kernel-ark/drivers/leds/Makefile
David Brownell de5c9edee7 PWM LED driver
This is a LED driver using the PWM on newer SOCs from Atmel; brightness is
controlled by changing the PWM duty cycle.  So for example if you've set up
two leds labeled "pwm0" and "pwm1":

	echo 0 > /sys/class/leds/pwm2/brightness	# off (0%)
	echo 80 > /sys/class/leds/pwm2/brightness
	echo 255 > /sys/class/leds/pwm2/brightness	# on (100%)

Note that "brightness" here isn't linear; maybe that should change.  Going
from 4 to 8 probably doubles perceived brightness, while 244 to 248 is
imperceptible.

This is mostly intended to be a simple example of PWM, although it's
realistic since LCD backlights are often driven with PWM to conserve
battery power (and offer brightness options).

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Andrew Victor <linux@maxim.org.za>
Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 09:22:38 -08:00

29 lines
1.1 KiB
Makefile

# LED Core
obj-$(CONFIG_NEW_LEDS) += led-core.o
obj-$(CONFIG_LEDS_CLASS) += led-class.o
obj-$(CONFIG_LEDS_TRIGGERS) += led-triggers.o
# LED Platform Drivers
obj-$(CONFIG_LEDS_ATMEL_PWM) += leds-atmel-pwm.o
obj-$(CONFIG_LEDS_CORGI) += leds-corgi.o
obj-$(CONFIG_LEDS_LOCOMO) += leds-locomo.o
obj-$(CONFIG_LEDS_SPITZ) += leds-spitz.o
obj-$(CONFIG_LEDS_TOSA) += leds-tosa.o
obj-$(CONFIG_LEDS_S3C24XX) += leds-s3c24xx.o
obj-$(CONFIG_LEDS_AMS_DELTA) += leds-ams-delta.o
obj-$(CONFIG_LEDS_NET48XX) += leds-net48xx.o
obj-$(CONFIG_LEDS_WRAP) += leds-wrap.o
obj-$(CONFIG_LEDS_H1940) += leds-h1940.o
obj-$(CONFIG_LEDS_COBALT_QUBE) += leds-cobalt-qube.o
obj-$(CONFIG_LEDS_COBALT_RAQ) += leds-cobalt-raq.o
obj-$(CONFIG_LEDS_GPIO) += leds-gpio.o
obj-$(CONFIG_LEDS_CM_X270) += leds-cm-x270.o
obj-$(CONFIG_LEDS_CLEVO_MAIL) += leds-clevo-mail.o
obj-$(CONFIG_LEDS_HP6XX) += leds-hp6xx.o
# LED Triggers
obj-$(CONFIG_LEDS_TRIGGER_TIMER) += ledtrig-timer.o
obj-$(CONFIG_LEDS_TRIGGER_IDE_DISK) += ledtrig-ide-disk.o
obj-$(CONFIG_LEDS_TRIGGER_HEARTBEAT) += ledtrig-heartbeat.o