Linux-2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 2080 insertions, 0 deletions

diff --git a/drivers/macintosh/therm_pm72.c b/drivers/macintosh/therm_pm72.c
new file mode 100644
index 0000000..82336a5
--- /dev/null
+++ b/drivers/macintosh/therm_pm72.c
@@ -0,0 +1,2080 @@
+/*
+ * Device driver for the thermostats & fan controller of  the
+ * Apple G5 "PowerMac7,2" desktop machines.
+ *
+ * (c) Copyright IBM Corp. 2003-2004
+ *
+ * Maintained by: Benjamin Herrenschmidt
+ *                <benh@kernel.crashing.org>
+ * 
+ *
+ * The algorithm used is the PID control algorithm, used the same
+ * way the published Darwin code does, using the same values that
+ * are present in the Darwin 7.0 snapshot property lists.
+ *
+ * As far as the CPUs control loops are concerned, I use the
+ * calibration & PID constants provided by the EEPROM,
+ * I do _not_ embed any value from the property lists, as the ones
+ * provided by Darwin 7.0 seem to always have an older version that
+ * what I've seen on the actual computers.
+ * It would be interesting to verify that though. Darwin has a
+ * version code of 1.0.0d11 for all control loops it seems, while
+ * so far, the machines EEPROMs contain a dataset versioned 1.0.0f
+ *
+ * Darwin doesn't provide source to all parts, some missing
+ * bits like the AppleFCU driver or the actual scale of some
+ * of the values returned by sensors had to be "guessed" some
+ * way... or based on what Open Firmware does.
+ *
+ * I didn't yet figure out how to get the slots power consumption
+ * out of the FCU, so that part has not been implemented yet and
+ * the slots fan is set to a fixed 50% PWM, hoping this value is
+ * safe enough ...
+ *
+ * Note: I have observed strange oscillations of the CPU control
+ * loop on a dual G5 here. When idle, the CPU exhaust fan tend to
+ * oscillates slowly (over several minutes) between the minimum
+ * of 300RPMs and approx. 1000 RPMs. I don't know what is causing
+ * this, it could be some incorrect constant or an error in the
+ * way I ported the algorithm, or it could be just normal. I
+ * don't have full understanding on the way Apple tweaked the PID
+ * algorithm for the CPU control, it is definitely not a standard
+ * implementation...
+ *
+ * TODO:  - Check MPU structure version/signature
+ *        - Add things like /sbin/overtemp for non-critical
+ *          overtemp conditions so userland can take some policy
+ *          decisions, like slewing down CPUs
+ *	  - Deal with fan and i2c failures in a better way
+ *	  - Maybe do a generic PID based on params used for
+ *	    U3 and Drives ? Definitely need to factor code a bit
+ *          bettter... also make sensor detection more robust using
+ *          the device-tree to probe for them
+ *        - Figure out how to get the slots consumption and set the
+ *          slots fan accordingly
+ *
+ * History:
+ *
+ *  Nov. 13, 2003 : 0.5
+ *	- First release
+ *
+ *  Nov. 14, 2003 : 0.6
+ *	- Read fan speed from FCU, low level fan routines now deal
+ *	  with errors & check fan status, though higher level don't
+ *	  do much.
+ *	- Move a bunch of definitions to .h file
+ *
+ *  Nov. 18, 2003 : 0.7
+ *	- Fix build on ppc64 kernel
+ *	- Move back statics definitions to .c file
+ *	- Avoid calling schedule_timeout with a negative number
+ *
+ *  Dec. 18, 2003 : 0.8
+ *	- Fix typo when reading back fan speed on 2 CPU machines
+ *
+ *  Mar. 11, 2004 : 0.9
+ *	- Rework code accessing the ADC chips, make it more robust and
+ *	  closer to the chip spec. Also make sure it is configured properly,
+ *        I've seen yet unexplained cases where on startup, I would have stale
+ *        values in the configuration register
+ *	- Switch back to use of target fan speed for PID, thus lowering
+ *        pressure on i2c
+ *
+ *  Oct. 20, 2004 : 1.1
+ *	- Add device-tree lookup for fan IDs, should detect liquid cooling
+ *        pumps when present
+ *	- Enable driver for PowerMac7,3 machines
+ *	- Split the U3/Backside cooling on U3 & U3H versions as Darwin does
+ *	- Add new CPU cooling algorithm for machines with liquid cooling
+ *	- Workaround for some PowerMac7,3 with empty "fan" node in the devtree
+ *	- Fix a signed/unsigned compare issue in some PID loops
+ *
+ *  Mar. 10, 2005 : 1.2
+ *	- Add basic support for Xserve G5
+ *	- Retreive pumps min/max from EEPROM image in device-tree (broken)
+ *	- Use min/max macros here or there
+ *	- Latest darwin updated U3H min fan speed to 20% PWM
+ *
+ */
+
+#include <linux/config.h>
+#include <linux/types.h>
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/delay.h>
+#include <linux/sched.h>
+#include <linux/i2c.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/spinlock.h>
+#include <linux/smp_lock.h>
+#include <linux/wait.h>
+#include <linux/reboot.h>
+#include <linux/kmod.h>
+#include <linux/i2c.h>
+#include <linux/i2c-dev.h>
+#include <asm/prom.h>
+#include <asm/machdep.h>
+#include <asm/io.h>
+#include <asm/system.h>
+#include <asm/sections.h>
+#include <asm/of_device.h>
+
+#include "therm_pm72.h"
+
+#define VERSION "1.2b2"
+
+#undef DEBUG
+
+#ifdef DEBUG
+#define DBG(args...)	printk(args)
+#else
+#define DBG(args...)	do { } while(0)
+#endif
+
+
+/*
+ * Driver statics
+ */
+
+static struct of_device *		of_dev;
+static struct i2c_adapter *		u3_0;
+static struct i2c_adapter *		u3_1;
+static struct i2c_adapter *		k2;
+static struct i2c_client *		fcu;
+static struct cpu_pid_state		cpu_state[2];
+static struct basckside_pid_params	backside_params;
+static struct backside_pid_state	backside_state;
+static struct drives_pid_state		drives_state;
+static struct dimm_pid_state		dimms_state;
+static int				state;
+static int				cpu_count;
+static int				cpu_pid_type;
+static pid_t				ctrl_task;
+static struct completion		ctrl_complete;
+static int				critical_state;
+static int				rackmac;
+static s32				dimm_output_clamp;
+
+static DECLARE_MUTEX(driver_lock);
+
+/*
+ * We have 3 types of CPU PID control. One is "split" old style control
+ * for intake & exhaust fans, the other is "combined" control for both
+ * CPUs that also deals with the pumps when present. To be "compatible"
+ * with OS X at this point, we only use "COMBINED" on the machines that
+ * are identified as having the pumps (though that identification is at
+ * least dodgy). Ultimately, we could probably switch completely to this
+ * algorithm provided we hack it to deal with the UP case
+ */
+#define CPU_PID_TYPE_SPLIT	0
+#define CPU_PID_TYPE_COMBINED	1
+#define CPU_PID_TYPE_RACKMAC	2
+
+/*
+ * This table describes all fans in the FCU. The "id" and "type" values
+ * are defaults valid for all earlier machines. Newer machines will
+ * eventually override the table content based on the device-tree
+ */
+struct fcu_fan_table
+{
+	char*	loc;	/* location code */
+	int	type;	/* 0 = rpm, 1 = pwm, 2 = pump */
+	int	id;	/* id or -1 */
+};
+
+#define FCU_FAN_RPM		0
+#define FCU_FAN_PWM		1
+
+#define FCU_FAN_ABSENT_ID	-1
+
+#define FCU_FAN_COUNT		ARRAY_SIZE(fcu_fans)
+
+struct fcu_fan_table	fcu_fans[] = {
+	[BACKSIDE_FAN_PWM_INDEX] = {
+		.loc	= "BACKSIDE,SYS CTRLR FAN",
+		.type	= FCU_FAN_PWM,
+		.id	= BACKSIDE_FAN_PWM_DEFAULT_ID,
+	},
+	[DRIVES_FAN_RPM_INDEX] = {
+		.loc	= "DRIVE BAY",
+		.type	= FCU_FAN_RPM,
+		.id	= DRIVES_FAN_RPM_DEFAULT_ID,
+	},
+	[SLOTS_FAN_PWM_INDEX] = {
+		.loc	= "SLOT,PCI FAN",
+		.type	= FCU_FAN_PWM,
+		.id	= SLOTS_FAN_PWM_DEFAULT_ID,
+	},
+	[CPUA_INTAKE_FAN_RPM_INDEX] = {
+		.loc	= "CPU A INTAKE",
+		.type	= FCU_FAN_RPM,
+		.id	= CPUA_INTAKE_FAN_RPM_DEFAULT_ID,
+	},
+	[CPUA_EXHAUST_FAN_RPM_INDEX] = {
+		.loc	= "CPU A EXHAUST",
+		.type	= FCU_FAN_RPM,
+		.id	= CPUA_EXHAUST_FAN_RPM_DEFAULT_ID,
+	},
+	[CPUB_INTAKE_FAN_RPM_INDEX] = {
+		.loc	= "CPU B INTAKE",
+		.type	= FCU_FAN_RPM,
+		.id	= CPUB_INTAKE_FAN_RPM_DEFAULT_ID,
+	},
+	[CPUB_EXHAUST_FAN_RPM_INDEX] = {
+		.loc	= "CPU B EXHAUST",
+		.type	= FCU_FAN_RPM,
+		.id	= CPUB_EXHAUST_FAN_RPM_DEFAULT_ID,
+	},
+	/* pumps aren't present by default, have to be looked up in the
+	 * device-tree
+	 */
+	[CPUA_PUMP_RPM_INDEX] = {
+		.loc	= "CPU A PUMP",
+		.type	= FCU_FAN_RPM,		
+		.id	= FCU_FAN_ABSENT_ID,
+	},
+	[CPUB_PUMP_RPM_INDEX] = {
+		.loc	= "CPU B PUMP",
+		.type	= FCU_FAN_RPM,
+		.id	= FCU_FAN_ABSENT_ID,
+	},
+	/* Xserve fans */
+	[CPU_A1_FAN_RPM_INDEX] = {
+		.loc	= "CPU A 1",
+		.type	= FCU_FAN_RPM,
+		.id	= FCU_FAN_ABSENT_ID,
+	},
+	[CPU_A2_FAN_RPM_INDEX] = {
+		.loc	= "CPU A 2",
+		.type	= FCU_FAN_RPM,
+		.id	= FCU_FAN_ABSENT_ID,
+	},
+	[CPU_A3_FAN_RPM_INDEX] = {
+		.loc	= "CPU A 3",
+		.type	= FCU_FAN_RPM,
+		.id	= FCU_FAN_ABSENT_ID,
+	},
+	[CPU_B1_FAN_RPM_INDEX] = {
+		.loc	= "CPU B 1",
+		.type	= FCU_FAN_RPM,
+		.id	= FCU_FAN_ABSENT_ID,
+	},
+	[CPU_B2_FAN_RPM_INDEX] = {
+		.loc	= "CPU B 2",
+		.type	= FCU_FAN_RPM,
+		.id	= FCU_FAN_ABSENT_ID,
+	},
+	[CPU_B3_FAN_RPM_INDEX] = {
+		.loc	= "CPU B 3",
+		.type	= FCU_FAN_RPM,
+		.id	= FCU_FAN_ABSENT_ID,
+	},
+};
+
+/*
+ * i2c_driver structure to attach to the host i2c controller
+ */
+
+static int therm_pm72_attach(struct i2c_adapter *adapter);
+static int therm_pm72_detach(struct i2c_adapter *adapter);
+
+static struct i2c_driver therm_pm72_driver =
+{
+	.owner		= THIS_MODULE,
+	.name		= "therm_pm72",
+	.flags		= I2C_DF_NOTIFY,
+	.attach_adapter	= therm_pm72_attach,
+	.detach_adapter	= therm_pm72_detach,
+};
+
+/*
+ * Utility function to create an i2c_client structure and
+ * attach it to one of u3 adapters
+ */
+static struct i2c_client *attach_i2c_chip(int id, const char *name)
+{
+	struct i2c_client *clt;
+	struct i2c_adapter *adap;
+
+	if (id & 0x200)
+		adap = k2;
+	else if (id & 0x100)
+		adap = u3_1;
+	else
+		adap = u3_0;
+	if (adap == NULL)
+		return NULL;
+
+	clt = kmalloc(sizeof(struct i2c_client), GFP_KERNEL);
+	if (clt == NULL)
+		return NULL;
+	memset(clt, 0, sizeof(struct i2c_client));
+
+	clt->addr = (id >> 1) & 0x7f;
+	clt->adapter = adap;
+	clt->driver = &therm_pm72_driver;
+	strncpy(clt->name, name, I2C_NAME_SIZE-1);
+
+	if (i2c_attach_client(clt)) {
+		printk(KERN_ERR "therm_pm72: Failed to attach to i2c ID 0x%x\n", id);
+		kfree(clt);
+		return NULL;
+	}
+	return clt;
+}
+
+/*
+ * Utility function to get rid of the i2c_client structure
+ * (will also detach from the adapter hopepfully)
+ */
+static void detach_i2c_chip(struct i2c_client *clt)
+{
+	i2c_detach_client(clt);
+	kfree(clt);
+}
+
+/*
+ * Here are the i2c chip access wrappers
+ */
+
+static void initialize_adc(struct cpu_pid_state *state)
+{
+	int rc;
+	u8 buf[2];
+
+	/* Read ADC the configuration register and cache it. We
+	 * also make sure Config2 contains proper values, I've seen
+	 * cases where we got stale grabage in there, thus preventing
+	 * proper reading of conv. values
+	 */
+
+	/* Clear Config2 */
+	buf[0] = 5;
+	buf[1] = 0;
+	i2c_master_send(state->monitor, buf, 2);
+
+	/* Read & cache Config1 */
+	buf[0] = 1;
+	rc = i2c_master_send(state->monitor, buf, 1);
+	if (rc > 0) {
+		rc = i2c_master_recv(state->monitor, buf, 1);
+		if (rc > 0) {
+			state->adc_config = buf[0];
+			DBG("ADC config reg: %02x\n", state->adc_config);
+			/* Disable shutdown mode */
+		       	state->adc_config &= 0xfe;
+			buf[0] = 1;
+			buf[1] = state->adc_config;
+			rc = i2c_master_send(state->monitor, buf, 2);
+		}
+	}
+	if (rc <= 0)
+		printk(KERN_ERR "therm_pm72: Error reading ADC config"
+		       " register !\n");
+}
+
+static int read_smon_adc(struct cpu_pid_state *state, int chan)
+{
+	int rc, data, tries = 0;
+	u8 buf[2];
+
+	for (;;) {
+		/* Set channel */
+		buf[0] = 1;
+		buf[1] = (state->adc_config & 0x1f) | (chan << 5);
+		rc = i2c_master_send(state->monitor, buf, 2);
+		if (rc <= 0)
+			goto error;
+		/* Wait for convertion */
+		msleep(1);
+		/* Switch to data register */
+		buf[0] = 4;
+		rc = i2c_master_send(state->monitor, buf, 1);
+		if (rc <= 0)
+			goto error;
+		/* Read result */
+		rc = i2c_master_recv(state->monitor, buf, 2);
+		if (rc < 0)
+			goto error;
+		data = ((u16)buf[0]) << 8 | (u16)buf[1];
+		return data >> 6;
+	error:
+		DBG("Error reading ADC, retrying...\n");
+		if (++tries > 10) {
+			printk(KERN_ERR "therm_pm72: Error reading ADC !\n");
+			return -1;
+		}
+		msleep(10);
+	}
+}
+
+static int read_lm87_reg(struct i2c_client * chip, int reg)
+{
+	int rc, tries = 0;
+	u8 buf;
+
+	for (;;) {
+		/* Set address */
+		buf = (u8)reg;
+		rc = i2c_master_send(chip, &buf, 1);
+		if (rc <= 0)
+			goto error;
+		rc = i2c_master_recv(chip, &buf, 1);
+		if (rc <= 0)
+			goto error;
+		return (int)buf;
+	error:
+		DBG("Error reading LM87, retrying...\n");
+		if (++tries > 10) {
+			printk(KERN_ERR "therm_pm72: Error reading LM87 !\n");
+			return -1;
+		}
+		msleep(10);
+	}
+}
+
+static int fan_read_reg(int reg, unsigned char *buf, int nb)
+{
+	int tries, nr, nw;
+
+	buf[0] = reg;
+	tries = 0;
+	for (;;) {
+		nw = i2c_master_send(fcu, buf, 1);
+		if (nw > 0 || (nw < 0 && nw != -EIO) || tries >= 100)
+			break;
+		msleep(10);
+		++tries;
+	}
+	if (nw <= 0) {
+		printk(KERN_ERR "Failure writing address to FCU: %d", nw);
+		return -EIO;
+	}
+	tries = 0;
+	for (;;) {
+		nr = i2c_master_recv(fcu, buf, nb);
+		if (nr > 0 || (nr < 0 && nr != ENODEV) || tries >= 100)
+			break;
+		msleep(10);
+		++tries;
+	}
+	if (nr <= 0)
+		printk(KERN_ERR "Failure reading data from FCU: %d", nw);
+	return nr;
+}
+
+static int fan_write_reg(int reg, const unsigned char *ptr, int nb)
+{
+	int tries, nw;
+	unsigned char buf[16];
+
+	buf[0] = reg;
+	memcpy(buf+1, ptr, nb);
+	++nb;
+	tries = 0;
+	for (;;) {
+		nw = i2c_master_send(fcu, buf, nb);
+		if (nw > 0 || (nw < 0 && nw != EIO) || tries >= 100)
+			break;
+		msleep(10);
+		++tries;
+	}
+	if (nw < 0)
+		printk(KERN_ERR "Failure writing to FCU: %d", nw);
+	return nw;
+}
+
+static int start_fcu(void)
+{
+	unsigned char buf = 0xff;
+	int rc;
+
+	rc = fan_write_reg(0xe, &buf, 1);
+	if (rc < 0)
+		return -EIO;
+	rc = fan_write_reg(0x2e, &buf, 1);
+	if (rc < 0)
+		return -EIO;
+	return 0;
+}
+
+static int set_rpm_fan(int fan_index, int rpm)
+{
+	unsigned char buf[2];
+	int rc, id;
+
+	if (fcu_fans[fan_index].type != FCU_FAN_RPM)
+		return -EINVAL;
+	id = fcu_fans[fan_index].id; 
+	if (id == FCU_FAN_ABSENT_ID)
+		return -EINVAL;
+
+	if (rpm < 300)
+		rpm = 300;
+	else if (rpm > 8191)
+		rpm = 8191;
+	buf[0] = rpm >> 5;
+	buf[1] = rpm << 3;
+	rc = fan_write_reg(0x10 + (id * 2), buf, 2);
+	if (rc < 0)
+		return -EIO;
+	return 0;
+}
+
+static int get_rpm_fan(int fan_index, int programmed)
+{
+	unsigned char failure;
+	unsigned char active;
+	unsigned char buf[2];
+	int rc, id, reg_base;
+
+	if (fcu_fans[fan_index].type != FCU_FAN_RPM)
+		return -EINVAL;
+	id = fcu_fans[fan_index].id; 
+	if (id == FCU_FAN_ABSENT_ID)
+		return -EINVAL;
+
+	rc = fan_read_reg(0xb, &failure, 1);
+	if (rc != 1)
+		return -EIO;
+	if ((failure & (1 << id)) != 0)
+		return -EFAULT;
+	rc = fan_read_reg(0xd, &active, 1);
+	if (rc != 1)
+		return -EIO;
+	if ((active & (1 << id)) == 0)
+		return -ENXIO;
+
+	/* Programmed value or real current speed */
+	reg_base = programmed ? 0x10 : 0x11;
+	rc = fan_read_reg(reg_base + (id * 2), buf, 2);
+	if (rc != 2)
+		return -EIO;
+
+	return (buf[0] << 5) | buf[1] >> 3;
+}
+
+static int set_pwm_fan(int fan_index, int pwm)
+{
+	unsigned char buf[2];
+	int rc, id;
+
+	if (fcu_fans[fan_index].type != FCU_FAN_PWM)
+		return -EINVAL;
+	id = fcu_fans[fan_index].id; 
+	if (id == FCU_FAN_ABSENT_ID)
+		return -EINVAL;
+
+	if (pwm < 10)
+		pwm = 10;
+	else if (pwm > 100)
+		pwm = 100;
+	pwm = (pwm * 2559) / 1000;
+	buf[0] = pwm;
+	rc = fan_write_reg(0x30 + (id * 2), buf, 1);
+	if (rc < 0)
+		return rc;
+	return 0;
+}
+
+static int get_pwm_fan(int fan_index)
+{
+	unsigned char failure;
+	unsigned char active;
+	unsigned char buf[2];
+	int rc, id;
+
+	if (fcu_fans[fan_index].type != FCU_FAN_PWM)
+		return -EINVAL;
+	id = fcu_fans[fan_index].id; 
+	if (id == FCU_FAN_ABSENT_ID)
+		return -EINVAL;
+
+	rc = fan_read_reg(0x2b, &failure, 1);
+	if (rc != 1)
+		return -EIO;
+	if ((failure & (1 << id)) != 0)
+		return -EFAULT;
+	rc = fan_read_reg(0x2d, &active, 1);
+	if (rc != 1)
+		return -EIO;
+	if ((active & (1 << id)) == 0)
+		return -ENXIO;
+
+	/* Programmed value or real current speed */
+	rc = fan_read_reg(0x30 + (id * 2), buf, 1);
+	if (rc != 1)
+		return -EIO;
+
+	return (buf[0] * 1000) / 2559;
+}
+
+/*
+ * Utility routine to read the CPU calibration EEPROM data
+ * from the device-tree
+ */
+static int read_eeprom(int cpu, struct mpu_data *out)
+{
+	struct device_node *np;
+	char nodename[64];
+	u8 *data;
+	int len;
+
+	/* prom.c routine for finding a node by path is a bit brain dead
+	 * and requires exact @xxx unit numbers. This is a bit ugly but
+	 * will work for these machines
+	 */
+	sprintf(nodename, "/u3@0,f8000000/i2c@f8001000/cpuid@a%d", cpu ? 2 : 0);
+	np = of_find_node_by_path(nodename);
+	if (np == NULL) {
+		printk(KERN_ERR "therm_pm72: Failed to retreive cpuid node from device-tree\n");
+		return -ENODEV;
+	}
+	data = (u8 *)get_property(np, "cpuid", &len);
+	if (data == NULL) {
+		printk(KERN_ERR "therm_pm72: Failed to retreive cpuid property from device-tree\n");
+		of_node_put(np);
+		return -ENODEV;
+	}
+	memcpy(out, data, sizeof(struct mpu_data));
+	of_node_put(np);
+	
+	return 0;
+}
+
+static void fetch_cpu_pumps_minmax(void)
+{
+	struct cpu_pid_state *state0 = &cpu_state[0];
+	struct cpu_pid_state *state1 = &cpu_state[1];
+	u16 pump_min = 0, pump_max = 0xffff;
+	u16 tmp[4];
+
+	/* Try to fetch pumps min/max infos from eeprom */
+
+	memcpy(&tmp, &state0->mpu.processor_part_num, 8);
+	if (tmp[0] != 0xffff && tmp[1] != 0xffff) {
+		pump_min = max(pump_min, tmp[0]);
+		pump_max = min(pump_max, tmp[1]);
+	}
+	if (tmp[2] != 0xffff && tmp[3] != 0xffff) {
+		pump_min = max(pump_min, tmp[2]);
+		pump_max = min(pump_max, tmp[3]);
+	}
+
+	/* Double check the values, this _IS_ needed as the EEPROM on
+	 * some dual 2.5Ghz G5s seem, at least, to have both min & max
+	 * same to the same value ... (grrrr)
+	 */
+	if (pump_min == pump_max || pump_min == 0 || pump_max == 0xffff) {
+		pump_min = CPU_PUMP_OUTPUT_MIN;
+		pump_max = CPU_PUMP_OUTPUT_MAX;
+	}
+
+	state0->pump_min = state1->pump_min = pump_min;
+	state0->pump_max = state1->pump_max = pump_max;
+}
+
+/* 
+ * Now, unfortunately, sysfs doesn't give us a nice void * we could
+ * pass around to the attribute functions, so we don't really have
+ * choice but implement a bunch of them...
+ *
+ * That sucks a bit, we take the lock because FIX32TOPRINT evaluates
+ * the input twice... I accept patches :)
+ */
+#define BUILD_SHOW_FUNC_FIX(name, data)				\
+static ssize_t show_##name(struct device *dev, char *buf)	\
+{								\
+	ssize_t r;						\
+	down(&driver_lock);					\
+	r = sprintf(buf, "%d.%03d", FIX32TOPRINT(data));	\
+	up(&driver_lock);					\
+	return r;						\
+}
+#define BUILD_SHOW_FUNC_INT(name, data)				\
+static ssize_t show_##name(struct device *dev, char *buf)	\
+{								\
+	return sprintf(buf, "%d", data);			\
+}
+
+BUILD_SHOW_FUNC_FIX(cpu0_temperature, cpu_state[0].last_temp)
+BUILD_SHOW_FUNC_FIX(cpu0_voltage, cpu_state[0].voltage)
+BUILD_SHOW_FUNC_FIX(cpu0_current, cpu_state[0].current_a)
+BUILD_SHOW_FUNC_INT(cpu0_exhaust_fan_rpm, cpu_state[0].rpm)
+BUILD_SHOW_FUNC_INT(cpu0_intake_fan_rpm, cpu_state[0].intake_rpm)
+
+BUILD_SHOW_FUNC_FIX(cpu1_temperature, cpu_state[1].last_temp)
+BUILD_SHOW_FUNC_FIX(cpu1_voltage, cpu_state[1].voltage)
+BUILD_SHOW_FUNC_FIX(cpu1_current, cpu_state[1].current_a)
+BUILD_SHOW_FUNC_INT(cpu1_exhaust_fan_rpm, cpu_state[1].rpm)
+BUILD_SHOW_FUNC_INT(cpu1_intake_fan_rpm, cpu_state[1].intake_rpm)
+
+BUILD_SHOW_FUNC_FIX(backside_temperature, backside_state.last_temp)
+BUILD_SHOW_FUNC_INT(backside_fan_pwm, backside_state.pwm)
+
+BUILD_SHOW_FUNC_FIX(drives_temperature, drives_state.last_temp)
+BUILD_SHOW_FUNC_INT(drives_fan_rpm, drives_state.rpm)
+
+BUILD_SHOW_FUNC_FIX(dimms_temperature, dimms_state.last_temp)
+
+static DEVICE_ATTR(cpu0_temperature,S_IRUGO,show_cpu0_temperature,NULL);
+static DEVICE_ATTR(cpu0_voltage,S_IRUGO,show_cpu0_voltage,NULL);
+static DEVICE_ATTR(cpu0_current,S_IRUGO,show_cpu0_current,NULL);
+static DEVICE_ATTR(cpu0_exhaust_fan_rpm,S_IRUGO,show_cpu0_exhaust_fan_rpm,NULL);
+static DEVICE_ATTR(cpu0_intake_fan_rpm,S_IRUGO,show_cpu0_intake_fan_rpm,NULL);
+
+static DEVICE_ATTR(cpu1_temperature,S_IRUGO,show_cpu1_temperature,NULL);
+static DEVICE_ATTR(cpu1_voltage,S_IRUGO,show_cpu1_voltage,NULL);
+static DEVICE_ATTR(cpu1_current,S_IRUGO,show_cpu1_current,NULL);
+static DEVICE_ATTR(cpu1_exhaust_fan_rpm,S_IRUGO,show_cpu1_exhaust_fan_rpm,NULL);
+static DEVICE_ATTR(cpu1_intake_fan_rpm,S_IRUGO,show_cpu1_intake_fan_rpm,NULL);
+
+static DEVICE_ATTR(backside_temperature,S_IRUGO,show_backside_temperature,NULL);
+static DEVICE_ATTR(backside_fan_pwm,S_IRUGO,show_backside_fan_pwm,NULL);
+
+static DEVICE_ATTR(drives_temperature,S_IRUGO,show_drives_temperature,NULL);
+static DEVICE_ATTR(drives_fan_rpm,S_IRUGO,show_drives_fan_rpm,NULL);
+
+static DEVICE_ATTR(dimms_temperature,S_IRUGO,show_dimms_temperature,NULL);
+
+/*
+ * CPUs fans control loop
+ */
+
+static int do_read_one_cpu_values(struct cpu_pid_state *state, s32 *temp, s32 *power)
+{
+	s32 ltemp, volts, amps;
+	int index, rc = 0;
+
+	/* Default (in case of error) */
+	*temp = state->cur_temp;
+	*power = state->cur_power;
+
+	if (cpu_pid_type == CPU_PID_TYPE_RACKMAC)
+		index = (state->index == 0) ?
+			CPU_A1_FAN_RPM_INDEX : CPU_B1_FAN_RPM_INDEX;
+	else
+		index = (state->index == 0) ?
+			CPUA_EXHAUST_FAN_RPM_INDEX : CPUB_EXHAUST_FAN_RPM_INDEX;
+
+	/* Read current fan status */
+	rc = get_rpm_fan(index, !RPM_PID_USE_ACTUAL_SPEED);
+	if (rc < 0) {
+		/* XXX What do we do now ? Nothing for now, keep old value, but
+		 * return error upstream
+		 */
+		DBG("  cpu %d, fan reading error !\n", state->index);
+	} else {
+		state->rpm = rc;
+		DBG("  cpu %d, exhaust RPM: %d\n", state->index, state->rpm);
+	}
+
+	/* Get some sensor readings and scale it */
+	ltemp = read_smon_adc(state, 1);
+	if (ltemp == -1) {
+		/* XXX What do we do now ? */
+		state->overtemp++;
+		if (rc == 0)
+			rc = -EIO;
+		DBG("  cpu %d, temp reading error !\n", state->index);
+	} else {
+		/* Fixup temperature according to diode calibration
+		 */
+		DBG("  cpu %d, temp raw: %04x, m_diode: %04x, b_diode: %04x\n",
+		    state->index,
+		    ltemp, state->mpu.mdiode, state->mpu.bdiode);
+		*temp = ((s32)ltemp * (s32)state->mpu.mdiode + ((s32)state->mpu.bdiode << 12)) >> 2;
+		state->last_temp = *temp;
+		DBG("  temp: %d.%03d\n", FIX32TOPRINT((*temp)));
+	}
+
+	/*
+	 * Read voltage & current and calculate power
+	 */
+	volts = read_smon_adc(state, 3);
+	amps = read_smon_adc(state, 4);
+
+	/* Scale voltage and current raw sensor values according to fixed scales
+	 * obtained in Darwin and calculate power from I and V
+	 */
+	volts *= ADC_CPU_VOLTAGE_SCALE;
+	amps *= ADC_CPU_CURRENT_SCALE;
+	*power = (((u64)volts) * ((u64)amps)) >> 16;
+	state->voltage = volts;
+	state->current_a = amps;
+	state->last_power = *power;
+
+	DBG("  cpu %d, current: %d.%03d, voltage: %d.%03d, power: %d.%03d W\n",
+	    state->index, FIX32TOPRINT(state->current_a),
+	    FIX32TOPRINT(state->voltage), FIX32TOPRINT(*power));
+
+	return 0;
+}
+
+static void do_cpu_pid(struct cpu_pid_state *state, s32 temp, s32 power)
+{
+	s32 power_target, integral, derivative, proportional, adj_in_target, sval;
+	s64 integ_p, deriv_p, prop_p, sum; 
+	int i;
+
+	/* Calculate power target value (could be done once for all)
+	 * and convert to a 16.16 fp number
+	 */
+	power_target = ((u32)(state->mpu.pmaxh - state->mpu.padjmax)) << 16;
+	DBG("  power target: %d.%03d, error: %d.%03d\n",
+	    FIX32TOPRINT(power_target), FIX32TOPRINT(power_target - power));
+
+	/* Store temperature and power in history array */
+	state->cur_temp = (state->cur_temp + 1) % CPU_TEMP_HISTORY_SIZE;
+	state->temp_history[state->cur_temp] = temp;
+	state->cur_power = (state->cur_power + 1) % state->count_power;
+	state->power_history[state->cur_power] = power;
+	state->error_history[state->cur_power] = power_target - power;
+	
+	/* If first loop, fill the history table */
+	if (state->first) {
+		for (i = 0; i < (state->count_power - 1); i++) {
+			state->cur_power = (state->cur_power + 1) % state->count_power;
+			state->power_history[state->cur_power] = power;
+			state->error_history[state->cur_power] = power_target - power;
+		}
+		for (i = 0; i < (CPU_TEMP_HISTORY_SIZE - 1); i++) {
+			state->cur_temp = (state->cur_temp + 1) % CPU_TEMP_HISTORY_SIZE;
+			state->temp_history[state->cur_temp] = temp;			
+		}
+		state->first = 0;
+	}
+
+	/* Calculate the integral term normally based on the "power" values */
+	sum = 0;
+	integral = 0;
+	for (i = 0; i < state->count_power; i++)
+		integral += state->error_history[i];
+	integral *= CPU_PID_INTERVAL;
+	DBG("  integral: %08x\n", integral);
+
+	/* Calculate the adjusted input (sense value).
+	 *   G_r is 12.20
+	 *   integ is 16.16
+	 *   so the result is 28.36
+	 *
+	 * input target is mpu.ttarget, input max is mpu.tmax
+	 */
+	integ_p = ((s64)state->mpu.pid_gr) * (s64)integral;
+	DBG("   integ_p: %d\n", (int)(integ_p >> 36));
+	sval = (state->mpu.tmax << 16) - ((integ_p >> 20) & 0xffffffff);
+	adj_in_target = (state->mpu.ttarget << 16);
+	if (adj_in_target > sval)
+		adj_in_target = sval;
+	DBG("   adj_in_target: %d.%03d, ttarget: %d\n", FIX32TOPRINT(adj_in_target),
+	    state->mpu.ttarget);
+
+	/* Calculate the derivative term */
+	derivative = state->temp_history[state->cur_temp] -
+		state->temp_history[(state->cur_temp + CPU_TEMP_HISTORY_SIZE - 1)
+				    % CPU_TEMP_HISTORY_SIZE];
+	derivative /= CPU_PID_INTERVAL;
+	deriv_p = ((s64)state->mpu.pid_gd) * (s64)derivative;
+	DBG("   deriv_p: %d\n", (int)(deriv_p >> 36));
+	sum += deriv_p;
+
+	/* Calculate the proportional term */
+	proportional = temp - adj_in_target;
+	prop_p = ((s64)state->mpu.pid_gp) * (s64)proportional;
+	DBG("   prop_p: %d\n", (int)(prop_p >> 36));
+	sum += prop_p;
+
+	/* Scale sum */
+	sum >>= 36;
+
+	DBG("   sum: %d\n", (int)sum);
+	state->rpm += (s32)sum;
+}
+
+static void do_monitor_cpu_combined(void)
+{
+	struct cpu_pid_state *state0 = &cpu_state[0];
+	struct cpu_pid_state *state1 = &cpu_state[1];
+	s32 temp0, power0, temp1, power1;
+	s32 temp_combi, power_combi;
+	int rc, intake, pump;
+
+	rc = do_read_one_cpu_values(state0, &temp0, &power0);
+	if (rc < 0) {
+		/* XXX What do we do now ? */
+	}
+	state1->overtemp = 0;
+	rc = do_read_one_cpu_values(state1, &temp1, &power1);
+	if (rc < 0) {
+		/* XXX What do we do now ? */
+	}
+	if (state1->overtemp)
+		state0->overtemp++;
+
+	temp_combi = max(temp0, temp1);
+	power_combi = max(power0, power1);
+
+	/* Check tmax, increment overtemp if we are there. At tmax+8, we go
+	 * full blown immediately and try to trigger a shutdown
+	 */
+	if (temp_combi >= ((state0->mpu.tmax + 8) << 16)) {
+		printk(KERN_WARNING "Warning ! Temperature way above maximum (%d) !\n",
+		       temp_combi >> 16);
+		state0->overtemp = CPU_MAX_OVERTEMP;
+	} else if (temp_combi > (state0->mpu.tmax << 16))
+		state0->overtemp++;
+	else
+		state0->overtemp = 0;
+	if (state0->overtemp >= CPU_MAX_OVERTEMP)
+		critical_state = 1;
+	if (state0->overtemp > 0) {
+		state0->rpm = state0->mpu.rmaxn_exhaust_fan;
+		state0->intake_rpm = intake = state0->mpu.rmaxn_intake_fan;
+		pump = state0->pump_min;
+		goto do_set_fans;
+	}
+
+	/* Do the PID */
+	do_cpu_pid(state0, temp_combi, power_combi);
+
+	/* Range check */
+	state0->rpm = max(state0->rpm, (int)state0->mpu.rminn_exhaust_fan);
+	state0->rpm = min(state0->rpm, (int)state0->mpu.rmaxn_exhaust_fan);
+
+	/* Calculate intake fan speed */
+	intake = (state0->rpm * CPU_INTAKE_SCALE) >> 16;
+	intake = max(intake, (int)state0->mpu.rminn_intake_fan);
+	intake = min(intake, (int)state0->mpu.rmaxn_intake_fan);
+	state0->intake_rpm = intake;
+
+	/* Calculate pump speed */
+	pump = (state0->rpm * state0->pump_max) /
+		state0->mpu.rmaxn_exhaust_fan;
+	pump = min(pump, state0->pump_max);
+	pump = max(pump, state0->pump_min);
+	
+ do_set_fans:
+	/* We copy values from state 0 to state 1 for /sysfs */
+	state1->rpm = state0->rpm;
+	state1->intake_rpm = state0->intake_rpm;
+
+	DBG("** CPU %d RPM: %d Ex, %d, Pump: %d, In, overtemp: %d\n",
+	    state1->index, (int)state1->rpm, intake, pump, state1->overtemp);
+
+	/* We should check for errors, shouldn't we ? But then, what
+	 * do we do once the error occurs ? For FCU notified fan
+	 * failures (-EFAULT) we probably want to notify userland
+	 * some way...
+	 */
+	set_rpm_fan(CPUA_INTAKE_FAN_RPM_INDEX, intake);
+	set_rpm_fan(CPUA_EXHAUST_FAN_RPM_INDEX, state0->rpm);
+	set_rpm_fan(CPUB_INTAKE_FAN_RPM_INDEX, intake);
+	set_rpm_fan(CPUB_EXHAUST_FAN_RPM_INDEX, state0->rpm);
+
+	if (fcu_fans[CPUA_PUMP_RPM_INDEX].id != FCU_FAN_ABSENT_ID)
+		set_rpm_fan(CPUA_PUMP_RPM_INDEX, pump);
+	if (fcu_fans[CPUB_PUMP_RPM_INDEX].id != FCU_FAN_ABSENT_ID)
+		set_rpm_fan(CPUB_PUMP_RPM_INDEX, pump);
+}
+
+static void do_monitor_cpu_split(struct cpu_pid_state *state)
+{
+	s32 temp, power;
+	int rc, intake;
+
+	/* Read current fan status */
+	rc = do_read_one_cpu_values(state, &temp, &power);
+	if (rc < 0) {
+		/* XXX What do we do now ? */
+	}
+
+	/* Check tmax, increment overtemp if we are there. At tmax+8, we go
+	 * full blown immediately and try to trigger a shutdown
+	 */
+	if (temp >= ((state->mpu.tmax + 8) << 16)) {
+		printk(KERN_WARNING "Warning ! CPU %d temperature way above maximum"
+		       " (%d) !\n",
+		       state->index, temp >> 16);
+		state->overtemp = CPU_MAX_OVERTEMP;
+	} else if (temp > (state->mpu.tmax << 16))
+		state->overtemp++;
+	else
+		state->overtemp = 0;
+	if (state->overtemp >= CPU_MAX_OVERTEMP)
+		critical_state = 1;
+	if (state->overtemp > 0) {
+		state->rpm = state->mpu.rmaxn_exhaust_fan;
+		state->intake_rpm = intake = state->mpu.rmaxn_intake_fan;
+		goto do_set_fans;
+	}
+
+	/* Do the PID */
+	do_cpu_pid(state, temp, power);
+
+	/* Range check */
+	state->rpm = max(state->rpm, (int)state->mpu.rminn_exhaust_fan);
+	state->rpm = min(state->rpm, (int)state->mpu.rmaxn_exhaust_fan);
+
+	/* Calculate intake fan */
+	intake = (state->rpm * CPU_INTAKE_SCALE) >> 16;
+	intake = max(intake, (int)state->mpu.rminn_intake_fan);
+	intake = min(intake, (int)state->mpu.rmaxn_intake_fan);
+	state->intake_rpm = intake;
+
+ do_set_fans:
+	DBG("** CPU %d RPM: %d Ex, %d In, overtemp: %d\n",
+	    state->index, (int)state->rpm, intake, state->overtemp);
+
+	/* We should check for errors, shouldn't we ? But then, what
+	 * do we do once the error occurs ? For FCU notified fan
+	 * failures (-EFAULT) we probably want to notify userland
+	 * some way...
+	 */
+	if (state->index == 0) {
+		set_rpm_fan(CPUA_INTAKE_FAN_RPM_INDEX, intake);
+		set_rpm_fan(CPUA_EXHAUST_FAN_RPM_INDEX, state->rpm);
+	} else {
+		set_rpm_fan(CPUB_INTAKE_FAN_RPM_INDEX, intake);
+		set_rpm_fan(CPUB_EXHAUST_FAN_RPM_INDEX, state->rpm);
+	}
+}
+
+static void do_monitor_cpu_rack(struct cpu_pid_state *state)
+{
+	s32 temp, power, fan_min;
+	int rc;
+
+	/* Read current fan status */
+	rc = do_read_one_cpu_values(state, &temp, &power);
+	if (rc < 0) {
+		/* XXX What do we do now ? */
+	}
+
+	/* Check tmax, increment overtemp if we are there. At tmax+8, we go
+	 * full blown immediately and try to trigger a shutdown
+	 */
+	if (temp >= ((state->mpu.tmax + 8) << 16)) {
+		printk(KERN_WARNING "Warning ! CPU %d temperature way above maximum"
+		       " (%d) !\n",
+		       state->index, temp >> 16);
+		state->overtemp = CPU_MAX_OVERTEMP;
+	} else if (temp > (state->mpu.tmax << 16))
+		state->overtemp++;
+	else
+		state->overtemp = 0;
+	if (state->overtemp >= CPU_MAX_OVERTEMP)
+		critical_state = 1;
+	if (state->overtemp > 0) {
+		state->rpm = state->intake_rpm = state->mpu.rmaxn_intake_fan;
+		goto do_set_fans;
+	}
+
+	/* Do the PID */
+	do_cpu_pid(state, temp, power);
+
+	/* Check clamp from dimms */
+	fan_min = dimm_output_clamp;
+	fan_min = max(fan_min, (int)state->mpu.rminn_intake_fan);
+
+	state->rpm = max(state->rpm, (int)fan_min);
+	state->rpm = min(state->rpm, (int)state->mpu.rmaxn_intake_fan);
+	state->intake_rpm = state->rpm;
+
+ do_set_fans:
+	DBG("** CPU %d RPM: %d overtemp: %d\n",
+	    state->index, (int)state->rpm, state->overtemp);
+
+	/* We should check for errors, shouldn't we ? But then, what
+	 * do we do once the error occurs ? For FCU notified fan
+	 * failures (-EFAULT) we probably want to notify userland
+	 * some way...
+	 */
+	if (state->index == 0) {
+		set_rpm_fan(CPU_A1_FAN_RPM_INDEX, state->rpm);
+		set_rpm_fan(CPU_A2_FAN_RPM_INDEX, state->rpm);
+		set_rpm_fan(CPU_A3_FAN_RPM_INDEX, state->rpm);
+	} else {
+		set_rpm_fan(CPU_B1_FAN_RPM_INDEX, state->rpm);
+		set_rpm_fan(CPU_B2_FAN_RPM_INDEX, state->rpm);
+		set_rpm_fan(CPU_B3_FAN_RPM_INDEX, state->rpm);
+	}
+}
+
+/*
+ * Initialize the state structure for one CPU control loop
+ */
+static int init_cpu_state(struct cpu_pid_state *state, int index)
+{
+	state->index = index;
+	state->first = 1;
+	state->rpm = (cpu_pid_type == CPU_PID_TYPE_RACKMAC) ? 4000 : 1000;
+	state->overtemp = 0;
+	state->adc_config = 0x00;
+
+
+	if (index == 0)
+		state->monitor = attach_i2c_chip(SUPPLY_MONITOR_ID, "CPU0_monitor");
+	else if (index == 1)
+		state->monitor = attach_i2c_chip(SUPPLY_MONITORB_ID, "CPU1_monitor");
+	if (state->monitor == NULL)
+		goto fail;
+
+	if (read_eeprom(index, &state->mpu))
+		goto fail;
+
+	state->count_power = state->mpu.tguardband;
+	if (state->count_power > CPU_POWER_HISTORY_SIZE) {
+		printk(KERN_WARNING "Warning ! too many power history slots\n");
+		state->count_power = CPU_POWER_HISTORY_SIZE;
+	}
+	DBG("CPU %d Using %d power history entries\n", index, state->count_power);
+
+	if (index == 0) {
+		device_create_file(&of_dev->dev, &dev_attr_cpu0_temperature);
+		device_create_file(&of_dev->dev, &dev_attr_cpu0_voltage);
+		device_create_file(&of_dev->dev, &dev_attr_cpu0_current);
+		device_create_file(&of_dev->dev, &dev_attr_cpu0_exhaust_fan_rpm);
+		device_create_file(&of_dev->dev, &dev_attr_cpu0_intake_fan_rpm);
+	} else {
+		device_create_file(&of_dev->dev, &dev_attr_cpu1_temperature);
+		device_create_file(&of_dev->dev, &dev_attr_cpu1_voltage);
+		device_create_file(&of_dev->dev, &dev_attr_cpu1_current);
+		device_create_file(&of_dev->dev, &dev_attr_cpu1_exhaust_fan_rpm);
+		device_create_file(&of_dev->dev, &dev_attr_cpu1_intake_fan_rpm);
+	}
+
+	return 0;
+ fail:
+	if (state->monitor)
+		detach_i2c_chip(state->monitor);
+	state->monitor = NULL;
+	
+	return -ENODEV;
+}
+
+/*
+ * Dispose of the state data for one CPU control loop
+ */
+static void dispose_cpu_state(struct cpu_pid_state *state)
+{
+	if (state->monitor == NULL)
+		return;
+
+	if (state->index == 0) {
+		device_remove_file(&of_dev->dev, &dev_attr_cpu0_temperature);
+		device_remove_file(&of_dev->dev, &dev_attr_cpu0_voltage);
+		device_remove_file(&of_dev->dev, &dev_attr_cpu0_current);
+		device_remove_file(&of_dev->dev, &dev_attr_cpu0_exhaust_fan_rpm);
+		device_remove_file(&of_dev->dev, &dev_attr_cpu0_intake_fan_rpm);
+	} else {
+		device_remove_file(&of_dev->dev, &dev_attr_cpu1_temperature);
+		device_remove_file(&of_dev->dev, &dev_attr_cpu1_voltage);
+		device_remove_file(&of_dev->dev, &dev_attr_cpu1_current);
+		device_remove_file(&of_dev->dev, &dev_attr_cpu1_exhaust_fan_rpm);
+		device_remove_file(&of_dev->dev, &dev_attr_cpu1_intake_fan_rpm);
+	}
+
+	detach_i2c_chip(state->monitor);
+	state->monitor = NULL;
+}
+
+/*
+ * Motherboard backside & U3 heatsink fan control loop
+ */
+static void do_monitor_backside(struct backside_pid_state *state)
+{
+	s32 temp, integral, derivative, fan_min;
+	s64 integ_p, deriv_p, prop_p, sum; 
+	int i, rc;
+
+	if (--state->ticks != 0)
+		return;
+	state->ticks = backside_params.interval;
+
+	DBG("backside:\n");
+
+	/* Check fan status */
+	rc = get_pwm_fan(BACKSIDE_FAN_PWM_INDEX);
+	if (rc < 0) {
+		printk(KERN_WARNING "Error %d reading backside fan !\n", rc);
+		/* XXX What do we do now ? */
+	} else
+		state->pwm = rc;
+	DBG("  current pwm: %d\n", state->pwm);
+
+	/* Get some sensor readings */
+	temp = i2c_smbus_read_byte_data(state->monitor, MAX6690_EXT_TEMP) << 16;
+	state->last_temp = temp;
+	DBG("  temp: %d.%03d, target: %d.%03d\n", FIX32TOPRINT(temp),
+	    FIX32TOPRINT(backside_params.input_target));
+
+	/* Store temperature and error in history array */
+	state->cur_sample = (state->cur_sample + 1) % BACKSIDE_PID_HISTORY_SIZE;
+	state->sample_history[state->cur_sample] = temp;
+	state->error_history[state->cur_sample] = temp - backside_params.input_target;
+	
+	/* If first loop, fill the history table */
+	if (state->first) {
+		for (i = 0; i < (BACKSIDE_PID_HISTORY_SIZE - 1); i++) {
+			state->cur_sample = (state->cur_sample + 1) %
+				BACKSIDE_PID_HISTORY_SIZE;
+			state->sample_history[state->cur_sample] = temp;
+			state->error_history[state->cur_sample] =
+				temp - backside_params.input_target;
+		}
+		state->first = 0;
+	}
+
+	/* Calculate the integral term */
+	sum = 0;
+	integral = 0;
+	for (i = 0; i < BACKSIDE_PID_HISTORY_SIZE; i++)
+		integral += state->error_history[i];
+	integral *= backside_params.interval;
+	DBG("  integral: %08x\n", integral);
+	integ_p = ((s64)backside_params.G_r) * (s64)integral;
+	DBG("   integ_p: %d\n", (int)(integ_p >> 36));
+	sum += integ_p;
+
+	/* Calculate the derivative term */
+	derivative = state->error_history[state->cur_sample] -
+		state->error_history[(state->cur_sample + BACKSIDE_PID_HISTORY_SIZE - 1)
+				    % BACKSIDE_PID_HISTORY_SIZE];
+	derivative /= backside_params.interval;
+	deriv_p = ((s64)backside_params.G_d) * (s64)derivative;
+	DBG("   deriv_p: %d\n", (int)(deriv_p >> 36));
+	sum += deriv_p;
+
+	/* Calculate the proportional term */
+	prop_p = ((s64)backside_params.G_p) * (s64)(state->error_history[state->cur_sample]);
+	DBG("   prop_p: %d\n", (int)(prop_p >> 36));
+	sum += prop_p;
+
+	/* Scale sum */
+	sum >>= 36;
+
+	DBG("   sum: %d\n", (int)sum);
+	if (backside_params.additive)
+		state->pwm += (s32)sum;
+	else
+		state->pwm = sum;
+
+	/* Check for clamp */
+	fan_min = (dimm_output_clamp * 100) / 14000;
+	fan_min = max(fan_min, backside_params.output_min);
+
+	state->pwm = max(state->pwm, fan_min);
+	state->pwm = min(state->pwm, backside_params.output_max);
+
+	DBG("** BACKSIDE PWM: %d\n", (int)state->pwm);
+	set_pwm_fan(BACKSIDE_FAN_PWM_INDEX, state->pwm);
+}
+
+/*
+ * Initialize the state structure for the backside fan control loop
+ */
+static int init_backside_state(struct backside_pid_state *state)
+{
+	struct device_node *u3;
+	int u3h = 1; /* conservative by default */
+
+	/*
+	 * There are different PID params for machines with U3 and machines
+	 * with U3H, pick the right ones now
+	 */
+	u3 = of_find_node_by_path("/u3@0,f8000000");
+	if (u3 != NULL) {
+		u32 *vers = (u32 *)get_property(u3, "device-rev", NULL);
+		if (vers)
+			if (((*vers) & 0x3f) < 0x34)
+				u3h = 0;
+		of_node_put(u3);
+	}
+
+	if (rackmac) {
+		backside_params.G_d = BACKSIDE_PID_RACK_G_d;
+		backside_params.input_target = BACKSIDE_PID_RACK_INPUT_TARGET;
+		backside_params.output_min = BACKSIDE_PID_U3H_OUTPUT_MIN;
+		backside_params.interval = BACKSIDE_PID_RACK_INTERVAL;
+		backside_params.G_p = BACKSIDE_PID_RACK_G_p;
+		backside_params.G_r = BACKSIDE_PID_G_r;
+		backside_params.output_max = BACKSIDE_PID_OUTPUT_MAX;
+		backside_params.additive = 0;
+	} else if (u3h) {
+		backside_params.G_d = BACKSIDE_PID_U3H_G_d;
+		backside_params.input_target = BACKSIDE_PID_U3H_INPUT_TARGET;
+		backside_params.output_min = BACKSIDE_PID_U3H_OUTPUT_MIN;
+		backside_params.interval = BACKSIDE_PID_INTERVAL;
+		backside_params.G_p = BACKSIDE_PID_G_p;
+		backside_params.G_r = BACKSIDE_PID_G_r;
+		backside_params.output_max = BACKSIDE_PID_OUTPUT_MAX;
+		backside_params.additive = 1;
+	} else {
+		backside_params.G_d = BACKSIDE_PID_U3_G_d;
+		backside_params.input_target = BACKSIDE_PID_U3_INPUT_TARGET;
+		backside_params.output_min = BACKSIDE_PID_U3_OUTPUT_MIN;
+		backside_params.interval = BACKSIDE_PID_INTERVAL;
+		backside_params.G_p = BACKSIDE_PID_G_p;
+		backside_params.G_r = BACKSIDE_PID_G_r;
+		backside_params.output_max = BACKSIDE_PID_OUTPUT_MAX;
+		backside_params.additive = 1;
+	}
+
+	state->ticks = 1;
+	state->first = 1;
+	state->pwm = 50;
+
+	state->monitor = attach_i2c_chip(BACKSIDE_MAX_ID, "backside_temp");
+	if (state->monitor == NULL)
+		return -ENODEV;
+
+	device_create_file(&of_dev->dev, &dev_attr_backside_temperature);
+	device_create_file(&of_dev->dev, &dev_attr_backside_fan_pwm);
+
+	return 0;
+}
+
+/*
+ * Dispose of the state data for the backside control loop
+ */
+static void dispose_backside_state(struct backside_pid_state *state)
+{
+	if (state->monitor == NULL)
+		return;
+
+	device_remove_file(&of_dev->dev, &dev_attr_backside_temperature);
+	device_remove_file(&of_dev->dev, &dev_attr_backside_fan_pwm);
+
+	detach_i2c_chip(state->monitor);
+	state->monitor = NULL;
+}
+ 
+/*
+ * Drives bay fan control loop
+ */
+static void do_monitor_drives(struct drives_pid_state *state)
+{
+	s32 temp, integral, derivative;
+	s64 integ_p, deriv_p, prop_p, sum; 
+	int i, rc;
+
+	if (--state->ticks != 0)
+		return;
+	state->ticks = DRIVES_PID_INTERVAL;
+
+	DBG("drives:\n");
+
+	/* Check fan status */
+	rc = get_rpm_fan(DRIVES_FAN_RPM_INDEX, !RPM_PID_USE_ACTUAL_SPEED);
+	if (rc < 0) {
+		printk(KERN_WARNING "Error %d reading drives fan !\n", rc);
+		/* XXX What do we do now ? */
+	} else
+		state->rpm = rc;
+	DBG("  current rpm: %d\n", state->rpm);
+
+	/* Get some sensor readings */
+	temp = le16_to_cpu(i2c_smbus_read_word_data(state->monitor, DS1775_TEMP)) << 8;
+	state->last_temp = temp;
+	DBG("  temp: %d.%03d, target: %d.%03d\n", FIX32TOPRINT(temp),
+	    FIX32TOPRINT(DRIVES_PID_INPUT_TARGET));
+
+	/* Store temperature and error in history array */
+	state->cur_sample = (state->cur_sample + 1) % DRIVES_PID_HISTORY_SIZE;
+	state->sample_history[state->cur_sample] = temp;
+	state->error_history[state->cur_sample] = temp - DRIVES_PID_INPUT_TARGET;
+	
+	/* If first loop, fill the history table */
+	if (state->first) {
+		for (i = 0; i < (DRIVES_PID_HISTORY_SIZE - 1); i++) {
+			state->cur_sample = (state->cur_sample + 1) %
+				DRIVES_PID_HISTORY_SIZE;
+			state->sample_history[state->cur_sample] = temp;
+			state->error_history[state->cur_sample] =
+				temp - DRIVES_PID_INPUT_TARGET;
+		}
+		state->first = 0;
+	}
+
+	/* Calculate the integral term */
+	sum = 0;
+	integral = 0;
+	for (i = 0; i < DRIVES_PID_HISTORY_SIZE; i++)
+		integral += state->error_history[i];
+	integral *= DRIVES_PID_INTERVAL;
+	DBG("  integral: %08x\n", integral);
+	integ_p = ((s64)DRIVES_PID_G_r) * (s64)integral;
+	DBG("   integ_p: %d\n", (int)(integ_p >> 36));
+	sum += integ_p;
+
+	/* Calculate the derivative term */
+	derivative = state->error_history[state->cur_sample] -
+		state->error_history[(state->cur_sample + DRIVES_PID_HISTORY_SIZE - 1)
+				    % DRIVES_PID_HISTORY_SIZE];
+	derivative /= DRIVES_PID_INTERVAL;
+	deriv_p = ((s64)DRIVES_PID_G_d) * (s64)derivative;
+	DBG("   deriv_p: %d\n", (int)(deriv_p >> 36));
+	sum += deriv_p;
+
+	/* Calculate the proportional term */
+	prop_p = ((s64)DRIVES_PID_G_p) * (s64)(state->error_history[state->cur_sample]);
+	DBG("   prop_p: %d\n", (int)(prop_p >> 36));
+	sum += prop_p;
+
+	/* Scale sum */
+	sum >>= 36;
+
+	DBG("   sum: %d\n", (int)sum);
+	state->rpm += (s32)sum;
+
+	state->rpm = max(state->rpm, DRIVES_PID_OUTPUT_MIN);
+	state->rpm = min(state->rpm, DRIVES_PID_OUTPUT_MAX);
+
+	DBG("** DRIVES RPM: %d\n", (int)state->rpm);
+	set_rpm_fan(DRIVES_FAN_RPM_INDEX, state->rpm);
+}
+
+/*
+ * Initialize the state structure for the drives bay fan control loop
+ */
+static int init_drives_state(struct drives_pid_state *state)
+{
+	state->ticks = 1;
+	state->first = 1;
+	state->rpm = 1000;
+
+	state->monitor = attach_i2c_chip(DRIVES_DALLAS_ID, "drives_temp");
+	if (state->monitor == NULL)
+		return -ENODEV;
+
+	device_create_file(&of_dev->dev, &dev_attr_drives_temperature);
+	device_create_file(&of_dev->dev, &dev_attr_drives_fan_rpm);
+
+	return 0;
+}
+
+/*
+ * Dispose of the state data for the drives control loop
+ */
+static void dispose_drives_state(struct drives_pid_state *state)
+{
+	if (state->monitor == NULL)
+		return;
+
+	device_remove_file(&of_dev->dev, &dev_attr_drives_temperature);
+	device_remove_file(&of_dev->dev, &dev_attr_drives_fan_rpm);
+
+	detach_i2c_chip(state->monitor);
+	state->monitor = NULL;
+}
+
+/*
+ * DIMMs temp control loop
+ */
+static void do_monitor_dimms(struct dimm_pid_state *state)
+{
+	s32 temp, integral, derivative, fan_min;
+	s64 integ_p, deriv_p, prop_p, sum;
+	int i;
+
+	if (--state->ticks != 0)
+		return;
+	state->ticks = DIMM_PID_INTERVAL;
+
+	DBG("DIMM:\n");
+
+	DBG("  current value: %d\n", state->output);
+
+	temp = read_lm87_reg(state->monitor, LM87_INT_TEMP);
+	if (temp < 0)
+		return;
+	temp <<= 16;
+	state->last_temp = temp;
+	DBG("  temp: %d.%03d, target: %d.%03d\n", FIX32TOPRINT(temp),
+	    FIX32TOPRINT(DIMM_PID_INPUT_TARGET));
+
+	/* Store temperature and error in history array */
+	state->cur_sample = (state->cur_sample + 1) % DIMM_PID_HISTORY_SIZE;
+	state->sample_history[state->cur_sample] = temp;
+	state->error_history[state->cur_sample] = temp - DIMM_PID_INPUT_TARGET;
+
+	/* If first loop, fill the history table */
+	if (state->first) {
+		for (i = 0; i < (DIMM_PID_HISTORY_SIZE - 1); i++) {
+			state->cur_sample = (state->cur_sample + 1) %
+				DIMM_PID_HISTORY_SIZE;
+			state->sample_history[state->cur_sample] = temp;
+			state->error_history[state->cur_sample] =
+				temp - DIMM_PID_INPUT_TARGET;
+		}
+		state->first = 0;
+	}
+
+	/* Calculate the integral term */
+	sum = 0;
+	integral = 0;
+	for (i = 0; i < DIMM_PID_HISTORY_SIZE; i++)
+		integral += state->error_history[i];
+	integral *= DIMM_PID_INTERVAL;
+	DBG("  integral: %08x\n", integral);
+	integ_p = ((s64)DIMM_PID_G_r) * (s64)integral;
+	DBG("   integ_p: %d\n", (int)(integ_p >> 36));
+	sum += integ_p;
+
+	/* Calculate the derivative term */
+	derivative = state->error_history[state->cur_sample] -
+		state->error_history[(state->cur_sample + DIMM_PID_HISTORY_SIZE - 1)
+				    % DIMM_PID_HISTORY_SIZE];
+	derivative /= DIMM_PID_INTERVAL;
+	deriv_p = ((s64)DIMM_PID_G_d) * (s64)derivative;
+	DBG("   deriv_p: %d\n", (int)(deriv_p >> 36));
+	sum += deriv_p;
+
+	/* Calculate the proportional term */
+	prop_p = ((s64)DIMM_PID_G_p) * (s64)(state->error_history[state->cur_sample]);
+	DBG("   prop_p: %d\n", (int)(prop_p >> 36));
+	sum += prop_p;
+
+	/* Scale sum */
+	sum >>= 36;
+
+	DBG("   sum: %d\n", (int)sum);
+	state->output = (s32)sum;
+	state->output = max(state->output, DIMM_PID_OUTPUT_MIN);
+	state->output = min(state->output, DIMM_PID_OUTPUT_MAX);
+	dimm_output_clamp = state->output;
+
+	DBG("** DIMM clamp value: %d\n", (int)state->output);
+
+	/* Backside PID is only every 5 seconds, force backside fan clamping now */
+	fan_min = (dimm_output_clamp * 100) / 14000;
+	fan_min = max(fan_min, backside_params.output_min);
+	if (backside_state.pwm < fan_min) {
+		backside_state.pwm = fan_min;
+		DBG(" -> applying clamp to backside fan now: %d  !\n", fan_min);
+		set_pwm_fan(BACKSIDE_FAN_PWM_INDEX, fan_min);
+	}
+}
+
+/*
+ * Initialize the state structure for the DIMM temp control loop
+ */
+static int init_dimms_state(struct dimm_pid_state *state)
+{
+	state->ticks = 1;
+	state->first = 1;
+	state->output = 4000;
+
+	state->monitor = attach_i2c_chip(XSERVE_DIMMS_LM87, "dimms_temp");
+	if (state->monitor == NULL)
+		return -ENODEV;
+
+       	device_create_file(&of_dev->dev, &dev_attr_dimms_temperature);
+
+	return 0;
+}
+
+/*
+ * Dispose of the state data for the drives control loop
+ */
+static void dispose_dimms_state(struct dimm_pid_state *state)
+{
+	if (state->monitor == NULL)
+		return;
+
+	device_remove_file(&of_dev->dev, &dev_attr_dimms_temperature);
+
+	detach_i2c_chip(state->monitor);
+	state->monitor = NULL;
+}
+
+static int call_critical_overtemp(void)
+{
+	char *argv[] = { critical_overtemp_path, NULL };
+	static char *envp[] = { "HOME=/",
+				"TERM=linux",
+				"PATH=/sbin:/usr/sbin:/bin:/usr/bin",
+				NULL };
+
+	return call_usermodehelper(critical_overtemp_path, argv, envp, 0);
+}
+
+
+/*
+ * Here's the kernel thread that calls the various control loops
+ */
+static int main_control_loop(void *x)
+{
+	daemonize("kfand");
+
+	DBG("main_control_loop started\n");
+
+	down(&driver_lock);
+
+	if (start_fcu() < 0) {
+		printk(KERN_ERR "kfand: failed to start FCU\n");
+		up(&driver_lock);
+		goto out;
+	}
+
+	/* Set the PCI fan once for now */
+	set_pwm_fan(SLOTS_FAN_PWM_INDEX, SLOTS_FAN_DEFAULT_PWM);
+
+	/* Initialize ADCs */
+	initialize_adc(&cpu_state[0]);
+	if (cpu_state[1].monitor != NULL)
+		initialize_adc(&cpu_state[1]);
+
+	up(&driver_lock);
+
+	while (state == state_attached) {
+		unsigned long elapsed, start;
+
+		start = jiffies;
+
+		down(&driver_lock);
+
+		/* First, we always calculate the new DIMMs state on an Xserve */
+		if (rackmac)
+			do_monitor_dimms(&dimms_state);
+
+		/* Then, the CPUs */
+		if (cpu_pid_type == CPU_PID_TYPE_COMBINED)
+			do_monitor_cpu_combined();
+		else if (cpu_pid_type == CPU_PID_TYPE_RACKMAC) {
+			do_monitor_cpu_rack(&cpu_state[0]);
+			if (cpu_state[1].monitor != NULL)
+				do_monitor_cpu_rack(&cpu_state[1]);
+			// better deal with UP
+		} else {
+			do_monitor_cpu_split(&cpu_state[0]);
+			if (cpu_state[1].monitor != NULL)
+				do_monitor_cpu_split(&cpu_state[1]);
+			// better deal with UP
+		}
+		/* Then, the rest */
+		do_monitor_backside(&backside_state);
+		if (!rackmac)
+			do_monitor_drives(&drives_state);
+		up(&driver_lock);
+
+		if (critical_state == 1) {
+			printk(KERN_WARNING "Temperature control detected a critical condition\n");
+			printk(KERN_WARNING "Attempting to shut down...\n");
+			if (call_critical_overtemp()) {
+				printk(KERN_WARNING "Can't call %s, power off now!\n",
+				       critical_overtemp_path);
+				machine_power_off();
+			}
+		}
+		if (critical_state > 0)
+			critical_state++;
+		if (critical_state > MAX_CRITICAL_STATE) {
+			printk(KERN_WARNING "Shutdown timed out, power off now !\n");
+			machine_power_off();
+		}
+
+		// FIXME: Deal with signals
+		set_current_state(TASK_INTERRUPTIBLE);
+		elapsed = jiffies - start;
+		if (elapsed < HZ)
+			schedule_timeout(HZ - elapsed);
+	}
+
+ out:
+	DBG("main_control_loop ended\n");
+
+	ctrl_task = 0;
+	complete_and_exit(&ctrl_complete, 0);
+}
+
+/*
+ * Dispose the control loops when tearing down
+ */
+static void dispose_control_loops(void)
+{
+	dispose_cpu_state(&cpu_state[0]);
+	dispose_cpu_state(&cpu_state[1]);
+	dispose_backside_state(&backside_state);
+	dispose_drives_state(&drives_state);
+	dispose_dimms_state(&dimms_state);
+}
+
+/*
+ * Create the control loops. U3-0 i2c bus is up, so we can now
+ * get to the various sensors
+ */
+static int create_control_loops(void)
+{
+	struct device_node *np;
+
+	/* Count CPUs from the device-tree, we don't care how many are
+	 * actually used by Linux
+	 */
+	cpu_count = 0;
+	for (np = NULL; NULL != (np = of_find_node_by_type(np, "cpu"));)
+		cpu_count++;
+
+	DBG("counted %d CPUs in the device-tree\n", cpu_count);
+
+	/* Decide the type of PID algorithm to use based on the presence of
+	 * the pumps, though that may not be the best way, that is good enough
+	 * for now
+	 */
+	if (rackmac)
+		cpu_pid_type = CPU_PID_TYPE_RACKMAC;
+	else if (machine_is_compatible("PowerMac7,3")
+	    && (cpu_count > 1)
+	    && fcu_fans[CPUA_PUMP_RPM_INDEX].id != FCU_FAN_ABSENT_ID
+	    && fcu_fans[CPUB_PUMP_RPM_INDEX].id != FCU_FAN_ABSENT_ID) {
+		printk(KERN_INFO "Liquid cooling pumps detected, using new algorithm !\n");
+		cpu_pid_type = CPU_PID_TYPE_COMBINED;
+	} else
+		cpu_pid_type = CPU_PID_TYPE_SPLIT;
+
+	/* Create control loops for everything. If any fail, everything
+	 * fails
+	 */
+	if (init_cpu_state(&cpu_state[0], 0))
+		goto fail;
+	if (cpu_pid_type == CPU_PID_TYPE_COMBINED)
+		fetch_cpu_pumps_minmax();
+
+	if (cpu_count > 1 && init_cpu_state(&cpu_state[1], 1))
+		goto fail;
+	if (init_backside_state(&backside_state))
+		goto fail;
+	if (rackmac && init_dimms_state(&dimms_state))
+		goto fail;
+	if (!rackmac && init_drives_state(&drives_state))
+		goto fail;
+
+	DBG("all control loops up !\n");
+
+	return 0;
+	
+ fail:
+	DBG("failure creating control loops, disposing\n");
+
+	dispose_control_loops();
+
+	return -ENODEV;
+}
+
+/*
+ * Start the control loops after everything is up, that is create
+ * the thread that will make them run
+ */
+static void start_control_loops(void)
+{
+	init_completion(&ctrl_complete);
+
+	ctrl_task = kernel_thread(main_control_loop, NULL, SIGCHLD | CLONE_KERNEL);
+}
+
+/*
+ * Stop the control loops when tearing down
+ */
+static void stop_control_loops(void)
+{
+	if (ctrl_task != 0)
+		wait_for_completion(&ctrl_complete);
+}
+
+/*
+ * Attach to the i2c FCU after detecting U3-1 bus
+ */
+static int attach_fcu(void)
+{
+	fcu = attach_i2c_chip(FAN_CTRLER_ID, "fcu");
+	if (fcu == NULL)
+		return -ENODEV;
+
+	DBG("FCU attached\n");
+
+	return 0;
+}
+
+/*
+ * Detach from the i2c FCU when tearing down
+ */
+static void detach_fcu(void)
+{
+	if (fcu)
+		detach_i2c_chip(fcu);
+	fcu = NULL;
+}
+
+/*
+ * Attach to the i2c controller. We probe the various chips based
+ * on the device-tree nodes and build everything for the driver to
+ * run, we then kick the driver monitoring thread
+ */
+static int therm_pm72_attach(struct i2c_adapter *adapter)
+{
+	down(&driver_lock);
+
+	/* Check state */
+	if (state == state_detached)
+		state = state_attaching;
+	if (state != state_attaching) {
+		up(&driver_lock);
+		return 0;
+	}
+
+	/* Check if we are looking for one of these */
+	if (u3_0 == NULL && !strcmp(adapter->name, "u3 0")) {
+		u3_0 = adapter;
+		DBG("found U3-0\n");
+		if (k2 || !rackmac)
+			if (create_control_loops())
+				u3_0 = NULL;
+	} else if (u3_1 == NULL && !strcmp(adapter->name, "u3 1")) {
+		u3_1 = adapter;
+		DBG("found U3-1, attaching FCU\n");
+		if (attach_fcu())
+			u3_1 = NULL;
+	} else if (k2 == NULL && !strcmp(adapter->name, "mac-io 0")) {
+		k2 = adapter;
+		DBG("Found K2\n");
+		if (u3_0 && rackmac)
+			if (create_control_loops())
+				k2 = NULL;
+	}
+	/* We got all we need, start control loops */
+	if (u3_0 != NULL && u3_1 != NULL && (k2 || !rackmac)) {
+		DBG("everything up, starting control loops\n");
+		state = state_attached;
+		start_control_loops();
+	}
+	up(&driver_lock);
+
+	return 0;
+}
+
+/*
+ * Called on every adapter when the driver or the i2c controller
+ * is going away.
+ */
+static int therm_pm72_detach(struct i2c_adapter *adapter)
+{
+	down(&driver_lock);
+
+	if (state != state_detached)
+		state = state_detaching;
+
+	/* Stop control loops if any */
+	DBG("stopping control loops\n");
+	up(&driver_lock);
+	stop_control_loops();
+	down(&driver_lock);
+
+	if (u3_0 != NULL && !strcmp(adapter->name, "u3 0")) {
+		DBG("lost U3-0, disposing control loops\n");
+		dispose_control_loops();
+		u3_0 = NULL;
+	}
+	
+	if (u3_1 != NULL && !strcmp(adapter->name, "u3 1")) {
+		DBG("lost U3-1, detaching FCU\n");
+		detach_fcu();
+		u3_1 = NULL;
+	}
+	if (u3_0 == NULL && u3_1 == NULL)
+		state = state_detached;
+
+	up(&driver_lock);
+
+	return 0;
+}
+
+static int fan_check_loc_match(const char *loc, int fan)
+{
+	char	tmp[64];
+	char	*c, *e;
+
+	strlcpy(tmp, fcu_fans[fan].loc, 64);
+
+	c = tmp;
+	for (;;) {
+		e = strchr(c, ',');
+		if (e)
+			*e = 0;
+		if (strcmp(loc, c) == 0)
+			return 1;
+		if (e == NULL)
+			break;
+		c = e + 1;
+	}
+	return 0;
+}
+
+static void fcu_lookup_fans(struct device_node *fcu_node)
+{
+	struct device_node *np = NULL;
+	int i;
+
+	/* The table is filled by default with values that are suitable
+	 * for the old machines without device-tree informations. We scan
+	 * the device-tree and override those values with whatever is
+	 * there
+	 */
+
+	DBG("Looking up FCU controls in device-tree...\n");
+
+	while ((np = of_get_next_child(fcu_node, np)) != NULL) {
+		int type = -1;
+		char *loc;
+		u32 *reg;
+
+		DBG(" control: %s, type: %s\n", np->name, np->type);
+
+		/* Detect control type */
+		if (!strcmp(np->type, "fan-rpm-control") ||
+		    !strcmp(np->type, "fan-rpm"))
+			type = FCU_FAN_RPM;
+		if (!strcmp(np->type, "fan-pwm-control") ||
+		    !strcmp(np->type, "fan-pwm"))
+			type = FCU_FAN_PWM;
+		/* Only care about fans for now */
+		if (type == -1)
+			continue;
+
+		/* Lookup for a matching location */
+		loc = (char *)get_property(np, "location", NULL);
+		reg = (u32 *)get_property(np, "reg", NULL);
+		if (loc == NULL || reg == NULL)
+			continue;
+		DBG(" matching location: %s, reg: 0x%08x\n", loc, *reg);
+
+		for (i = 0; i < FCU_FAN_COUNT; i++) {
+			int fan_id;
+
+			if (!fan_check_loc_match(loc, i))
+				continue;
+			DBG(" location match, index: %d\n", i);
+			fcu_fans[i].id = FCU_FAN_ABSENT_ID;
+			if (type != fcu_fans[i].type) {
+				printk(KERN_WARNING "therm_pm72: Fan type mismatch "
+				       "in device-tree for %s\n", np->full_name);
+				break;
+			}
+			if (type == FCU_FAN_RPM)
+				fan_id = ((*reg) - 0x10) / 2;
+			else
+				fan_id = ((*reg) - 0x30) / 2;
+			if (fan_id > 7) {
+				printk(KERN_WARNING "therm_pm72: Can't parse "
+				       "fan ID in device-tree for %s\n", np->full_name);
+				break;
+			}
+			DBG(" fan id -> %d, type -> %d\n", fan_id, type);
+			fcu_fans[i].id = fan_id;
+		}
+	}
+
+	/* Now dump the array */
+	printk(KERN_INFO "Detected fan controls:\n");
+	for (i = 0; i < FCU_FAN_COUNT; i++) {
+		if (fcu_fans[i].id == FCU_FAN_ABSENT_ID)
+			continue;
+		printk(KERN_INFO "  %d: %s fan, id %d, location: %s\n", i,
+		       fcu_fans[i].type == FCU_FAN_RPM ? "RPM" : "PWM",
+		       fcu_fans[i].id, fcu_fans[i].loc);
+	}
+}
+
+static int fcu_of_probe(struct of_device* dev, const struct of_match *match)
+{
+	int rc;
+
+	state = state_detached;
+
+	/* Lookup the fans in the device tree */
+	fcu_lookup_fans(dev->node);
+
+	/* Add the driver */
+	rc = i2c_add_driver(&therm_pm72_driver);
+	if (rc < 0)
+		return rc;
+	return 0;
+}
+
+static int fcu_of_remove(struct of_device* dev)
+{
+	i2c_del_driver(&therm_pm72_driver);
+
+	return 0;
+}
+
+static struct of_match fcu_of_match[] = 
+{
+	{
+	.name 		= OF_ANY_MATCH,
+	.type		= "fcu",
+	.compatible	= OF_ANY_MATCH
+	},
+	{},
+};
+
+static struct of_platform_driver fcu_of_platform_driver = 
+{
+	.name 		= "temperature",
+	.match_table	= fcu_of_match,
+	.probe		= fcu_of_probe,
+	.remove		= fcu_of_remove
+};
+
+/*
+ * Check machine type, attach to i2c controller
+ */
+static int __init therm_pm72_init(void)
+{
+	struct device_node *np;
+
+	rackmac = machine_is_compatible("RackMac3,1");
+
+	if (!machine_is_compatible("PowerMac7,2") &&
+	    !machine_is_compatible("PowerMac7,3") &&
+	    !rackmac)
+	    	return -ENODEV;
+
+	printk(KERN_INFO "PowerMac G5 Thermal control driver %s\n", VERSION);
+
+	np = of_find_node_by_type(NULL, "fcu");
+	if (np == NULL) {
+		/* Some machines have strangely broken device-tree */
+		np = of_find_node_by_path("/u3@0,f8000000/i2c@f8001000/fan@15e");
+		if (np == NULL) {
+			    printk(KERN_ERR "Can't find FCU in device-tree !\n");
+			    return -ENODEV;
+		}
+	}
+	of_dev = of_platform_device_create(np, "temperature");
+	if (of_dev == NULL) {
+		printk(KERN_ERR "Can't register FCU platform device !\n");
+		return -ENODEV;
+	}
+
+	of_register_driver(&fcu_of_platform_driver);
+	
+	return 0;
+}
+
+static void __exit therm_pm72_exit(void)
+{
+	of_unregister_driver(&fcu_of_platform_driver);
+
+	if (of_dev)
+		of_device_unregister(of_dev);
+}
+
+module_init(therm_pm72_init);
+module_exit(therm_pm72_exit);
+
+MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
+MODULE_DESCRIPTION("Driver for Apple's PowerMac G5 thermal control");
+MODULE_LICENSE("GPL");
+