minix/drivers/tsl2550
David van Moolenbroek 6331e8f845 Retire the synchronous character driver protocol
- change all sync char drivers into async drivers;
- retire support for the sync protocol in libchardev;
- remove async dev style, as this is now the default;
- remove dev_status from VFS;
- clean up now-unused protocol messages.

Change-Id: I6aacff712292f6b29f2ccd51bc1e7d7003723e87
2014-02-18 11:25:02 +01:00
..
Makefile tsl2550: driver for the TSL2550 light sensor 2013-08-22 16:53:49 -04:00
README.txt tsl2550: driver for the TSL2550 light sensor 2013-08-22 16:53:49 -04:00
tsl2550.c Retire the synchronous character driver protocol 2014-02-18 11:25:02 +01:00

TSL2550 Driver (Ambient Light Sensor)
=====================================

Overview
--------

This is the driver for the ambient light sensor commonly found on the
WeatherCape expansion board for the BeagleBone.

Interface
---------

This driver implements the character device interface. It supports reading
through /dev/tsl2550b{1,3}s39. When read from, it returns a string containing
a data label, a colon, and the sensor value.

Example output of `cat /dev/tsl2550b3s39`:

ILLUMINANCE     : 830

Illuminance is expressed in lux. Valid values are 0 to 1846.

Limitations
-----------

Extended mode isn't implemented. Normal mode should be sufficient for most
applications.

Testing the Code
----------------

The driver should have been started by a script in /etc/rc.capes/ If not,
this is how you start up an instance:

cd /dev && MAKEDEV tsl2550b3s39
/bin/service up /usr/sbin/tsl2550 -label tsl2550.3.39 -dev /dev/tsl2550b3s39 \
	-args 'bus=3 address=0x39'

Getting the sensor value:

cat /dev/tsl2550b3s39

Killing an instance:

/bin/service down tsl2550.3.39