#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/kobject.h>
#include <linux/sysfs.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/mutex.h>
#include <linux/slab.h>

#define DRIVER_NAME "vfiec_hwmon"

/* SuperIO配置端口 */
#define REG_2E 0x2e
#define REG_4E 0x4e
#define DEV 0x07
#define PME 0x04 /* EC逻辑设备 */
#define GPIO 0x07
#define DEVID 0x20
#define DEVREV 0x22
#define IT87_ACT_REG 0x30
#define IT87_BASE_REG 0x60

/* IT8786E设备ID */
#define IT8786E_DEVID 0x8786

/* EC寄存器偏移 (相对于EC基地址) */
#define IT87_EC_OFFSET 5
#define IT87_ADDR_REG_OFFSET 0
#define IT87_DATA_REG_OFFSET 1

/* EC内部寄存器 */
#define IT87_REG_CONFIG 0x00
#define IT87_REG_FAN_MAIN_CTRL 0x13
#define IT87_REG_FAN_CTL 0x14
#define IT87_REG_FAN_16BIT 0x0c

/* 风扇寄存器 */
static const u8 IT87_REG_FAN[] = {0x0d, 0x0e, 0x0f, 0x80, 0x82, 0x4c};
static const u8 IT87_REG_FANX[] = {0x18, 0x19, 0x1a, 0x81, 0x83, 0x4d};

/* PWM寄存器 */
static const u8 IT87_REG_PWM[] = {0x15, 0x16, 0x17, 0x7f, 0xa7, 0xaf};
static const u8 IT87_REG_PWM_DUTY[] = {0x63, 0x6b, 0x73, 0x7b, 0xa3, 0xab};

/* 温度寄存器 */
#define IT87_REG_TEMP(nr) (0x29 + (nr))

/* 特性标志 */
#define FEAT_16BIT_FANS BIT(3)
#define FEAT_NEWER_AUTOPWM BIT(1)
#define FEAT_TEMP_OFFSET BIT(4)
#define FEAT_TEMP_PECI BIT(5)
#define FEAT_PWM_FREQ2 BIT(16)

/* 设备数据结构 */
struct vfiec_data
{
	unsigned short addr; /* EC基地址 */
	int sioaddr;		 /* SuperIO地址 */
	u32 features;
	u8 fan_main_ctrl;
	u8 has_fan;
	struct mutex lock;
};

static struct vfiec_data *g_data = NULL;
extern struct kobject *hwmon_kobj;

/* ========== SuperIO操作 ========== */

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);
}

/* ========== EC寄存器读写 ========== */

static int ec_read_reg(struct vfiec_data *data, u8 reg)
{
	outb_p(reg, data->addr + IT87_ADDR_REG_OFFSET);
	return inb_p(data->addr + IT87_DATA_REG_OFFSET);
}

static void ec_write_reg(struct vfiec_data *data, u8 reg, u8 value)
{
	outb_p(reg, data->addr + IT87_ADDR_REG_OFFSET);
	outb_p(value, data->addr + IT87_DATA_REG_OFFSET);
}

/* ========== 数据转换 ========== */

#define FAN16_FROM_REG(val) ((val) == 0 ? -1 : (val) == 0xffff ? 0 \
															   : 1350000 / ((val) * 2))

#define FAN_FROM_REG(val, div) ((val) == 0 ? -1 : (val) == 255 ? 0 \
															   : 1350000 / ((val) * (div)))

#define TEMP_FROM_REG(val) ((val) * 1000)

static int pwm_from_reg(u8 reg)
{
	/* IT8786使用newer autopwm，直接返回8位值 */
	return reg;
}

static u8 pwm_to_reg(long val)
{
	return (u8)(val & 0xff);
}

/* ========== 风扇模式检测 ========== */

static int pwm_mode(struct vfiec_data *data, int nr)
{
	u8 pwm_ctrl = ec_read_reg(data, IT87_REG_PWM[nr]);

	if (nr < 3 && !(data->fan_main_ctrl & BIT(nr)))
		return 0; /* Full speed */
	if (pwm_ctrl & 0x80)
		return 2; /* Automatic mode */

	return 1; /* Manual mode */
}

/* ========== 设备探测 ========== */

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;
}

/* ========== sysfs属性回调 ========== */

/* fan1_input */
static ssize_t fan1_input_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
{
	struct vfiec_data *data = g_data;
	int val;
	u16 reg;
	mutex_lock(&data->lock);
	reg = ec_read_reg(data, IT87_REG_FAN[0]);
	reg |= (ec_read_reg(data, IT87_REG_FANX[0]) << 8);
	val = FAN16_FROM_REG(reg);
	mutex_unlock(&data->lock);
	return sprintf(buf, "%d\n", val);
}

/* fan2_input */
static ssize_t fan2_input_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
{
	struct vfiec_data *data = g_data;
	int val;
	u16 reg;
	mutex_lock(&data->lock);
	reg = ec_read_reg(data, IT87_REG_FAN[1]);
	reg |= (ec_read_reg(data, IT87_REG_FANX[1]) << 8);
	val = FAN16_FROM_REG(reg);
	mutex_unlock(&data->lock);
	return sprintf(buf, "%d\n", val);
}

/* pwm1 */
static ssize_t pwm1_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
{
	struct vfiec_data *data = g_data;
	int val;
	mutex_lock(&data->lock);
	val = pwm_from_reg(ec_read_reg(data, IT87_REG_PWM_DUTY[0]));
	mutex_unlock(&data->lock);
	return sprintf(buf, "%d\n", val);
}

static ssize_t pwm1_store(struct kobject *kobj, struct kobj_attribute *attr,
						  const char *buf, size_t count)
{
	struct vfiec_data *data = g_data;
	long val;
	int mode;
	int ret;
	ret = kstrtol(buf, 10, &val);
	if (ret < 0)
		return ret;
	if (val < 0 || val > 255)
		return -EINVAL;
	mutex_lock(&data->lock);

	if(val > 200)
		val = 200;

	mode = pwm_mode(data, 0);
	if (mode == 1)
	{
		ec_write_reg(data, IT87_REG_PWM_DUTY[0], pwm_to_reg(val));
		ret = count;
	}
	else
	{
		ret = -EINVAL;
	}
	mutex_unlock(&data->lock);
	return ret;
}

/* pwm2 */
static ssize_t pwm2_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
{
	struct vfiec_data *data = g_data;
	int val;
	mutex_lock(&data->lock);
	val = pwm_from_reg(ec_read_reg(data, IT87_REG_PWM_DUTY[1]));
	mutex_unlock(&data->lock);
	return sprintf(buf, "%d\n", val);
}

static ssize_t pwm2_store(struct kobject *kobj, struct kobj_attribute *attr,
						  const char *buf, size_t count)
{
	struct vfiec_data *data = g_data;
	long val;
	int mode;
	int ret;
	ret = kstrtol(buf, 10, &val);
	if (ret < 0)
		return ret;
	if (val < 0 || val > 255)
		return -EINVAL;
	mutex_lock(&data->lock);

	if(val > 200)
		val = 200;

	mode = pwm_mode(data, 1);
	if (mode == 1)
	{
		ec_write_reg(data, IT87_REG_PWM_DUTY[1], pwm_to_reg(val));
		ret = count;
	}
	else
	{
		ret = -EINVAL;
	}
	mutex_unlock(&data->lock);
	return ret;
}

/* pwm1_enable */
static ssize_t pwm1_enable_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
{
	struct vfiec_data *data = g_data;
	int val;
	mutex_lock(&data->lock);
	val = pwm_mode(data, 0);
	mutex_unlock(&data->lock);
	return sprintf(buf, "%d\n", val);
}

static ssize_t pwm1_enable_store(struct kobject *kobj, struct kobj_attribute *attr,
								 const char *buf, size_t count)
{
	struct vfiec_data *data = g_data;
	long val;
	int ret;
	u8 reg;
	int nr = 0;
	ret = kstrtol(buf, 10, &val);
	if (ret < 0)
		return ret;
	mutex_lock(&data->lock);
	if (val == 1)
	{
		/* Manual mode */
		reg = ec_read_reg(data, IT87_REG_PWM[nr]);
		reg = (reg & 0x7c) | (nr & 0x03); /* temp map */
		ec_write_reg(data, IT87_REG_PWM[nr], reg);
		data->fan_main_ctrl |= BIT(nr);
		ec_write_reg(data, IT87_REG_FAN_MAIN_CTRL, data->fan_main_ctrl);
	}
	else if (val == 2)
	{
		/* Auto mode */
		reg = ec_read_reg(data, IT87_REG_PWM[nr]);
		reg = 0x80 | (reg & 0x7c) | (nr & 0x03);
		ec_write_reg(data, IT87_REG_PWM[nr], reg);
		data->fan_main_ctrl |= BIT(nr);
		ec_write_reg(data, IT87_REG_FAN_MAIN_CTRL, data->fan_main_ctrl);
	}
	else
	{
		mutex_unlock(&data->lock);
		return -EINVAL;
	}
	mutex_unlock(&data->lock);
	return count;
}

/* pwm2_enable */
static ssize_t pwm2_enable_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
{
	struct vfiec_data *data = g_data;
	int val;
	mutex_lock(&data->lock);
	val = pwm_mode(data, 1);
	mutex_unlock(&data->lock);
	return sprintf(buf, "%d\n", val);
}

static ssize_t pwm2_enable_store(struct kobject *kobj, struct kobj_attribute *attr,
								 const char *buf, size_t count)
{
	struct vfiec_data *data = g_data;
	long val;
	int ret;
	u8 reg;
	int nr = 1;
	ret = kstrtol(buf, 10, &val);
	if (ret < 0)
		return ret;
	mutex_lock(&data->lock);
	if (val == 1)
	{
		/* Manual mode */
		reg = ec_read_reg(data, IT87_REG_PWM[nr]);
		reg = (reg & 0x7c) | (nr & 0x03); /* temp map */
		ec_write_reg(data, IT87_REG_PWM[nr], reg);
		data->fan_main_ctrl |= BIT(nr);
		ec_write_reg(data, IT87_REG_FAN_MAIN_CTRL, data->fan_main_ctrl);
	}
	else if (val == 2)
	{
		/* Auto mode */
		reg = ec_read_reg(data, IT87_REG_PWM[nr]);
		reg = 0x80 | (reg & 0x7c) | (nr & 0x03);
		ec_write_reg(data, IT87_REG_PWM[nr], reg);
		data->fan_main_ctrl |= BIT(nr);
		ec_write_reg(data, IT87_REG_FAN_MAIN_CTRL, data->fan_main_ctrl);
	}
	else
	{
		mutex_unlock(&data->lock);
		return -EINVAL;
	}
	mutex_unlock(&data->lock);
	return count;
}

/* ========== 定义kobj_attribute ========== */

static struct kobj_attribute fan1_input_attr =
	__ATTR(fan1_input, 0444, fan1_input_show, NULL);

static struct kobj_attribute fan2_input_attr =
	__ATTR(fan2_input, 0444, fan2_input_show, NULL);

static struct kobj_attribute pwm1_attr =
	__ATTR(pwm1, 0644, pwm1_show, pwm1_store);

static struct kobj_attribute pwm2_attr =
	__ATTR(pwm2, 0644, pwm2_show, pwm2_store);

static struct kobj_attribute pwm1_enable_attr =
	__ATTR(pwm1_enable, 0644, pwm1_enable_show, pwm1_enable_store);

static struct kobj_attribute pwm2_enable_attr =
	__ATTR(pwm2_enable, 0644, pwm2_enable_show, pwm2_enable_store);

static struct attribute *hwmon_attrs[] = {
	&fan1_input_attr.attr,
	&fan2_input_attr.attr,
	&pwm1_attr.attr,
	&pwm2_attr.attr,
	&pwm1_enable_attr.attr,
	&pwm2_enable_attr.attr,
	NULL,
};

static struct attribute_group fan_attr_group = {
	.attrs = hwmon_attrs,
};

/* ========== 模块初始化 ========== */

static void set_auto_mode(int nr)
{
	u8 reg;
	struct vfiec_data *data = g_data;
	reg = ec_read_reg(data, IT87_REG_PWM[nr]);
	reg = 0x80 | (reg & 0x7c) | (nr & 0x03);
	ec_write_reg(data, IT87_REG_PWM[nr], reg);
	data->fan_main_ctrl |= BIT(nr);
	ec_write_reg(data, IT87_REG_FAN_MAIN_CTRL, data->fan_main_ctrl);
}
int fan_init(void)
{
	int err;
	unsigned short address = 0;
	struct vfiec_data *data;

	/* 探测SuperIO */
	err = vfiec_find(REG_2E, &address);
	if (err)
	{
		err = vfiec_find(REG_4E, &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 + IT87_EC_OFFSET;
	data->sioaddr = (err == 0) ? REG_2E : REG_4E; /* 简化判断 */
	data->features = FEAT_16BIT_FANS | FEAT_NEWER_AUTOPWM | FEAT_TEMP_OFFSET | FEAT_TEMP_PECI | FEAT_PWM_FREQ2;
	mutex_init(&data->lock);

	/* 请求I/O区域 */
	if (!request_region(data->addr, 2, DRIVER_NAME))
	{
		pr_err("Failed to request I/O region 0x%x\n", data->addr);
		kfree(data);
		return -EBUSY;
	}

	/* 读取初始状态 */
	data->fan_main_ctrl = ec_read_reg(data, IT87_REG_FAN_MAIN_CTRL);
	data->has_fan = (data->fan_main_ctrl >> 4) & 0x07;

	/* 启用16位风扇模式 */
	ec_write_reg(data, IT87_REG_FAN_16BIT,
				 ec_read_reg(data, IT87_REG_FAN_16BIT) | 0x07);

	/* 启动监控 */
	ec_write_reg(data, IT87_REG_CONFIG,
				 (ec_read_reg(data, IT87_REG_CONFIG) & 0x3e) | 0x01);

	g_data = data;

	/* 注册属性组 */
	err = sysfs_create_group(hwmon_kobj, &fan_attr_group);
	if (err)
	{
		pr_err("Failed to create sysfs attributes\n");
		goto err_release;
	}

	set_auto_mode(0);
	set_auto_mode(1);
	pr_info("VFIEC hwmon driver loaded, path: /sys/kernel/vfiec/hwmon/\n");
	return 0;

err_release:
	release_region(data->addr, 2);
	kfree(data);
	g_data = NULL;
	return err;
}

void fan_exit(void)
{
	if (g_data)
	{
		sysfs_remove_group(hwmon_kobj, &fan_attr_group);
		release_region(g_data->addr, 2);
		kfree(g_data);
		g_data = NULL;
	}
	pr_info("VFIEC hwmon driver unloaded\n");
}