backlight: Add Nvidia-based Apple Macbook Pro backlight driver

Nvidia-based Apple Macbook Pros don't appear to handle backlight control
through the graphics card registers or ACPI, but instead trigger changes
via SMI calls. This driver registers a generic backlight device that
lets existing userspace deal with it. Code derived from Julien Blache's
Pommed application.

Signed-off-by: Julien Blache <jb@jblache.org>
Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Richard Purdie <rpurdie@rpsys.net>

1 files changed, 9 insertions, 0 deletions

diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
index 30bf7f2f1635..62547bd2ea49 100644
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -119,3 +119,12 @@ config BACKLIGHT_PWM
         help
           If you have a LCD backlight adjustable by PWM, say Y to enable
           this driver.
+
+config BACKLIGHT_MBP_NVIDIA
+       tristate "MacBook Pro Nvidia Backlight Driver"
+       depends on BACKLIGHT_CLASS_DEVICE && X86
+       default n
+       help
+         If you have an Apple Macbook Pro with Nvidia graphics hardware say Y
+         to enable a driver for its backlight
+