Here's a patch for the f71882fg driver (against Linux 2.6.24.5, it's what I have and need) that enables a sysfs interface for fan speed control. It's written after the chip's reference.
New interfaces:
- fan[1-4]_type (RO): Fan type (PWM, linear, 4-pin)
- fan[1-4]_mode (RO): Fan mode (auto/manual, RPM/PWM)
- fan[1-4]_speed (RW): Allows setting a fan speed according to the mode. Expects either RPM count ow PWM. PWM is set on a scale of 0 (0% duty cycle) to 255 (100% duty cycle).
Type and mode are output both numerical (one character at the beginning of the line) and with a descriptive test, as described in the chip reference. The speed value semantics are depending on the mode.
The patch has some commented debugging output still in it.
I tested it on an MSI P35 Neo2 board, and could verify it to work in PWM mode on two connected fans. No other platform was tested, so this is strictly WORKSFORME.
Regards,
Nicos Gollan <gtdev@spearhead.de>