powerpc/powermac: New windfarm driver for PowerMac G5 (AGP) and Xserve G5

This replaces the old therm_pm72 using the same windfarm infrastructure
that was used for other PowerMac G5 models. The fan speeds and sensors
should now be visible in the same location in sysfs.

The driver is split into separate core modules for PowerMac7,2 (and 7,3)
and RackMac3,1, with a lot of the shared code now in the separate sensor
and control modules.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 740 insertions, 0 deletions

diff --git a/drivers/macintosh/windfarm_rm31.c b/drivers/macintosh/windfarm_rm31.c
new file mode 100644
index 000000000000..3eca6d4b52fc
--- /dev/null
+++ b/drivers/macintosh/windfarm_rm31.c
@@ -0,0 +1,740 @@
+/*
+ * Windfarm PowerMac thermal control.
+ * Control loops for RackMack3,1 (Xserve G5)
+ *
+ * Copyright (C) 2012 Benjamin Herrenschmidt, IBM Corp.
+ *
+ * Use and redistribute under the terms of the GNU GPL v2.
+ */
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/platform_device.h>
+#include <linux/reboot.h>
+#include <asm/prom.h>
+#include <asm/smu.h>
+
+#include "windfarm.h"
+#include "windfarm_pid.h"
+#include "windfarm_mpu.h"
+
+#define VERSION "1.0"
+
+#undef DEBUG
+#undef LOTSA_DEBUG
+
+#ifdef DEBUG
+#define DBG(args...)	printk(args)
+#else
+#define DBG(args...)	do { } while(0)
+#endif
+
+#ifdef LOTSA_DEBUG
+#define DBG_LOTS(args...)	printk(args)
+#else
+#define DBG_LOTS(args...)	do { } while(0)
+#endif
+
+/* define this to force CPU overtemp to 60 degree, useful for testing
+ * the overtemp code
+ */
+#undef HACKED_OVERTEMP
+
+/* We currently only handle 2 chips */
+#define NR_CHIPS	2
+#define NR_CPU_FANS	3 * NR_CHIPS
+
+/* Controls and sensors */
+static struct wf_sensor *sens_cpu_temp[NR_CHIPS];
+static struct wf_sensor *sens_cpu_volts[NR_CHIPS];
+static struct wf_sensor *sens_cpu_amps[NR_CHIPS];
+static struct wf_sensor *backside_temp;
+static struct wf_sensor *slots_temp;
+static struct wf_sensor *dimms_temp;
+
+static struct wf_control *cpu_fans[NR_CHIPS][3];
+static struct wf_control *backside_fan;
+static struct wf_control *slots_fan;
+static struct wf_control *cpufreq_clamp;
+
+/* We keep a temperature history for average calculation of 180s */
+#define CPU_TEMP_HIST_SIZE	180
+
+/* PID loop state */
+static const struct mpu_data *cpu_mpu_data[NR_CHIPS];
+static struct wf_cpu_pid_state cpu_pid[NR_CHIPS];
+static u32 cpu_thist[CPU_TEMP_HIST_SIZE];
+static int cpu_thist_pt;
+static s64 cpu_thist_total;
+static s32 cpu_all_tmax = 100 << 16;
+static struct wf_pid_state backside_pid;
+static int backside_tick;
+static struct wf_pid_state slots_pid;
+static int slots_tick;
+static int slots_speed;
+static struct wf_pid_state dimms_pid;
+static int dimms_output_clamp;
+
+static int nr_chips;
+static bool have_all_controls;
+static bool have_all_sensors;
+static bool started;
+
+static int failure_state;
+#define FAILURE_SENSOR		1
+#define FAILURE_FAN		2
+#define FAILURE_PERM		4
+#define FAILURE_LOW_OVERTEMP	8
+#define FAILURE_HIGH_OVERTEMP	16
+
+/* Overtemp values */
+#define LOW_OVER_AVERAGE	0
+#define LOW_OVER_IMMEDIATE	(10 << 16)
+#define LOW_OVER_CLEAR		((-10) << 16)
+#define HIGH_OVER_IMMEDIATE	(14 << 16)
+#define HIGH_OVER_AVERAGE	(10 << 16)
+#define HIGH_OVER_IMMEDIATE	(14 << 16)
+
+
+static void cpu_max_all_fans(void)
+{
+	int i;
+
+	/* We max all CPU fans in case of a sensor error. We also do the
+	 * cpufreq clamping now, even if it's supposedly done later by the
+	 * generic code anyway, we do it earlier here to react faster
+	 */
+	if (cpufreq_clamp)
+		wf_control_set_max(cpufreq_clamp);
+	for (i = 0; i < nr_chips; i++) {
+		if (cpu_fans[i][0])
+			wf_control_set_max(cpu_fans[i][0]);
+		if (cpu_fans[i][1])
+			wf_control_set_max(cpu_fans[i][1]);
+		if (cpu_fans[i][2])
+			wf_control_set_max(cpu_fans[i][2]);
+	}
+}
+
+static int cpu_check_overtemp(s32 temp)
+{
+	int new_state = 0;
+	s32 t_avg, t_old;
+	static bool first = true;
+
+	/* First check for immediate overtemps */
+	if (temp >= (cpu_all_tmax + LOW_OVER_IMMEDIATE)) {
+		new_state |= FAILURE_LOW_OVERTEMP;
+		if ((failure_state & FAILURE_LOW_OVERTEMP) == 0)
+			printk(KERN_ERR "windfarm: Overtemp due to immediate CPU"
+			       " temperature !\n");
+	}
+	if (temp >= (cpu_all_tmax + HIGH_OVER_IMMEDIATE)) {
+		new_state |= FAILURE_HIGH_OVERTEMP;
+		if ((failure_state & FAILURE_HIGH_OVERTEMP) == 0)
+			printk(KERN_ERR "windfarm: Critical overtemp due to"
+			       " immediate CPU temperature !\n");
+	}
+
+	/*
+	 * The first time around, initialize the array with the first
+	 * temperature reading
+	 */
+	if (first) {
+		int i;
+
+		cpu_thist_total = 0;
+		for (i = 0; i < CPU_TEMP_HIST_SIZE; i++) {
+			cpu_thist[i] = temp;
+			cpu_thist_total += temp;
+		}
+		first = false;
+	}
+
+	/*
+	 * We calculate a history of max temperatures and use that for the
+	 * overtemp management
+	 */
+	t_old = cpu_thist[cpu_thist_pt];
+	cpu_thist[cpu_thist_pt] = temp;
+	cpu_thist_pt = (cpu_thist_pt + 1) % CPU_TEMP_HIST_SIZE;
+	cpu_thist_total -= t_old;
+	cpu_thist_total += temp;
+	t_avg = cpu_thist_total / CPU_TEMP_HIST_SIZE;
+
+	DBG_LOTS("  t_avg = %d.%03d (out: %d.%03d, in: %d.%03d)\n",
+		 FIX32TOPRINT(t_avg), FIX32TOPRINT(t_old), FIX32TOPRINT(temp));
+
+	/* Now check for average overtemps */
+	if (t_avg >= (cpu_all_tmax + LOW_OVER_AVERAGE)) {
+		new_state |= FAILURE_LOW_OVERTEMP;
+		if ((failure_state & FAILURE_LOW_OVERTEMP) == 0)
+			printk(KERN_ERR "windfarm: Overtemp due to average CPU"
+			       " temperature !\n");
+	}
+	if (t_avg >= (cpu_all_tmax + HIGH_OVER_AVERAGE)) {
+		new_state |= FAILURE_HIGH_OVERTEMP;
+		if ((failure_state & FAILURE_HIGH_OVERTEMP) == 0)
+			printk(KERN_ERR "windfarm: Critical overtemp due to"
+			       " average CPU temperature !\n");
+	}
+
+	/* Now handle overtemp conditions. We don't currently use the windfarm
+	 * overtemp handling core as it's not fully suited to the needs of those
+	 * new machine. This will be fixed later.
+	 */
+	if (new_state) {
+		/* High overtemp -> immediate shutdown */
+		if (new_state & FAILURE_HIGH_OVERTEMP)
+			machine_power_off();
+		if ((failure_state & new_state) != new_state)
+			cpu_max_all_fans();
+		failure_state |= new_state;
+	} else if ((failure_state & FAILURE_LOW_OVERTEMP) &&
+		   (temp < (cpu_all_tmax + LOW_OVER_CLEAR))) {
+		printk(KERN_ERR "windfarm: Overtemp condition cleared !\n");
+		failure_state &= ~FAILURE_LOW_OVERTEMP;
+	}
+
+	return failure_state & (FAILURE_LOW_OVERTEMP | FAILURE_HIGH_OVERTEMP);
+}
+
+static int read_one_cpu_vals(int cpu, s32 *temp, s32 *power)
+{
+	s32 dtemp, volts, amps;
+	int rc;
+
+	/* Get diode temperature */
+	rc = wf_sensor_get(sens_cpu_temp[cpu], &dtemp);
+	if (rc) {
+		DBG("  CPU%d: temp reading error !\n", cpu);
+		return -EIO;
+	}
+	DBG_LOTS("  CPU%d: temp   = %d.%03d\n", cpu, FIX32TOPRINT((dtemp)));
+	*temp = dtemp;
+
+	/* Get voltage */
+	rc = wf_sensor_get(sens_cpu_volts[cpu], &volts);
+	if (rc) {
+		DBG("  CPU%d, volts reading error !\n", cpu);
+		return -EIO;
+	}
+	DBG_LOTS("  CPU%d: volts  = %d.%03d\n", cpu, FIX32TOPRINT((volts)));
+
+	/* Get current */
+	rc = wf_sensor_get(sens_cpu_amps[cpu], &amps);
+	if (rc) {
+		DBG("  CPU%d, current reading error !\n", cpu);
+		return -EIO;
+	}
+	DBG_LOTS("  CPU%d: amps   = %d.%03d\n", cpu, FIX32TOPRINT((amps)));
+
+	/* Calculate power */
+
+	/* Scale voltage and current raw sensor values according to fixed scales
+	 * obtained in Darwin and calculate power from I and V
+	 */
+	*power = (((u64)volts) * ((u64)amps)) >> 16;
+
+	DBG_LOTS("  CPU%d: power  = %d.%03d\n", cpu, FIX32TOPRINT((*power)));
+
+	return 0;
+
+}
+
+static void cpu_fans_tick(void)
+{
+	int err, cpu, i;
+	s32 speed, temp, power, t_max = 0;
+
+	DBG_LOTS("* cpu fans_tick_split()\n");
+
+	for (cpu = 0; cpu < nr_chips; ++cpu) {
+		struct wf_cpu_pid_state *sp = &cpu_pid[cpu];
+
+		/* Read current speed */
+		wf_control_get(cpu_fans[cpu][0], &sp->target);
+
+		err = read_one_cpu_vals(cpu, &temp, &power);
+		if (err) {
+			failure_state |= FAILURE_SENSOR;
+			cpu_max_all_fans();
+			return;
+		}
+
+		/* Keep track of highest temp */
+		t_max = max(t_max, temp);
+
+		/* Handle possible overtemps */
+		if (cpu_check_overtemp(t_max))
+			return;
+
+		/* Run PID */
+		wf_cpu_pid_run(sp, power, temp);
+
+		DBG_LOTS("  CPU%d: target = %d RPM\n", cpu, sp->target);
+
+		/* Apply DIMMs clamp */
+		speed = max(sp->target, dimms_output_clamp);
+
+		/* Apply result to all cpu fans */
+		for (i = 0; i < 3; i++) {
+			err = wf_control_set(cpu_fans[cpu][i], speed);
+			if (err) {
+				pr_warning("wf_rm31: Fan %s reports error %d\n",
+					   cpu_fans[cpu][i]->name, err);
+				failure_state |= FAILURE_FAN;
+			}
+		}
+	}
+}
+
+/* Implementation... */
+static int cpu_setup_pid(int cpu)
+{
+	struct wf_cpu_pid_param pid;
+	const struct mpu_data *mpu = cpu_mpu_data[cpu];
+	s32 tmax, ttarget, ptarget;
+	int fmin, fmax, hsize;
+
+	/* Get PID params from the appropriate MPU EEPROM */
+	tmax = mpu->tmax << 16;
+	ttarget = mpu->ttarget << 16;
+	ptarget = ((s32)(mpu->pmaxh - mpu->padjmax)) << 16;
+
+	DBG("wf_72: CPU%d ttarget = %d.%03d, tmax = %d.%03d\n",
+	    cpu, FIX32TOPRINT(ttarget), FIX32TOPRINT(tmax));
+
+	/* We keep a global tmax for overtemp calculations */
+	if (tmax < cpu_all_tmax)
+		cpu_all_tmax = tmax;
+
+	/* Set PID min/max by using the rear fan min/max */
+	fmin = wf_control_get_min(cpu_fans[cpu][0]);
+	fmax = wf_control_get_max(cpu_fans[cpu][0]);
+	DBG("wf_72: CPU%d max RPM range = [%d..%d]\n", cpu, fmin, fmax);
+
+	/* History size */
+	hsize = min_t(int, mpu->tguardband, WF_PID_MAX_HISTORY);
+	DBG("wf_72: CPU%d history size = %d\n", cpu, hsize);
+
+	/* Initialize PID loop */
+	pid.interval	= 1;	/* seconds */
+	pid.history_len = hsize;
+	pid.gd		= mpu->pid_gd;
+	pid.gp		= mpu->pid_gp;
+	pid.gr		= mpu->pid_gr;
+	pid.tmax	= tmax;
+	pid.ttarget	= ttarget;
+	pid.pmaxadj	= ptarget;
+	pid.min		= fmin;
+	pid.max		= fmax;
+
+	wf_cpu_pid_init(&cpu_pid[cpu], &pid);
+	cpu_pid[cpu].target = 4000;
+	
+	return 0;
+}
+
+/* Backside/U3 fan */
+static struct wf_pid_param backside_param = {
+	.interval	= 1,
+	.history_len	= 2,
+	.gd		= 0x00500000,
+	.gp		= 0x0004cccc,
+	.gr		= 0,
+	.itarget	= 70 << 16,
+	.additive	= 0,
+	.min		= 20,
+	.max		= 100,
+};
+
+/* DIMMs temperature (clamp the backside fan) */
+static struct wf_pid_param dimms_param = {
+	.interval	= 1,
+	.history_len	= 20,
+	.gd		= 0,
+	.gp		= 0,
+	.gr		= 0x06553600,
+	.itarget	= 50 << 16,
+	.additive	= 0,
+	.min		= 4000,
+	.max		= 14000,
+};
+
+static void backside_fan_tick(void)
+{
+	s32 temp, dtemp;
+	int speed, dspeed, fan_min;
+	int err;
+
+	if (!backside_fan || !backside_temp || !dimms_temp || !backside_tick)
+		return;
+	if (--backside_tick > 0)
+		return;
+	backside_tick = backside_pid.param.interval;
+
+	DBG_LOTS("* backside fans tick\n");
+
+	/* Update fan speed from actual fans */
+	err = wf_control_get(backside_fan, &speed);
+	if (!err)
+		backside_pid.target = speed;
+
+	err = wf_sensor_get(backside_temp, &temp);
+	if (err) {
+		printk(KERN_WARNING "windfarm: U3 temp sensor error %d\n",
+		       err);
+		failure_state |= FAILURE_SENSOR;
+		wf_control_set_max(backside_fan);
+		return;
+	}
+	speed = wf_pid_run(&backside_pid, temp);
+
+	DBG_LOTS("backside PID temp=%d.%.3d speed=%d\n",
+		 FIX32TOPRINT(temp), speed);
+
+	err = wf_sensor_get(dimms_temp, &dtemp);
+	if (err) {
+		printk(KERN_WARNING "windfarm: DIMMs temp sensor error %d\n",
+		       err);
+		failure_state |= FAILURE_SENSOR;
+		wf_control_set_max(backside_fan);
+		return;
+	}
+	dspeed = wf_pid_run(&dimms_pid, dtemp);
+	dimms_output_clamp = dspeed;
+
+	fan_min = (dspeed * 100) / 14000;
+	fan_min = max(fan_min, backside_param.min);
+	speed = max(speed, fan_min);
+
+	err = wf_control_set(backside_fan, speed);
+	if (err) {
+		printk(KERN_WARNING "windfarm: backside fan error %d\n", err);
+		failure_state |= FAILURE_FAN;
+	}
+}
+
+static void backside_setup_pid(void)
+{
+	/* first time initialize things */
+	s32 fmin = wf_control_get_min(backside_fan);
+	s32 fmax = wf_control_get_max(backside_fan);
+	struct wf_pid_param param;
+
+	param = backside_param;
+	param.min = max(param.min, fmin);
+	param.max = min(param.max, fmax);
+	wf_pid_init(&backside_pid, &param);
+
+	param = dimms_param;
+	wf_pid_init(&dimms_pid, &param);
+
+	backside_tick = 1;
+
+	pr_info("wf_rm31: Backside control loop started.\n");
+}
+
+/* Slots fan */
+static const struct wf_pid_param slots_param = {
+	.interval	= 5,
+	.history_len	= 2,
+	.gd		= 30 << 20,
+	.gp		= 5 << 20,
+	.gr		= 0,
+	.itarget	= 40 << 16,
+	.additive	= 1,
+	.min		= 300,
+	.max		= 4000,
+};
+
+static void slots_fan_tick(void)
+{
+	s32 temp;
+	int speed;
+	int err;
+
+	if (!slots_fan || !slots_temp || !slots_tick)
+		return;
+	if (--slots_tick > 0)
+		return;
+	slots_tick = slots_pid.param.interval;
+
+	DBG_LOTS("* slots fans tick\n");
+
+	err = wf_sensor_get(slots_temp, &temp);
+	if (err) {
+		pr_warning("wf_rm31: slots temp sensor error %d\n", err);
+		failure_state |= FAILURE_SENSOR;
+		wf_control_set_max(slots_fan);
+		return;
+	}
+	speed = wf_pid_run(&slots_pid, temp);
+
+	DBG_LOTS("slots PID temp=%d.%.3d speed=%d\n",
+		 FIX32TOPRINT(temp), speed);
+
+	slots_speed = speed;
+	err = wf_control_set(slots_fan, speed);
+	if (err) {
+		printk(KERN_WARNING "windfarm: slots bay fan error %d\n", err);
+		failure_state |= FAILURE_FAN;
+	}
+}
+
+static void slots_setup_pid(void)
+{
+	/* first time initialize things */
+	s32 fmin = wf_control_get_min(slots_fan);
+	s32 fmax = wf_control_get_max(slots_fan);
+	struct wf_pid_param param = slots_param;
+
+	param.min = max(param.min, fmin);
+	param.max = min(param.max, fmax);
+	wf_pid_init(&slots_pid, &param);
+	slots_tick = 1;
+
+	pr_info("wf_rm31: Slots control loop started.\n");
+}
+
+static void set_fail_state(void)
+{
+	cpu_max_all_fans();
+
+	if (backside_fan)
+		wf_control_set_max(backside_fan);
+	if (slots_fan)
+		wf_control_set_max(slots_fan);
+}
+
+static void rm31_tick(void)
+{
+	int i, last_failure;
+
+	if (!started) {
+		started = 1;
+		printk(KERN_INFO "windfarm: CPUs control loops started.\n");
+		for (i = 0; i < nr_chips; ++i) {
+			if (cpu_setup_pid(i) < 0) {
+				failure_state = FAILURE_PERM;
+				set_fail_state();
+				break;
+			}
+		}
+		DBG_LOTS("cpu_all_tmax=%d.%03d\n", FIX32TOPRINT(cpu_all_tmax));
+
+		backside_setup_pid();
+		slots_setup_pid();
+
+#ifdef HACKED_OVERTEMP
+		cpu_all_tmax = 60 << 16;
+#endif
+	}
+
+	/* Permanent failure, bail out */
+	if (failure_state & FAILURE_PERM)
+		return;
+
+	/*
+	 * Clear all failure bits except low overtemp which will be eventually
+	 * cleared by the control loop itself
+	 */
+	last_failure = failure_state;
+	failure_state &= FAILURE_LOW_OVERTEMP;
+	backside_fan_tick();
+	slots_fan_tick();
+
+	/* We do CPUs last because they can be clamped high by
+	 * DIMM temperature
+	 */
+	cpu_fans_tick();
+
+	DBG_LOTS("  last_failure: 0x%x, failure_state: %x\n",
+		 last_failure, failure_state);
+
+	/* Check for failures. Any failure causes cpufreq clamping */
+	if (failure_state && last_failure == 0 && cpufreq_clamp)
+		wf_control_set_max(cpufreq_clamp);
+	if (failure_state == 0 && last_failure && cpufreq_clamp)
+		wf_control_set_min(cpufreq_clamp);
+
+	/* That's it for now, we might want to deal with other failures
+	 * differently in the future though
+	 */
+}
+
+static void rm31_new_control(struct wf_control *ct)
+{
+	bool all_controls;
+
+	if (!strcmp(ct->name, "cpu-fan-a-0"))
+		cpu_fans[0][0] = ct;
+	else if (!strcmp(ct->name, "cpu-fan-b-0"))
+		cpu_fans[0][1] = ct;
+	else if (!strcmp(ct->name, "cpu-fan-c-0"))
+		cpu_fans[0][2] = ct;
+	else if (!strcmp(ct->name, "cpu-fan-a-1"))
+		cpu_fans[1][0] = ct;
+	else if (!strcmp(ct->name, "cpu-fan-b-1"))
+		cpu_fans[1][1] = ct;
+	else if (!strcmp(ct->name, "cpu-fan-c-1"))
+		cpu_fans[1][2] = ct;
+	else if (!strcmp(ct->name, "backside-fan"))
+		backside_fan = ct;
+	else if (!strcmp(ct->name, "slots-fan"))
+		slots_fan = ct;
+	else if (!strcmp(ct->name, "cpufreq-clamp"))
+		cpufreq_clamp = ct;
+
+	all_controls =
+		cpu_fans[0][0] &&
+		cpu_fans[0][1] &&
+		cpu_fans[0][2] &&
+		backside_fan &&
+		slots_fan;
+	if (nr_chips > 1)
+		all_controls &=
+			cpu_fans[1][0] &&
+			cpu_fans[1][1] &&
+			cpu_fans[1][2];
+	have_all_controls = all_controls;
+}
+
+
+static void rm31_new_sensor(struct wf_sensor *sr)
+{
+	bool all_sensors;
+
+	if (!strcmp(sr->name, "cpu-diode-temp-0"))
+		sens_cpu_temp[0] = sr;
+	else if (!strcmp(sr->name, "cpu-diode-temp-1"))
+		sens_cpu_temp[1] = sr;
+	else if (!strcmp(sr->name, "cpu-voltage-0"))
+		sens_cpu_volts[0] = sr;
+	else if (!strcmp(sr->name, "cpu-voltage-1"))
+		sens_cpu_volts[1] = sr;
+	else if (!strcmp(sr->name, "cpu-current-0"))
+		sens_cpu_amps[0] = sr;
+	else if (!strcmp(sr->name, "cpu-current-1"))
+		sens_cpu_amps[1] = sr;
+	else if (!strcmp(sr->name, "backside-temp"))
+		backside_temp = sr;
+	else if (!strcmp(sr->name, "slots-temp"))
+		slots_temp = sr;
+	else if (!strcmp(sr->name, "dimms-temp"))
+		dimms_temp = sr;
+
+	all_sensors =
+		sens_cpu_temp[0] &&
+		sens_cpu_volts[0] &&
+		sens_cpu_amps[0] &&
+		backside_temp &&
+		slots_temp &&
+		dimms_temp;
+	if (nr_chips > 1)
+		all_sensors &=
+			sens_cpu_temp[1] &&
+			sens_cpu_volts[1] &&
+			sens_cpu_amps[1];
+
+	have_all_sensors = all_sensors;
+}
+
+static int rm31_wf_notify(struct notifier_block *self,
+			  unsigned long event, void *data)
+{
+	switch (event) {
+	case WF_EVENT_NEW_SENSOR:
+		rm31_new_sensor(data);
+		break;
+	case WF_EVENT_NEW_CONTROL:
+		rm31_new_control(data);
+		break;
+	case WF_EVENT_TICK:
+		if (have_all_controls && have_all_sensors)
+			rm31_tick();
+	}
+	return 0;
+}
+
+static struct notifier_block rm31_events = {
+	.notifier_call = rm31_wf_notify,
+};
+
+static int wf_rm31_probe(struct platform_device *dev)
+{
+	wf_register_client(&rm31_events);
+	return 0;
+}
+
+static int __devexit wf_rm31_remove(struct platform_device *dev)
+{
+	wf_unregister_client(&rm31_events);
+
+	/* should release all sensors and controls */
+	return 0;
+}
+
+static struct platform_driver wf_rm31_driver = {
+	.probe	= wf_rm31_probe,
+	.remove	= wf_rm31_remove,
+	.driver	= {
+		.name = "windfarm",
+		.owner	= THIS_MODULE,
+	},
+};
+
+static int __init wf_rm31_init(void)
+{
+	struct device_node *cpu;
+	int i;
+
+	if (!of_machine_is_compatible("RackMac3,1"))
+		return -ENODEV;
+
+	/* Count the number of CPU cores */
+	nr_chips = 0;
+	for (cpu = NULL; (cpu = of_find_node_by_type(cpu, "cpu")) != NULL; )
+		++nr_chips;
+	if (nr_chips > NR_CHIPS)
+		nr_chips = NR_CHIPS;
+
+	pr_info("windfarm: Initializing for desktop G5 with %d chips\n",
+		nr_chips);
+
+	/* Get MPU data for each CPU */
+	for (i = 0; i < nr_chips; i++) {
+		cpu_mpu_data[i] = wf_get_mpu(i);
+		if (!cpu_mpu_data[i]) {
+			pr_err("wf_rm31: Failed to find MPU data for CPU %d\n", i);
+			return -ENXIO;
+		}
+	}
+
+#ifdef MODULE
+	request_module("windfarm_fcu_controls");
+	request_module("windfarm_lm75_sensor");
+	request_module("windfarm_lm87_sensor");
+	request_module("windfarm_ad7417_sensor");
+	request_module("windfarm_max6690_sensor");
+	request_module("windfarm_cpufreq_clamp");
+#endif /* MODULE */
+
+	platform_driver_register(&wf_rm31_driver);
+	return 0;
+}
+
+static void __exit wf_rm31_exit(void)
+{
+	platform_driver_unregister(&wf_rm31_driver);
+}
+
+module_init(wf_rm31_init);
+module_exit(wf_rm31_exit);
+
+MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
+MODULE_DESCRIPTION("Thermal control for Xserve G5");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:windfarm");