// SPDX-License-Identifier: GPL-2.0+
// Copyright IBM Corp 2019

#include <linux/device.h>
#include <linux/export.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/math64.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/property.h>
#include <linux/sysfs.h>
#include <linux/unaligned.h>

#include "common.h"

#define EXTN_FLAG_SENSOR_ID		BIT(7)

#define OCC_ERROR_COUNT_THRESHOLD	2	/* required by OCC spec */

#define OCC_STATE_SAFE			4
#define OCC_SAFE_TIMEOUT		msecs_to_jiffies(60000) /* 1 min */

#define OCC_UPDATE_FREQUENCY		msecs_to_jiffies(1000)

#define OCC_TEMP_SENSOR_FAULT		0xFF

#define OCC_FRU_TYPE_VRM		3

/* OCC sensor type and version definitions */

struct temp_sensor_1 {
	u16 sensor_id;
	u16 value;
} __packed;

struct temp_sensor_2 {
	u32 sensor_id;
	u8 fru_type;
	u8 value;
} __packed;

struct temp_sensor_10 {
	u32 sensor_id;
	u8 fru_type;
	u8 value;
	u8 throttle;
	u8 reserved;
} __packed;

struct freq_sensor_1 {
	u16 sensor_id;
	u16 value;
} __packed;

struct freq_sensor_2 {
	u32 sensor_id;
	u16 value;
} __packed;

struct power_sensor_1 {
	u16 sensor_id;
	u32 update_tag;
	u32 accumulator;
	u16 value;
} __packed;

struct power_sensor_2 {
	u32 sensor_id;
	u8 function_id;
	u8 apss_channel;
	u16 reserved;
	u32 update_tag;
	u64 accumulator;
	u16 value;
} __packed;

struct power_sensor_data {
	u16 value;
	u32 update_tag;
	u64 accumulator;
} __packed;

struct power_sensor_data_and_time {
	u16 update_time;
	u16 value;
	u32 update_tag;
	u64 accumulator;
} __packed;

struct power_sensor_a0 {
	u32 sensor_id;
	struct power_sensor_data_and_time system;
	u32 reserved;
	struct power_sensor_data_and_time proc;
	struct power_sensor_data vdd;
	struct power_sensor_data vdn;
} __packed;

struct caps_sensor_2 {
	u16 cap;
	u16 system_power;
	u16 n_cap;
	u16 max;
	u16 min;
	u16 user;
	u8 user_source;
} __packed;

struct caps_sensor_3 {
	u16 cap;
	u16 system_power;
	u16 n_cap;
	u16 max;
	u16 hard_min;
	u16 soft_min;
	u16 user;
	u8 user_source;
} __packed;

struct extended_sensor {
	union {
		u8 name[4];
		u32 sensor_id;
	};
	u8 flags;
	u8 reserved;
	u8 data[6];
} __packed;

static int occ_poll(struct occ *occ)
{
	int rc;
	u8 cmd[7];
	struct occ_poll_response_header *header;

	/* big endian */
	cmd[0] = 0;			/* sequence number */
	cmd[1] = 0;			/* cmd type */
	cmd[2] = 0;			/* data length msb */
	cmd[3] = 1;			/* data length lsb */
	cmd[4] = occ->poll_cmd_data;	/* data */
	cmd[5] = 0;			/* checksum msb */
	cmd[6] = 0;			/* checksum lsb */

	/* mutex should already be locked if necessary */
	rc = occ->send_cmd(occ, cmd, sizeof(cmd), &occ->resp, sizeof(occ->resp));
	if (rc) {
		occ->last_error = rc;
		if (occ->error_count++ > OCC_ERROR_COUNT_THRESHOLD)
			occ->error = rc;

		goto done;
	}

	/* clear error since communication was successful */
	occ->error_count = 0;
	occ->last_error = 0;
	occ->error = 0;

	/* check for safe state */
	header = (struct occ_poll_response_header *)occ->resp.data;
	if (header->occ_state == OCC_STATE_SAFE) {
		if (occ->last_safe) {
			if (time_after(jiffies,
				       occ->last_safe + OCC_SAFE_TIMEOUT))
				occ->error = -EHOSTDOWN;
		} else {
			occ->last_safe = jiffies;
		}
	} else {
		occ->last_safe = 0;
	}

done:
	occ_sysfs_poll_done(occ);
	return rc;
}

static int occ_set_user_power_cap(struct occ *occ, u16 user_power_cap)
{
	int rc;
	u8 cmd[8];
	u8 resp[8];
	__be16 user_power_cap_be = cpu_to_be16(user_power_cap);

	cmd[0] = 0;	/* sequence number */
	cmd[1] = 0x22;	/* cmd type */
	cmd[2] = 0;	/* data length msb */
	cmd[3] = 2;	/* data length lsb */

	memcpy(&cmd[4], &user_power_cap_be, 2);

	cmd[6] = 0;	/* checksum msb */
	cmd[7] = 0;	/* checksum lsb */

	rc = mutex_lock_interruptible(&occ->lock);
	if (rc)
		return rc;

	rc = occ->send_cmd(occ, cmd, sizeof(cmd), resp, sizeof(resp));

	mutex_unlock(&occ->lock);

	return rc;
}

int occ_update_response(struct occ *occ)
{
	int rc = mutex_lock_interruptible(&occ->lock);

	if (rc)
		return rc;

	/* limit the maximum rate of polling the OCC */
	if (time_after(jiffies, occ->next_update)) {
		rc = occ_poll(occ);
		occ->next_update = jiffies + OCC_UPDATE_FREQUENCY;
	} else {
		rc = occ->last_error;
	}

	mutex_unlock(&occ->lock);
	return rc;
}

static ssize_t occ_show_temp_1(struct device *dev,
			       struct device_attribute *attr, char *buf)
{
	int rc;
	u32 val = 0;
	struct temp_sensor_1 *temp;
	struct occ *occ = dev_get_drvdata(dev);
	struct occ_sensors *sensors = &occ->sensors;
	struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr);

	rc = occ_update_response(occ);
	if (rc)
		return rc;

	temp = ((struct temp_sensor_1 *)sensors->temp.data) + sattr->index;

	switch (sattr->nr) {
	case 0:
		val = get_unaligned_be16(&temp->sensor_id);
		break;
	case 1:
		/*
		 * If a sensor reading has expired and couldn't be refreshed,
		 * OCC returns 0xFFFF for that sensor.
		 */
		if (temp->value == 0xFFFF)
			return -EREMOTEIO;
		val = get_unaligned_be16(&temp->value) * 1000;
		break;
	default:
		return -EINVAL;
	}

	return sysfs_emit(buf, "%u\n", val);
}

static ssize_t occ_show_temp_2(struct device *dev,
			       struct device_attribute *attr, char *buf)
{
	int rc;
	u32 val = 0;
	struct temp_sensor_2 *temp;
	struct occ *occ = dev_get_drvdata(dev);
	struct occ_sensors *sensors = &occ->sensors;
	struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr);

	rc = occ_update_response(occ);
	if (rc)
		return rc;

	temp = ((struct temp_sensor_2 *)sensors->temp.data) + sattr->index;

	switch (sattr->nr) {
	case 0:
		val = get_unaligned_be32(&temp->sensor_id);
		break;
	case 1:
		val = temp->value;
		if (val == OCC_TEMP_SENSOR_FAULT)
			return -EREMOTEIO;

		/*
		 * VRM doesn't return temperature, only alarm bit. This
		 * attribute maps to tempX_alarm instead of tempX_input for
		 * VRM
		 */
		if (temp->fru_type != OCC_FRU_TYPE_VRM) {
			/* sensor not ready */
			if (val == 0)
				return -EAGAIN;

			val *= 1000;
		}
		break;
	case 2:
		val = temp->fru_type;
		break;
	case 3:
		val = temp->value == OCC_TEMP_SENSOR_FAULT;
		break;
	default:
		return -EINVAL;
	}

	return sysfs_emit(buf, "%u\n", val);
}

static ssize_t occ_show_temp_10(struct device *dev,
				struct device_attribute *attr, char *buf)
{
	int rc;
	u32 val = 0;
	struct temp_sensor_10 *temp;
	struct occ *occ = dev_get_drvdata(dev);
	struct occ_sensors *sensors = &occ->sensors;
	struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr);

	rc = occ_update_response(occ);
	if (rc)
		return rc;

	temp = ((struct temp_sensor_10 *)sensors->temp.data) + sattr->index;

	switch (sattr->nr) {
	case 0:
		val = get_unaligned_be32(&temp->sensor_id);
		break;
	case 1:
		val = temp->value;
		if (val == OCC_TEMP_SENSOR_FAULT)
			return -EREMOTEIO;

		/* sensor not ready */
		if (val == 0)
			return -EAGAIN;

		val *= 1000;
		break;
	case 2:
		val = temp->fru_type;
		break;
	case 3:
		val = temp->value == OCC_TEMP_SENSOR_FAULT;
		break;
	case 4:
		val = temp->throttle * 1000;
		break;
	default:
		return -EINVAL;
	}

	return sysfs_emit(buf, "%u\n", val);
}

static ssize_t occ_show_freq_1(struct device *dev,
			       struct device_attribute *attr, char *buf)
{
	int rc;
	u16 val = 0;
	struct freq_sensor_1 *freq;
	struct occ *occ = dev_get_drvdata(dev);
	struct occ_sensors *sensors = &occ->sensors;
	struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr);

	rc = occ_update_response(occ);
	if (rc)
		return rc;

	freq = ((struct freq_sensor_1 *)sensors->freq.data) + sattr->index;

	switch (sattr->nr) {
	case 0:
		val = get_unaligned_be16(&freq->sensor_id);
		break;
	case 1:
		val = get_unaligned_be16(&freq->value);
		break;
	default:
		return -EINVAL;
	}

	return sysfs_emit(buf, "%u\n", val);
}

static ssize_t occ_show_freq_2(struct device *dev,
			       struct device_attribute *attr, char *buf)
{
	int rc;
	u32 val = 0;
	struct freq_sensor_2 *freq;
	struct occ *occ = dev_get_drvdata(dev);
	struct occ_sensors *sensors = &occ->sensors;
	struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr);

	rc = occ_update_response(occ);
	if (rc)
		return rc;

	freq = ((struct freq_sensor_2 *)sensors->freq.data) + sattr->index;

	switch (sattr->nr) {
	case 0:
		val = get_unaligned_be32(&freq->sensor_id);
		break;
	case 1:
		val = get_unaligned_be16(&freq->value);
		break;
	default:
		return -EINVAL;
	}

	return sysfs_emit(buf, "%u\n", val);
}

static u64 occ_get_powr_avg(u64 accum, u32 samples)
{
	return (samples == 0) ? 0 :
		mul_u64_u32_div(accum, 1000000UL, samples);
}

static ssize_t occ_show_power_1(struct device *dev,
				struct device_attribute *attr, char *buf)
{
	int rc;
	u64 val = 0;
	struct power_sensor_1 *power;
	struct occ *occ = dev_get_drvdata(dev);
	struct occ_sensors *sensors = &occ->sensors;
	struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr);

	rc = occ_update_response(occ);
	if (rc)
		return rc;

	power = ((struct power_sensor_1 *)sensors->power.data) + sattr->index;

	switch (sattr->nr) {
	case 0:
		val = get_unaligned_be16(&power->sensor_id);
		break;
	case 1:
		val = occ_get_powr_avg(get_unaligned_be32(&power->accumulator),
				       get_unaligned_be32(&power->update_tag));
		break;
	case 2:
		val = (u64)get_unaligned_be32(&power->update_tag) *
			   occ->powr_sample_time_us;
		break;
	case 3:
		val = get_unaligned_be16(&power->value) * 1000000ULL;
		break;
	default:
		return -EINVAL;
	}

	return sysfs_emit(buf, "%llu\n", val);
}

static ssize_t occ_show_power_2(struct device *dev,
				struct device_attribute *attr, char *buf)
{
	int rc;
	u64 val = 0;
	struct power_sensor_2 *power;
	struct occ *occ = dev_get_drvdata(dev);
	struct occ_sensors *sensors = &occ->sensors;
	struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr);

	rc = occ_update_response(occ);
	if (rc)
		return rc;

	power = ((struct power_sensor_2 *)sensors->power.data) + sattr->index;

	switch (sattr->nr) {
	case 0:
		return sysfs_emit(buf, "%u_%u_%u\n",
				  get_unaligned_be32(&power->sensor_id),
				  power->function_id, power->apss_channel);
	case 1:
		val = occ_get_powr_avg(get_unaligned_be64(&power->accumulator),
				       get_unaligned_be32(&power->update_tag));
		break;
	case 2:
		val = (u64)get_unaligned_be32(&power->update_tag) *
			   occ->powr_sample_time_us;
		break;
	case 3:
		val = get_unaligned_be16(&power->value) * 1000000ULL;
		break;
	default:
		return -EINVAL;
	}

	return sysfs_emit(buf, "%llu\n", val);
}

static ssize_t occ_show_power_a0(struct device *dev,
				 struct device_attribute *attr, char *buf)
{
	int rc;
	u64 val = 0;
	struct power_sensor_a0 *power;
	struct occ *occ = dev_get_drvdata(dev);
	struct occ_sensors *sensors = &occ->sensors;
	struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr);

	rc = occ_update_response(occ);
	if (rc)
		return rc;

	power = ((struct power_sensor_a0 *)sensors->power.data) + sattr->index;

	switch (sattr->nr) {
	case 0:
		return sysfs_emit(buf, "%u_system\n",
				  get_unaligned_be32(&power->sensor_id));
	case 1:
		val = occ_get_powr_avg(get_unaligned_be64(&power->system.accumulator),
				       get_unaligned_be32(&power->system.update_tag));
		break;
	case 2:
		val = (u64)get_unaligned_be32(&power->system.update_tag) *
			   occ->powr_sample_time_us;
		break;
	case 3:
		val = get_unaligned_be16(&power->system.value) * 1000000ULL;
		break;
	case 4:
		return sysfs_emit(buf, "%u_proc\n",
				  get_unaligned_be32(&power->sensor_id));
	case 5:
		val = occ_get_powr_avg(get_unaligned_be64(&power->proc.accumulator),
				       get_unaligned_be32(&power->proc.update_tag));
		break;
	case 6:
		val = (u64)get_unaligned_be32(&power->proc.update_tag) *
			   occ->powr_sample_time_us;
		break;
	case 7:
		val = get_unaligned_be16(&power->proc.value) * 1000000ULL;
		break;
	case 8:
		return sysfs_emit(buf, "%u_vdd\n",
				  get_unaligned_be32(&power->sensor_id));
	case 9:
		val = occ_get_powr_avg(get_unaligned_be64(&power->vdd.accumulator),
				       get_unaligned_be32(&power->vdd.update_tag));
		break;
	case 10:
		val = (u64)get_unaligned_be32(&power->vdd.update_tag) *
			   occ->powr_sample_time_us;
		break;
	case 11:
		val = get_unaligned_be16(&power->vdd.value) * 1000000ULL;
		break;
	case 12:
		return sysfs_emit(buf, "%u_vdn\n",
				  get_unaligned_be32(&power->sensor_id));
	case 13:
		val = occ_get_powr_avg(get_unaligned_be64(&power->vdn.accumulator),
				       get_unaligned_be32(&power->vdn.update_tag));
		break;
	case 14:
		val = (u64)get_unaligned_be32(&power->vdn.update_tag) *
			   occ->powr_sample_time_us;
		break;
	case 15:
		val = get_unaligned_be16(&power->vdn.value) * 1000000ULL;
		break;
	default:
		return -EINVAL;
	}

	return sysfs_emit(buf, "%llu\n", val);
}

static ssize_t occ_show_caps_1_2(struct device *dev,
				 struct device_attribute *attr, char *buf)
{
	int rc;
	u64 val = 0;
	struct caps_sensor_2 *caps;
	struct occ *occ = dev_get_drvdata(dev);
	struct occ_sensors *sensors = &occ->sensors;
	struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr);

	rc = occ_update_response(occ);
	if (rc)
		return rc;

	caps = ((struct caps_sensor_2 *)sensors->caps.data) + sattr->index;

	switch (sattr->nr) {
	case 0:
		return sysfs_emit(buf, "system\n");
	case 1:
		val = get_unaligned_be16(&caps->cap) * 1000000ULL;
		break;
	case 2:
		val = get_unaligned_be16(&caps->system_power) * 1000000ULL;
		break;
	case 3:
		val = get_unaligned_be16(&caps->n_cap) * 1000000ULL;
		break;
	case 4:
		val = get_unaligned_be16(&caps->max) * 1000000ULL;
		break;
	case 5:
		val = get_unaligned_be16(&caps->min) * 1000000ULL;
		break;
	case 6:
		val = get_unaligned_be16(&caps->user) * 1000000ULL;
		break;
	case 7:
		if (occ->sensors.caps.version == 1)
			return -EINVAL;

		val = caps->user_source;
		break;
	default:
		return -EINVAL;
	}

	return sysfs_emit(buf, "%llu\n", val);
}

static ssize_t occ_show_caps_3(struct device *dev,
			       struct device_attribute *attr, char *buf)
{
	int rc;
	u64 val = 0;
	struct caps_sensor_3 *caps;
	struct occ *occ = dev_get_drvdata(dev);
	struct occ_sensors *sensors = &occ->sensors;
	struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr);

	rc = occ_update_response(occ);
	if (rc)
		return rc;

	caps = ((struct caps_sensor_3 *)sensors->caps.data) + sattr->index;

	switch (sattr->nr) {
	case 0:
		return sysfs_emit(buf, "system\n");
	case 1:
		val = get_unaligned_be16(&caps->cap) * 1000000ULL;
		break;
	case 2:
		val = get_unaligned_be16(&caps->system_power) * 1000000ULL;
		break;
	case 3:
		val = get_unaligned_be16(&caps->n_cap) * 1000000ULL;
		break;
	case 4:
		val = get_unaligned_be16(&caps->max) * 1000000ULL;
		break;
	case 5:
		val = get_unaligned_be16(&caps->hard_min) * 1000000ULL;
		break;
	case 6:
		val = get_unaligned_be16(&caps->user) * 1000000ULL;
		break;
	case 7:
		val = caps->user_source;
		break;
	case 8:
		val = get_unaligned_be16(&caps->soft_min) * 1000000ULL;
		break;
	default:
		return -EINVAL;
	}

	return sysfs_emit(buf, "%llu\n", val);
}

static ssize_t occ_store_caps_user(struct device *dev,
				   struct device_attribute *attr,
				   const char *buf, size_t count)
{
	int rc;
	u16 user_power_cap;
	unsigned long long value;
	struct occ *occ = dev_get_drvdata(dev);

	rc = kstrtoull(buf, 0, &value);
	if (rc)
		return rc;

	user_power_cap = div64_u64(value, 1000000ULL); /* microwatt to watt */

	rc = occ_set_user_power_cap(occ, user_power_cap);
	if (rc)
		return rc;

	return count;
}

static ssize_t occ_show_extended(struct device *dev,
				 struct device_attribute *attr, char *buf)
{
	int rc;
	struct extended_sensor *extn;
	struct occ *occ = dev_get_drvdata(dev);
	struct occ_sensors *sensors = &occ->sensors;
	struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr);

	rc = occ_update_response(occ);
	if (rc)
		return rc;

	extn = ((struct extended_sensor *)sensors->extended.data) +
		sattr->index;

	switch (sattr->nr) {
	case 0:
		if (extn->flags & EXTN_FLAG_SENSOR_ID) {
			rc = sysfs_emit(buf, "%u\n",
					get_unaligned_be32(&extn->sensor_id));
		} else {
			rc = sysfs_emit(buf, "%4phN\n", extn->name);
		}
		break;
	case 1:
		rc = sysfs_emit(buf, "%02x\n", extn->flags);
		break;
	case 2:
		rc = sysfs_emit(buf, "%6phN\n", extn->data);
		break;
	default:
		return -EINVAL;
	}

	return rc;
}

/*
 * A helper to make it easier to define an occ_attribute. Since these
 * are dynamically allocated, we cannot use the existing kernel macros which
 * stringify the name argument.
 */
__printf(7, 8)
static void occ_init_attribute(struct occ_attribute *attr, int mode,
	ssize_t (*show)(struct device *dev, struct device_attribute *attr, char *buf),
	ssize_t (*store)(struct device *dev, struct device_attribute *attr,
				   const char *buf, size_t count),
	int nr, int index, const char *fmt, ...)
{
	va_list args;

	va_start(args, fmt);
	vsnprintf(attr->name, sizeof(attr->name), fmt, args);
	va_end(args);

	attr->sensor.dev_attr.attr.name = attr->name;
	attr->sensor.dev_attr.attr.mode = mode;
	attr->sensor.dev_attr.show = show;
	attr->sensor.dev_attr.store = store;
	attr->sensor.index = index;
	attr->sensor.nr = nr;
}

/*
 * Allocate and instatiate sensor_device_attribute_2s. It's most efficient to
 * use our own instead of the built-in hwmon attribute types.
 */
static int occ_setup_sensor_attrs(struct occ *occ)
{
	unsigned int i, s, num_attrs = 0;
	struct device *dev = occ->bus_dev;
	struct occ_sensors *sensors = &occ->sensors;
	struct occ_attribute *attr;
	struct temp_sensor_2 *temp;
	ssize_t (*show_temp)(struct device *, struct device_attribute *,
			     char *) = occ_show_temp_1;
	ssize_t (*show_freq)(struct device *, struct device_attribute *,
			     char *) = occ_show_freq_1;
	ssize_t (*show_power)(struct device *, struct device_attribute *,
			      char *) = occ_show_power_1;
	ssize_t (*show_caps)(struct device *, struct device_attribute *,
			     char *) = occ_show_caps_1_2;

	switch (sensors->temp.version) {
	case 1:
		num_attrs += (sensors->temp.num_sensors * 2);
		break;
	case 2:
		num_attrs += (sensors->temp.num_sensors * 4);
		show_temp = occ_show_temp_2;
		break;
	case 0x10:
		num_attrs += (sensors->temp.num_sensors * 5);
		show_temp = occ_show_temp_10;
		break;
	default:
		sensors->temp.num_sensors = 0;
	}

	switch (sensors->freq.version) {
	case 2:
		show_freq = occ_show_freq_2;
		fallthrough;
	case 1:
		num_attrs += (sensors->freq.num_sensors * 2);
		break;
	default:
		sensors->freq.num_sensors = 0;
	}

	switch (sensors->power.version) {
	case 2:
		show_power = occ_show_power_2;
		fallthrough;
	case 1:
		num_attrs += (sensors->power.num_sensors * 4);
		break;
	case 0xA0:
		num_attrs += (sensors->power.num_sensors * 16);
		show_power = occ_show_power_a0;
		break;
	default:
		sensors->power.num_sensors = 0;
	}

	switch (sensors->caps.version) {
	case 1:
		num_attrs += (sensors->caps.num_sensors * 7);
		break;
	case 2:
		num_attrs += (sensors->caps.num_sensors * 8);
		break;
	case 3:
		show_caps = occ_show_caps_3;
		num_attrs += (sensors->caps.num_sensors * 9);
		break;
	default:
		sensors->caps.num_sensors = 0;
	}

	switch (sensors->extended.version) {
	case 1:
		num_attrs += (sensors->extended.num_sensors * 3);
		break;
	default:
		sensors->extended.num_sensors = 0;
	}

	occ->attrs = devm_kcalloc(dev, num_attrs, sizeof(*occ->attrs),
				  GFP_KERNEL);
	if (!occ->attrs)
		return -ENOMEM;

	/* null-terminated list */
	occ->group.attrs = devm_kcalloc(dev, num_attrs + 1,
					sizeof(*occ->group.attrs),
					GFP_KERNEL);
	if (!occ->group.attrs)
		return -ENOMEM;

	attr = occ->attrs;

	for (i = 0; i < sensors->temp.num_sensors; ++i) {
		s = i + 1;
		temp = ((struct temp_sensor_2 *)sensors->temp.data) + i;

		occ_init_attribute(attr, 0444, show_temp, NULL,
				   0, i, "temp%d_label", s);
		attr++;

		if (sensors->temp.version == 2 &&
		    temp->fru_type == OCC_FRU_TYPE_VRM) {
			occ_init_attribute(attr, 0444, show_temp, NULL,
					   1, i, "temp%d_alarm", s);
		} else {
			occ_init_attribute(attr, 0444, show_temp, NULL,
					   1, i, "temp%d_input", s);
		}

		attr++;

		if (sensors->temp.version > 1) {
			occ_init_attribute(attr, 0444, show_temp, NULL,
					   2, i, "temp%d_fru_type", s);
			attr++;

			occ_init_attribute(attr, 0444, show_temp, NULL,
					   3, i, "temp%d_fault", s);
			attr++;

			if (sensors->temp.version == 0x10) {
				occ_init_attribute(attr, 0444, show_temp, NULL,
						   4, i, "temp%d_max", s);
				attr++;
			}
		}
	}

	for (i = 0; i < sensors->freq.num_sensors; ++i) {
		s = i + 1;

		occ_init_attribute(attr, 0444, show_freq, NULL,
				   0, i, "freq%d_label", s);
		attr++;

		occ_init_attribute(attr, 0444, show_freq, NULL,
				   1, i, "freq%d_input", s);
		attr++;
	}

	if (sensors->power.version == 0xA0) {
		/*
		 * Special case for many-attribute power sensor. Split it into
		 * a sensor number per power type, emulating several sensors.
		 */
		for (i = 0; i < sensors->power.num_sensors; ++i) {
			unsigned int j;
			unsigned int nr = 0;

			s = (i * 4) + 1;

			for (j = 0; j < 4; ++j) {
				occ_init_attribute(attr, 0444, show_power,
						   NULL, nr++, i,
						   "power%d_label", s);
				attr++;

				occ_init_attribute(attr, 0444, show_power,
						   NULL, nr++, i,
						   "power%d_average", s);
				attr++;

				occ_init_attribute(attr, 0444, show_power,
						   NULL, nr++, i,
						   "power%d_average_interval", s);
				attr++;

				occ_init_attribute(attr, 0444, show_power,
						   NULL, nr++, i,
						   "power%d_input", s);
				attr++;

				s++;
			}
		}

		s = (sensors->power.num_sensors * 4) + 1;
	} else {
		for (i = 0; i < sensors->power.num_sensors; ++i) {
			s = i + 1;

			occ_init_attribute(attr, 0444, show_power, NULL,
					   0, i, "power%d_label", s);
			attr++;

			occ_init_attribute(attr, 0444, show_power, NULL,
					   1, i, "power%d_average", s);
			attr++;

			occ_init_attribute(attr, 0444, show_power, NULL,
					   2, i, "power%d_average_interval", s);
			attr++;

			occ_init_attribute(attr, 0444, show_power, NULL,
					   3, i, "power%d_input", s);
			attr++;
		}

		s = sensors->power.num_sensors + 1;
	}

	if (sensors->caps.num_sensors >= 1) {
		occ_init_attribute(attr, 0444, show_caps, NULL,
				   0, 0, "power%d_label", s);
		attr++;

		occ_init_attribute(attr, 0444, show_caps, NULL,
				   1, 0, "power%d_cap", s);
		attr++;

		occ_init_attribute(attr, 0444, show_caps, NULL,
				   2, 0, "power%d_input", s);
		attr++;

		occ_init_attribute(attr, 0444, show_caps, NULL,
				   3, 0, "power%d_cap_not_redundant", s);
		attr++;

		occ_init_attribute(attr, 0444, show_caps, NULL,
				   4, 0, "power%d_cap_max", s);
		attr++;

		occ_init_attribute(attr, 0444, show_caps, NULL,
				   5, 0, "power%d_cap_min", s);
		attr++;

		occ_init_attribute(attr, 0644, show_caps, occ_store_caps_user,
				   6, 0, "power%d_cap_user", s);
		attr++;

		if (sensors->caps.version > 1) {
			occ_init_attribute(attr, 0444, show_caps, NULL,
					   7, 0, "power%d_cap_user_source", s);
			attr++;

			if (sensors->caps.version > 2) {
				occ_init_attribute(attr, 0444, show_caps, NULL,
						   8, 0,
						   "power%d_cap_min_soft", s);
				attr++;
			}
		}
	}

	for (i = 0; i < sensors->extended.num_sensors; ++i) {
		s = i + 1;

		occ_init_attribute(attr, 0444, occ_show_extended, NULL,
				   0, i, "extn%d_label", s);
		attr++;

		occ_init_attribute(attr, 0444, occ_show_extended, NULL,
				   1, i, "extn%d_flags", s);
		attr++;

		occ_init_attribute(attr, 0444, occ_show_extended, NULL,
				   2, i, "extn%d_input", s);
		attr++;
	}

	/* put the sensors in the group */
	for (i = 0; i < num_attrs; ++i) {
		sysfs_attr_init(&occ->attrs[i].sensor.dev_attr.attr);
		occ->group.attrs[i] = &occ->attrs[i].sensor.dev_attr.attr;
	}

	return 0;
}

/* only need to do this once at startup, as OCC won't change sensors on us */
static void occ_parse_poll_response(struct occ *occ)
{
	unsigned int i, old_offset, offset = 0, size = 0;
	struct occ_sensor *sensor;
	struct occ_sensors *sensors = &occ->sensors;
	struct occ_response *resp = &occ->resp;
	struct occ_poll_response *poll =
		(struct occ_poll_response *)&resp->data[0];
	struct occ_poll_response_header *header = &poll->header;
	struct occ_sensor_data_block *block = &poll->block;

	dev_info(occ->bus_dev, "OCC found, code level: %.16s\n",
		 header->occ_code_level);

	for (i = 0; i < header->num_sensor_data_blocks; ++i) {
		block = (struct occ_sensor_data_block *)((u8 *)block + offset);
		old_offset = offset;
		offset = (block->header.num_sensors *
			  block->header.sensor_length) + sizeof(block->header);
		size += offset;

		/* validate all the length/size fields */
		if ((size + sizeof(*header)) >= OCC_RESP_DATA_BYTES) {
			dev_warn(occ->bus_dev, "exceeded response buffer\n");
			return;
		}

		dev_dbg(occ->bus_dev, " %04x..%04x: %.4s (%d sensors)\n",
			old_offset, offset - 1, block->header.eye_catcher,
			block->header.num_sensors);

		/* match sensor block type */
		if (strncmp(block->header.eye_catcher, "TEMP", 4) == 0)
			sensor = &sensors->temp;
		else if (strncmp(block->header.eye_catcher, "FREQ", 4) == 0)
			sensor = &sensors->freq;
		else if (strncmp(block->header.eye_catcher, "POWR", 4) == 0)
			sensor = &sensors->power;
		else if (strncmp(block->header.eye_catcher, "CAPS", 4) == 0)
			sensor = &sensors->caps;
		else if (strncmp(block->header.eye_catcher, "EXTN", 4) == 0)
			sensor = &sensors->extended;
		else {
			dev_warn(occ->bus_dev, "sensor not supported %.4s\n",
				 block->header.eye_catcher);
			continue;
		}

		sensor->num_sensors = block->header.num_sensors;
		sensor->version = block->header.sensor_format;
		sensor->data = &block->data;
	}

	dev_dbg(occ->bus_dev, "Max resp size: %u+%zd=%zd\n", size,
		sizeof(*header), size + sizeof(*header));
}

int occ_active(struct occ *occ, bool active)
{
	int rc = mutex_lock_interruptible(&occ->lock);

	if (rc)
		return rc;

	if (active) {
		if (occ->active) {
			rc = -EALREADY;
			goto unlock;
		}

		occ->error_count = 0;
		occ->last_safe = 0;

		rc = occ_poll(occ);
		if (rc < 0) {
			dev_err(occ->bus_dev,
				"failed to get OCC poll response=%02x: %d\n",
				occ->resp.return_status, rc);
			goto unlock;
		}

		occ->active = true;
		occ->next_update = jiffies + OCC_UPDATE_FREQUENCY;
		occ_parse_poll_response(occ);

		rc = occ_setup_sensor_attrs(occ);
		if (rc) {
			dev_err(occ->bus_dev,
				"failed to setup sensor attrs: %d\n", rc);
			goto unlock;
		}

		occ->hwmon = hwmon_device_register_with_groups(occ->bus_dev,
							       "occ", occ,
							       occ->groups);
		if (IS_ERR(occ->hwmon)) {
			rc = PTR_ERR(occ->hwmon);
			occ->hwmon = NULL;
			dev_err(occ->bus_dev,
				"failed to register hwmon device: %d\n", rc);
			goto unlock;
		}
	} else {
		if (!occ->active) {
			rc = -EALREADY;
			goto unlock;
		}

		if (occ->hwmon)
			hwmon_device_unregister(occ->hwmon);
		occ->active = false;
		occ->hwmon = NULL;
	}

unlock:
	mutex_unlock(&occ->lock);
	return rc;
}

int occ_setup(struct occ *occ)
{
	int rc;

	mutex_init(&occ->lock);
	occ->groups[0] = &occ->group;

	rc = occ_setup_sysfs(occ);
	if (rc) {
		dev_err(occ->bus_dev, "failed to setup sysfs: %d\n", rc);
		return rc;
	}

	if (!device_property_read_bool(occ->bus_dev, "ibm,no-poll-on-init")) {
		rc = occ_active(occ, true);
		if (rc)
			occ_shutdown_sysfs(occ);
	}

	return rc;
}
EXPORT_SYMBOL_GPL(occ_setup);

void occ_shutdown(struct occ *occ)
{
	mutex_lock(&occ->lock);

	occ_shutdown_sysfs(occ);

	if (occ->hwmon)
		hwmon_device_unregister(occ->hwmon);
	occ->hwmon = NULL;

	mutex_unlock(&occ->lock);
}
EXPORT_SYMBOL_GPL(occ_shutdown);

MODULE_AUTHOR("Eddie James <eajames@linux.ibm.com>");
MODULE_DESCRIPTION("Common OCC hwmon code");
MODULE_LICENSE("GPL");