minix/drivers/tsl2550
David van Moolenbroek 597151d963 libchardriver: full API rewrite
The new API now covers the entire character driver protocol, while
hiding all the message details. It should therefore be used by all
new character drivers. All existing drivers that already made use of
libchardriver have been changed to use the new API.

As one of the most important API changes, support for scatter and
gather transfers has been removed, as several key drivers already
did not support this, and it could be supported at the safecopy
level instead (for a future readv/writev).

Additional changes include:

- respond to block device open requests to avoid hanging VFS threads;
- add support for sef_cancel.

Change-Id: I1bab6c1cb66916c71b87aeb1db54a9bdf171fe6b
2014-03-01 09:04:50 +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 libchardriver: full API rewrite 2014-03-01 09:04:50 +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