1. 07 Mar, 2010 1 commit
  2. 17 Dec, 2009 1 commit
  3. 16 Dec, 2009 3 commits
  4. 07 Sep, 2009 2 commits
  5. 23 Jun, 2009 3 commits
  6. 06 Apr, 2009 8 commits
  7. 30 Mar, 2009 1 commit
  8. 20 Feb, 2009 1 commit
  9. 16 Jan, 2009 1 commit
  10. 08 Jan, 2009 3 commits
  11. 20 Oct, 2008 4 commits
  12. 17 Oct, 2008 1 commit
  13. 23 Sep, 2008 2 commits
  14. 01 Sep, 2008 1 commit
  15. 23 Jul, 2008 2 commits
  16. 24 Apr, 2008 3 commits
  17. 23 Apr, 2008 1 commit
  18. 19 Apr, 2008 1 commit
  19. 08 Feb, 2008 1 commit
    • David Brownell's avatar
      PWM LED driver · de5c9ede
      David Brownell authored
      
      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: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
      Signed-off-by: default avatarHaavard 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: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      de5c9ede