projects / mirror_ubuntu-zesty-kernel.git / blame
| Commit | Line | Data |
|---|---|---|
| ba224e2c JD |
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 | |
| 6aa693b8 | 8 | Datasheet: No longer available |
| ba224e2c JD |
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 are supported at the moment. | |
| 22 | ||
| 328716bc JD |
23 | This chip also has fan controlling features (up to 4 PWM outputs), |
| 24 | which are partly supported by this driver. | |
| ba224e2c JD |
25 | |
| 26 | The driver assumes that no more than one chip is present, which seems | |
| 27 | reasonable. | |
| 28 | ||
| 29 | ||
| 30 | Fan Monitoring | |
| 31 | -------------- | |
| 32 | ||
| 33 | Fan rotation speeds are reported as 14-bit values from a gated clock | |
| 34 | signal. Speeds down to 83 RPM can be measured. | |
| 35 | ||
| 36 | An alarm is triggered if the rotation speed drops below a programmable | |
| fd589a8f | 37 | limit. Another alarm is triggered if the speed is too low to be measured |
| ba224e2c | 38 | (including stalled or missing fan). |
| 328716bc JD |
39 | |
| 40 | ||
| 41 | Fan Speed Control | |
| 42 | ----------------- | |
| 43 | ||
| 44 | Fan speed can be controlled by PWM outputs. There are 4 possible modes: | |
| 45 | always off, always on, manual and automatic. The latter isn't supported | |
| 46 | by the driver: you can only return to that mode if it was the original | |
| 47 | setting, and the configuration interface is missing. |