Thank you, Pavel and Jacek
2017-02-12 18:45 GMT-02:00 Jacek Anaszewski <jacek.anaszewski@xxxxxxxxx>:
> Hi Paulo,
>
> Thanks for the patch,
> Pavel - thanks for the review.
>
> Patch applied to the for-4.12 branch of linux-leds.git.
>
> Best regards,
> Jacek Anaszewski
>
> On 02/10/2017 12:07 AM, Paulo Costa wrote:
>> 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 <me@xxxxxxxxxxxxxxxxxx>
>> CC: Pavel Machek <pavel@xxxxxx>
>> ---
>> v2:
>> * Fix concurrency issues during initialization
>> * Round up the division
>> ---
>> drivers/leds/trigger/ledtrig-cpu.c | 33 +++++++++++++++++++++++++++++++--
>> 1 file changed, 31 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/leds/trigger/ledtrig-cpu.c b/drivers/leds/trigger/ledtrig-cpu.c
>> index 22f0634..06ec733 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);
>>
>> @@ -113,6 +137,11 @@ static int __init ledtrig_cpu_init(void)
>> 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
>> * fine with this trigger.
>>
