led-triggers: create a trigger for CPU activity

Attempting to consolidate the ARM LED code, this removes the
custom RealView LED trigger code to turn LEDs on and off in
response to CPU activity and replace it with a standard trigger.

(bryan.wu@canonical.com:
It introduces several syscore stubs into this trigger.
It also provides ledtrig_cpu trigger event stub in <linux/leds.h>.
Although it was inspired by ARM work, it can be used in other arch.)

Cc: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Bryan Wu <bryan.wu@canonical.com>
Reviewed-by: Jamie Iles <jamie@jamieiles.com>
Tested-by: Jochen Friedrich <jochen@scram.de>

1 files changed, 10 insertions, 0 deletions

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 12b2b55c519e..c96fd29199da 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -469,6 +469,16 @@ config LEDS_TRIGGER_BACKLIGHT
 
           If unsure, say N.
 
+config LEDS_TRIGGER_CPU
+        bool "LED CPU Trigger"
+        depends on LEDS_TRIGGERS
+        help
+          This allows LEDs to be controlled by active CPUs. This shows
+          the active CPUs across an array of LEDs so you can see which
+          CPUs are active on the system at any given moment.
+
+          If unsure, say N.
+
 config LEDS_TRIGGER_GPIO
         tristate "LED GPIO Trigger"
         depends on LEDS_TRIGGERS