[POWERPC] Xserve G5 thermal control fixes

The thermal control for the Xserve G5s had a few issues. For one, the
way to program the RPM fans speeds into the FCU is different between it
and the desktop models, which I didn't figure out until recently, and it
was missing a control loop for the slots fan, running it too fast.  Both
of those problems were causing the machine to be much more noisy than
necessary.  This patch also changes the fixed value of the slots fan for
desktop G5s to 40% instead of 50%.  It seems to still have a pretty good
airflow that way and is much less noisy.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

drivers/macintosh/therm_pm72.h

@@ -105,6 +105,7 @@ static char * critical_overtemp_path = "/sbin/critical_overtemp";
 #define DRIVES_DALLAS_ID	0x94
 #define BACKSIDE_MAX_ID		0x98
 #define XSERVE_DIMMS_LM87	0x25a
+#define XSERVE_SLOTS_LM75	0x290
 
 /*
  * Some MAX6690, DS1775, LM87 register definitions
@@ -198,7 +199,7 @@ struct drives_pid_state
 
 #define SLOTS_FAN_PWM_DEFAULT_ID	2
 #define SLOTS_FAN_PWM_INDEX		2
-#define	SLOTS_FAN_DEFAULT_PWM		50 /* Do better here ! */
+#define	SLOTS_FAN_DEFAULT_PWM		40 /* Do better here ! */
 
 
 /*
@@ -206,7 +207,7 @@ struct drives_pid_state
  */
 #define DIMM_PID_G_d			0
 #define DIMM_PID_G_p			0
-#define DIMM_PID_G_r			0x6553600
+#define DIMM_PID_G_r			0x06553600
 #define DIMM_PID_INPUT_TARGET		3276800
 #define DIMM_PID_INTERVAL    		1
 #define DIMM_PID_OUTPUT_MAX		14000
@@ -226,6 +227,31 @@ struct dimm_pid_state
 };
 
 
+/*
+ * PID factors for the Xserve Slots control loop
+ */
+#define SLOTS_PID_G_d			0
+#define SLOTS_PID_G_p			0
+#define SLOTS_PID_G_r			0x00100000
+#define SLOTS_PID_INPUT_TARGET		3200000
+#define SLOTS_PID_INTERVAL    		1
+#define SLOTS_PID_OUTPUT_MAX		100
+#define SLOTS_PID_OUTPUT_MIN		20
+#define SLOTS_PID_HISTORY_SIZE		20
+
+struct slots_pid_state
+{
+	int			ticks;
+	struct i2c_client *	monitor;
+	s32	       		sample_history[SLOTS_PID_HISTORY_SIZE];
+	s32			error_history[SLOTS_PID_HISTORY_SIZE];
+	int			cur_sample;
+	s32			last_temp;
+	int			first;
+	int			pwm;
+};
+
+
 
 /* Desktops */
 
@@ -283,6 +309,9 @@ struct cpu_pid_state
 	s32			pump_max;
 };
 
+/* Tickle FCU every 10 seconds */
+#define FCU_TICKLE_TICKS	10
+
 /*
  * Driver state
  */