backlight: add LM3533 backlight driver

Add sub-driver for the backlights on National Semiconductor / TI LM3533
lighting power chips.

The chip provides 256 brightness levels and ambient-light-sensor and pwm
input control.

[akpm@linux-foundation.org: fix warning]
[akpm@linux-foundation.org: fix the type of `mode']
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Rob Landley <rob@landley.net>
Cc: Samuel Ortiz <sameo@linux.intel.com>
Cc: Jonathan Cameron <jic23@cam.ac.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 48 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-class-backlight-driver-lm3533 b/Documentation/ABI/testing/sysfs-class-backlight-driver-lm3533
new file mode 100644
index 000000000000..77cf7ac949af
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-backlight-driver-lm3533
@@ -0,0 +1,48 @@
+What:           /sys/class/backlight/<backlight>/als_channel
+Date:           May 2012
+KernelVersion:  3.5
+Contact:        Johan Hovold <jhovold@gmail.com>
+Description:
+                Get the ALS output channel used as input in
+                ALS-current-control mode (0, 1), where
+
+                0 - out_current0 (backlight 0)
+                1 - out_current1 (backlight 1)
+
+What:           /sys/class/backlight/<backlight>/als_en
+Date:           May 2012
+KernelVersion:  3.5
+Contact:        Johan Hovold <jhovold@gmail.com>
+Description:
+                Enable ALS-current-control mode (0, 1).
+
+What:           /sys/class/backlight/<backlight>/id
+Date:           April 2012
+KernelVersion:  3.5
+Contact:        Johan Hovold <jhovold@gmail.com>
+Description:
+                Get the id of this backlight (0, 1).
+
+What:           /sys/class/backlight/<backlight>/linear
+Date:           April 2012
+KernelVersion:  3.5
+Contact:        Johan Hovold <jhovold@gmail.com>
+Description:
+                Set the brightness-mapping mode (0, 1), where
+
+                0 - exponential mode
+                1 - linear mode
+
+What:           /sys/class/backlight/<backlight>/pwm
+Date:           April 2012
+KernelVersion:  3.5
+Contact:        Johan Hovold <jhovold@gmail.com>
+Description:
+                Set the PWM-input control mask (5 bits), where
+
+                bit 5 - PWM-input enabled in Zone 4
+                bit 4 - PWM-input enabled in Zone 3
+                bit 3 - PWM-input enabled in Zone 2
+                bit 2 - PWM-input enabled in Zone 1
+                bit 1 - PWM-input enabled in Zone 0
+                bit 0 - PWM-input enabled