Allow initialization of pattern used in pattern trigger from Device Tree
property.
This is especially useful for embedded systems where the pattern trigger
would be used to indicate the process of boot status in a nice,
user-friendly blinking way. This initialization pattern will be used
till user-space is brought up and sets its own pattern, indicating the
boot status is for example finished.
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
We will meet below issue due to mutex_lock() is called in interrupt context.
The mutex lock is used to protect the pattern trigger data, but before changing
new pattern trigger data (pattern values or repeat value) by users, we always
cancel the timer firstly to clear previous patterns' performance. That means
there is no race in pattern_trig_timer_function(), so we can drop the mutex
lock in pattern_trig_timer_function() to avoid this issue.
Moreover we can move the timer cancelling into mutex protection, since there
is no deadlock risk if we remove the mutex lock in pattern_trig_timer_function().
BUG: sleeping function called from invalid context at kernel/locking/mutex.c:254
in_atomic(): 1, irqs_disabled(): 0, pid: 0, name: swapper/1
CPU: 1 PID: 0 Comm: swapper/1 Not tainted
4.20.0-rc1-koelsch-00841-ga338c8181013c1a9 #171
Hardware name: Generic R-Car Gen2 (Flattened Device Tree)
[<c020f19c>] (unwind_backtrace) from [<c020aecc>] (show_stack+0x10/0x14)
[<c020aecc>] (show_stack) from [<c07affb8>] (dump_stack+0x7c/0x9c)
[<c07affb8>] (dump_stack) from [<c02417d4>] (___might_sleep+0xf4/0x158)
[<c02417d4>] (___might_sleep) from [<c07c92c4>] (mutex_lock+0x18/0x60)
[<c07c92c4>] (mutex_lock) from [<c067b28c>] (pattern_trig_timer_function+0x1c/0x11c)
[<c067b28c>] (pattern_trig_timer_function) from [<c027f6fc>] (call_timer_fn+0x1c/0x90)
[<c027f6fc>] (call_timer_fn) from [<c027f944>] (expire_timers+0x94/0xa4)
[<c027f944>] (expire_timers) from [<c027fc98>] (run_timer_softirq+0x108/0x15c)
[<c027fc98>] (run_timer_softirq) from [<c02021cc>] (__do_softirq+0x1d4/0x258)
[<c02021cc>] (__do_softirq) from [<c0224d24>] (irq_exit+0x64/0xc4)
[<c0224d24>] (irq_exit) from [<c0268dd0>] (__handle_domain_irq+0x80/0xb4)
[<c0268dd0>] (__handle_domain_irq) from [<c045e1b0>] (gic_handle_irq+0x58/0x90)
[<c045e1b0>] (gic_handle_irq) from [<c02019f8>] (__irq_svc+0x58/0x74)
Exception stack(0xeb483f60 to 0xeb483fa8)
3f60: 00000000 00000000 eb9afaa0 c0217e80 00000000 ffffe000 00000000 c0e06408
3f80: 00000002 c0e0647c c0c6a5f0 00000000 c0e04900 eb483fb0 c0207ea8 c0207e98
3fa0: 60020013 ffffffff
[<c02019f8>] (__irq_svc) from [<c0207e98>] (arch_cpu_idle+0x1c/0x38)
[<c0207e98>] (arch_cpu_idle) from [<c0247ca8>] (do_idle+0x138/0x268)
[<c0247ca8>] (do_idle) from [<c0248050>] (cpu_startup_entry+0x18/0x1c)
[<c0248050>] (cpu_startup_entry) from [<402022ec>] (0x402022ec)
Fixes: 5fd752b6b3 ("leds: core: Introduce LED pattern trigger")
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Reported-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
Check for zero duration before skipping step. This fixes pattern
echo "0 1000 10 2550 0 1000" > pattern
which should do [ .-xXx-.] but does [ Xx-.]
Signed-off-by: Pavel Machek <pavel@ucw.cz>
Suggested-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
This patch adds a new LED trigger that LED device can configure
to employ software or hardware pattern engine.
Consumers can write 'pattern' file to enable the software pattern
which alters the brightness for the specified duration with one
software timer.
Moreover consumers can write 'hw_pattern' file to enable the hardware
pattern for some LED controllers which can autonomously control
brightness over time, according to some preprogrammed hardware
patterns.
Signed-off-by: Raphael Teysseyre <rteysseyre@gmail.com>
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
