Hi, On Thu, Jul 02, 2020 at 04:47:11PM +0200, megous hlavni wrote: > Some LED controllers may come with an internal HW triggering mechanism > for the LED and an ability to switch between user control of the LED, > or the internal control. One such example is AXP20X PMIC, that allows > wither for user control of the LED, or for internal control based on > the state of the battery charger. > > Add support for registering per-LED device trigger. > > Names of private triggers need to be globally unique, but may clash > with other private triggers. This is enforced during trigger > registration. Developers can register private triggers just like > the normal triggers, by setting private_led to a classdev > of the LED the trigger is associated with.
I've prepared this patch based on the note here: https://www.kernel.org/doc/html/latest/leds/leds-class.html Future Development: At the moment, a trigger can’t be created specifically for a single LED. There are a number of cases where a trigger might only be mappable to a particular LED (ACPI?). The addition of triggers provided by the LED driver should cover this option and be possible to add without breaking the current interface. Does it look good? I plan to use this interface in the axp20x driver I've sent previously, if this patch is acceptable. thank you and regards, o. > Signed-off-by: Ondrej Jirman <meg...@megous.com> > --- > drivers/leds/led-triggers.c | 12 +++++++++--- > include/linux/leds.h | 3 +++ > 2 files changed, 12 insertions(+), 3 deletions(-) > > diff --git a/drivers/leds/led-triggers.c b/drivers/leds/led-triggers.c > index 79e30d2cb7a5..3011e2658404 100644 > --- a/drivers/leds/led-triggers.c > +++ b/drivers/leds/led-triggers.c > @@ -50,7 +50,8 @@ ssize_t led_trigger_write(struct file *filp, struct kobject > *kobj, > > down_read(&triggers_list_lock); > list_for_each_entry(trig, &trigger_list, next_trig) { > - if (sysfs_streq(buf, trig->name)) { > + if (sysfs_streq(buf, trig->name) && > + (!trig->private_led || trig->private_led == led_cdev)) { > down_write(&led_cdev->trigger_lock); > led_trigger_set(led_cdev, trig); > up_write(&led_cdev->trigger_lock); > @@ -96,6 +97,9 @@ static int led_trigger_format(char *buf, size_t size, > bool hit = led_cdev->trigger && > !strcmp(led_cdev->trigger->name, trig->name); > > + if (trig->private_led && trig->private_led != led_cdev) > + continue; > + > len += led_trigger_snprintf(buf + len, size - len, > " %s%s%s", hit ? "[" : "", > trig->name, hit ? "]" : ""); > @@ -243,7 +247,8 @@ void led_trigger_set_default(struct led_classdev > *led_cdev) > down_read(&triggers_list_lock); > down_write(&led_cdev->trigger_lock); > list_for_each_entry(trig, &trigger_list, next_trig) { > - if (!strcmp(led_cdev->default_trigger, trig->name)) { > + if (!strcmp(led_cdev->default_trigger, trig->name) && > + (!trig->private_led || trig->private_led == led_cdev)) { > led_cdev->flags |= LED_INIT_DEFAULT_TRIGGER; > led_trigger_set(led_cdev, trig); > break; > @@ -280,7 +285,8 @@ int led_trigger_register(struct led_trigger *trig) > down_write(&triggers_list_lock); > /* Make sure the trigger's name isn't already in use */ > list_for_each_entry(_trig, &trigger_list, next_trig) { > - if (!strcmp(_trig->name, trig->name)) { > + if (!strcmp(_trig->name, trig->name) && > + (!_trig->private_led || _trig->private_led == > trig->private_led)) { > up_write(&triggers_list_lock); > return -EEXIST; > } > diff --git a/include/linux/leds.h b/include/linux/leds.h > index 2451962d1ec5..0d7577c752ad 100644 > --- a/include/linux/leds.h > +++ b/include/linux/leds.h > @@ -345,6 +345,9 @@ struct led_trigger { > int (*activate)(struct led_classdev *led_cdev); > void (*deactivate)(struct led_classdev *led_cdev); > > + /* LED-private triggers have the LED device set here. */ > + struct led_classdev *private_led; I'm not sure what the best descriptive name is here. ^ regards, o. > /* LEDs under control by this trigger (for simple triggers) */ > rwlock_t leddev_list_lock; > struct list_head led_cdevs; > -- > 2.27.0 >
