linux/Documentation/leds/leds-blinkm.txt
Jan-Simon Möller b54cf35a7f 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>
2012-07-24 16:00:51 +08:00

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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