/*
   * Copyright (C) 2007-2009 Luca Tettamanti <kronos.it@gmail.com>
   *
   * This file is released under the GPLv2
   * See COPYING in the top level directory of the kernel tree.
   */

  #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 <acpi/acpi.h>
  #include <acpi/acpixf.h>
  #include <acpi/acpi_drivers.h>
  #include <acpi/acpi_bus.h>
  
  
  #define ATK_HID "ATK0110"
  
  /* 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 inteface */
  	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 {
  		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 int atk_remove(struct acpi_device *device, int type);
  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 void atk_free_sensors(struct atk_data *data);
  
  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
  ", 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
  ", 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
  ", 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
  ", value);
  }
  
  static ssize_t atk_name_show(struct device *dev,
  				struct device_attribute *attr, char *buf)
  {
  	return sprintf(buf, "atk0110
  ");
  }
  static struct device_attribute atk_name_attr =
  		__ATTR(name, 0444, atk_name_show, NULL);
  
  static void atk_init_attribute(struct device_attribute *attr, char *name,
  		sysfs_show_func show)
  {
  	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
  ", obj->type);
  		return -EINVAL;
  	}
  
  	if (obj->package.count != expected_size) {
  		dev_warn(dev, "Invalid package size: %d, expected: %d
  ",
  				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
  ", 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
  ", 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
  ", tmp->type);
  		return -EINVAL;
  	}
  
  	tmp = &obj->package.elements[HWMON_PACK_UNK2];
  	if (tmp->type != ACPI_TYPE_INTEGER) {
  		dev_warn(dev, "Invalid type (unk2): %d
  ", 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
  ", 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
  ", 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
  ", 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
  ", what,
  			flags->integer.value,
  			name->string.pointer,
  			limit1->integer.value, limit2->integer.value,
  			enable->integer.value ? "enabled" : "disabled");
  #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
  ", __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
  ", 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
  ", 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
  ", 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
  ",
  				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
  ", 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
  ",
  				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
  ", 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);
  
  		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;
  
  	return err;
  }
  
  DEFINE_SIMPLE_ATTRIBUTE(atk_debugfs_gitm,
  			atk_debugfs_gitm_get,
  			NULL,
  			"0x%08llx
  ")
  
  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
  ", obj->integer.value);
  		break;
  	case ACPI_TYPE_STRING:
  		ret = snprintf(buf, sz, "%s
  ", 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;
  	struct dentry *f;
  
  	data->debugfs.id = 0;
  
  	d = debugfs_create_dir("asus_atk0110", NULL);
  	if (!d || IS_ERR(d))
  		return;
  
  	f = debugfs_create_x32("id", S_IRUSR | S_IWUSR, d, &data->debugfs.id);
  	if (!f || IS_ERR(f))
  		goto cleanup;
  
  	f = debugfs_create_file("gitm", S_IRUSR, d, data,
  			&atk_debugfs_gitm);
  	if (!f || IS_ERR(f))
  		goto cleanup;
  
  	f = debugfs_create_file("ggrp", S_IRUSR, d, data,
  			&atk_debugfs_ggrp_fops);
  	if (!f || IS_ERR(f))
  		goto cleanup;
  
  	data->debugfs.root = d;
  
  	return;
  cleanup:
  	debugfs_remove_recursive(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)
  ",
  				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
  ", 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 = kzalloc(sizeof(*sensor), GFP_KERNEL);
  	if (!sensor)
  		return -ENOMEM;
  
  	sensor->acpi_name = kstrdup(name->string.pointer, GFP_KERNEL);
  	if (!sensor->acpi_name) {
  		err = -ENOMEM;
  		goto out;
  	}
  
  	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;
  out:
  	kfree(sensor->acpi_name);
  	kfree(sensor);
  	return err;
  }
  
  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
  ",
  				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
  ",
  				acpi_format_exception(status));
  
  		ret = -ENODEV;
  		goto cleanup;
  	}
  
  	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
  ",
  				acpi_format_exception(status));
  
  		ret = -ENODEV;
  		goto cleanup;
  	}
  
  	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;
  cleanup:
  	atk_free_sensors(data);
  	return ret;
  }

  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
  ", 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
  ");
  
  	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
  ");
  		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
  ");
  		err = -EIO;
  	} else {
  		err = (buf->value != 0);
  		dev_dbg(dev, "EC is %sabled
  ",
  				err ? "en" : "dis");
  	}
  
  	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 %sable the EC
  ",
  				enable ? "en" : "dis");
  		return PTR_ERR(obj);
  	}
  	ec_ret = (struct atk_acpi_ret_buffer *)obj->buffer.pointer;
  	if (ec_ret->flags == 0) {
  		dev_err(dev, "Failed to %sable the EC
  ",
  				enable ? "en" : "dis");
  		err = -EIO;
  	} else {
  		dev_info(dev, "EC %sabled
  ",
  				enable ? "en" : "dis");
  	}
  
  	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
  ");

  	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_create_files(struct atk_data *data)
  {
  	struct atk_sensor_data *s;
  	int err;
  
  	list_for_each_entry(s, &data->sensor_list, list) {

  		sysfs_attr_init(&s->input_attr.attr);

  		err = device_create_file(data->hwmon_dev, &s->input_attr);
  		if (err)
  			return err;

  		sysfs_attr_init(&s->label_attr.attr);

  		err = device_create_file(data->hwmon_dev, &s->label_attr);
  		if (err)
  			return err;

  		sysfs_attr_init(&s->limit1_attr.attr);

  		err = device_create_file(data->hwmon_dev, &s->limit1_attr);
  		if (err)
  			return err;

  		sysfs_attr_init(&s->limit2_attr.attr);

  		err = device_create_file(data->hwmon_dev, &s->limit2_attr);
  		if (err)
  			return err;
  	}
  
  	err = device_create_file(data->hwmon_dev, &atk_name_attr);
  
  	return err;
  }
  
  static void atk_remove_files(struct atk_data *data)
  {
  	struct atk_sensor_data *s;
  
  	list_for_each_entry(s, &data->sensor_list, list) {
  		device_remove_file(data->hwmon_dev, &s->input_attr);
  		device_remove_file(data->hwmon_dev, &s->label_attr);
  		device_remove_file(data->hwmon_dev, &s->limit1_attr);
  		device_remove_file(data->hwmon_dev, &s->limit2_attr);
  	}
  	device_remove_file(data->hwmon_dev, &atk_name_attr);
  }
  
  static void atk_free_sensors(struct atk_data *data)
  {
  	struct list_head *head = &data->sensor_list;
  	struct atk_sensor_data *s, *tmp;
  
  	list_for_each_entry_safe(s, tmp, head, list) {
  		kfree(s->acpi_name);
  		kfree(s);
  	}
  }
  
  static int atk_register_hwmon(struct atk_data *data)
  {
  	struct device *dev = &data->acpi_dev->dev;
  	int err;
  
  	dev_dbg(dev, "registering hwmon device
  ");
  	data->hwmon_dev = hwmon_device_register(dev);
  	if (IS_ERR(data->hwmon_dev))
  		return PTR_ERR(data->hwmon_dev);
  
  	dev_dbg(dev, "populating sysfs directory
  ");
  	err = atk_create_files(data);
  	if (err)
  		goto remove;
  
  	return 0;
  remove:
  	/* Cleanup the registered files */
  	atk_remove_files(data);
  	hwmon_device_unregister(data->hwmon_dev);
  	return err;
  }

  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
  ",
  				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
  ",
  				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
  ",
  				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
  ",
  				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
  ",
  				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
  ",

  				 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 (data->rtmp_handle && data->rvlt_handle && data->rfan_handle)
  		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...
  ");
  
  	data = kzalloc(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
  ");

  	} 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
  ",
  					id->string.pointer);
  		}
  		ACPI_FREE(buf.pointer);

  	}

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

  	}

  	if (data->old_interface) {
  		dev_dbg(&device->dev, "Using old hwmon interface
  ");

  		err = atk_enumerate_old_hwmon(data);

  	} else {
  		dev_dbg(&device->dev, "Using new hwmon interface
  ");

  		err = atk_enumerate_new_hwmon(data);

  	}

  	if (err < 0)
  		goto out;
  	if (err == 0) {
  		dev_info(&device->dev,
  			 "No usable sensor detected, bailing out
  ");
  		err = -ENODEV;
  		goto out;
  	}
  
  	err = atk_register_hwmon(data);
  	if (err)
  		goto cleanup;

  	atk_debugfs_init(data);

  	device->driver_data = data;
  	return 0;
  cleanup:
  	atk_free_sensors(data);
  out:

  	if (data->disable_ec)
  		atk_ec_ctl(data, 0);

  	kfree(data);
  	return err;
  }
  
  static int atk_remove(struct acpi_device *device, int type)
  {
  	struct atk_data *data = device->driver_data;
  	dev_dbg(&device->dev, "removing...
  ");
  
  	device->driver_data = NULL;

  	atk_debugfs_cleanup(data);

  	atk_remove_files(data);
  	atk_free_sensors(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
  ");
  	}

  	kfree(data);
  
  	return 0;
  }
  
  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("atk: Resources not safely usable due to "
  		       "acpi_enforce_resources kernel parameter
  ");
  		return -EBUSY;
  	}

  	ret = acpi_bus_register_driver(&atk_driver);
  	if (ret)
  		pr_info("atk: acpi_bus_register_driver failed: %d
  ", ret);
  
  	return ret;
  }
  
  static void __exit atk0110_exit(void)
  {
  	acpi_bus_unregister_driver(&atk_driver);
  }
  
  module_init(atk0110_init);
  module_exit(atk0110_exit);
  
  MODULE_LICENSE("GPL");