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authorDavid Brownell <dbrownell@users.sourceforge.net>2008-02-06 04:39:26 -0500
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2008-02-06 13:41:16 -0500
commita9a84c37d1ee50db8f3752b117caf2b48dcd4f8a (patch)
treeadac878234cbe372624c5d33e7d70322972392d7 /drivers/video/backlight
parentb1230ee50a9903a987feaad767fb71e2fd173894 (diff)
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 <dbrownell@users.sourceforge.net> Signed-off-by: Nicolas 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: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/video/backlight')
-rw-r--r--drivers/video/backlight/Kconfig13
1 files changed, 13 insertions, 0 deletions
diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
index 9609a6c676be..924e2551044a 100644
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -50,6 +50,19 @@ config BACKLIGHT_CLASS_DEVICE
50 To have support for your specific LCD panel you will have to 50 To have support for your specific LCD panel you will have to
51 select the proper drivers which depend on this option. 51 select the proper drivers which depend on this option.
52 52
53config BACKLIGHT_ATMEL_LCDC
54 bool "Atmel LCDC Contrast-as-Backlight control"
55 depends on BACKLIGHT_CLASS_DEVICE && FB_ATMEL
56 default y if MACH_SAM9261EK || MACH_SAM9263EK
57 help
58 This provides a backlight control internal to the Atmel LCDC
59 driver. If the LCD "contrast control" on your board is wired
60 so it controls the backlight brightness, select this option to
61 export this as a PWM-based backlight control.
62
63 If in doubt, it's safe to enable this option; it doesn't kick
64 in unless the board's description says it's wired that way.
65
53config BACKLIGHT_CORGI 66config BACKLIGHT_CORGI
54 tristate "Generic (aka Sharp Corgi) Backlight Driver" 67 tristate "Generic (aka Sharp Corgi) Backlight Driver"
55 depends on BACKLIGHT_CLASS_DEVICE 68 depends on BACKLIGHT_CLASS_DEVICE