Accept "default" written to sysfs trigger attr.
If the text "default" is written to the LED's sysfs 'trigger' attr, then
call led_trigger_set_default() to set the LED to its default trigger.
If the default trigger is set to "none", then led_trigger_set_default()
will remove a trigger. This is in contrast to the default trigger being
unset, in which case led_trigger_set_default() does nothing.
---
Documentation/ABI/testing/sysfs-class-led | 6 ++++++
drivers/leds/led-triggers.c | 26 ++++++++++++++++++++++-
2 files changed, 31 insertions(+), 1 deletion(-)
diff --git a/Documentation/ABI/testing/sysfs-class-led b/Documentation/ABI/testing/sysfs-class-led
index 2e24ac3bd7ef..0313b82644f2 100644
--- a/Documentation/ABI/testing/sysfs-class-led
+++ b/Documentation/ABI/testing/sysfs-class-led
@@ -72,6 +72,12 @@ Description:
/sys/class/leds/<led> once a given trigger is selected. For
their documentation see `sysfs-class-led-trigger-*`.
+ Writing "none" removes the trigger for this LED.
+
+ Writing "default" sets the trigger to the LED's default trigger
+ (which would often be configured in the device tree for the
+ hardware).
+
What: /sys/class/leds/<led>/inverted
Date: January 2011
KernelVersion: 2.6.38
diff --git a/drivers/leds/led-triggers.c b/drivers/leds/led-triggers.c
index b2d40f87a5ff..00c898af9969 100644
--- a/drivers/leds/led-triggers.c
+++ b/drivers/leds/led-triggers.c
@@ -49,11 +49,21 @@ ssize_t led_trigger_write(struct file *filp, struct kobject *kobj,
goto unlock;
}
+ /* Empty string. Do nothing. */
+ if (sysfs_streq(buf, "")) {
+ goto unlock;
+ }
+
if (sysfs_streq(buf, "none")) {
led_trigger_remove(led_cdev);
goto unlock;
}
+ if (sysfs_streq(buf, "default")) {
+ led_trigger_set_default(led_cdev);
+ goto unlock;
+ }
+
down_read(&triggers_list_lock);
list_for_each_entry(trig, &trigger_list, next_trig) {
if (sysfs_streq(buf, trig->name) && trigger_relevant(led_cdev, trig)) {
@@ -98,6 +108,9 @@ static int led_trigger_format(char *buf, size_t size,
int len = led_trigger_snprintf(buf, size, "%s",
led_cdev->trigger ? "none" : "[none]");
+ if (led_cdev->default_trigger && led_cdev->default_trigger[0])
+ len += led_trigger_snprintf(buf + len, size - len, " default");
+
list_for_each_entry(trig, &trigger_list, next_trig) {
bool hit;
@@ -278,9 +291,20 @@ void led_trigger_set_default(struct led_classdev *led_cdev)
struct led_trigger *trig;
bool found = false;
- if (!led_cdev->default_trigger)
+ /* NULL pointer or empty string. Do nothing. */
+ if (!led_cdev->default_trigger || !led_cdev->default_trigger[0])
return;
+ /* This case isn't sensible. Do nothing. */
+ if (!strcmp(led_cdev->default_trigger, "default"))
+ return;
+
+ /* Remove trigger. */
+ if (!strcmp(led_cdev->default_trigger, "none")) {
+ led_trigger_remove(led_cdev);
+ return;
+ }
+
down_read(&triggers_list_lock);
down_write(&led_cdev->trigger_lock);
list_for_each_entry(trig, &trigger_list, next_trig) {
--
2.48.1
