drivers/macintosh/windfarm_smu_sensors.c - third_party/linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Windfarm PowerMac thermal control. SMU based sensors
  *
  * (c) Copyright 2005 Benjamin Herrenschmidt, IBM Corp.
  *                    <benh@kernel.crashing.org>
  */

 #include <linux/types.h>
 #include <linux/errno.h>
 #include <linux/kernel.h>
 #include <linux/delay.h>
 #include <linux/slab.h>
 #include <linux/init.h>
 #include <linux/wait.h>
 #include <linux/completion.h>
 #include <linux/of.h>

 #include <asm/machdep.h>
 #include <asm/io.h>
 #include <asm/sections.h>
 #include <asm/smu.h>

 #include "windfarm.h"

 #define VERSION "0.2"

 #undef DEBUG

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

 /*
  * Various SMU "partitions" calibration objects for which we
  * keep pointers here for use by bits & pieces of the driver
  */
 static struct smu_sdbp_cpuvcp *cpuvcp;
 static int  cpuvcp_version;
 static struct smu_sdbp_cpudiode *cpudiode;
 static struct smu_sdbp_slotspow *slotspow;
 static u8 *debugswitches;

 /*
  * SMU basic sensors objects
  */

 static LIST_HEAD(smu_ads);

 struct smu_ad_sensor {
 	struct list_head	link;
 	u32			reg;		/* index in SMU */
 	struct wf_sensor	sens;
 };
 #define to_smu_ads(c) container_of(c, struct smu_ad_sensor, sens)

 static void smu_ads_release(struct wf_sensor *sr)
 {
 	struct smu_ad_sensor *ads = to_smu_ads(sr);

 	kfree(ads);
 }

 static int smu_read_adc(u8 id, s32 *value)
 {
 	struct smu_simple_cmd	cmd;
 	DECLARE_COMPLETION_ONSTACK(comp);
 	int rc;

 	rc = smu_queue_simple(&cmd, SMU_CMD_READ_ADC, 1,
 			      smu_done_complete, &comp, id);
 	if (rc)
 		return rc;
 	wait_for_completion(&comp);
 	if (cmd.cmd.status != 0)
 		return cmd.cmd.status;
 	if (cmd.cmd.reply_len != 2) {
 		printk(KERN_ERR "winfarm: read ADC 0x%x returned %d bytes !\n",
 		       id, cmd.cmd.reply_len);
 		return -EIO;
 	}
 	*value = *((u16 *)cmd.buffer);
 	return 0;
 }

 static int smu_cputemp_get(struct wf_sensor *sr, s32 *value)
 {
 	struct smu_ad_sensor *ads = to_smu_ads(sr);
 	int rc;
 	s32 val;
 	s64 scaled;

 	rc = smu_read_adc(ads->reg, &val);
 	if (rc) {
 		printk(KERN_ERR "windfarm: read CPU temp failed, err %d\n",
 		       rc);
 		return rc;
 	}

 	/* Ok, we have to scale & adjust, taking units into account */
 	scaled = (s64)(((u64)val) * (u64)cpudiode->m_value);
 	scaled >>= 3;
 	scaled += ((s64)cpudiode->b_value) << 9;
 	*value = (s32)(scaled << 1);

 	return 0;
 }

 static int smu_cpuamp_get(struct wf_sensor *sr, s32 *value)
 {
 	struct smu_ad_sensor *ads = to_smu_ads(sr);
 	s32 val, scaled;
 	int rc;

 	rc = smu_read_adc(ads->reg, &val);
 	if (rc) {
 		printk(KERN_ERR "windfarm: read CPU current failed, err %d\n",
 		       rc);
 		return rc;
 	}

 	/* Ok, we have to scale & adjust, taking units into account */
 	scaled = (s32)(val * (u32)cpuvcp->curr_scale);
 	scaled += (s32)cpuvcp->curr_offset;
 	*value = scaled << 4;

 	return 0;
 }

 static int smu_cpuvolt_get(struct wf_sensor *sr, s32 *value)
 {
 	struct smu_ad_sensor *ads = to_smu_ads(sr);
 	s32 val, scaled;
 	int rc;

 	rc = smu_read_adc(ads->reg, &val);
 	if (rc) {
 		printk(KERN_ERR "windfarm: read CPU voltage failed, err %d\n",
 		       rc);
 		return rc;
 	}

 	/* Ok, we have to scale & adjust, taking units into account */
 	scaled = (s32)(val * (u32)cpuvcp->volt_scale);
 	scaled += (s32)cpuvcp->volt_offset;
 	*value = scaled << 4;

 	return 0;
 }

 static int smu_slotspow_get(struct wf_sensor *sr, s32 *value)
 {
 	struct smu_ad_sensor *ads = to_smu_ads(sr);
 	s32 val, scaled;
 	int rc;

 	rc = smu_read_adc(ads->reg, &val);
 	if (rc) {
 		printk(KERN_ERR "windfarm: read slots power failed, err %d\n",
 		       rc);
 		return rc;
 	}

 	/* Ok, we have to scale & adjust, taking units into account */
 	scaled = (s32)(val * (u32)slotspow->pow_scale);
 	scaled += (s32)slotspow->pow_offset;
 	*value = scaled << 4;

 	return 0;
 }


 static const struct wf_sensor_ops smu_cputemp_ops = {
 	.get_value	= smu_cputemp_get,
 	.release	= smu_ads_release,
 	.owner		= THIS_MODULE,
 };
 static const struct wf_sensor_ops smu_cpuamp_ops = {
 	.get_value	= smu_cpuamp_get,
 	.release	= smu_ads_release,
 	.owner		= THIS_MODULE,
 };
 static const struct wf_sensor_ops smu_cpuvolt_ops = {
 	.get_value	= smu_cpuvolt_get,
 	.release	= smu_ads_release,
 	.owner		= THIS_MODULE,
 };
 static const struct wf_sensor_ops smu_slotspow_ops = {
 	.get_value	= smu_slotspow_get,
 	.release	= smu_ads_release,
 	.owner		= THIS_MODULE,
 };


 static struct smu_ad_sensor *smu_ads_create(struct device_node *node)
 {
 	struct smu_ad_sensor *ads;
 	const char *l;
 	const u32 *v;

 	ads = kmalloc(sizeof(struct smu_ad_sensor), GFP_KERNEL);
 	if (ads == NULL)
 		return NULL;
 	l = of_get_property(node, "location", NULL);
 	if (l == NULL)
 		goto fail;

 	/* We currently pick the sensors based on the OF name and location
 	 * properties, while Darwin uses the sensor-id's.
 	 * The problem with the IDs is that they are model specific while it
 	 * looks like apple has been doing a reasonably good job at keeping
 	 * the names and locations consistents so I'll stick with the names
 	 * and locations for now.
 	 */
 	if (of_node_is_type(node, "temp-sensor") &&
 	    !strcmp(l, "CPU T-Diode")) {
 		ads->sens.ops = &smu_cputemp_ops;
 		ads->sens.name = "cpu-temp";
 		if (cpudiode == NULL) {
 			DBG("wf: cpudiode partition (%02x) not found\n",
 			    SMU_SDB_CPUDIODE_ID);
 			goto fail;
 		}
 	} else if (of_node_is_type(node, "current-sensor") &&
 		   !strcmp(l, "CPU Current")) {
 		ads->sens.ops = &smu_cpuamp_ops;
 		ads->sens.name = "cpu-current";
 		if (cpuvcp == NULL) {
 			DBG("wf: cpuvcp partition (%02x) not found\n",
 			    SMU_SDB_CPUVCP_ID);
 			goto fail;
 		}
 	} else if (of_node_is_type(node, "voltage-sensor") &&
 		   !strcmp(l, "CPU Voltage")) {
 		ads->sens.ops = &smu_cpuvolt_ops;
 		ads->sens.name = "cpu-voltage";
 		if (cpuvcp == NULL) {
 			DBG("wf: cpuvcp partition (%02x) not found\n",
 			    SMU_SDB_CPUVCP_ID);
 			goto fail;
 		}
 	} else if (of_node_is_type(node, "power-sensor") &&
 		   !strcmp(l, "Slots Power")) {
 		ads->sens.ops = &smu_slotspow_ops;
 		ads->sens.name = "slots-power";
 		if (slotspow == NULL) {
 			DBG("wf: slotspow partition (%02x) not found\n",
 			    SMU_SDB_SLOTSPOW_ID);
 			goto fail;
 		}
 	} else
 		goto fail;

 	v = of_get_property(node, "reg", NULL);
 	if (v == NULL)
 		goto fail;
 	ads->reg = *v;

 	if (wf_register_sensor(&ads->sens))
 		goto fail;
 	return ads;
  fail:
 	kfree(ads);
 	return NULL;
 }

 /*
  * SMU Power combo sensor object
  */

 struct smu_cpu_power_sensor {
 	struct list_head	link;
 	struct wf_sensor	*volts;
 	struct wf_sensor	*amps;
 	int			fake_volts : 1;
 	int			quadratic : 1;
 	struct wf_sensor	sens;
 };
 #define to_smu_cpu_power(c) container_of(c, struct smu_cpu_power_sensor, sens)

 static struct smu_cpu_power_sensor *smu_cpu_power;

 static void smu_cpu_power_release(struct wf_sensor *sr)
 {
 	struct smu_cpu_power_sensor *pow = to_smu_cpu_power(sr);

 	if (pow->volts)
 		wf_put_sensor(pow->volts);
 	if (pow->amps)
 		wf_put_sensor(pow->amps);
 	kfree(pow);
 }

 static int smu_cpu_power_get(struct wf_sensor *sr, s32 *value)
 {
 	struct smu_cpu_power_sensor *pow = to_smu_cpu_power(sr);
 	s32 volts, amps, power;
 	u64 tmps, tmpa, tmpb;
 	int rc;

 	rc = pow->amps->ops->get_value(pow->amps, &amps);
 	if (rc)
 		return rc;

 	if (pow->fake_volts) {
 		*value = amps * 12 - 0x30000;
 		return 0;
 	}

 	rc = pow->volts->ops->get_value(pow->volts, &volts);
 	if (rc)
 		return rc;

 	power = (s32)((((u64)volts) * ((u64)amps)) >> 16);
 	if (!pow->quadratic) {
 		*value = power;
 		return 0;
 	}
 	tmps = (((u64)power) * ((u64)power)) >> 16;
 	tmpa = ((u64)cpuvcp->power_quads[0]) * tmps;
 	tmpb = ((u64)cpuvcp->power_quads[1]) * ((u64)power);
 	*value = (tmpa >> 28) + (tmpb >> 28) + (cpuvcp->power_quads[2] >> 12);

 	return 0;
 }

 static const struct wf_sensor_ops smu_cpu_power_ops = {
 	.get_value	= smu_cpu_power_get,
 	.release	= smu_cpu_power_release,
 	.owner		= THIS_MODULE,
 };


 static struct smu_cpu_power_sensor *
 smu_cpu_power_create(struct wf_sensor *volts, struct wf_sensor *amps)
 {
 	struct smu_cpu_power_sensor *pow;

 	pow = kmalloc(sizeof(struct smu_cpu_power_sensor), GFP_KERNEL);
 	if (pow == NULL)
 		return NULL;
 	pow->sens.ops = &smu_cpu_power_ops;
 	pow->sens.name = "cpu-power";

 	wf_get_sensor(volts);
 	pow->volts = volts;
 	wf_get_sensor(amps);
 	pow->amps = amps;

 	/* Some early machines need a faked voltage */
 	if (debugswitches && ((*debugswitches) & 0x80)) {
 		printk(KERN_INFO "windfarm: CPU Power sensor using faked"
 		       " voltage !\n");
 		pow->fake_volts = 1;
 	} else
 		pow->fake_volts = 0;

 	/* Try to use quadratic transforms on PowerMac8,1 and 9,1 for now,
 	 * I yet have to figure out what's up with 8,2 and will have to
 	 * adjust for later, unless we can 100% trust the SDB partition...
 	 */
 	if ((of_machine_is_compatible("PowerMac8,1") ||
 	     of_machine_is_compatible("PowerMac8,2") ||
 	     of_machine_is_compatible("PowerMac9,1")) &&
 	    cpuvcp_version >= 2) {
 		pow->quadratic = 1;
 		DBG("windfarm: CPU Power using quadratic transform\n");
 	} else
 		pow->quadratic = 0;

 	if (wf_register_sensor(&pow->sens))
 		goto fail;
 	return pow;
  fail:
 	kfree(pow);
 	return NULL;
 }

 static void smu_fetch_param_partitions(void)
 {
 	const struct smu_sdbp_header *hdr;

 	/* Get CPU voltage/current/power calibration data */
 	hdr = smu_get_sdb_partition(SMU_SDB_CPUVCP_ID, NULL);
 	if (hdr != NULL) {
 		cpuvcp = (struct smu_sdbp_cpuvcp *)&hdr[1];
 		/* Keep version around */
 		cpuvcp_version = hdr->version;
 	}

 	/* Get CPU diode calibration data */
 	hdr = smu_get_sdb_partition(SMU_SDB_CPUDIODE_ID, NULL);
 	if (hdr != NULL)
 		cpudiode = (struct smu_sdbp_cpudiode *)&hdr[1];

 	/* Get slots power calibration data if any */
 	hdr = smu_get_sdb_partition(SMU_SDB_SLOTSPOW_ID, NULL);
 	if (hdr != NULL)
 		slotspow = (struct smu_sdbp_slotspow *)&hdr[1];

 	/* Get debug switches if any */
 	hdr = smu_get_sdb_partition(SMU_SDB_DEBUG_SWITCHES_ID, NULL);
 	if (hdr != NULL)
 		debugswitches = (u8 *)&hdr[1];
 }

 static int __init smu_sensors_init(void)
 {
 	struct device_node *smu, *sensors, *s;
 	struct smu_ad_sensor *volt_sensor = NULL, *curr_sensor = NULL;

 	if (!smu_present())
 		return -ENODEV;

 	/* Get parameters partitions */
 	smu_fetch_param_partitions();

 	smu = of_find_node_by_type(NULL, "smu");
 	if (smu == NULL)
 		return -ENODEV;

 	/* Look for sensors subdir */
 	for_each_child_of_node(smu, sensors)
 		if (of_node_name_eq(sensors, "sensors"))
 			break;

 	of_node_put(smu);

 	/* Create basic sensors */
 	for (s = NULL;
 	     sensors && (s = of_get_next_child(sensors, s)) != NULL;) {
 		struct smu_ad_sensor *ads;

 		ads = smu_ads_create(s);
 		if (ads == NULL)
 			continue;
 		list_add(&ads->link, &smu_ads);
 		/* keep track of cpu voltage & current */
 		if (!strcmp(ads->sens.name, "cpu-voltage"))
 			volt_sensor = ads;
 		else if (!strcmp(ads->sens.name, "cpu-current"))
 			curr_sensor = ads;
 	}

 	of_node_put(sensors);

 	/* Create CPU power sensor if possible */
 	if (volt_sensor && curr_sensor)
 		smu_cpu_power = smu_cpu_power_create(&volt_sensor->sens,
 						     &curr_sensor->sens);

 	return 0;
 }

 static void __exit smu_sensors_exit(void)
 {
 	struct smu_ad_sensor *ads;

 	/* dispose of power sensor */
 	if (smu_cpu_power)
 		wf_unregister_sensor(&smu_cpu_power->sens);

 	/* dispose of basic sensors */
 	while (!list_empty(&smu_ads)) {
 		ads = list_entry(smu_ads.next, struct smu_ad_sensor, link);
 		list_del(&ads->link);
 		wf_unregister_sensor(&ads->sens);
 	}
 }


 module_init(smu_sensors_init);
 module_exit(smu_sensors_exit);

 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
 MODULE_DESCRIPTION("SMU sensor objects for PowerMacs thermal control");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Windfarm PowerMac thermal control. SMU based sensors
	*
	* (c) Copyright 2005 Benjamin Herrenschmidt, IBM Corp.
	* <benh@kernel.crashing.org>
	*/

	#include <linux/types.h>
	#include <linux/errno.h>
	#include <linux/kernel.h>
	#include <linux/delay.h>
	#include <linux/slab.h>
	#include <linux/init.h>
	#include <linux/wait.h>
	#include <linux/completion.h>
	#include <linux/of.h>

	#include <asm/machdep.h>
	#include <asm/io.h>
	#include <asm/sections.h>
	#include <asm/smu.h>

	#include "windfarm.h"

	#define VERSION "0.2"

	#undef DEBUG

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

	/*
	* Various SMU "partitions" calibration objects for which we
	* keep pointers here for use by bits & pieces of the driver
	*/
	static struct smu_sdbp_cpuvcp *cpuvcp;
	static int cpuvcp_version;
	static struct smu_sdbp_cpudiode *cpudiode;
	static struct smu_sdbp_slotspow *slotspow;
	static u8 *debugswitches;

	/*
	* SMU basic sensors objects
	*/

	static LIST_HEAD(smu_ads);

	struct smu_ad_sensor {
	struct list_head link;
	u32 reg; /* index in SMU */
	struct wf_sensor sens;
	};
	#define to_smu_ads(c) container_of(c, struct smu_ad_sensor, sens)

	static void smu_ads_release(struct wf_sensor *sr)
	{
	struct smu_ad_sensor *ads = to_smu_ads(sr);

	kfree(ads);
	}

	static int smu_read_adc(u8 id, s32 *value)
	{
	struct smu_simple_cmd cmd;
	DECLARE_COMPLETION_ONSTACK(comp);
	int rc;

	rc = smu_queue_simple(&cmd, SMU_CMD_READ_ADC, 1,
	smu_done_complete, &comp, id);
	if (rc)
	return rc;
	wait_for_completion(&comp);
	if (cmd.cmd.status != 0)
	return cmd.cmd.status;
	if (cmd.cmd.reply_len != 2) {
	printk(KERN_ERR "winfarm: read ADC 0x%x returned %d bytes !\n",
	id, cmd.cmd.reply_len);
	return -EIO;
	}
	value = ((u16 *)cmd.buffer);
	return 0;
	}

	static int smu_cputemp_get(struct wf_sensor sr, s32 value)
	{
	struct smu_ad_sensor *ads = to_smu_ads(sr);
	int rc;
	s32 val;
	s64 scaled;

	rc = smu_read_adc(ads->reg, &val);
	if (rc) {
	printk(KERN_ERR "windfarm: read CPU temp failed, err %d\n",
	rc);
	return rc;
	}

	/* Ok, we have to scale & adjust, taking units into account */
	scaled = (s64)(((u64)val) * (u64)cpudiode->m_value);
	scaled >>= 3;
	scaled += ((s64)cpudiode->b_value) << 9;
	*value = (s32)(scaled << 1);

	return 0;
	}

	static int smu_cpuamp_get(struct wf_sensor sr, s32 value)
	{
	struct smu_ad_sensor *ads = to_smu_ads(sr);
	s32 val, scaled;
	int rc;

	rc = smu_read_adc(ads->reg, &val);
	if (rc) {
	printk(KERN_ERR "windfarm: read CPU current failed, err %d\n",
	rc);
	return rc;
	}

	/* Ok, we have to scale & adjust, taking units into account */
	scaled = (s32)(val * (u32)cpuvcp->curr_scale);
	scaled += (s32)cpuvcp->curr_offset;
	*value = scaled << 4;

	return 0;
	}

	static int smu_cpuvolt_get(struct wf_sensor sr, s32 value)
	{
	struct smu_ad_sensor *ads = to_smu_ads(sr);
	s32 val, scaled;
	int rc;

	rc = smu_read_adc(ads->reg, &val);
	if (rc) {
	printk(KERN_ERR "windfarm: read CPU voltage failed, err %d\n",
	rc);
	return rc;
	}

	/* Ok, we have to scale & adjust, taking units into account */
	scaled = (s32)(val * (u32)cpuvcp->volt_scale);
	scaled += (s32)cpuvcp->volt_offset;
	*value = scaled << 4;

	return 0;
	}

	static int smu_slotspow_get(struct wf_sensor sr, s32 value)
	{
	struct smu_ad_sensor *ads = to_smu_ads(sr);
	s32 val, scaled;
	int rc;

	rc = smu_read_adc(ads->reg, &val);
	if (rc) {
	printk(KERN_ERR "windfarm: read slots power failed, err %d\n",
	rc);
	return rc;
	}

	/* Ok, we have to scale & adjust, taking units into account */
	scaled = (s32)(val * (u32)slotspow->pow_scale);
	scaled += (s32)slotspow->pow_offset;
	*value = scaled << 4;

	return 0;
	}


	static const struct wf_sensor_ops smu_cputemp_ops = {
	.get_value = smu_cputemp_get,
	.release = smu_ads_release,
	.owner = THIS_MODULE,
	};
	static const struct wf_sensor_ops smu_cpuamp_ops = {
	.get_value = smu_cpuamp_get,
	.release = smu_ads_release,
	.owner = THIS_MODULE,
	};
	static const struct wf_sensor_ops smu_cpuvolt_ops = {
	.get_value = smu_cpuvolt_get,
	.release = smu_ads_release,
	.owner = THIS_MODULE,
	};
	static const struct wf_sensor_ops smu_slotspow_ops = {
	.get_value = smu_slotspow_get,
	.release = smu_ads_release,
	.owner = THIS_MODULE,
	};


	static struct smu_ad_sensor smu_ads_create(struct device_node node)
	{
	struct smu_ad_sensor *ads;
	const char *l;
	const u32 *v;

	ads = kmalloc(sizeof(struct smu_ad_sensor), GFP_KERNEL);
	if (ads == NULL)
	return NULL;
	l = of_get_property(node, "location", NULL);
	if (l == NULL)
	goto fail;

	/* We currently pick the sensors based on the OF name and location
	* properties, while Darwin uses the sensor-id's.
	* The problem with the IDs is that they are model specific while it
	* looks like apple has been doing a reasonably good job at keeping
	* the names and locations consistents so I'll stick with the names
	* and locations for now.
	*/
	if (of_node_is_type(node, "temp-sensor") &&
	!strcmp(l, "CPU T-Diode")) {
	ads->sens.ops = &smu_cputemp_ops;
	ads->sens.name = "cpu-temp";
	if (cpudiode == NULL) {
	DBG("wf: cpudiode partition (%02x) not found\n",
	SMU_SDB_CPUDIODE_ID);
	goto fail;
	}
	} else if (of_node_is_type(node, "current-sensor") &&
	!strcmp(l, "CPU Current")) {
	ads->sens.ops = &smu_cpuamp_ops;
	ads->sens.name = "cpu-current";
	if (cpuvcp == NULL) {
	DBG("wf: cpuvcp partition (%02x) not found\n",
	SMU_SDB_CPUVCP_ID);
	goto fail;
	}
	} else if (of_node_is_type(node, "voltage-sensor") &&
	!strcmp(l, "CPU Voltage")) {
	ads->sens.ops = &smu_cpuvolt_ops;
	ads->sens.name = "cpu-voltage";
	if (cpuvcp == NULL) {
	DBG("wf: cpuvcp partition (%02x) not found\n",
	SMU_SDB_CPUVCP_ID);
	goto fail;
	}
	} else if (of_node_is_type(node, "power-sensor") &&
	!strcmp(l, "Slots Power")) {
	ads->sens.ops = &smu_slotspow_ops;
	ads->sens.name = "slots-power";
	if (slotspow == NULL) {
	DBG("wf: slotspow partition (%02x) not found\n",
	SMU_SDB_SLOTSPOW_ID);
	goto fail;
	}
	} else
	goto fail;

	v = of_get_property(node, "reg", NULL);
	if (v == NULL)
	goto fail;
	ads->reg = *v;

	if (wf_register_sensor(&ads->sens))
	goto fail;
	return ads;
	fail:
	kfree(ads);
	return NULL;
	}

	/*
	* SMU Power combo sensor object
	*/

	struct smu_cpu_power_sensor {
	struct list_head link;
	struct wf_sensor *volts;
	struct wf_sensor *amps;
	int fake_volts : 1;
	int quadratic : 1;
	struct wf_sensor sens;
	};
	#define to_smu_cpu_power(c) container_of(c, struct smu_cpu_power_sensor, sens)

	static struct smu_cpu_power_sensor *smu_cpu_power;

	static void smu_cpu_power_release(struct wf_sensor *sr)
	{
	struct smu_cpu_power_sensor *pow = to_smu_cpu_power(sr);

	if (pow->volts)
	wf_put_sensor(pow->volts);
	if (pow->amps)
	wf_put_sensor(pow->amps);
	kfree(pow);
	}

	static int smu_cpu_power_get(struct wf_sensor sr, s32 value)
	{
	struct smu_cpu_power_sensor *pow = to_smu_cpu_power(sr);
	s32 volts, amps, power;
	u64 tmps, tmpa, tmpb;
	int rc;

	rc = pow->amps->ops->get_value(pow->amps, &amps);
	if (rc)
	return rc;

	if (pow->fake_volts) {
	value = amps 12 - 0x30000;
	return 0;
	}

	rc = pow->volts->ops->get_value(pow->volts, &volts);
	if (rc)
	return rc;

	power = (s32)((((u64)volts) * ((u64)amps)) >> 16);
	if (!pow->quadratic) {
	*value = power;
	return 0;
	}
	tmps = (((u64)power) * ((u64)power)) >> 16;
	tmpa = ((u64)cpuvcp->power_quads[0]) * tmps;
	tmpb = ((u64)cpuvcp->power_quads[1]) * ((u64)power);
	*value = (tmpa >> 28) + (tmpb >> 28) + (cpuvcp->power_quads[2] >> 12);

	return 0;
	}

	static const struct wf_sensor_ops smu_cpu_power_ops = {
	.get_value = smu_cpu_power_get,
	.release = smu_cpu_power_release,
	.owner = THIS_MODULE,
	};


	static struct smu_cpu_power_sensor *
	smu_cpu_power_create(struct wf_sensor volts, struct wf_sensor amps)
	{
	struct smu_cpu_power_sensor *pow;

	pow = kmalloc(sizeof(struct smu_cpu_power_sensor), GFP_KERNEL);
	if (pow == NULL)
	return NULL;
	pow->sens.ops = &smu_cpu_power_ops;
	pow->sens.name = "cpu-power";

	wf_get_sensor(volts);
	pow->volts = volts;
	wf_get_sensor(amps);
	pow->amps = amps;

	/* Some early machines need a faked voltage */
	if (debugswitches && ((*debugswitches) & 0x80)) {
	printk(KERN_INFO "windfarm: CPU Power sensor using faked"
	" voltage !\n");
	pow->fake_volts = 1;
	} else
	pow->fake_volts = 0;

	/* Try to use quadratic transforms on PowerMac8,1 and 9,1 for now,
	* I yet have to figure out what's up with 8,2 and will have to
	* adjust for later, unless we can 100% trust the SDB partition...
	*/
	if ((of_machine_is_compatible("PowerMac8,1") \|\|
	of_machine_is_compatible("PowerMac8,2") \|\|
	of_machine_is_compatible("PowerMac9,1")) &&
	cpuvcp_version >= 2) {
	pow->quadratic = 1;
	DBG("windfarm: CPU Power using quadratic transform\n");
	} else
	pow->quadratic = 0;

	if (wf_register_sensor(&pow->sens))
	goto fail;
	return pow;
	fail:
	kfree(pow);
	return NULL;
	}

	static void smu_fetch_param_partitions(void)
	{
	const struct smu_sdbp_header *hdr;

	/* Get CPU voltage/current/power calibration data */
	hdr = smu_get_sdb_partition(SMU_SDB_CPUVCP_ID, NULL);
	if (hdr != NULL) {
	cpuvcp = (struct smu_sdbp_cpuvcp *)&hdr[1];
	/* Keep version around */
	cpuvcp_version = hdr->version;
	}

	/* Get CPU diode calibration data */
	hdr = smu_get_sdb_partition(SMU_SDB_CPUDIODE_ID, NULL);
	if (hdr != NULL)
	cpudiode = (struct smu_sdbp_cpudiode *)&hdr[1];

	/* Get slots power calibration data if any */
	hdr = smu_get_sdb_partition(SMU_SDB_SLOTSPOW_ID, NULL);
	if (hdr != NULL)
	slotspow = (struct smu_sdbp_slotspow *)&hdr[1];

	/* Get debug switches if any */
	hdr = smu_get_sdb_partition(SMU_SDB_DEBUG_SWITCHES_ID, NULL);
	if (hdr != NULL)
	debugswitches = (u8 *)&hdr[1];
	}

	static int __init smu_sensors_init(void)
	{
	struct device_node smu, sensors, *s;
	struct smu_ad_sensor volt_sensor = NULL, curr_sensor = NULL;

	if (!smu_present())
	return -ENODEV;

	/* Get parameters partitions */
	smu_fetch_param_partitions();

	smu = of_find_node_by_type(NULL, "smu");
	if (smu == NULL)
	return -ENODEV;

	/* Look for sensors subdir */
	for_each_child_of_node(smu, sensors)
	if (of_node_name_eq(sensors, "sensors"))
	break;

	of_node_put(smu);

	/* Create basic sensors */
	for (s = NULL;
	sensors && (s = of_get_next_child(sensors, s)) != NULL;) {
	struct smu_ad_sensor *ads;

	ads = smu_ads_create(s);
	if (ads == NULL)
	continue;
	list_add(&ads->link, &smu_ads);
	/* keep track of cpu voltage & current */
	if (!strcmp(ads->sens.name, "cpu-voltage"))
	volt_sensor = ads;
	else if (!strcmp(ads->sens.name, "cpu-current"))
	curr_sensor = ads;
	}

	of_node_put(sensors);

	/* Create CPU power sensor if possible */
	if (volt_sensor && curr_sensor)
	smu_cpu_power = smu_cpu_power_create(&volt_sensor->sens,
	&curr_sensor->sens);

	return 0;
	}

	static void __exit smu_sensors_exit(void)
	{
	struct smu_ad_sensor *ads;

	/* dispose of power sensor */
	if (smu_cpu_power)
	wf_unregister_sensor(&smu_cpu_power->sens);

	/* dispose of basic sensors */
	while (!list_empty(&smu_ads)) {
	ads = list_entry(smu_ads.next, struct smu_ad_sensor, link);
	list_del(&ads->link);
	wf_unregister_sensor(&ads->sens);
	}
	}


	module_init(smu_sensors_init);
	module_exit(smu_sensors_exit);

	MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
	MODULE_DESCRIPTION("SMU sensor objects for PowerMacs thermal control");
	MODULE_LICENSE("GPL");