• David Brownell's avatar
    atmel_lcdfb: backlight control · a9a84c37
    David Brownell authored
    On the sam9 EK boards, the LCD backlight is hooked up to a PWM output from
    the LCD controller.  It's controlled by "contrast" registers though.
    
    This patch lets boards declare that they have that kind of backlight
    control.  The driver can then export this control, letting screenblank and
    other operations actually take effect ...  reducing the typically
    substantial power drain from the backlight.
    
    Note that it's not fully cooked
      - doesn't force backlight off during system suspend
      - the "power" and "blank" events may not be done right
    This should be easily added in the future.
    
    [nicolas.ferre@atmel.com: remove unneeded inline and rename functions]
    Signed-off-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
    Signed-off-by: default avatarNicolas Ferre <nicolas.ferre@atmel.com>
    Cc: Andrew Victor <linux@maxim.org.za>
    Cc: Russell King <rmk@arm.linux.org.uk>
    Cc: "Antonino A. Daplas" <adaplas@pol.net>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    a9a84c37
atmel_lcdfb.c 26.3 KB