About Kernel Documentation Linux Kernel Contact Linux Resources Linux Blog

Documentation / hwmon / pc87427




Custom Search

Based on kernel version 3.13. Page generated on 2014-01-20 22:03 EST.

1	Kernel driver pc87427
2	=====================
3	
4	Supported chips:
5	  * National Semiconductor PC87427
6	    Prefix: 'pc87427'
7	    Addresses scanned: none, address read from Super I/O config space
8	    Datasheet: No longer available
9	
10	Author: Jean Delvare <khali@linux-fr.org>
11	
12	Thanks to Amir Habibi at Candelis for setting up a test system, and to
13	Michael Kress for testing several iterations of this driver.
14	
15	
16	Description
17	-----------
18	
19	The National Semiconductor Super I/O chip includes complete hardware
20	monitoring capabilities. It can monitor up to 18 voltages, 8 fans and
21	6 temperature sensors. Only the fans and temperatures are supported at
22	the moment, voltages aren't.
23	
24	This chip also has fan controlling features (up to 4 PWM outputs),
25	which are partly supported by this driver.
26	
27	The driver assumes that no more than one chip is present, which seems
28	reasonable.
29	
30	
31	Fan Monitoring
32	--------------
33	
34	Fan rotation speeds are reported as 14-bit values from a gated clock
35	signal. Speeds down to 83 RPM can be measured.
36	
37	An alarm is triggered if the rotation speed drops below a programmable
38	limit. Another alarm is triggered if the speed is too low to be measured
39	(including stalled or missing fan).
40	
41	
42	Fan Speed Control
43	-----------------
44	
45	Fan speed can be controlled by PWM outputs. There are 4 possible modes:
46	always off, always on, manual and automatic. The latter isn't supported
47	by the driver: you can only return to that mode if it was the original
48	setting, and the configuration interface is missing.
49	
50	
51	Temperature Monitoring
52	----------------------
53	
54	The PC87427 relies on external sensors (following the SensorPath
55	standard), so the resolution and range depend on the type of sensor
56	connected. The integer part can be 8-bit or 9-bit, and can be signed or
57	not. I couldn't find a way to figure out the external sensor data
58	temperature format, so user-space adjustment (typically by a factor 2)
59	may be required.
Hide Line Numbers
About Kernel Documentation Linux Kernel Contact Linux Resources Linux Blog

Information is copyright its respective author. All material is available from the Linux Kernel Source distributed under a GPL License. This page is provided as a free service by mjmwired.net.