// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2007-2009 Luca Tettamanti <kronos.it@gmail.com>
 *
 * See COPYING in the top level directory of the kernel tree.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/debugfs.h>
#include <linux/kernel.h>
#include <linux/hwmon.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/dmi.h>
#include <linux/jiffies.h>
#include <linux/err.h>
#include <linux/acpi.h>
#include <linux/string_choices.h>

#define ATK_HID "ATK0110"

static bool new_if;
module_param(new_if, bool, 0);
MODULE_PARM_DESC(new_if, "Override detection heuristic and force the use of the new ATK0110 interface");

static const struct dmi_system_id __initconst atk_force_new_if[] = {
        {
                /* Old interface has broken MCH temp monitoring */
                .ident = "Asus Sabertooth X58",
                .matches = {
                        DMI_MATCH(DMI_BOARD_NAME, "SABERTOOTH X58")
                }
        }, {
                /* Old interface reads the same sensor for fan0 and fan1 */
                .ident = "Asus M5A78L",
                .matches = {
                        DMI_MATCH(DMI_BOARD_NAME, "M5A78L")
                }
        },
        { }
};

/*
 * Minimum time between readings, enforced in order to avoid
 * hogging the CPU.
 */
#define CACHE_TIME              HZ

#define BOARD_ID                "MBIF"
#define METHOD_ENUMERATE        "GGRP"
#define METHOD_READ             "GITM"
#define METHOD_WRITE            "SITM"
#define METHOD_OLD_READ_TMP     "RTMP"
#define METHOD_OLD_READ_VLT     "RVLT"
#define METHOD_OLD_READ_FAN     "RFAN"
#define METHOD_OLD_ENUM_TMP     "TSIF"
#define METHOD_OLD_ENUM_VLT     "VSIF"
#define METHOD_OLD_ENUM_FAN     "FSIF"

#define ATK_MUX_HWMON           0x00000006ULL
#define ATK_MUX_MGMT            0x00000011ULL

#define ATK_CLASS_MASK          0xff000000ULL
#define ATK_CLASS_FREQ_CTL      0x03000000ULL
#define ATK_CLASS_FAN_CTL       0x04000000ULL
#define ATK_CLASS_HWMON         0x06000000ULL
#define ATK_CLASS_MGMT          0x11000000ULL

#define ATK_TYPE_MASK           0x00ff0000ULL
#define HWMON_TYPE_VOLT         0x00020000ULL
#define HWMON_TYPE_TEMP         0x00030000ULL
#define HWMON_TYPE_FAN          0x00040000ULL

#define ATK_ELEMENT_ID_MASK     0x0000ffffULL

#define ATK_EC_ID               0x11060004ULL

enum atk_pack_member {
        HWMON_PACK_FLAGS,
        HWMON_PACK_NAME,
        HWMON_PACK_LIMIT1,
        HWMON_PACK_LIMIT2,
        HWMON_PACK_ENABLE
};

/* New package format */
#define _HWMON_NEW_PACK_SIZE    7
#define _HWMON_NEW_PACK_FLAGS   0
#define _HWMON_NEW_PACK_NAME    1
#define _HWMON_NEW_PACK_UNK1    2
#define _HWMON_NEW_PACK_UNK2    3
#define _HWMON_NEW_PACK_LIMIT1  4
#define _HWMON_NEW_PACK_LIMIT2  5
#define _HWMON_NEW_PACK_ENABLE  6

/* Old package format */
#define _HWMON_OLD_PACK_SIZE    5
#define _HWMON_OLD_PACK_FLAGS   0
#define _HWMON_OLD_PACK_NAME    1
#define _HWMON_OLD_PACK_LIMIT1  2
#define _HWMON_OLD_PACK_LIMIT2  3
#define _HWMON_OLD_PACK_ENABLE  4


struct atk_data {
        struct device *hwmon_dev;
        acpi_handle atk_handle;
        struct acpi_device *acpi_dev;

        bool old_interface;

        /* old interface */
        acpi_handle rtmp_handle;
        acpi_handle rvlt_handle;
        acpi_handle rfan_handle;
        /* new interface */
        acpi_handle enumerate_handle;
        acpi_handle read_handle;
        acpi_handle write_handle;

        bool disable_ec;

        int voltage_count;
        int temperature_count;
        int fan_count;
        struct list_head sensor_list;
        struct attribute_group attr_group;
        const struct attribute_group *attr_groups[2];

        struct {
                struct dentry *root;
                u32 id;
        } debugfs;
};


typedef ssize_t (*sysfs_show_func)(struct device *dev,
                        struct device_attribute *attr, char *buf);

static const struct acpi_device_id atk_ids[] = {
        {ATK_HID, 0},
        {"", 0},
};
MODULE_DEVICE_TABLE(acpi, atk_ids);

#define ATTR_NAME_SIZE 16 /* Worst case is "tempN_input" */

struct atk_sensor_data {
        struct list_head list;
        struct atk_data *data;
        struct device_attribute label_attr;
        struct device_attribute input_attr;
        struct device_attribute limit1_attr;
        struct device_attribute limit2_attr;
        char label_attr_name[ATTR_NAME_SIZE];
        char input_attr_name[ATTR_NAME_SIZE];
        char limit1_attr_name[ATTR_NAME_SIZE];
        char limit2_attr_name[ATTR_NAME_SIZE];
        u64 id;
        u64 type;
        u64 limit1;
        u64 limit2;
        u64 cached_value;
        unsigned long last_updated; /* in jiffies */
        bool is_valid;
        char const *acpi_name;
};

/*
 * Return buffer format:
 * [0-3] "value" is valid flag
 * [4-7] value
 * [8- ] unknown stuff on newer mobos
 */
struct atk_acpi_ret_buffer {
        u32 flags;
        u32 value;
        u8 data[];
};

/* Input buffer used for GITM and SITM methods */
struct atk_acpi_input_buf {
        u32 id;
        u32 param1;
        u32 param2;
};

static int atk_add(struct acpi_device *device);
static void atk_remove(struct acpi_device *device);
static void atk_print_sensor(struct atk_data *data, union acpi_object *obj);
static int atk_read_value(struct atk_sensor_data *sensor, u64 *value);

static struct acpi_driver atk_driver = {
        .name   = ATK_HID,
        .class  = "hwmon",
        .ids    = atk_ids,
        .ops    = {
                .add    = atk_add,
                .remove = atk_remove,
        },
};

#define input_to_atk_sensor(attr) \
        container_of(attr, struct atk_sensor_data, input_attr)

#define label_to_atk_sensor(attr) \
        container_of(attr, struct atk_sensor_data, label_attr)

#define limit1_to_atk_sensor(attr) \
        container_of(attr, struct atk_sensor_data, limit1_attr)

#define limit2_to_atk_sensor(attr) \
        container_of(attr, struct atk_sensor_data, limit2_attr)

static ssize_t atk_input_show(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        struct atk_sensor_data *s = input_to_atk_sensor(attr);
        u64 value;
        int err;

        err = atk_read_value(s, &value);
        if (err)
                return err;

        if (s->type == HWMON_TYPE_TEMP)
                /* ACPI returns decidegree */
                value *= 100;

        return sprintf(buf, "%llu\n", value);
}

static ssize_t atk_label_show(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        struct atk_sensor_data *s = label_to_atk_sensor(attr);

        return sprintf(buf, "%s\n", s->acpi_name);
}

static ssize_t atk_limit1_show(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        struct atk_sensor_data *s = limit1_to_atk_sensor(attr);
        u64 value = s->limit1;

        if (s->type == HWMON_TYPE_TEMP)
                value *= 100;

        return sprintf(buf, "%lld\n", value);
}

static ssize_t atk_limit2_show(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        struct atk_sensor_data *s = limit2_to_atk_sensor(attr);
        u64 value = s->limit2;

        if (s->type == HWMON_TYPE_TEMP)
                value *= 100;

        return sprintf(buf, "%lld\n", value);
}

static void atk_init_attribute(struct device_attribute *attr, char *name,
                sysfs_show_func show)
{
        sysfs_attr_init(&attr->attr);
        attr->attr.name = name;
        attr->attr.mode = 0444;
        attr->show = show;
        attr->store = NULL;
}


static union acpi_object *atk_get_pack_member(struct atk_data *data,
                                                union acpi_object *pack,
                                                enum atk_pack_member m)
{
        bool old_if = data->old_interface;
        int offset;

        switch (m) {
        case HWMON_PACK_FLAGS:
                offset = old_if ? _HWMON_OLD_PACK_FLAGS : _HWMON_NEW_PACK_FLAGS;
                break;
        case HWMON_PACK_NAME:
                offset = old_if ? _HWMON_OLD_PACK_NAME : _HWMON_NEW_PACK_NAME;
                break;
        case HWMON_PACK_LIMIT1:
                offset = old_if ? _HWMON_OLD_PACK_LIMIT1 :
                                  _HWMON_NEW_PACK_LIMIT1;
                break;
        case HWMON_PACK_LIMIT2:
                offset = old_if ? _HWMON_OLD_PACK_LIMIT2 :
                                  _HWMON_NEW_PACK_LIMIT2;
                break;
        case HWMON_PACK_ENABLE:
                offset = old_if ? _HWMON_OLD_PACK_ENABLE :
                                  _HWMON_NEW_PACK_ENABLE;
                break;
        default:
                return NULL;
        }

        return &pack->package.elements[offset];
}


/*
 * New package format is:
 * - flag (int)
 *      class - used for de-muxing the request to the correct GITn
 *      type (volt, temp, fan)
 *      sensor id |
 *      sensor id - used for de-muxing the request _inside_ the GITn
 * - name (str)
 * - unknown (int)
 * - unknown (int)
 * - limit1 (int)
 * - limit2 (int)
 * - enable (int)
 *
 * The old package has the same format but it's missing the two unknown fields.
 */
static int validate_hwmon_pack(struct atk_data *data, union acpi_object *obj)
{
        struct device *dev = &data->acpi_dev->dev;
        union acpi_object *tmp;
        bool old_if = data->old_interface;
        int const expected_size = old_if ? _HWMON_OLD_PACK_SIZE :
                                           _HWMON_NEW_PACK_SIZE;

        if (obj->type != ACPI_TYPE_PACKAGE) {
                dev_warn(dev, "Invalid type: %d\n", obj->type);
                return -EINVAL;
        }

        if (obj->package.count != expected_size) {
                dev_warn(dev, "Invalid package size: %d, expected: %d\n",
                                obj->package.count, expected_size);
                return -EINVAL;
        }

        tmp = atk_get_pack_member(data, obj, HWMON_PACK_FLAGS);
        if (tmp->type != ACPI_TYPE_INTEGER) {
                dev_warn(dev, "Invalid type (flag): %d\n", tmp->type);
                return -EINVAL;
        }

        tmp = atk_get_pack_member(data, obj, HWMON_PACK_NAME);
        if (tmp->type != ACPI_TYPE_STRING) {
                dev_warn(dev, "Invalid type (name): %d\n", tmp->type);
                return -EINVAL;
        }

        /* Don't check... we don't know what they're useful for anyway */
#if 0
        tmp = &obj->package.elements[HWMON_PACK_UNK1];
        if (tmp->type != ACPI_TYPE_INTEGER) {
                dev_warn(dev, "Invalid type (unk1): %d\n", tmp->type);
                return -EINVAL;
        }

        tmp = &obj->package.elements[HWMON_PACK_UNK2];
        if (tmp->type != ACPI_TYPE_INTEGER) {
                dev_warn(dev, "Invalid type (unk2): %d\n", tmp->type);
                return -EINVAL;
        }
#endif

        tmp = atk_get_pack_member(data, obj, HWMON_PACK_LIMIT1);
        if (tmp->type != ACPI_TYPE_INTEGER) {
                dev_warn(dev, "Invalid type (limit1): %d\n", tmp->type);
                return -EINVAL;
        }

        tmp = atk_get_pack_member(data, obj, HWMON_PACK_LIMIT2);
        if (tmp->type != ACPI_TYPE_INTEGER) {
                dev_warn(dev, "Invalid type (limit2): %d\n", tmp->type);
                return -EINVAL;
        }

        tmp = atk_get_pack_member(data, obj, HWMON_PACK_ENABLE);
        if (tmp->type != ACPI_TYPE_INTEGER) {
                dev_warn(dev, "Invalid type (enable): %d\n", tmp->type);
                return -EINVAL;
        }

        atk_print_sensor(data, obj);

        return 0;
}

#ifdef DEBUG
static char const *atk_sensor_type(union acpi_object *flags)
{
        u64 type = flags->integer.value & ATK_TYPE_MASK;
        char const *what;

        switch (type) {
        case HWMON_TYPE_VOLT:
                what = "voltage";
                break;
        case HWMON_TYPE_TEMP:
                what = "temperature";
                break;
        case HWMON_TYPE_FAN:
                what = "fan";
                break;
        default:
                what = "unknown";
                break;
        }

        return what;
}
#endif

static void atk_print_sensor(struct atk_data *data, union acpi_object *obj)
{
#ifdef DEBUG
        struct device *dev = &data->acpi_dev->dev;
        union acpi_object *flags;
        union acpi_object *name;
        union acpi_object *limit1;
        union acpi_object *limit2;
        union acpi_object *enable;
        char const *what;

        flags = atk_get_pack_member(data, obj, HWMON_PACK_FLAGS);
        name = atk_get_pack_member(data, obj, HWMON_PACK_NAME);
        limit1 = atk_get_pack_member(data, obj, HWMON_PACK_LIMIT1);
        limit2 = atk_get_pack_member(data, obj, HWMON_PACK_LIMIT2);
        enable = atk_get_pack_member(data, obj, HWMON_PACK_ENABLE);

        what = atk_sensor_type(flags);

        dev_dbg(dev, "%s: %#llx %s [%llu-%llu] %s\n", what,
                        flags->integer.value,
                        name->string.pointer,
                        limit1->integer.value, limit2->integer.value,
                        str_enabled_disabled(enable->integer.value));
#endif
}

static int atk_read_value_old(struct atk_sensor_data *sensor, u64 *value)
{
        struct atk_data *data = sensor->data;
        struct device *dev = &data->acpi_dev->dev;
        struct acpi_object_list params;
        union acpi_object id;
        acpi_status status;
        acpi_handle method;

        switch (sensor->type) {
        case HWMON_TYPE_VOLT:
                method = data->rvlt_handle;
                break;
        case HWMON_TYPE_TEMP:
                method = data->rtmp_handle;
                break;
        case HWMON_TYPE_FAN:
                method = data->rfan_handle;
                break;
        default:
                return -EINVAL;
        }

        id.type = ACPI_TYPE_INTEGER;
        id.integer.value = sensor->id;

        params.count = 1;
        params.pointer = &id;

        status = acpi_evaluate_integer(method, NULL, &params, value);
        if (status != AE_OK) {
                dev_warn(dev, "%s: ACPI exception: %s\n", __func__,
                                acpi_format_exception(status));
                return -EIO;
        }

        return 0;
}

static union acpi_object *atk_ggrp(struct atk_data *data, u16 mux)
{
        struct device *dev = &data->acpi_dev->dev;
        struct acpi_buffer buf;
        acpi_status ret;
        struct acpi_object_list params;
        union acpi_object id;
        union acpi_object *pack;

        id.type = ACPI_TYPE_INTEGER;
        id.integer.value = mux;
        params.count = 1;
        params.pointer = &id;

        buf.length = ACPI_ALLOCATE_BUFFER;
        ret = acpi_evaluate_object(data->enumerate_handle, NULL, &params, &buf);
        if (ret != AE_OK) {
                dev_err(dev, "GGRP[%#x] ACPI exception: %s\n", mux,
                                acpi_format_exception(ret));
                return ERR_PTR(-EIO);
        }
        pack = buf.pointer;
        if (pack->type != ACPI_TYPE_PACKAGE) {
                /* Execution was successful, but the id was not found */
                ACPI_FREE(pack);
                return ERR_PTR(-ENOENT);
        }

        if (pack->package.count < 1) {
                dev_err(dev, "GGRP[%#x] package is too small\n", mux);
                ACPI_FREE(pack);
                return ERR_PTR(-EIO);
        }
        return pack;
}

static union acpi_object *atk_gitm(struct atk_data *data, u64 id)
{
        struct device *dev = &data->acpi_dev->dev;
        struct atk_acpi_input_buf buf;
        union acpi_object tmp;
        struct acpi_object_list params;
        struct acpi_buffer ret;
        union acpi_object *obj;
        acpi_status status;

        buf.id = id;
        buf.param1 = 0;
        buf.param2 = 0;

        tmp.type = ACPI_TYPE_BUFFER;
        tmp.buffer.pointer = (u8 *)&buf;
        tmp.buffer.length = sizeof(buf);

        params.count = 1;
        params.pointer = (void *)&tmp;

        ret.length = ACPI_ALLOCATE_BUFFER;
        status = acpi_evaluate_object_typed(data->read_handle, NULL, &params,
                        &ret, ACPI_TYPE_BUFFER);
        if (status != AE_OK) {
                dev_warn(dev, "GITM[%#llx] ACPI exception: %s\n", id,
                                acpi_format_exception(status));
                return ERR_PTR(-EIO);
        }
        obj = ret.pointer;

        /* Sanity check */
        if (obj->buffer.length < 8) {
                dev_warn(dev, "Unexpected ASBF length: %u\n",
                                obj->buffer.length);
                ACPI_FREE(obj);
                return ERR_PTR(-EIO);
        }
        return obj;
}

static union acpi_object *atk_sitm(struct atk_data *data,
                struct atk_acpi_input_buf *buf)
{
        struct device *dev = &data->acpi_dev->dev;
        struct acpi_object_list params;
        union acpi_object tmp;
        struct acpi_buffer ret;
        union acpi_object *obj;
        acpi_status status;

        tmp.type = ACPI_TYPE_BUFFER;
        tmp.buffer.pointer = (u8 *)buf;
        tmp.buffer.length = sizeof(*buf);

        params.count = 1;
        params.pointer = &tmp;

        ret.length = ACPI_ALLOCATE_BUFFER;
        status = acpi_evaluate_object_typed(data->write_handle, NULL, &params,
                        &ret, ACPI_TYPE_BUFFER);
        if (status != AE_OK) {
                dev_warn(dev, "SITM[%#x] ACPI exception: %s\n", buf->id,
                                acpi_format_exception(status));
                return ERR_PTR(-EIO);
        }
        obj = ret.pointer;

        /* Sanity check */
        if (obj->buffer.length < 8) {
                dev_warn(dev, "Unexpected ASBF length: %u\n",
                                obj->buffer.length);
                ACPI_FREE(obj);
                return ERR_PTR(-EIO);
        }
        return obj;
}

static int atk_read_value_new(struct atk_sensor_data *sensor, u64 *value)
{
        struct atk_data *data = sensor->data;
        struct device *dev = &data->acpi_dev->dev;
        union acpi_object *obj;
        struct atk_acpi_ret_buffer *buf;
        int err = 0;

        obj = atk_gitm(data, sensor->id);
        if (IS_ERR(obj))
                return PTR_ERR(obj);

        buf = (struct atk_acpi_ret_buffer *)obj->buffer.pointer;
        if (buf->flags == 0) {
                /*
                 * The reading is not valid, possible causes:
                 * - sensor failure
                 * - enumeration was FUBAR (and we didn't notice)
                 */
                dev_warn(dev, "Read failed, sensor = %#llx\n", sensor->id);
                err = -EIO;
                goto out;
        }

        *value = buf->value;
out:
        ACPI_FREE(obj);
        return err;
}

static int atk_read_value(struct atk_sensor_data *sensor, u64 *value)
{
        int err;

        if (!sensor->is_valid ||
            time_after(jiffies, sensor->last_updated + CACHE_TIME)) {
                if (sensor->data->old_interface)
                        err = atk_read_value_old(sensor, value);
                else
                        err = atk_read_value_new(sensor, value);

                if (err)
                        return err;

                sensor->is_valid = true;
                sensor->last_updated = jiffies;
                sensor->cached_value = *value;
        } else {
                *value = sensor->cached_value;
                err = 0;
        }

        return err;
}

#ifdef CONFIG_DEBUG_FS
static int atk_debugfs_gitm_get(void *p, u64 *val)
{
        struct atk_data *data = p;
        union acpi_object *ret;
        struct atk_acpi_ret_buffer *buf;
        int err = 0;

        if (!data->read_handle)
                return -ENODEV;

        if (!data->debugfs.id)
                return -EINVAL;

        ret = atk_gitm(data, data->debugfs.id);
        if (IS_ERR(ret))
                return PTR_ERR(ret);

        buf = (struct atk_acpi_ret_buffer *)ret->buffer.pointer;
        if (buf->flags)
                *val = buf->value;
        else
                err = -EIO;

        ACPI_FREE(ret);
        return err;
}

DEFINE_DEBUGFS_ATTRIBUTE(atk_debugfs_gitm, atk_debugfs_gitm_get, NULL,
                         "0x%08llx\n");

static int atk_acpi_print(char *buf, size_t sz, union acpi_object *obj)
{
        int ret = 0;

        switch (obj->type) {
        case ACPI_TYPE_INTEGER:
                ret = snprintf(buf, sz, "0x%08llx\n", obj->integer.value);
                break;
        case ACPI_TYPE_STRING:
                ret = snprintf(buf, sz, "%s\n", obj->string.pointer);
                break;
        }

        return ret;
}

static void atk_pack_print(char *buf, size_t sz, union acpi_object *pack)
{
        int ret;
        int i;

        for (i = 0; i < pack->package.count; i++) {
                union acpi_object *obj = &pack->package.elements[i];

                ret = atk_acpi_print(buf, sz, obj);
                if (ret >= sz)
                        break;
                buf += ret;
                sz -= ret;
        }
}

static int atk_debugfs_ggrp_open(struct inode *inode, struct file *file)
{
        struct atk_data *data = inode->i_private;
        char *buf = NULL;
        union acpi_object *ret;
        u8 cls;
        int i;

        if (!data->enumerate_handle)
                return -ENODEV;
        if (!data->debugfs.id)
                return -EINVAL;

        cls = (data->debugfs.id & 0xff000000) >> 24;
        ret = atk_ggrp(data, cls);
        if (IS_ERR(ret))
                return PTR_ERR(ret);

        for (i = 0; i < ret->package.count; i++) {
                union acpi_object *pack = &ret->package.elements[i];
                union acpi_object *id;

                if (pack->type != ACPI_TYPE_PACKAGE)
                        continue;
                if (!pack->package.count)
                        continue;
                id = &pack->package.elements[0];
                if (id->integer.value == data->debugfs.id) {
                        /* Print the package */
                        buf = kzalloc(512, GFP_KERNEL);
                        if (!buf) {
                                ACPI_FREE(ret);
                                return -ENOMEM;
                        }
                        atk_pack_print(buf, 512, pack);
                        break;
                }
        }
        ACPI_FREE(ret);

        if (!buf)
                return -EINVAL;

        file->private_data = buf;

        return nonseekable_open(inode, file);
}

static ssize_t atk_debugfs_ggrp_read(struct file *file, char __user *buf,
                size_t count, loff_t *pos)
{
        char *str = file->private_data;
        size_t len = strlen(str);

        return simple_read_from_buffer(buf, count, pos, str, len);
}

static int atk_debugfs_ggrp_release(struct inode *inode, struct file *file)
{
        kfree(file->private_data);
        return 0;
}

static const struct file_operations atk_debugfs_ggrp_fops = {
        .read           = atk_debugfs_ggrp_read,
        .open           = atk_debugfs_ggrp_open,
        .release        = atk_debugfs_ggrp_release,
};

static void atk_debugfs_init(struct atk_data *data)
{
        struct dentry *d;

        data->debugfs.id = 0;

        d = debugfs_create_dir("asus_atk0110", NULL);

        debugfs_create_x32("id", 0600, d, &data->debugfs.id);
        debugfs_create_file_unsafe("gitm", 0400, d, data, &atk_debugfs_gitm);
        debugfs_create_file("ggrp", 0400, d, data, &atk_debugfs_ggrp_fops);

        data->debugfs.root = d;
}

static void atk_debugfs_cleanup(struct atk_data *data)
{
        debugfs_remove_recursive(data->debugfs.root);
}

#else /* CONFIG_DEBUG_FS */

static void atk_debugfs_init(struct atk_data *data)
{
}

static void atk_debugfs_cleanup(struct atk_data *data)
{
}
#endif

static int atk_add_sensor(struct atk_data *data, union acpi_object *obj)
{
        struct device *dev = &data->acpi_dev->dev;
        union acpi_object *flags;
        union acpi_object *name;
        union acpi_object *limit1;
        union acpi_object *limit2;
        union acpi_object *enable;
        struct atk_sensor_data *sensor;
        char const *base_name;
        char const *limit1_name;
        char const *limit2_name;
        u64 type;
        int err;
        int *num;
        int start;

        if (obj->type != ACPI_TYPE_PACKAGE) {
                /* wft is this? */
                dev_warn(dev, "Unknown type for ACPI object: (%d)\n",
                                obj->type);
                return -EINVAL;
        }

        err = validate_hwmon_pack(data, obj);
        if (err)
                return err;

        /* Ok, we have a valid hwmon package */
        type = atk_get_pack_member(data, obj, HWMON_PACK_FLAGS)->integer.value
               & ATK_TYPE_MASK;

        switch (type) {
        case HWMON_TYPE_VOLT:
                base_name = "in";
                limit1_name = "min";
                limit2_name = "max";
                num = &data->voltage_count;
                start = 0;
                break;
        case HWMON_TYPE_TEMP:
                base_name = "temp";
                limit1_name = "max";
                limit2_name = "crit";
                num = &data->temperature_count;
                start = 1;
                break;
        case HWMON_TYPE_FAN:
                base_name = "fan";
                limit1_name = "min";
                limit2_name = "max";
                num = &data->fan_count;
                start = 1;
                break;
        default:
                dev_warn(dev, "Unknown sensor type: %#llx\n", type);
                return -EINVAL;
        }

        enable = atk_get_pack_member(data, obj, HWMON_PACK_ENABLE);
        if (!enable->integer.value)
                /* sensor is disabled */
                return 0;

        flags = atk_get_pack_member(data, obj, HWMON_PACK_FLAGS);
        name = atk_get_pack_member(data, obj, HWMON_PACK_NAME);
        limit1 = atk_get_pack_member(data, obj, HWMON_PACK_LIMIT1);
        limit2 = atk_get_pack_member(data, obj, HWMON_PACK_LIMIT2);

        sensor = devm_kzalloc(dev, sizeof(*sensor), GFP_KERNEL);
        if (!sensor)
                return -ENOMEM;

        sensor->acpi_name = devm_kstrdup(dev, name->string.pointer, GFP_KERNEL);
        if (!sensor->acpi_name)
                return -ENOMEM;

        INIT_LIST_HEAD(&sensor->list);
        sensor->type = type;
        sensor->data = data;
        sensor->id = flags->integer.value;
        sensor->limit1 = limit1->integer.value;
        if (data->old_interface)
                sensor->limit2 = limit2->integer.value;
        else
                /* The upper limit is expressed as delta from lower limit */
                sensor->limit2 = sensor->limit1 + limit2->integer.value;

        snprintf(sensor->input_attr_name, ATTR_NAME_SIZE,
                        "%s%d_input", base_name, start + *num);
        atk_init_attribute(&sensor->input_attr,
                        sensor->input_attr_name,
                        atk_input_show);

        snprintf(sensor->label_attr_name, ATTR_NAME_SIZE,
                        "%s%d_label", base_name, start + *num);
        atk_init_attribute(&sensor->label_attr,
                        sensor->label_attr_name,
                        atk_label_show);

        snprintf(sensor->limit1_attr_name, ATTR_NAME_SIZE,
                        "%s%d_%s", base_name, start + *num, limit1_name);
        atk_init_attribute(&sensor->limit1_attr,
                        sensor->limit1_attr_name,
                        atk_limit1_show);

        snprintf(sensor->limit2_attr_name, ATTR_NAME_SIZE,
                        "%s%d_%s", base_name, start + *num, limit2_name);
        atk_init_attribute(&sensor->limit2_attr,
                        sensor->limit2_attr_name,
                        atk_limit2_show);

        list_add(&sensor->list, &data->sensor_list);
        (*num)++;

        return 1;
}

static int atk_enumerate_old_hwmon(struct atk_data *data)
{
        struct device *dev = &data->acpi_dev->dev;
        struct acpi_buffer buf;
        union acpi_object *pack;
        acpi_status status;
        int i, ret;
        int count = 0;

        /* Voltages */
        buf.length = ACPI_ALLOCATE_BUFFER;
        status = acpi_evaluate_object_typed(data->atk_handle,
                        METHOD_OLD_ENUM_VLT, NULL, &buf, ACPI_TYPE_PACKAGE);
        if (status != AE_OK) {
                dev_warn(dev, METHOD_OLD_ENUM_VLT ": ACPI exception: %s\n",
                                acpi_format_exception(status));

                return -ENODEV;
        }

        pack = buf.pointer;
        for (i = 1; i < pack->package.count; i++) {
                union acpi_object *obj = &pack->package.elements[i];

                ret = atk_add_sensor(data, obj);
                if (ret > 0)
                        count++;
        }
        ACPI_FREE(buf.pointer);

        /* Temperatures */
        buf.length = ACPI_ALLOCATE_BUFFER;
        status = acpi_evaluate_object_typed(data->atk_handle,
                        METHOD_OLD_ENUM_TMP, NULL, &buf, ACPI_TYPE_PACKAGE);
        if (status != AE_OK) {
                dev_warn(dev, METHOD_OLD_ENUM_TMP ": ACPI exception: %s\n",
                                acpi_format_exception(status));

                return -ENODEV;
        }

        pack = buf.pointer;
        for (i = 1; i < pack->package.count; i++) {
                union acpi_object *obj = &pack->package.elements[i];

                ret = atk_add_sensor(data, obj);
                if (ret > 0)
                        count++;
        }
        ACPI_FREE(buf.pointer);

        /* Fans */
        buf.length = ACPI_ALLOCATE_BUFFER;
        status = acpi_evaluate_object_typed(data->atk_handle,
                        METHOD_OLD_ENUM_FAN, NULL, &buf, ACPI_TYPE_PACKAGE);
        if (status != AE_OK) {
                dev_warn(dev, METHOD_OLD_ENUM_FAN ": ACPI exception: %s\n",
                                acpi_format_exception(status));

                return -ENODEV;
        }

        pack = buf.pointer;
        for (i = 1; i < pack->package.count; i++) {
                union acpi_object *obj = &pack->package.elements[i];

                ret = atk_add_sensor(data, obj);
                if (ret > 0)
                        count++;
        }
        ACPI_FREE(buf.pointer);

        return count;
}

static int atk_ec_present(struct atk_data *data)
{
        struct device *dev = &data->acpi_dev->dev;
        union acpi_object *pack;
        union acpi_object *ec;
        int ret;
        int i;

        pack = atk_ggrp(data, ATK_MUX_MGMT);
        if (IS_ERR(pack)) {
                if (PTR_ERR(pack) == -ENOENT) {
                        /* The MGMT class does not exists - that's ok */
                        dev_dbg(dev, "Class %#llx not found\n", ATK_MUX_MGMT);
                        return 0;
                }
                return PTR_ERR(pack);
        }

        /* Search the EC */
        ec = NULL;
        for (i = 0; i < pack->package.count; i++) {
                union acpi_object *obj = &pack->package.elements[i];
                union acpi_object *id;

                if (obj->type != ACPI_TYPE_PACKAGE)
                        continue;

                id = &obj->package.elements[0];
                if (id->type != ACPI_TYPE_INTEGER)
                        continue;

                if (id->integer.value == ATK_EC_ID) {
                        ec = obj;
                        break;
                }
        }

        ret = (ec != NULL);
        if (!ret)
                /* The system has no EC */
                dev_dbg(dev, "EC not found\n");

        ACPI_FREE(pack);
        return ret;
}

static int atk_ec_enabled(struct atk_data *data)
{
        struct device *dev = &data->acpi_dev->dev;
        union acpi_object *obj;
        struct atk_acpi_ret_buffer *buf;
        int err;

        obj = atk_gitm(data, ATK_EC_ID);
        if (IS_ERR(obj)) {
                dev_err(dev, "Unable to query EC status\n");
                return PTR_ERR(obj);
        }
        buf = (struct atk_acpi_ret_buffer *)obj->buffer.pointer;

        if (buf->flags == 0) {
                dev_err(dev, "Unable to query EC status\n");
                err = -EIO;
        } else {
                err = (buf->value != 0);
                dev_dbg(dev, "EC is %s\n", str_enabled_disabled(err));
        }

        ACPI_FREE(obj);
        return err;
}

static int atk_ec_ctl(struct atk_data *data, int enable)
{
        struct device *dev = &data->acpi_dev->dev;
        union acpi_object *obj;
        struct atk_acpi_input_buf sitm;
        struct atk_acpi_ret_buffer *ec_ret;
        int err = 0;

        sitm.id = ATK_EC_ID;
        sitm.param1 = enable;
        sitm.param2 = 0;

        obj = atk_sitm(data, &sitm);
        if (IS_ERR(obj)) {
                dev_err(dev, "Failed to %s the EC\n", str_enable_disable(enable));
                return PTR_ERR(obj);
        }
        ec_ret = (struct atk_acpi_ret_buffer *)obj->buffer.pointer;
        if (ec_ret->flags == 0) {
                dev_err(dev, "Failed to %s the EC\n", str_enable_disable(enable));
                err = -EIO;
        } else {
                dev_info(dev, "EC %s\n", str_enabled_disabled(enable));
        }

        ACPI_FREE(obj);
        return err;
}

static int atk_enumerate_new_hwmon(struct atk_data *data)
{
        struct device *dev = &data->acpi_dev->dev;
        union acpi_object *pack;
        int err;
        int i;

        err = atk_ec_present(data);
        if (err < 0)
                return err;
        if (err) {
                err = atk_ec_enabled(data);
                if (err < 0)
                        return err;
                /* If the EC was disabled we will disable it again on unload */
                data->disable_ec = err;

                err = atk_ec_ctl(data, 1);
                if (err) {
                        data->disable_ec = false;
                        return err;
                }
        }

        dev_dbg(dev, "Enumerating hwmon sensors\n");

        pack = atk_ggrp(data, ATK_MUX_HWMON);
        if (IS_ERR(pack))
                return PTR_ERR(pack);

        for (i = 0; i < pack->package.count; i++) {
                union acpi_object *obj = &pack->package.elements[i];

                atk_add_sensor(data, obj);
        }

        err = data->voltage_count + data->temperature_count + data->fan_count;

        ACPI_FREE(pack);
        return err;
}

static int atk_init_attribute_groups(struct atk_data *data)
{
        struct device *dev = &data->acpi_dev->dev;
        struct atk_sensor_data *s;
        struct attribute **attrs;
        int i = 0;
        int len = (data->voltage_count + data->temperature_count
                        + data->fan_count) * 4 + 1;

        attrs = devm_kcalloc(dev, len, sizeof(struct attribute *), GFP_KERNEL);
        if (!attrs)
                return -ENOMEM;

        list_for_each_entry(s, &data->sensor_list, list) {
                attrs[i++] = &s->input_attr.attr;
                attrs[i++] = &s->label_attr.attr;
                attrs[i++] = &s->limit1_attr.attr;
                attrs[i++] = &s->limit2_attr.attr;
        }

        data->attr_group.attrs = attrs;
        data->attr_groups[0] = &data->attr_group;

        return 0;
}

static int atk_register_hwmon(struct atk_data *data)
{
        struct device *dev = &data->acpi_dev->dev;

        dev_dbg(dev, "registering hwmon device\n");
        data->hwmon_dev = hwmon_device_register_with_groups(dev, "atk0110",
                                                            data,
                                                            data->attr_groups);

        return PTR_ERR_OR_ZERO(data->hwmon_dev);
}

static int atk_probe_if(struct atk_data *data)
{
        struct device *dev = &data->acpi_dev->dev;
        acpi_handle ret;
        acpi_status status;
        int err = 0;

        /* RTMP: read temperature */
        status = acpi_get_handle(data->atk_handle, METHOD_OLD_READ_TMP, &ret);
        if (ACPI_SUCCESS(status))
                data->rtmp_handle = ret;
        else
                dev_dbg(dev, "method " METHOD_OLD_READ_TMP " not found: %s\n",
                                acpi_format_exception(status));

        /* RVLT: read voltage */
        status = acpi_get_handle(data->atk_handle, METHOD_OLD_READ_VLT, &ret);
        if (ACPI_SUCCESS(status))
                data->rvlt_handle = ret;
        else
                dev_dbg(dev, "method " METHOD_OLD_READ_VLT " not found: %s\n",
                                acpi_format_exception(status));

        /* RFAN: read fan status */
        status = acpi_get_handle(data->atk_handle, METHOD_OLD_READ_FAN, &ret);
        if (ACPI_SUCCESS(status))
                data->rfan_handle = ret;
        else
                dev_dbg(dev, "method " METHOD_OLD_READ_FAN " not found: %s\n",
                                acpi_format_exception(status));

        /* Enumeration */
        status = acpi_get_handle(data->atk_handle, METHOD_ENUMERATE, &ret);
        if (ACPI_SUCCESS(status))
                data->enumerate_handle = ret;
        else
                dev_dbg(dev, "method " METHOD_ENUMERATE " not found: %s\n",
                                acpi_format_exception(status));

        /* De-multiplexer (read) */
        status = acpi_get_handle(data->atk_handle, METHOD_READ, &ret);
        if (ACPI_SUCCESS(status))
                data->read_handle = ret;
        else
                dev_dbg(dev, "method " METHOD_READ " not found: %s\n",
                                acpi_format_exception(status));

        /* De-multiplexer (write) */
        status = acpi_get_handle(data->atk_handle, METHOD_WRITE, &ret);
        if (ACPI_SUCCESS(status))
                data->write_handle = ret;
        else
                dev_dbg(dev, "method " METHOD_WRITE " not found: %s\n",
                                 acpi_format_exception(status));

        /*
         * Check for hwmon methods: first check "old" style methods; note that
         * both may be present: in this case we stick to the old interface;
         * analysis of multiple DSDTs indicates that when both interfaces
         * are present the new one (GGRP/GITM) is not functional.
         */
        if (new_if)
                dev_info(dev, "Overriding interface detection\n");
        if (data->rtmp_handle &&
                        data->rvlt_handle && data->rfan_handle && !new_if)
                data->old_interface = true;
        else if (data->enumerate_handle && data->read_handle &&
                        data->write_handle)
                data->old_interface = false;
        else
                err = -ENODEV;

        return err;
}

static int atk_add(struct acpi_device *device)
{
        acpi_status ret;
        int err;
        struct acpi_buffer buf;
        union acpi_object *obj;
        struct atk_data *data;

        dev_dbg(&device->dev, "adding...\n");

        data = devm_kzalloc(&device->dev, sizeof(*data), GFP_KERNEL);
        if (!data)
                return -ENOMEM;

        data->acpi_dev = device;
        data->atk_handle = device->handle;
        INIT_LIST_HEAD(&data->sensor_list);
        data->disable_ec = false;

        buf.length = ACPI_ALLOCATE_BUFFER;
        ret = acpi_evaluate_object_typed(data->atk_handle, BOARD_ID, NULL,
                        &buf, ACPI_TYPE_PACKAGE);
        if (ret != AE_OK) {
                dev_dbg(&device->dev, "atk: method MBIF not found\n");
        } else {
                obj = buf.pointer;
                if (obj->package.count >= 2) {
                        union acpi_object *id = &obj->package.elements[1];
                        if (id->type == ACPI_TYPE_STRING)
                                dev_dbg(&device->dev, "board ID = %s\n",
                                        id->string.pointer);
                }
                ACPI_FREE(buf.pointer);
        }

        err = atk_probe_if(data);
        if (err) {
                dev_err(&device->dev, "No usable hwmon interface detected\n");
                goto out;
        }

        if (data->old_interface) {
                dev_dbg(&device->dev, "Using old hwmon interface\n");
                err = atk_enumerate_old_hwmon(data);
        } else {
                dev_dbg(&device->dev, "Using new hwmon interface\n");
                err = atk_enumerate_new_hwmon(data);
        }
        if (err < 0)
                goto out;
        if (err == 0) {
                dev_info(&device->dev,
                         "No usable sensor detected, bailing out\n");
                err = -ENODEV;
                goto out;
        }

        err = atk_init_attribute_groups(data);
        if (err)
                goto out;
        err = atk_register_hwmon(data);
        if (err)
                goto out;

        atk_debugfs_init(data);

        device->driver_data = data;
        return 0;
out:
        if (data->disable_ec)
                atk_ec_ctl(data, 0);
        return err;
}

static void atk_remove(struct acpi_device *device)
{
        struct atk_data *data = device->driver_data;
        dev_dbg(&device->dev, "removing...\n");

        device->driver_data = NULL;

        atk_debugfs_cleanup(data);

        hwmon_device_unregister(data->hwmon_dev);

        if (data->disable_ec) {
                if (atk_ec_ctl(data, 0))
                        dev_err(&device->dev, "Failed to disable EC\n");
        }
}

static int __init atk0110_init(void)
{
        int ret;

        /* Make sure it's safe to access the device through ACPI */
        if (!acpi_resources_are_enforced()) {
                pr_err("Resources not safely usable due to acpi_enforce_resources kernel parameter\n");
                return -EBUSY;
        }

        if (dmi_check_system(atk_force_new_if))
                new_if = true;

        ret = acpi_bus_register_driver(&atk_driver);
        if (ret)
                pr_info("acpi_bus_register_driver failed: %d\n", ret);

        return ret;
}

static void __exit atk0110_exit(void)
{
        acpi_bus_unregister_driver(&atk_driver);
}

module_init(atk0110_init);
module_exit(atk0110_exit);

MODULE_DESCRIPTION("ASUS ATK0110 driver");
MODULE_LICENSE("GPL");