// 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");