From 0b88b71c7762a406ff99c625935474dc42a25003 Mon Sep 17 00:00:00 2001 From: Paulo Costa Date: Thu, 9 Feb 2017 21:07:35 -0200 Subject: leds/trigger/cpu: Add LED trigger for all CPUs aggregated Currently there is one CPU led trigger per cpu ('cpu0', 'cpu1', ...) This patch adds a new trigger, 'cpu', with brightness proportional to the number of active CPUs. If multiple brightness levels aren't supported on the LED, it effectively indicates if there is any CPU active. This is particularly useful on tiny linux boards with more CPU cores than LED pins. Signed-off-by: Paulo Costa Acked-by: Pavel Machek Signed-off-by: Jacek Anaszewski --- drivers/leds/trigger/ledtrig-cpu.c | 33 +++++++++++++++++++++++++++++++-- 1 file changed, 31 insertions(+), 2 deletions(-) (limited to 'drivers/leds/trigger') diff --git a/drivers/leds/trigger/ledtrig-cpu.c b/drivers/leds/trigger/ledtrig-cpu.c index a41896468cb3..66a626091936 100644 --- a/drivers/leds/trigger/ledtrig-cpu.c +++ b/drivers/leds/trigger/ledtrig-cpu.c @@ -31,12 +31,16 @@ #define MAX_NAME_LEN 8 struct led_trigger_cpu { + bool is_active; char name[MAX_NAME_LEN]; struct led_trigger *_trig; }; static DEFINE_PER_CPU(struct led_trigger_cpu, cpu_trig); +static struct led_trigger *trig_cpu_all; +static atomic_t num_active_cpus = ATOMIC_INIT(0); + /** * ledtrig_cpu - emit a CPU event as a trigger * @evt: CPU event to be emitted @@ -47,26 +51,46 @@ static DEFINE_PER_CPU(struct led_trigger_cpu, cpu_trig); void ledtrig_cpu(enum cpu_led_event ledevt) { struct led_trigger_cpu *trig = this_cpu_ptr(&cpu_trig); + bool is_active = trig->is_active; /* Locate the correct CPU LED */ switch (ledevt) { case CPU_LED_IDLE_END: case CPU_LED_START: /* Will turn the LED on, max brightness */ - led_trigger_event(trig->_trig, LED_FULL); + is_active = true; break; case CPU_LED_IDLE_START: case CPU_LED_STOP: case CPU_LED_HALTED: /* Will turn the LED off */ - led_trigger_event(trig->_trig, LED_OFF); + is_active = false; break; default: /* Will leave the LED as it is */ break; } + + if (is_active != trig->is_active) { + unsigned int active_cpus; + unsigned int total_cpus; + + /* Update trigger state */ + trig->is_active = is_active; + atomic_add(is_active ? 1 : -1, &num_active_cpus); + active_cpus = atomic_read(&num_active_cpus); + total_cpus = num_present_cpus(); + + led_trigger_event(trig->_trig, + is_active ? LED_FULL : LED_OFF); + + + led_trigger_event(trig_cpu_all, + DIV_ROUND_UP(LED_FULL * active_cpus, total_cpus)); + + } } EXPORT_SYMBOL(ledtrig_cpu); @@ -112,6 +136,11 @@ static int __init ledtrig_cpu_init(void) /* Supports up to 9999 cpu cores */ BUILD_BUG_ON(CONFIG_NR_CPUS > 9999); + /* + * Registering a trigger for all CPUs. + */ + led_trigger_register_simple("cpu", &trig_cpu_all); + /* * Registering CPU led trigger for each CPU core here * ignores CPU hotplug, but after this CPU hotplug works -- cgit v1.2.3