mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-28 15:13:55 +08:00
008e5f3350
Add support for the 6 temperature monitoring channels of the PC87427. Note that the sensors resolution can vary, and I couldn't find a way to figure it out, so we might have to compensate in user-space. Signed-off-by: Jean Delvare <khali@linux-fr.org> Acked-by: Guenter Roeck <guenter.roeck@ericsson.com>
60 lines
1.9 KiB
Plaintext
60 lines
1.9 KiB
Plaintext
Kernel driver pc87427
|
|
=====================
|
|
|
|
Supported chips:
|
|
* National Semiconductor PC87427
|
|
Prefix: 'pc87427'
|
|
Addresses scanned: none, address read from Super I/O config space
|
|
Datasheet: No longer available
|
|
|
|
Author: Jean Delvare <khali@linux-fr.org>
|
|
|
|
Thanks to Amir Habibi at Candelis for setting up a test system, and to
|
|
Michael Kress for testing several iterations of this driver.
|
|
|
|
|
|
Description
|
|
-----------
|
|
|
|
The National Semiconductor Super I/O chip includes complete hardware
|
|
monitoring capabilities. It can monitor up to 18 voltages, 8 fans and
|
|
6 temperature sensors. Only the fans and temperatures are supported at
|
|
the moment, voltages aren't.
|
|
|
|
This chip also has fan controlling features (up to 4 PWM outputs),
|
|
which are partly supported by this driver.
|
|
|
|
The driver assumes that no more than one chip is present, which seems
|
|
reasonable.
|
|
|
|
|
|
Fan Monitoring
|
|
--------------
|
|
|
|
Fan rotation speeds are reported as 14-bit values from a gated clock
|
|
signal. Speeds down to 83 RPM can be measured.
|
|
|
|
An alarm is triggered if the rotation speed drops below a programmable
|
|
limit. Another alarm is triggered if the speed is too low to be measured
|
|
(including stalled or missing fan).
|
|
|
|
|
|
Fan Speed Control
|
|
-----------------
|
|
|
|
Fan speed can be controlled by PWM outputs. There are 4 possible modes:
|
|
always off, always on, manual and automatic. The latter isn't supported
|
|
by the driver: you can only return to that mode if it was the original
|
|
setting, and the configuration interface is missing.
|
|
|
|
|
|
Temperature Monitoring
|
|
----------------------
|
|
|
|
The PC87427 relies on external sensors (following the SensorPath
|
|
standard), so the resolution and range depend on the type of sensor
|
|
connected. The integer part can be 8-bit or 9-bit, and can be signed or
|
|
not. I couldn't find a way to figure out the external sensor data
|
|
temperature format, so user-space adjustment (typically by a factor 2)
|
|
may be required.
|