Re: [PATCH 2/5] leds: triggers: Add a led_trigger_event_nosleep API

[Jacek Anaszewski]

Hi Ezequiel,

On 04/04/2016 10:22 PM, Ezequiel Garcia wrote:

Now that we can mark any LED (even those in use by delayed blink
triggers) to trigger on a kernel panic, let's introduce a nosleep
led_trigger_event API.

This API is needed to skip the delayed blink path on
led_trigger_event. LEDs that are switched on a kernel panic,
might be in use by a delayed blink trigger.

This will be used by the panic LED trigger.

Signed-off-by: Ezequiel Garcia <ezequ...@vanguardiasur.com.ar>
---
  drivers/leds/led-triggers.c | 26 ++++++++++++++++++++++----
  include/linux/leds.h        |  4 ++++
  2 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/drivers/leds/led-triggers.c b/drivers/leds/led-triggers.c
index f5c9d7c4d181..00b9d8497777 100644
--- a/drivers/leds/led-triggers.c
+++ b/drivers/leds/led-triggers.c
@@ -307,8 +307,9 @@ EXPORT_SYMBOL_GPL(devm_led_trigger_register);

  /* Simple LED Tigger Interface */

-void led_trigger_event(struct led_trigger *trig,
-                       enum led_brightness brightness)
+static void do_led_trigger_event(struct led_trigger *trig,
+                                enum led_brightness brightness,
+                                bool nosleep)
  {
        struct led_classdev *led_cdev;

@@ -316,12 +317,29 @@ void led_trigger_event(struct led_trigger *trig,
                return;

        read_lock(&trig->leddev_list_lock);
-       list_for_each_entry(led_cdev, &trig->led_cdevs, trig_list)
-               led_set_brightness(led_cdev, brightness);

led_set_brightness() can gently disable blinking if passed 0 in the
brightness argument. IMHO this patch is not needed then.

+       list_for_each_entry(led_cdev, &trig->led_cdevs, trig_list) {
+               if (nosleep)
+                       led_set_brightness_nosleep(led_cdev, brightness);
+               else
+                       led_set_brightness(led_cdev, brightness);
+       }
        read_unlock(&trig->leddev_list_lock);
  }
+
+void led_trigger_event(struct led_trigger *trig,
+                      enum led_brightness brightness)
+{
+       do_led_trigger_event(trig, brightness, false);
+}
  EXPORT_SYMBOL_GPL(led_trigger_event);

+void led_trigger_event_nosleep(struct led_trigger *trig,
+                              enum led_brightness brightness)
+{
+       do_led_trigger_event(trig, brightness, true);
+}
+EXPORT_SYMBOL_GPL(led_trigger_event_nosleep);
+
  static void led_trigger_blink_setup(struct led_trigger *trig,
                             unsigned long *delay_on,
                             unsigned long *delay_off,
diff --git a/include/linux/leds.h b/include/linux/leds.h
index 7f1428bb1e69..d33b230ce66d 100644
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -259,6 +259,8 @@ extern void led_trigger_register_simple(const char *name,
  extern void led_trigger_unregister_simple(struct led_trigger *trigger);
  extern void led_trigger_event(struct led_trigger *trigger,
                                enum led_brightness event);
+extern void led_trigger_event_nosleep(struct led_trigger *trigger,
+                               enum led_brightness event);
  extern void led_trigger_blink(struct led_trigger *trigger,
                              unsigned long *delay_on,
                              unsigned long *delay_off);
@@ -305,6 +307,8 @@ static inline void led_trigger_register_simple(const char 
*name,
  static inline void led_trigger_unregister_simple(struct led_trigger *trigger) 
{}
  static inline void led_trigger_event(struct led_trigger *trigger,
                                enum led_brightness event) {}
+static inline void led_trigger_event_nosleep(struct led_trigger *trigger,
+                               enum led_brightness event) {}
  static inline void led_trigger_blink(struct led_trigger *trigger,
                                      unsigned long *delay_on,
                                      unsigned long *delay_off) {}

--
Best regards,
Jacek Anaszewski