LEDS: add BlinkM RGB LED driver, documentation and update MAINTAINERS

Add driver for BlinkM device to drivers/leds/.
Add entry to MAINTAINERS file.
Add documentation in Documentation/leds/.

A BlinkM is a RGB LED controlled through I2C.

This driver implements an interface to the LED framework
and another sysfs group to access the internal options
of the BlinkM.

rev6: Use module_i2c_driver().
rev5: Removed own workqueue in favor of events wq.
rev4: Fixed comments by Bryan Wu.
rev3: Fixed issues found by Jonathan Neuschäfer.

(bryan.wu@canonical.com: remove 2 trailing whitespace)

Signed-off-by: Jan-Simon Möller <jansimon.moeller@gmx.de>
Signed-off-by: Bryan Wu <bryan.wu@canonical.com>

1 files changed, 80 insertions, 0 deletions

diff --git a/Documentation/leds/leds-blinkm.txt b/Documentation/leds/leds-blinkm.txt
new file mode 100644
index 000000000000..9dd92f4cf4e1
--- /dev/null
+++ b/Documentation/leds/leds-blinkm.txt
@@ -0,0 +1,80 @@
+The leds-blinkm driver supports the devices of the BlinkM family.
+
+They are RGB-LED modules driven by a (AT)tiny microcontroller and
+communicate through I2C. The default address of these modules is
+0x09 but this can be changed through a command. By this you could
+dasy-chain up to 127 BlinkMs on an I2C bus.
+
+The device accepts RGB and HSB color values through separate commands.
+Also you can store blinking sequences as "scripts" in
+the controller and run them. Also fading is an option.
+
+The interface this driver provides is 2-fold:
+
+a) LED class interface for use with triggers
+############################################
+
+The registration follows the scheme:
+blinkm-<i2c-bus-nr>-<i2c-device-nr>-<color>
+
+$ ls -h /sys/class/leds/blinkm-6-*
+/sys/class/leds/blinkm-6-9-blue:
+brightness  device  max_brightness  power  subsystem  trigger  uevent
+
+/sys/class/leds/blinkm-6-9-green:
+brightness  device  max_brightness  power  subsystem  trigger  uevent
+
+/sys/class/leds/blinkm-6-9-red:
+brightness  device  max_brightness  power  subsystem  trigger  uevent
+
+(same is /sys/bus/i2c/devices/6-0009/leds)
+
+We can control the colors separated into red, green and blue and
+assign triggers on each color.
+
+E.g.:
+
+$ cat blinkm-6-9-blue/brightness
+05
+
+$ echo 200 > blinkm-6-9-blue/brightness
+$
+
+$ modprobe ledtrig-heartbeat
+$ echo heartbeat > blinkm-6-9-green/trigger
+$
+
+
+b) Sysfs group to control rgb, fade, hsb, scripts ...
+#####################################################
+
+This extended interface is available as folder blinkm
+in the sysfs folder of the I2C device.
+E.g. below /sys/bus/i2c/devices/6-0009/blinkm
+
+$ ls -h /sys/bus/i2c/devices/6-0009/blinkm/
+blue  green  red  test
+
+Currently supported is just setting red, green, blue
+and a test sequence.
+
+E.g.:
+
+$ cat *
+00
+00
+00
+#Write into test to start test sequence!#
+
+$ echo 1 > test
+$
+
+$ echo 255 > red
+$
+
+
+
+as of 6/2012
+
+dl9pf <at> gmx <dot> de
+