From a9a84c37d1ee50db8f3752b117caf2b48dcd4f8a Mon Sep 17 00:00:00 2001 From: David Brownell Date: Wed, 6 Feb 2008 01:39:26 -0800 Subject: atmel_lcdfb: backlight control 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: David Brownell Signed-off-by: Nicolas Ferre Cc: Andrew Victor Cc: Russell King Cc: "Antonino A. Daplas" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/video/backlight/Kconfig | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'drivers/video/backlight') diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig index 9609a6c676b..924e2551044 100644 --- a/drivers/video/backlight/Kconfig +++ b/drivers/video/backlight/Kconfig @@ -50,6 +50,19 @@ config BACKLIGHT_CLASS_DEVICE To have support for your specific LCD panel you will have to select the proper drivers which depend on this option. +config BACKLIGHT_ATMEL_LCDC + bool "Atmel LCDC Contrast-as-Backlight control" + depends on BACKLIGHT_CLASS_DEVICE && FB_ATMEL + default y if MACH_SAM9261EK || MACH_SAM9263EK + help + This provides a backlight control internal to the Atmel LCDC + driver. If the LCD "contrast control" on your board is wired + so it controls the backlight brightness, select this option to + export this as a PWM-based backlight control. + + If in doubt, it's safe to enable this option; it doesn't kick + in unless the board's description says it's wired that way. + config BACKLIGHT_CORGI tristate "Generic (aka Sharp Corgi) Backlight Driver" depends on BACKLIGHT_CLASS_DEVICE -- cgit v1.2.3