drivers/macintosh/windfarm_smu_sat.c - arm/linux-arm64-legacy - Git at Google

 /*
  * Windfarm PowerMac thermal control.  SMU "satellite" controller sensors.
  *
  * Copyright (C) 2005 Paul Mackerras, IBM Corp. <paulus@samba.org>
  *
  * Released under the terms of the GNU GPL v2.
  */

 #include <linux/types.h>
 #include <linux/errno.h>
 #include <linux/kernel.h>
 #include <linux/slab.h>
 #include <linux/init.h>
 #include <linux/wait.h>
 #include <linux/i2c.h>
 #include <asm/semaphore.h>
 #include <asm/prom.h>
 #include <asm/smu.h>
 #include <asm/pmac_low_i2c.h>

 #include "windfarm.h"

 #define VERSION "0.2"

 #define DEBUG

 #ifdef DEBUG
 #define DBG(args...)	printk(args)
 #else
 #define DBG(args...)	do { } while(0)
 #endif

 /* If the cache is older than 800ms we'll refetch it */
 #define MAX_AGE		msecs_to_jiffies(800)

 struct wf_sat {
 	int			nr;
 	atomic_t		refcnt;
 	struct semaphore	mutex;
 	unsigned long		last_read; /* jiffies when cache last updated */
 	u8			cache[16];
 	struct i2c_client	i2c;
 	struct device_node	*node;
 };

 static struct wf_sat *sats[2];

 struct wf_sat_sensor {
 	int		index;
 	int		index2;		/* used for power sensors */
 	int		shift;
 	struct wf_sat	*sat;
 	struct wf_sensor sens;
 };

 #define wf_to_sat(c)	container_of(c, struct wf_sat_sensor, sens)
 #define i2c_to_sat(c)	container_of(c, struct wf_sat, i2c)

 static int wf_sat_attach(struct i2c_adapter *adapter);
 static int wf_sat_detach(struct i2c_client *client);

 static struct i2c_driver wf_sat_driver = {
 	.driver = {
 		.name		= "wf_smu_sat",
 	},
 	.attach_adapter	= wf_sat_attach,
 	.detach_client	= wf_sat_detach,
 };

 /*
  * XXX i2c_smbus_read_i2c_block_data doesn't pass the requested
  * length down to the low-level driver, so we use this, which
  * works well enough with the SMU i2c driver code...
  */
 static int sat_read_block(struct i2c_client *client, u8 command,
 			  u8 *values, int len)
 {
 	union i2c_smbus_data data;
 	int err;

 	data.block[0] = len;
 	err = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
 			     I2C_SMBUS_READ, command, I2C_SMBUS_I2C_BLOCK_DATA,
 			     &data);
 	if (!err)
 		memcpy(values, data.block, len);
 	return err;
 }

 struct smu_sdbp_header *smu_sat_get_sdb_partition(unsigned int sat_id, int id,
 						  unsigned int *size)
 {
 	struct wf_sat *sat;
 	int err;
 	unsigned int i, len;
 	u8 *buf;
 	u8 data[4];

 	/* TODO: Add the resulting partition to the device-tree */

 	if (sat_id > 1 || (sat = sats[sat_id]) == NULL)
 		return NULL;

 	err = i2c_smbus_write_word_data(&sat->i2c, 8, id << 8);
 	if (err) {
 		printk(KERN_ERR "smu_sat_get_sdb_part wr error %d\n", err);
 		return NULL;
 	}

 	len = i2c_smbus_read_word_data(&sat->i2c, 9);
 	if (len < 0) {
 		printk(KERN_ERR "smu_sat_get_sdb_part rd len error\n");
 		return NULL;
 	}
 	if (len == 0) {
 		printk(KERN_ERR "smu_sat_get_sdb_part no partition %x\n", id);
 		return NULL;
 	}

 	len = le16_to_cpu(len);
 	len = (len + 3) & ~3;
 	buf = kmalloc(len, GFP_KERNEL);
 	if (buf == NULL)
 		return NULL;

 	for (i = 0; i < len; i += 4) {
 		err = sat_read_block(&sat->i2c, 0xa, data, 4);
 		if (err) {
 			printk(KERN_ERR "smu_sat_get_sdb_part rd err %d\n",
 			       err);
 			goto fail;
 		}
 		buf[i] = data[1];
 		buf[i+1] = data[0];
 		buf[i+2] = data[3];
 		buf[i+3] = data[2];
 	}
 #ifdef DEBUG
 	DBG(KERN_DEBUG "sat %d partition %x:", sat_id, id);
 	for (i = 0; i < len; ++i)
 		DBG(" %x", buf[i]);
 	DBG("\n");
 #endif

 	if (size)
 		*size = len;
 	return (struct smu_sdbp_header *) buf;

  fail:
 	kfree(buf);
 	return NULL;
 }
 EXPORT_SYMBOL_GPL(smu_sat_get_sdb_partition);

 /* refresh the cache */
 static int wf_sat_read_cache(struct wf_sat *sat)
 {
 	int err;

 	err = sat_read_block(&sat->i2c, 0x3f, sat->cache, 16);
 	if (err)
 		return err;
 	sat->last_read = jiffies;
 #ifdef LOTSA_DEBUG
 	{
 		int i;
 		DBG(KERN_DEBUG "wf_sat_get: data is");
 		for (i = 0; i < 16; ++i)
 			DBG(" %.2x", sat->cache[i]);
 		DBG("\n");
 	}
 #endif
 	return 0;
 }

 static int wf_sat_get(struct wf_sensor *sr, s32 *value)
 {
 	struct wf_sat_sensor *sens = wf_to_sat(sr);
 	struct wf_sat *sat = sens->sat;
 	int i, err;
 	s32 val;

 	if (sat->i2c.adapter == NULL)
 		return -ENODEV;

 	down(&sat->mutex);
 	if (time_after(jiffies, (sat->last_read + MAX_AGE))) {
 		err = wf_sat_read_cache(sat);
 		if (err)
 			goto fail;
 	}

 	i = sens->index * 2;
 	val = ((sat->cache[i] << 8) + sat->cache[i+1]) << sens->shift;
 	if (sens->index2 >= 0) {
 		i = sens->index2 * 2;
 		/* 4.12 * 8.8 -> 12.20; shift right 4 to get 16.16 */
 		val = (val * ((sat->cache[i] << 8) + sat->cache[i+1])) >> 4;
 	}

 	*value = val;
 	err = 0;

  fail:
 	up(&sat->mutex);
 	return err;
 }

 static void wf_sat_release(struct wf_sensor *sr)
 {
 	struct wf_sat_sensor *sens = wf_to_sat(sr);
 	struct wf_sat *sat = sens->sat;

 	if (atomic_dec_and_test(&sat->refcnt)) {
 		if (sat->i2c.adapter) {
 			i2c_detach_client(&sat->i2c);
 			sat->i2c.adapter = NULL;
 		}
 		if (sat->nr >= 0)
 			sats[sat->nr] = NULL;
 		kfree(sat);
 	}
 	kfree(sens);
 }

 static struct wf_sensor_ops wf_sat_ops = {
 	.get_value	= wf_sat_get,
 	.release	= wf_sat_release,
 	.owner		= THIS_MODULE,
 };

 static void wf_sat_create(struct i2c_adapter *adapter, struct device_node *dev)
 {
 	struct wf_sat *sat;
 	struct wf_sat_sensor *sens;
 	const u32 *reg;
 	const char *loc, *type;
 	u8 addr, chip, core;
 	struct device_node *child;
 	int shift, cpu, index;
 	char *name;
 	int vsens[2], isens[2];

 	reg = of_get_property(dev, "reg", NULL);
 	if (reg == NULL)
 		return;
 	addr = *reg;
 	DBG(KERN_DEBUG "wf_sat: creating sat at address %x\n", addr);

 	sat = kzalloc(sizeof(struct wf_sat), GFP_KERNEL);
 	if (sat == NULL)
 		return;
 	sat->nr = -1;
 	sat->node = of_node_get(dev);
 	atomic_set(&sat->refcnt, 0);
 	init_MUTEX(&sat->mutex);
 	sat->i2c.addr = (addr >> 1) & 0x7f;
 	sat->i2c.adapter = adapter;
 	sat->i2c.driver = &wf_sat_driver;
 	strncpy(sat->i2c.name, "smu-sat", I2C_NAME_SIZE-1);

 	if (i2c_attach_client(&sat->i2c)) {
 		printk(KERN_ERR "windfarm: failed to attach smu-sat to i2c\n");
 		goto fail;
 	}

 	vsens[0] = vsens[1] = -1;
 	isens[0] = isens[1] = -1;
 	child = NULL;
 	while ((child = of_get_next_child(dev, child)) != NULL) {
 		reg = of_get_property(child, "reg", NULL);
 		type = of_get_property(child, "device_type", NULL);
 		loc = of_get_property(child, "location", NULL);
 		if (reg == NULL || loc == NULL)
 			continue;

 		/* the cooked sensors are between 0x30 and 0x37 */
 		if (*reg < 0x30 || *reg > 0x37)
 			continue;
 		index = *reg - 0x30;

 		/* expect location to be CPU [AB][01] ... */
 		if (strncmp(loc, "CPU ", 4) != 0)
 			continue;
 		chip = loc[4] - 'A';
 		core = loc[5] - '0';
 		if (chip > 1 || core > 1) {
 			printk(KERN_ERR "wf_sat_create: don't understand "
 			       "location %s for %s\n", loc, child->full_name);
 			continue;
 		}
 		cpu = 2 * chip + core;
 		if (sat->nr < 0)
 			sat->nr = chip;
 		else if (sat->nr != chip) {
 			printk(KERN_ERR "wf_sat_create: can't cope with "
 			       "multiple CPU chips on one SAT (%s)\n", loc);
 			continue;
 		}

 		if (strcmp(type, "voltage-sensor") == 0) {
 			name = "cpu-voltage";
 			shift = 4;
 			vsens[core] = index;
 		} else if (strcmp(type, "current-sensor") == 0) {
 			name = "cpu-current";
 			shift = 8;
 			isens[core] = index;
 		} else if (strcmp(type, "temp-sensor") == 0) {
 			name = "cpu-temp";
 			shift = 10;
 		} else
 			continue;	/* hmmm shouldn't happen */

 		/* the +16 is enough for "cpu-voltage-n" */
 		sens = kzalloc(sizeof(struct wf_sat_sensor) + 16, GFP_KERNEL);
 		if (sens == NULL) {
 			printk(KERN_ERR "wf_sat_create: couldn't create "
 			       "%s sensor %d (no memory)\n", name, cpu);
 			continue;
 		}
 		sens->index = index;
 		sens->index2 = -1;
 		sens->shift = shift;
 		sens->sat = sat;
 		atomic_inc(&sat->refcnt);
 		sens->sens.ops = &wf_sat_ops;
 		sens->sens.name = (char *) (sens + 1);
 		snprintf(sens->sens.name, 16, "%s-%d", name, cpu);

 		if (wf_register_sensor(&sens->sens)) {
 			atomic_dec(&sat->refcnt);
 			kfree(sens);
 		}
 	}

 	/* make the power sensors */
 	for (core = 0; core < 2; ++core) {
 		if (vsens[core] < 0 || isens[core] < 0)
 			continue;
 		cpu = 2 * sat->nr + core;
 		sens = kzalloc(sizeof(struct wf_sat_sensor) + 16, GFP_KERNEL);
 		if (sens == NULL) {
 			printk(KERN_ERR "wf_sat_create: couldn't create power "
 			       "sensor %d (no memory)\n", cpu);
 			continue;
 		}
 		sens->index = vsens[core];
 		sens->index2 = isens[core];
 		sens->shift = 0;
 		sens->sat = sat;
 		atomic_inc(&sat->refcnt);
 		sens->sens.ops = &wf_sat_ops;
 		sens->sens.name = (char *) (sens + 1);
 		snprintf(sens->sens.name, 16, "cpu-power-%d", cpu);

 		if (wf_register_sensor(&sens->sens)) {
 			atomic_dec(&sat->refcnt);
 			kfree(sens);
 		}
 	}

 	if (sat->nr >= 0)
 		sats[sat->nr] = sat;

 	return;

  fail:
 	kfree(sat);
 }

 static int wf_sat_attach(struct i2c_adapter *adapter)
 {
 	struct device_node *busnode, *dev = NULL;
 	struct pmac_i2c_bus *bus;

 	bus = pmac_i2c_adapter_to_bus(adapter);
 	if (bus == NULL)
 		return -ENODEV;
 	busnode = pmac_i2c_get_bus_node(bus);

 	while ((dev = of_get_next_child(busnode, dev)) != NULL)
 		if (device_is_compatible(dev, "smu-sat"))
 			wf_sat_create(adapter, dev);
 	return 0;
 }

 static int wf_sat_detach(struct i2c_client *client)
 {
 	struct wf_sat *sat = i2c_to_sat(client);

 	/* XXX TODO */

 	sat->i2c.adapter = NULL;
 	return 0;
 }

 static int __init sat_sensors_init(void)
 {
 	return i2c_add_driver(&wf_sat_driver);
 }

 static void __exit sat_sensors_exit(void)
 {
 	i2c_del_driver(&wf_sat_driver);
 }

 module_init(sat_sensors_init);
 /*module_exit(sat_sensors_exit); Uncomment when cleanup is implemented */

 MODULE_AUTHOR("Paul Mackerras <paulus@samba.org>");
 MODULE_DESCRIPTION("SMU satellite sensors for PowerMac thermal control");
 MODULE_LICENSE("GPL");
	/*
	* Windfarm PowerMac thermal control. SMU "satellite" controller sensors.
	*
	* Copyright (C) 2005 Paul Mackerras, IBM Corp. <paulus@samba.org>
	*
	* Released under the terms of the GNU GPL v2.
	*/

	#include <linux/types.h>
	#include <linux/errno.h>
	#include <linux/kernel.h>
	#include <linux/slab.h>
	#include <linux/init.h>
	#include <linux/wait.h>
	#include <linux/i2c.h>
	#include <asm/semaphore.h>
	#include <asm/prom.h>
	#include <asm/smu.h>
	#include <asm/pmac_low_i2c.h>

	#include "windfarm.h"

	#define VERSION "0.2"

	#define DEBUG

	#ifdef DEBUG
	#define DBG(args...) printk(args)
	#else
	#define DBG(args...) do { } while(0)
	#endif

	/* If the cache is older than 800ms we'll refetch it */
	#define MAX_AGE msecs_to_jiffies(800)

	struct wf_sat {
	int nr;
	atomic_t refcnt;
	struct semaphore mutex;
	unsigned long last_read; /* jiffies when cache last updated */
	u8 cache[16];
	struct i2c_client i2c;
	struct device_node *node;
	};

	static struct wf_sat *sats[2];

	struct wf_sat_sensor {
	int index;
	int index2; /* used for power sensors */
	int shift;
	struct wf_sat *sat;
	struct wf_sensor sens;
	};

	#define wf_to_sat(c) container_of(c, struct wf_sat_sensor, sens)
	#define i2c_to_sat(c) container_of(c, struct wf_sat, i2c)

	static int wf_sat_attach(struct i2c_adapter *adapter);
	static int wf_sat_detach(struct i2c_client *client);

	static struct i2c_driver wf_sat_driver = {
	.driver = {
	.name = "wf_smu_sat",
	},
	.attach_adapter = wf_sat_attach,
	.detach_client = wf_sat_detach,
	};

	/*
	* XXX i2c_smbus_read_i2c_block_data doesn't pass the requested
	* length down to the low-level driver, so we use this, which
	* works well enough with the SMU i2c driver code...
	*/
	static int sat_read_block(struct i2c_client *client, u8 command,
	u8 *values, int len)
	{
	union i2c_smbus_data data;
	int err;

	data.block[0] = len;
	err = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
	I2C_SMBUS_READ, command, I2C_SMBUS_I2C_BLOCK_DATA,
	&data);
	if (!err)
	memcpy(values, data.block, len);
	return err;
	}

	struct smu_sdbp_header *smu_sat_get_sdb_partition(unsigned int sat_id, int id,
	unsigned int *size)
	{
	struct wf_sat *sat;
	int err;
	unsigned int i, len;
	u8 *buf;
	u8 data[4];

	/* TODO: Add the resulting partition to the device-tree */

	if (sat_id > 1 \|\| (sat = sats[sat_id]) == NULL)
	return NULL;

	err = i2c_smbus_write_word_data(&sat->i2c, 8, id << 8);
	if (err) {
	printk(KERN_ERR "smu_sat_get_sdb_part wr error %d\n", err);
	return NULL;
	}

	len = i2c_smbus_read_word_data(&sat->i2c, 9);
	if (len < 0) {
	printk(KERN_ERR "smu_sat_get_sdb_part rd len error\n");
	return NULL;
	}
	if (len == 0) {
	printk(KERN_ERR "smu_sat_get_sdb_part no partition %x\n", id);
	return NULL;
	}

	len = le16_to_cpu(len);
	len = (len + 3) & ~3;
	buf = kmalloc(len, GFP_KERNEL);
	if (buf == NULL)
	return NULL;

	for (i = 0; i < len; i += 4) {
	err = sat_read_block(&sat->i2c, 0xa, data, 4);
	if (err) {
	printk(KERN_ERR "smu_sat_get_sdb_part rd err %d\n",
	err);
	goto fail;
	}
	buf[i] = data[1];
	buf[i+1] = data[0];
	buf[i+2] = data[3];
	buf[i+3] = data[2];
	}
	#ifdef DEBUG
	DBG(KERN_DEBUG "sat %d partition %x:", sat_id, id);
	for (i = 0; i < len; ++i)
	DBG(" %x", buf[i]);
	DBG("\n");
	#endif

	if (size)
	*size = len;
	return (struct smu_sdbp_header *) buf;

	fail:
	kfree(buf);
	return NULL;
	}
	EXPORT_SYMBOL_GPL(smu_sat_get_sdb_partition);

	/* refresh the cache */
	static int wf_sat_read_cache(struct wf_sat *sat)
	{
	int err;

	err = sat_read_block(&sat->i2c, 0x3f, sat->cache, 16);
	if (err)
	return err;
	sat->last_read = jiffies;
	#ifdef LOTSA_DEBUG
	{
	int i;
	DBG(KERN_DEBUG "wf_sat_get: data is");
	for (i = 0; i < 16; ++i)
	DBG(" %.2x", sat->cache[i]);
	DBG("\n");
	}
	#endif
	return 0;
	}

	static int wf_sat_get(struct wf_sensor sr, s32 value)
	{
	struct wf_sat_sensor *sens = wf_to_sat(sr);
	struct wf_sat *sat = sens->sat;
	int i, err;
	s32 val;

	if (sat->i2c.adapter == NULL)
	return -ENODEV;

	down(&sat->mutex);
	if (time_after(jiffies, (sat->last_read + MAX_AGE))) {
	err = wf_sat_read_cache(sat);
	if (err)
	goto fail;
	}

	i = sens->index * 2;
	val = ((sat->cache[i] << 8) + sat->cache[i+1]) << sens->shift;
	if (sens->index2 >= 0) {
	i = sens->index2 * 2;
	/* 4.12 * 8.8 -> 12.20; shift right 4 to get 16.16 */
	val = (val * ((sat->cache[i] << 8) + sat->cache[i+1])) >> 4;
	}

	*value = val;
	err = 0;

	fail:
	up(&sat->mutex);
	return err;
	}

	static void wf_sat_release(struct wf_sensor *sr)
	{
	struct wf_sat_sensor *sens = wf_to_sat(sr);
	struct wf_sat *sat = sens->sat;

	if (atomic_dec_and_test(&sat->refcnt)) {
	if (sat->i2c.adapter) {
	i2c_detach_client(&sat->i2c);
	sat->i2c.adapter = NULL;
	}
	if (sat->nr >= 0)
	sats[sat->nr] = NULL;
	kfree(sat);
	}
	kfree(sens);
	}

	static struct wf_sensor_ops wf_sat_ops = {
	.get_value = wf_sat_get,
	.release = wf_sat_release,
	.owner = THIS_MODULE,
	};

	static void wf_sat_create(struct i2c_adapter adapter, struct device_node dev)
	{
	struct wf_sat *sat;
	struct wf_sat_sensor *sens;
	const u32 *reg;
	const char loc, type;
	u8 addr, chip, core;
	struct device_node *child;
	int shift, cpu, index;
	char *name;
	int vsens[2], isens[2];

	reg = of_get_property(dev, "reg", NULL);
	if (reg == NULL)
	return;
	addr = *reg;
	DBG(KERN_DEBUG "wf_sat: creating sat at address %x\n", addr);

	sat = kzalloc(sizeof(struct wf_sat), GFP_KERNEL);
	if (sat == NULL)
	return;
	sat->nr = -1;
	sat->node = of_node_get(dev);
	atomic_set(&sat->refcnt, 0);
	init_MUTEX(&sat->mutex);
	sat->i2c.addr = (addr >> 1) & 0x7f;
	sat->i2c.adapter = adapter;
	sat->i2c.driver = &wf_sat_driver;
	strncpy(sat->i2c.name, "smu-sat", I2C_NAME_SIZE-1);

	if (i2c_attach_client(&sat->i2c)) {
	printk(KERN_ERR "windfarm: failed to attach smu-sat to i2c\n");
	goto fail;
	}

	vsens[0] = vsens[1] = -1;
	isens[0] = isens[1] = -1;
	child = NULL;
	while ((child = of_get_next_child(dev, child)) != NULL) {
	reg = of_get_property(child, "reg", NULL);
	type = of_get_property(child, "device_type", NULL);
	loc = of_get_property(child, "location", NULL);
	if (reg == NULL \|\| loc == NULL)
	continue;

	/* the cooked sensors are between 0x30 and 0x37 */
	if (reg < 0x30 \|\| reg > 0x37)
	continue;
	index = *reg - 0x30;

	/* expect location to be CPU [AB][01] ... */
	if (strncmp(loc, "CPU ", 4) != 0)
	continue;
	chip = loc[4] - 'A';
	core = loc[5] - '0';
	if (chip > 1 \|\| core > 1) {
	printk(KERN_ERR "wf_sat_create: don't understand "
	"location %s for %s\n", loc, child->full_name);
	continue;
	}
	cpu = 2 * chip + core;
	if (sat->nr < 0)
	sat->nr = chip;
	else if (sat->nr != chip) {
	printk(KERN_ERR "wf_sat_create: can't cope with "
	"multiple CPU chips on one SAT (%s)\n", loc);
	continue;
	}

	if (strcmp(type, "voltage-sensor") == 0) {
	name = "cpu-voltage";
	shift = 4;
	vsens[core] = index;
	} else if (strcmp(type, "current-sensor") == 0) {
	name = "cpu-current";
	shift = 8;
	isens[core] = index;
	} else if (strcmp(type, "temp-sensor") == 0) {
	name = "cpu-temp";
	shift = 10;
	} else
	continue; /* hmmm shouldn't happen */

	/* the +16 is enough for "cpu-voltage-n" */
	sens = kzalloc(sizeof(struct wf_sat_sensor) + 16, GFP_KERNEL);
	if (sens == NULL) {
	printk(KERN_ERR "wf_sat_create: couldn't create "
	"%s sensor %d (no memory)\n", name, cpu);
	continue;
	}
	sens->index = index;
	sens->index2 = -1;
	sens->shift = shift;
	sens->sat = sat;
	atomic_inc(&sat->refcnt);
	sens->sens.ops = &wf_sat_ops;
	sens->sens.name = (char *) (sens + 1);
	snprintf(sens->sens.name, 16, "%s-%d", name, cpu);

	if (wf_register_sensor(&sens->sens)) {
	atomic_dec(&sat->refcnt);
	kfree(sens);
	}
	}

	/* make the power sensors */
	for (core = 0; core < 2; ++core) {
	if (vsens[core] < 0 \|\| isens[core] < 0)
	continue;
	cpu = 2 * sat->nr + core;
	sens = kzalloc(sizeof(struct wf_sat_sensor) + 16, GFP_KERNEL);
	if (sens == NULL) {
	printk(KERN_ERR "wf_sat_create: couldn't create power "
	"sensor %d (no memory)\n", cpu);
	continue;
	}
	sens->index = vsens[core];
	sens->index2 = isens[core];
	sens->shift = 0;
	sens->sat = sat;
	atomic_inc(&sat->refcnt);
	sens->sens.ops = &wf_sat_ops;
	sens->sens.name = (char *) (sens + 1);
	snprintf(sens->sens.name, 16, "cpu-power-%d", cpu);

	if (wf_register_sensor(&sens->sens)) {
	atomic_dec(&sat->refcnt);
	kfree(sens);
	}
	}

	if (sat->nr >= 0)
	sats[sat->nr] = sat;

	return;

	fail:
	kfree(sat);
	}

	static int wf_sat_attach(struct i2c_adapter *adapter)
	{
	struct device_node busnode, dev = NULL;
	struct pmac_i2c_bus *bus;

	bus = pmac_i2c_adapter_to_bus(adapter);
	if (bus == NULL)
	return -ENODEV;
	busnode = pmac_i2c_get_bus_node(bus);

	while ((dev = of_get_next_child(busnode, dev)) != NULL)
	if (device_is_compatible(dev, "smu-sat"))
	wf_sat_create(adapter, dev);
	return 0;
	}

	static int wf_sat_detach(struct i2c_client *client)
	{
	struct wf_sat *sat = i2c_to_sat(client);

	/* XXX TODO */

	sat->i2c.adapter = NULL;
	return 0;
	}

	static int __init sat_sensors_init(void)
	{
	return i2c_add_driver(&wf_sat_driver);
	}

	static void __exit sat_sensors_exit(void)
	{
	i2c_del_driver(&wf_sat_driver);
	}

	module_init(sat_sensors_init);
	/module_exit(sat_sensors_exit); Uncomment when cleanup is implemented /

	MODULE_AUTHOR("Paul Mackerras <paulus@samba.org>");
	MODULE_DESCRIPTION("SMU satellite sensors for PowerMac thermal control");
	MODULE_LICENSE("GPL");