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| From | David Lin <dtwlin@google.com> |
| Newsgroups | linux.kernel |
| Subject | [PATCH 2/3] leds: Add the LED_BRIGHTNESS_FAST flag |
| Date | Sun, 30 Apr 2017 23:40:02 +0200 |
| Message-ID | <tC4Js-8ub-29@gated-at.bofh.it> (permalink) |
| References | <tC4Jr-8ub-11@gated-at.bofh.it> |
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This patch adds the LED_BRIGHTNESS_FAST flag to allow the driver to
indicate that the brightness_set() callback is implemented on a fastpath
so that the LED core may choose to for example use a hrtimer to
implement the duration of a trigger for better timing accuracy.
Suggested-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
Signed-off-by: David Lin <dtwlin@google.com>
---
Documentation/leds/leds-class.txt | 5 +++++
include/linux/leds.h | 1 +
2 files changed, 6 insertions(+)
diff --git a/Documentation/leds/leds-class.txt b/Documentation/leds/leds-class.txt
index 836cb16d6f09..70d7a3dca621 100644
--- a/Documentation/leds/leds-class.txt
+++ b/Documentation/leds/leds-class.txt
@@ -80,6 +80,11 @@ flag must be set in flags before registering. Calling
led_classdev_notify_brightness_hw_changed on a classdev not registered with
the LED_BRIGHT_HW_CHANGED flag is a bug and will trigger a WARN_ON.
+Optionally, the driver may choose to register with the LED_BRIGHTNESS_FAST flag.
+This flag indicates that the driver implements the brightness_set() callback
+function using a fastpath so the LED core can use hrtimer if the driver requires
+high precision for the trigger timing.
+
Hardware accelerated blink of LEDs
==================================
diff --git a/include/linux/leds.h b/include/linux/leds.h
index f9d10a9efcbe..78d2880ccd39 100644
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -49,6 +49,7 @@ struct led_classdev {
#define LED_HW_PLUGGABLE BIT(19)
#define LED_PANIC_INDICATOR BIT(20)
#define LED_BRIGHT_HW_CHANGED BIT(21)
+#define LED_BRIGHTNESS_FAST BIT(22)
/* set_brightness_work / blink_timer flags, atomic, private. */
unsigned long work_flags;
--
2.13.0.rc0.306.g87b477812d-goog
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[PATCH 0/3] led: ledtrig-transient: add support for hrtimer David Lin <dtwlin@google.com> - 2017-04-30 23:40 +0200
[PATCH 2/3] leds: Add the LED_BRIGHTNESS_FAST flag David Lin <dtwlin@google.com> - 2017-04-30 23:40 +0200
Re: [PATCH 0/3] led: ledtrig-transient: add support for hrtimer David Lin <dtwlin@google.com> - 2017-05-04 02:30 +0200
Re: [PATCH 0/3] led: ledtrig-transient: add support for hrtimer Pavel Machek <pavel@ucw.cz> - 2017-05-08 23:10 +0200
Re: [PATCH 0/3] led: ledtrig-transient: add support for hrtimer Jacek Anaszewski <jacek.anaszewski@gmail.com> - 2017-05-09 22:50 +0200
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