[PATCH] powerpc: Thermal control for dual core G5s

This patch adds a windfarm module, windfarm_pm112, for the dual core G5s
(both 2 and 4 core models), keeping the machine from getting into
vacuum-cleaner mode ;) For proper credits, the patch was initially
written by Paul Mackerras, and slightly reworked by me to add overtemp
handling among others. The patch also removes the sysfs attributes from
windfarm_pm81 and windfarm_pm91 and instead adds code to the windfarm
core to automagically expose attributes for sensor & controls.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/macintosh/windfarm_pid.h

@@ -72,6 +72,7 @@ struct wf_cpu_pid_state {
 	int	index; 				/* index of current power */
 	int	tindex; 			/* index of current temp */
 	s32	target;				/* current target value */
+	s32	last_delta;			/* last Tactual - Ttarget */
 	s32	powers[WF_PID_MAX_HISTORY];	/* power history buffer */
 	s32	errors[WF_PID_MAX_HISTORY];	/* error history buffer */
 	s32	temps[2];			/* temp. history buffer */