of the activation path which calls the activate() callback before calling
device_add_groups().

Fixes: a7e7a3156300 ("leds: triggers: add device attribute support")
Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20240504162533.76780-1-hdegoede@redhat.com
Signed-off-by: Lee Jones <lee@kernel.org>

show more ...

leds: trigger: Add led_mc_trigger_event() function

Add a new led_mc_trigger_event() function for triggers which want to
change the color of a multi-color LED based on their trigger conditions.

Sign

leds: trigger: Add led_mc_trigger_event() function

Add a new led_mc_trigger_event() function for triggers which want to
change the color of a multi-color LED based on their trigger conditions.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
Reviewed-by: Andy Shevchenko <andy@kernel.org>
Link: https://lore.kernel.org/r/20240531114124.45346-6-hdegoede@redhat.com
Signed-off-by: Lee Jones <lee@kernel.org>

show more ...

leds: trigger: Store brightness set by led_trigger_event()

If a simple trigger is assigned to a LED, then the LED may be off until
the next led_trigger_event() call. This may be an issue for simple

leds: trigger: Store brightness set by led_trigger_event()

If a simple trigger is assigned to a LED, then the LED may be off until
the next led_trigger_event() call. This may be an issue for simple
triggers with rare led_trigger_event() calls, e.g. power supply
charging indicators (drivers/power/supply/power_supply_leds.c).
Therefore persist the brightness value of the last led_trigger_event()
call and use this value if the trigger is assigned to a LED.
In addition add a getter for the trigger brightness value.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Link: https://lore.kernel.org/r/b1358b25-3f30-458d-8240-5705ae007a8a@gmail.com
Signed-off-by: Lee Jones <lee@kernel.org>

show more ...

leds: triggers: Add helper led_match_default_trigger

Avoid code duplication and factor out common functionality to new
helper led_match_default_trigger().

Signed-off-by: Heiner Kallweit <hkallweit1

leds: triggers: Add helper led_match_default_trigger

Avoid code duplication and factor out common functionality to new
helper led_match_default_trigger().

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Link: https://lore.kernel.org/r/d78eef6f-c18c-4546-b83e-6d1890849154@gmail.com
Signed-off-by: Lee Jones <lee@kernel.org>

show more ...

leds: trigger: Stop exporting trigger_list

Commit 682e98564ffb ("leds: trigger: panic: Simplify
led_trigger_set_panic") removed the last external user of variable
trigger_list. So stop exporting it.

leds: trigger: Stop exporting trigger_list

Commit 682e98564ffb ("leds: trigger: panic: Simplify
led_trigger_set_panic") removed the last external user of variable
trigger_list. So stop exporting it. If in future a need should arise
again to access this variable, I think we better add some accessor
instead of exporting the variable directly.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Link: https://lore.kernel.org/r/ca185fb1-3a66-46b9-920e-bfecbe39c6bf@gmail.com
Signed-off-by: Lee Jones <lee@kernel.org>

show more ...

leds: trigger: Load trigger modules on-demand if used as default trigger

Even if a trigger is set as default trigger for a LED device,
the respective trigger module (if built as module) isn't automa

leds: trigger: Load trigger modules on-demand if used as default trigger

Even if a trigger is set as default trigger for a LED device,
the respective trigger module (if built as module) isn't automatically
loaded by the kernel if the LED device is registered. I think we can
do better. Try to load the module asynchronously by alias
ledtrig:<trigger name>. This requires that such an alias is added to
relevant triggers.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Link: https://lore.kernel.org/r/79adb260-06ad-443a-a68e-abe4498c3298@gmail.com
Signed-off-by: Lee Jones <lee@kernel.org>

show more ...

leds: trigger: Remove unused function led_trigger_rename_static()

This function was added with a8df7b1ab70b ("leds: add led_trigger_rename
function") 11 yrs ago, but it has no users. So remove it.

leds: trigger: Remove unused function led_trigger_rename_static()

This function was added with a8df7b1ab70b ("leds: add led_trigger_rename
function") 11 yrs ago, but it has no users. So remove it.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Link: https://lore.kernel.org/r/d90f30be-f661-4db7-b0b5-d09d07a78a68@gmail.com
Signed-off-by: Lee Jones <lee@kernel.org>

show more ...

leds: Clear LED_INIT_DEFAULT_TRIGGER when clearing current trigger

Not all triggers use LED_INIT_DEFAULT_TRIGGER, which means that it
will not get cleared when the default trigger is a trigger which

leds: Clear LED_INIT_DEFAULT_TRIGGER when clearing current trigger

Not all triggers use LED_INIT_DEFAULT_TRIGGER, which means that it
will not get cleared when the default trigger is a trigger which
does not use it such as "default-on".

If the default trigger then later gets replaced by a trigger which
does check LED_INIT_DEFAULT_TRIGGER, such as "timer" then that trigger
will behave as if it is the default trigger which it should not do.

To fix this clear the LED_INIT_DEFAULT_TRIGGER flag when clearing
the current trigger, so that it will not be set for any subsequently
set (non default) triggers.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
Tested-by: Yauhen Kharuzhy <jekhor@gmail.com>
Link: https://lore.kernel.org/r/20230510162234.291439-5-hdegoede@redhat.com
Signed-off-by: Lee Jones <lee@kernel.org>

show more ...

leds: Fix oops about sleeping in led_trigger_blink()

led_trigger_blink() calls led_blink_set() from a RCU read-side critical
section so led_blink_set() must not sleep. Note sleeping was not allowed

leds: Fix oops about sleeping in led_trigger_blink()

led_trigger_blink() calls led_blink_set() from a RCU read-side critical
section so led_blink_set() must not sleep. Note sleeping was not allowed
before the switch to RCU either because a spinlock was held before.

led_blink_set() does not sleep when sw-blinking is used, but
many LED controller drivers with hw blink support have a blink_set
function which may sleep, leading to an oops like this one:

[ 832.605062] ------------[ cut here ]------------
[ 832.605085] Voluntary context switch within RCU read-side critical section!
[ 832.605119] WARNING: CPU: 2 PID: 370 at kernel/rcu/tree_plugin.h:318 rcu_note_context_switch+0x4ee/0x690
<snip>
[ 832.606453] Call Trace:
[ 832.606466] <TASK>
[ 832.606487] __schedule+0x9f/0x1480
[ 832.606527] schedule+0x5d/0xe0
[ 832.606549] schedule_timeout+0x79/0x140
[ 832.606572] ? __pfx_process_timeout+0x10/0x10
[ 832.606599] wait_for_completion_timeout+0x6f/0x140
[ 832.606627] i2c_dw_xfer+0x101/0x460
[ 832.606659] ? psi_group_change+0x168/0x400
[ 832.606680] __i2c_transfer+0x172/0x6d0
[ 832.606709] i2c_smbus_xfer_emulated+0x27d/0x9c0
[ 832.606732] ? __schedule+0x430/0x1480
[ 832.606753] ? preempt_count_add+0x6a/0xa0
[ 832.606778] ? get_nohz_timer_target+0x18/0x190
[ 832.606796] ? lock_timer_base+0x61/0x80
[ 832.606817] ? preempt_count_add+0x6a/0xa0
[ 832.606842] __i2c_smbus_xfer+0xa2/0x3f0
[ 832.606862] i2c_smbus_xfer+0x66/0xf0
[ 832.606882] i2c_smbus_read_byte_data+0x41/0x70
[ 832.606901] ? _raw_spin_unlock_irqrestore+0x23/0x40
[ 832.606922] ? __pm_runtime_suspend+0x46/0xc0
[ 832.606946] cht_wc_byte_reg_read+0x2e/0x60
[ 832.606972] _regmap_read+0x5c/0x120
[ 832.606997] _regmap_update_bits+0x96/0xc0
[ 832.607023] regmap_update_bits_base+0x5b/0x90
[ 832.607053] cht_wc_leds_brightness_get+0x412/0x910 [leds_cht_wcove]
[ 832.607094] led_blink_setup+0x28/0x100
[ 832.607119] led_trigger_blink+0x40/0x70
[ 832.607145] power_supply_update_leds+0x1b7/0x1c0
[ 832.607174] power_supply_changed_work+0x67/0xe0
[ 832.607198] process_one_work+0x1c8/0x3c0
[ 832.607222] worker_thread+0x4d/0x380
[ 832.607243] ? __pfx_worker_thread+0x10/0x10
[ 832.607258] kthread+0xe9/0x110
[ 832.607279] ? __pfx_kthread+0x10/0x10
[ 832.607300] ret_from_fork+0x2c/0x50
[ 832.607337] </TASK>
[ 832.607344] ---[ end trace 0000000000000000 ]---

Add a new led_blink_set_nosleep() function which defers the actual
led_blink_set() call to a workqueue when necessary to fix this.

This also fixes an existing race where a pending led_set_brightness() has
been deferred to set_brightness_work and might then race with a later
led_cdev->blink_set() call. Note this race is only an issue with triggers
mixing led_trigger_event() and led_trigger_blink() calls, sysfs API
calls and led_trigger_blink_oneshot() are not affected.

Note rather then adding a separate blink_set_blocking callback this uses
the presence of the already existing brightness_set_blocking callback to
detect if the blinking call should be deferred to set_brightness_work.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
Tested-by: Yauhen Kharuzhy <jekhor@gmail.com>
Link: https://lore.kernel.org/r/20230510162234.291439-4-hdegoede@redhat.com
Signed-off-by: Lee Jones <lee@kernel.org>

show more ...

leds: Change led_trigger_blink[_oneshot]() delay parameters to pass-by-value

led_blink_set[_oneshot]()'s delay_on and delay_off function parameters
are pass by reference, so that hw-blink implementa

leds: Change led_trigger_blink[_oneshot]() delay parameters to pass-by-value

led_blink_set[_oneshot]()'s delay_on and delay_off function parameters
are pass by reference, so that hw-blink implementations can report
back the actual achieved delays when the values have been rounded
to something the hw supports.

This is really only interesting for the sysfs API / the timer trigger.
Other triggers don't really care about this and none of the callers of
led_trigger_blink[_oneshot]() do anything with the returned delay values.

Change the led_trigger_blink[_oneshot]() delay parameters to pass-by-value,
there are 2 reasons for this:

1. led_cdev->blink_set() may sleep, while led_trigger_blink() may not.
So on hw where led_cdev->blink_set() sleeps the call needs to be deferred
to a workqueue, in which case the actual achieved delays are unknown
(this is a preparation patch for the deferring).

2. Since the callers don't care about the actual achieved delays, allowing
callers to directly pass a value leads to simpler code for most callers.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
Tested-by: Yauhen Kharuzhy <jekhor@gmail.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Acked-by: Florian Westphal <fw@strlen.de>
Link: https://lore.kernel.org/r/20230510162234.291439-2-hdegoede@redhat.com
Signed-off-by: Lee Jones <lee@kernel.org>

show more ...

leds: trigger: use RCU to protect the led_cdevs list

Even with the previous commit 27af8e2c90fb
("leds: trigger: fix potential deadlock with libata")
to this file, we still get lockdep unhappy, and

leds: trigger: use RCU to protect the led_cdevs list

Even with the previous commit 27af8e2c90fb
("leds: trigger: fix potential deadlock with libata")
to this file, we still get lockdep unhappy, and Boqun
explained the report here:
https://lore.kernel.org/r/YNA+d1X4UkoQ7g8a@boqun-archlinux

Effectively, this means that the read_lock_irqsave() isn't
enough here because another CPU might be trying to do a
write lock, and thus block the readers.

This is all pretty messy, but it doesn't seem right that
the LEDs framework imposes some locking requirements on
users, in particular we'd have to make the spinlock in the
iwlwifi driver always disable IRQs, even if we don't need
that for any other reason, just to avoid this deadlock.

Since writes to the led_cdevs list are rare (and are done
by userspace), just switch the list to RCU. This costs a
synchronize_rcu() at removal time so we can ensure things
are correct, but that seems like a small price to pay for
getting lock-free iterations and no deadlocks (nor any
locking requirements imposed on users.)

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Pavel Machek <pavel@ucw.cz>

show more ...

leds: trigger: fix potential deadlock with libata

We have the following potential deadlock condition:

========================================================
WARNING: possible irq lock inversion

leds: trigger: fix potential deadlock with libata

We have the following potential deadlock condition:

========================================================
WARNING: possible irq lock inversion dependency detected
5.10.0-rc2+ #25 Not tainted
--------------------------------------------------------
swapper/3/0 just changed the state of lock:
ffff8880063bd618 (&host->lock){-...}-{2:2}, at: ata_bmdma_interrupt+0x27/0x200
but this lock took another, HARDIRQ-READ-unsafe lock in the past:
(&trig->leddev_list_lock){.+.?}-{2:2}

and interrupts could create inverse lock ordering between them.

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

CPU0 CPU1
---- ----
lock(&trig->leddev_list_lock);
local_irq_disable();
lock(&host->lock);
lock(&trig->leddev_list_lock);
<Interrupt>
lock(&host->lock);

*** DEADLOCK ***

no locks held by swapper/3/0.

the shortest dependencies between 2nd lock and 1st lock:
-> (&trig->leddev_list_lock){.+.?}-{2:2} ops: 46 {
HARDIRQ-ON-R at:
lock_acquire+0x15f/0x420
_raw_read_lock+0x42/0x90
led_trigger_event+0x2b/0x70
rfkill_global_led_trigger_worker+0x94/0xb0
process_one_work+0x240/0x560
worker_thread+0x58/0x3d0
kthread+0x151/0x170
ret_from_fork+0x1f/0x30
IN-SOFTIRQ-R at:
lock_acquire+0x15f/0x420
_raw_read_lock+0x42/0x90
led_trigger_event+0x2b/0x70
kbd_bh+0x9e/0xc0
tasklet_action_common.constprop.0+0xe9/0x100
tasklet_action+0x22/0x30
__do_softirq+0xcc/0x46d
run_ksoftirqd+0x3f/0x70
smpboot_thread_fn+0x116/0x1f0
kthread+0x151/0x170
ret_from_fork+0x1f/0x30
SOFTIRQ-ON-R at:
lock_acquire+0x15f/0x420
_raw_read_lock+0x42/0x90
led_trigger_event+0x2b/0x70
rfkill_global_led_trigger_worker+0x94/0xb0
process_one_work+0x240/0x560
worker_thread+0x58/0x3d0
kthread+0x151/0x170
ret_from_fork+0x1f/0x30
INITIAL READ USE at:
lock_acquire+0x15f/0x420
_raw_read_lock+0x42/0x90
led_trigger_event+0x2b/0x70
rfkill_global_led_trigger_worker+0x94/0xb0
process_one_work+0x240/0x560
worker_thread+0x58/0x3d0
kthread+0x151/0x170
ret_from_fork+0x1f/0x30
}
... key at: [<ffffffff83da4c00>] __key.0+0x0/0x10
... acquired at:
_raw_read_lock+0x42/0x90
led_trigger_blink_oneshot+0x3b/0x90
ledtrig_disk_activity+0x3c/0xa0
ata_qc_complete+0x26/0x450
ata_do_link_abort+0xa3/0xe0
ata_port_freeze+0x2e/0x40
ata_hsm_qc_complete+0x94/0xa0
ata_sff_hsm_move+0x177/0x7a0
ata_sff_pio_task+0xc7/0x1b0
process_one_work+0x240/0x560
worker_thread+0x58/0x3d0
kthread+0x151/0x170
ret_from_fork+0x1f/0x30

-> (&host->lock){-...}-{2:2} ops: 69 {
IN-HARDIRQ-W at:
lock_acquire+0x15f/0x420
_raw_spin_lock_irqsave+0x52/0xa0
ata_bmdma_interrupt+0x27/0x200
__handle_irq_event_percpu+0xd5/0x2b0
handle_irq_event+0x57/0xb0
handle_edge_irq+0x8c/0x230
asm_call_irq_on_stack+0xf/0x20
common_interrupt+0x100/0x1c0
asm_common_interrupt+0x1e/0x40
native_safe_halt+0xe/0x10
arch_cpu_idle+0x15/0x20
default_idle_call+0x59/0x1c0
do_idle+0x22c/0x2c0
cpu_startup_entry+0x20/0x30
start_secondary+0x11d/0x150
secondary_startup_64_no_verify+0xa6/0xab
INITIAL USE at:
lock_acquire+0x15f/0x420
_raw_spin_lock_irqsave+0x52/0xa0
ata_dev_init+0x54/0xe0
ata_link_init+0x8b/0xd0
ata_port_alloc+0x1f1/0x210
ata_host_alloc+0xf1/0x130
ata_host_alloc_pinfo+0x14/0xb0
ata_pci_sff_prepare_host+0x41/0xa0
ata_pci_bmdma_prepare_host+0x14/0x30
piix_init_one+0x21f/0x600
local_pci_probe+0x48/0x80
pci_device_probe+0x105/0x1c0
really_probe+0x221/0x490
driver_probe_device+0xe9/0x160
device_driver_attach+0xb2/0xc0
__driver_attach+0x91/0x150
bus_for_each_dev+0x81/0xc0
driver_attach+0x1e/0x20
bus_add_driver+0x138/0x1f0
driver_register+0x91/0xf0
__pci_register_driver+0x73/0x80
piix_init+0x1e/0x2e
do_one_initcall+0x5f/0x2d0
kernel_init_freeable+0x26f/0x2cf
kernel_init+0xe/0x113
ret_from_fork+0x1f/0x30
}
... key at: [<ffffffff83d9fdc0>] __key.6+0x0/0x10
... acquired at:
__lock_acquire+0x9da/0x2370
lock_acquire+0x15f/0x420
_raw_spin_lock_irqsave+0x52/0xa0
ata_bmdma_interrupt+0x27/0x200
__handle_irq_event_percpu+0xd5/0x2b0
handle_irq_event+0x57/0xb0
handle_edge_irq+0x8c/0x230
asm_call_irq_on_stack+0xf/0x20
common_interrupt+0x100/0x1c0
asm_common_interrupt+0x1e/0x40
native_safe_halt+0xe/0x10
arch_cpu_idle+0x15/0x20
default_idle_call+0x59/0x1c0
do_idle+0x22c/0x2c0
cpu_startup_entry+0x20/0x30
start_secondary+0x11d/0x150
secondary_startup_64_no_verify+0xa6/0xab

This lockdep splat is reported after:
commit e918188611f0 ("locking: More accurate annotations for read_lock()")

To clarify:
- read-locks are recursive only in interrupt context (when
in_interrupt() returns true)
- after acquiring host->lock in CPU1, another cpu (i.e. CPU2) may call
write_lock(&trig->leddev_list_lock) that would be blocked by CPU0
that holds trig->leddev_list_lock in read-mode
- when CPU1 (ata_ac_complete()) tries to read-lock
trig->leddev_list_lock, it would be blocked by the write-lock waiter
on CPU2 (because we are not in interrupt context, so the read-lock is
not recursive)
- at this point if an interrupt happens on CPU0 and
ata_bmdma_interrupt() is executed it will try to acquire host->lock,
that is held by CPU1, that is currently blocked by CPU2, so:

* CPU0 blocked by CPU1
* CPU1 blocked by CPU2
* CPU2 blocked by CPU0

*** DEADLOCK ***

The deadlock scenario is better represented by the following schema
(thanks to Boqun Feng <boqun.feng@gmail.com> for the schema and the
detailed explanation of the deadlock condition):

CPU 0: CPU 1: CPU 2:
----- ----- -----
led_trigger_event():
read_lock(&trig->leddev_list_lock);
<workqueue>
ata_hsm_qc_complete():
spin_lock_irqsave(&host->lock);
write_lock(&trig->leddev_list_lock);
ata_port_freeze():
ata_do_link_abort():
ata_qc_complete():
ledtrig_disk_activity():
led_trigger_blink_oneshot():
read_lock(&trig->leddev_list_lock);
// ^ not in in_interrupt() context, so could get blocked by CPU 2
<interrupt>
ata_bmdma_interrupt():
spin_lock_irqsave(&host->lock);

Fix by using read_lock_irqsave/irqrestore() in led_trigger_event(), so
that no interrupt can happen in between, preventing the deadlock
condition.

Apply the same change to led_trigger_blink_setup() as well, since the
same deadlock scenario can also happen in power_supply_update_bat_leds()
-> led_trigger_blink() -> led_trigger_blink_setup() (workqueue context),
and potentially prevent other similar usages.

Link: https://lore.kernel.org/lkml/20201101092614.GB3989@xps-13-7390/
Fixes: eb25cb9956cc ("leds: convert IDE trigger to common disk trigger")
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Signed-off-by: Pavel Machek <pavel@ucw.cz>

show more ...

leds: trigger: add support for LED-private device triggers

Some LED controllers may come with an internal HW triggering mechanism
for the LED and the ability to switch between SW control and the
int

leds: trigger: add support for LED-private device triggers

Some LED controllers may come with an internal HW triggering mechanism
for the LED and the ability to switch between SW control and the
internal HW control. This includes most PHYs, various ethernet switches,
the Turris Omnia LED controller or AXP20X PMIC.

This adds support for registering such triggers.

This code is based on work by Pavel Machek <pavel@ucw.cz> and
Ondřej Jirman <megous@megous.com>.

Signed-off-by: Marek Behún <marek.behun@nic.cz>
Acked-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
Signed-off-by: Pavel Machek <pavel@ucw.cz>

show more ...

leds: fix spelling mistake

Fix typo: "Tigger" --> "Trigger"

Signed-off-by: Flavio Suligoi <f.suligoi@asem.it>
Reviewed-by: Alexander Dahl <ada@thorsis.com>
Signed-off-by: Pavel Machek <pavel@ucw.cz>

leds: remove PAGE_SIZE limit of /sys/class/leds/<led>/trigger

Reading /sys/class/leds/<led>/trigger returns all available LED triggers.
However, the size of this file is limited to PAGE_SIZE because

leds: remove PAGE_SIZE limit of /sys/class/leds/<led>/trigger

Reading /sys/class/leds/<led>/trigger returns all available LED triggers.
However, the size of this file is limited to PAGE_SIZE because of the
limitation for sysfs attribute.

Enabling LED CPU trigger on systems with thousands of CPUs easily hits
PAGE_SIZE limit, and makes it impossible to see all available LED triggers
and which trigger is currently activated.

We work around it here by converting /sys/class/leds/<led>/trigger to
binary attribute, which is not limited by length. This is _not_ good
design, do not copy it.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Dan Murphy <dmurphy@ti.com>A
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Pavel Machek <pavel@ucw.cz>

show more ...

led: triggers: Fix dereferencing of null pointer

Error was detected by PVS-Studio:
V522 Dereferencing of the null pointer 'led_cdev->trigger' might take place.

Fixes: 2282e125a406 ("leds: triggers:

led: triggers: Fix dereferencing of null pointer

Error was detected by PVS-Studio:
V522 Dereferencing of the null pointer 'led_cdev->trigger' might take place.

Fixes: 2282e125a406 ("leds: triggers: let struct led_trigger::activate() return an error code")
Signed-off-by: Oleh Kravchenko <oleg@kaa.org.ua>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>

show more ...

led: triggers: Fix a memory leak bug

In led_trigger_set(), 'event' is allocated in kasprintf(). However, it is
not deallocated in the following execution if the label 'err_activate' or
'err_add_grou

led: triggers: Fix a memory leak bug

In led_trigger_set(), 'event' is allocated in kasprintf(). However, it is
not deallocated in the following execution if the label 'err_activate' or
'err_add_groups' is entered, leading to memory leaks. To fix this issue,
free 'event' before returning the error.

Fixes: 52c47742f79d ("leds: triggers: send uevent when changing triggers")
Signed-off-by: Wenwen Wang <wenwen@cs.uga.edu>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>

show more ...

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

Based on 2 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of th

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

Based on 2 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

led: triggers: Initialize LED_INIT_DEFAULT_TRIGGER if trigger is brought after class

Trigger driver can be initialized after the LED class device driver. In
such case led_trigger_set_default() won'

led: triggers: Initialize LED_INIT_DEFAULT_TRIGGER if trigger is brought after class

Trigger driver can be initialized after the LED class device driver. In
such case led_trigger_set_default() won't be called and flag
LED_INIT_DEFAULT_TRIGGER should be set from led_trigger_register().

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>

show more ...

led: triggers: Add LED_INIT_DEFAULT_TRIGGER flag

Add the flag LED_INIT_DEFAULT_TRIGGER for indicating that trigger
being set is a default trigger for the LED class device, and
thus it should be init

led: triggers: Add LED_INIT_DEFAULT_TRIGGER flag

Add the flag LED_INIT_DEFAULT_TRIGGER for indicating that trigger
being set is a default trigger for the LED class device, and
thus it should be initialized with settings provided in the fwnode.

Set the flag in the led_trigger_set_default(). It is expected to be
cleared in the activate() op of a trigger after trigger fwnode
initialization data is parsed and applied. This should happen only
once after LED class device registration, to allow leaving triggers
in the idle state on re-apply and let the users apply their own
settings without interference from the default ones.

Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>

show more ...

led: triggers: Break the for loop after default trigger is found

It is of no avail to continue iterating through registered
triggers in the led_trigger_set_default() after the trigger to set
has bee

led: triggers: Break the for loop after default trigger is found

It is of no avail to continue iterating through registered
triggers in the led_trigger_set_default() after the trigger to set
has been found. Add "break" statement to fix this omission.

Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>

show more ...

leds: triggers: handle .trigger_data and .activated() in the core

This helps keeping these two fields consistent and drivers don't need to
care for this themselves any more.

Note that .activated is

leds: triggers: handle .trigger_data and .activated() in the core

This helps keeping these two fields consistent and drivers don't need to
care for this themselves any more.

Note that .activated isn't set to true automatically because that might
confuse some triggers when deactivating (e.g. ledtrig-gpio).

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>

show more ...

leds: triggers: add device attribute support

As many triggers use device attributes, add support for these in
led_trigger_set which allows simplifying the drivers accordingly.

Signed-off-by: Uwe Kl

leds: triggers: add device attribute support

As many triggers use device attributes, add support for these in
led_trigger_set which allows simplifying the drivers accordingly.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>

show more ...