#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/kobject.h>
#include <linux/sysfs.h>
#include <linux/acpi.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/delay.h>
#include "gpioregs.h"

#define IT87_REG_TEMP(nr)       (0x29 + (nr))

#define DEV             0x07
#define PME             0x04
#define REG_2E          0x2e
#define REG_4E          0x4e
#define DEVID           0x20
#define IT87_ACT_REG    0x30
#define IT87_BASE_REG   0x60
#define IT8786E_DEVID   0x8786
#define DRIVER_NAME     "tempperature_sysfs"

struct temp_data {
    unsigned short addr;
    struct mutex lock;
};


static struct temp_data *g_data = NULL;

extern struct kobject *hwmon_kobj;



static int ec_read_reg(struct temp_data *data, u8 reg)
{
    outb_p(reg, data->addr + 0);
    return inb_p(data->addr + 1);
}

static ssize_t temp1_input_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
{
    struct temp_data *data = g_data;
    int val;
    mutex_lock(&data->lock);
    val = ((s8)ec_read_reg(data, IT87_REG_TEMP(0)));
    mutex_unlock(&data->lock);
    return sprintf(buf, "%d\n", val);
}

static ssize_t temp2_input_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
{
    struct temp_data *data = g_data;
    int val;
    mutex_lock(&data->lock);
    val = ((s8)ec_read_reg(data, IT87_REG_TEMP(1)));
    mutex_unlock(&data->lock);
    return sprintf(buf, "%d\n", val);
}

static struct kobj_attribute temp1_input_attr =
    __ATTR(temp1_input, 0444, temp1_input_show, NULL);

static struct kobj_attribute temp2_input_attr =
    __ATTR(temp2_input, 0444, temp2_input_show, NULL);

static struct attribute *temperature_sysfs_attrs[] = {
    &temp1_input_attr.attr,
    &temp2_input_attr.attr,
    NULL,
};

static struct attribute_group temperature_sysfs_attr_group = {
    .attrs = temperature_sysfs_attrs,
};


static inline int superio_inw(int ioreg, int reg)
{
    int val;
    outb(reg++, ioreg);
    val = inb(ioreg + 1) << 8;
    outb(reg, ioreg);
    val |= inb(ioreg + 1);
    return val;
}

static inline int superio_inb(int ioreg, int reg)
{
    outb(reg, ioreg);
    return inb(ioreg + 1);
}

static inline void superio_outb(int ioreg, int reg, int val)
{
    outb(reg, ioreg);
    outb(val, ioreg + 1);
}

static inline void superio_select(int ioreg, int ldn)
{
    outb(DEV, ioreg);
    outb(ldn, ioreg + 1);
}

static inline int superio_enter(int ioreg)
{
    if (!request_muxed_region(ioreg, 2, DRIVER_NAME))
        return -EBUSY;
    outb(0x87, ioreg);
    outb(0x01, ioreg);
    outb(0x55, ioreg);
    outb(ioreg == REG_4E ? 0xaa : 0x55, ioreg);
    return 0;
}

static inline void superio_exit(int ioreg)
{
    outb(0x02, ioreg);
    outb(0x02, ioreg + 1);
    release_region(ioreg, 2);
}

static int vfiec_find(int sioaddr, unsigned short *address)
{
    int err;
    u16 chip_type;

    err = superio_enter(sioaddr);
    if (err)
        return err;

    chip_type = superio_inw(sioaddr, DEVID);

    if (chip_type != IT8786E_DEVID) {
        superio_exit(sioaddr);
        return -ENODEV;
    }

    superio_select(sioaddr, PME);
    if (!(superio_inb(sioaddr, IT87_ACT_REG) & 0x01)) {
        pr_info("Device not activated\n");
        superio_exit(sioaddr);
        return -ENODEV;
    }

    *address = superio_inw(sioaddr, IT87_BASE_REG) & ~0x07;
    if (*address == 0) {
        pr_info("Base address not set\n");
        superio_exit(sioaddr);
        return -ENODEV;
    }

    pr_info("Found IT8786E chip at 0x%x\n", *address);
    superio_exit(sioaddr);
    return 0;
}

int temperature_sysfs_init(void)
{
    int ret = 0;
    int err;
    unsigned short address = 0;
    struct temp_data *data;

    /* 探测SuperIO */
    err = vfiec_find(0x2e, &address);
    if (err) {
        err = vfiec_find(0x4e, &address);
        if (err) {
            pr_err("IT8786E not found\n");
            return -ENODEV;
        }
    }

    /* 分配数据结构 */
    data = kzalloc(sizeof(*data), GFP_KERNEL);
    if (!data)
        return -ENOMEM;

    data->addr = address + 5;
    mutex_init(&data->lock);
    g_data = data;

    ret = sysfs_create_group(hwmon_kobj, &temperature_sysfs_attr_group);

    return ret;
}

void temperature_sysfs_exit(void)
{
    sysfs_remove_group(hwmon_kobj, &temperature_sysfs_attr_group);
}