/*
   * drivers/hwmon/applesmc.c - driver for Apple's SMC (accelerometer, temperature
   * sensors, fan control, keyboard backlight control) used in Intel-based Apple
   * computers.
   *
   * Copyright (C) 2007 Nicolas Boichat <nicolas@boichat.ch>

   * Copyright (C) 2010 Henrik Rydberg <rydberg@euromail.se>

   *
   * Based on hdaps.c driver:
   * Copyright (C) 2005 Robert Love <rml@novell.com>
   * Copyright (C) 2005 Jesper Juhl <jesper.juhl@gmail.com>
   *
   * Fan control based on smcFanControl:
   * Copyright (C) 2006 Hendrik Holtmann <holtmann@mac.com>
   *
   * This program is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License v2 as published by the
   * Free Software Foundation.
   *
   * This program is distributed in the hope that it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
   * more details.
   *
   * You should have received a copy of the GNU General Public License along with
   * this program; if not, write to the Free Software Foundation, Inc.,
   * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
   */

  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

  #include <linux/delay.h>
  #include <linux/platform_device.h>

  #include <linux/input-polldev.h>

  #include <linux/kernel.h>

  #include <linux/slab.h>

  #include <linux/module.h>
  #include <linux/timer.h>
  #include <linux/dmi.h>
  #include <linux/mutex.h>
  #include <linux/hwmon-sysfs.h>

  #include <linux/io.h>

  #include <linux/leds.h>
  #include <linux/hwmon.h>
  #include <linux/workqueue.h>
  
  /* data port used by Apple SMC */
  #define APPLESMC_DATA_PORT	0x300
  /* command/status port used by Apple SMC */
  #define APPLESMC_CMD_PORT	0x304
  
  #define APPLESMC_NR_PORTS	32 /* 0x300-0x31f */
  
  #define APPLESMC_MAX_DATA_LENGTH 32

  /* wait up to 32 ms for a status change. */

  #define APPLESMC_MIN_WAIT	0x0040
  #define APPLESMC_MAX_WAIT	0x8000

  #define APPLESMC_STATUS_MASK	0x0f
  #define APPLESMC_READ_CMD	0x10
  #define APPLESMC_WRITE_CMD	0x11
  #define APPLESMC_GET_KEY_BY_INDEX_CMD	0x12
  #define APPLESMC_GET_KEY_TYPE_CMD	0x13
  
  #define KEY_COUNT_KEY		"#KEY" /* r-o ui32 */

  #define LIGHT_SENSOR_LEFT_KEY	"ALV0" /* r-o {alv (6-10 bytes) */
  #define LIGHT_SENSOR_RIGHT_KEY	"ALV1" /* r-o {alv (6-10 bytes) */

  #define BACKLIGHT_KEY		"LKSB" /* w-o {lkb (2 bytes) */

  #define CLAMSHELL_KEY		"MSLD" /* r-o ui8 (unused) */

  
  #define MOTION_SENSOR_X_KEY	"MO_X" /* r-o sp78 (2 bytes) */
  #define MOTION_SENSOR_Y_KEY	"MO_Y" /* r-o sp78 (2 bytes) */
  #define MOTION_SENSOR_Z_KEY	"MO_Z" /* r-o sp78 (2 bytes) */
  #define MOTION_SENSOR_KEY	"MOCN" /* r/w ui16 */
  
  #define FANS_COUNT		"FNum" /* r-o ui8 */
  #define FANS_MANUAL		"FS! " /* r-w ui16 */

  #define FAN_ID_FMT		"F%dID" /* r-o char[16] */

  /* List of keys used to read/write fan speeds */

  static const char *const fan_speed_fmt[] = {
  	"F%dAc",		/* actual speed */
  	"F%dMn",		/* minimum speed (rw) */
  	"F%dMx",		/* maximum speed */
  	"F%dSf",		/* safe speed - not all models */
  	"F%dTg",		/* target speed (manual: rw) */

  };
  
  #define INIT_TIMEOUT_MSECS	5000	/* wait up to 5s for device init ... */
  #define INIT_WAIT_MSECS		50	/* ... in 50ms increments */

  #define APPLESMC_POLL_INTERVAL	50	/* msecs */

  #define APPLESMC_INPUT_FUZZ	4	/* input event threshold */
  #define APPLESMC_INPUT_FLAT	4
  
  #define SENSOR_X 0
  #define SENSOR_Y 1
  #define SENSOR_Z 2

  #define to_index(attr) (to_sensor_dev_attr(attr)->index & 0xffff)
  #define to_option(attr) (to_sensor_dev_attr(attr)->index >> 16)

  /* Dynamic device node attributes */
  struct applesmc_dev_attr {
  	struct sensor_device_attribute sda;	/* hwmon attributes */
  	char name[32];				/* room for node file name */
  };
  
  /* Dynamic device node group */
  struct applesmc_node_group {
  	char *format;				/* format string */
  	void *show;				/* show function */
  	void *store;				/* store function */

  	int option;				/* function argument */

  	struct applesmc_dev_attr *nodes;	/* dynamic node array */
  };

  /* AppleSMC entry - cached register information */
  struct applesmc_entry {
  	char key[5];		/* four-letter key code */
  	u8 valid;		/* set when entry is successfully read once */
  	u8 len;			/* bounded by APPLESMC_MAX_DATA_LENGTH */
  	char type[5];		/* four-letter type code */
  	u8 flags;		/* 0x10: func; 0x40: write; 0x80: read */
  };
  
  /* Register lookup and registers common to all SMCs */
  static struct applesmc_registers {
  	struct mutex mutex;		/* register read/write mutex */
  	unsigned int key_count;		/* number of SMC registers */

  	unsigned int fan_count;		/* number of fans */

  	unsigned int temp_count;	/* number of temperature registers */
  	unsigned int temp_begin;	/* temperature lower index bound */
  	unsigned int temp_end;		/* temperature upper index bound */

  	int num_light_sensors;		/* number of light sensors */
  	bool has_accelerometer;		/* has motion sensor */
  	bool has_key_backlight;		/* has keyboard backlight */

  	bool init_complete;		/* true when fully initialized */
  	struct applesmc_entry *cache;	/* cached key entries */
  } smcreg = {
  	.mutex = __MUTEX_INITIALIZER(smcreg.mutex),
  };

  static const int debug;
  static struct platform_device *pdev;
  static s16 rest_x;
  static s16 rest_y;

  static u8 backlight_state[2];

  static struct device *hwmon_dev;

  static struct input_polled_dev *applesmc_idev;

  /*
   * Last index written to key_at_index sysfs file, and value to use for all other
   * key_at_index_* sysfs files.
   */
  static unsigned int key_at_index;
  
  static struct workqueue_struct *applesmc_led_wq;
  
  /*

   * __wait_status - Wait up to 32ms for the status port to get a certain value

   * (masked with 0x0f), returning zero if the value is obtained.  Callers must
   * hold applesmc_lock.
   */
  static int __wait_status(u8 val)
  {

  	int us;

  
  	val = val & APPLESMC_STATUS_MASK;

  	for (us = APPLESMC_MIN_WAIT; us < APPLESMC_MAX_WAIT; us <<= 1) {
  		udelay(us);

  		if ((inb(APPLESMC_CMD_PORT) & APPLESMC_STATUS_MASK) == val)

  			return 0;

  	}

  	return -EIO;
  }
  
  /*

   * special treatment of command port - on newer macbooks, it seems necessary
   * to resend the command byte before polling the status again. Callers must
   * hold applesmc_lock.
   */
  static int send_command(u8 cmd)
  {

  	int us;
  	for (us = APPLESMC_MIN_WAIT; us < APPLESMC_MAX_WAIT; us <<= 1) {

  		outb(cmd, APPLESMC_CMD_PORT);

  		udelay(us);

  		if ((inb(APPLESMC_CMD_PORT) & APPLESMC_STATUS_MASK) == 0x0c)
  			return 0;

  	}

  	return -EIO;
  }

  static int send_argument(const char *key)

  {
  	int i;

  	for (i = 0; i < 4; i++) {
  		outb(key[i], APPLESMC_DATA_PORT);
  		if (__wait_status(0x04))
  			return -EIO;
  	}

  	return 0;
  }
  
  static int read_smc(u8 cmd, const char *key, u8 *buffer, u8 len)
  {
  	int i;
  
  	if (send_command(cmd) || send_argument(key)) {
  		pr_warn("%s: read arg fail
  ", key);
  		return -EIO;
  	}

  
  	outb(len, APPLESMC_DATA_PORT);

  
  	for (i = 0; i < len; i++) {

  		if (__wait_status(0x05)) {
  			pr_warn("%s: read data fail
  ", key);

  			return -EIO;

  		}

  		buffer[i] = inb(APPLESMC_DATA_PORT);

  	}

  
  	return 0;
  }

  static int write_smc(u8 cmd, const char *key, const u8 *buffer, u8 len)

  {
  	int i;

  	if (send_command(cmd) || send_argument(key)) {
  		pr_warn("%s: write arg fail
  ", key);

  		return -EIO;

  	}
  
  	outb(len, APPLESMC_DATA_PORT);
  
  	for (i = 0; i < len; i++) {

  		if (__wait_status(0x04)) {
  			pr_warn("%s: write data fail
  ", key);

  			return -EIO;

  		}

  		outb(buffer[i], APPLESMC_DATA_PORT);
  	}
  
  	return 0;
  }

  static int read_register_count(unsigned int *count)
  {
  	__be32 be;
  	int ret;
  
  	ret = read_smc(APPLESMC_READ_CMD, KEY_COUNT_KEY, (u8 *)&be, 4);
  	if (ret)
  		return ret;
  
  	*count = be32_to_cpu(be);
  	return 0;
  }

  /*

   * Serialized I/O
   *
   * Returns zero on success or a negative error on failure.
   * All functions below are concurrency safe - callers should NOT hold lock.

   */

  
  static int applesmc_read_entry(const struct applesmc_entry *entry,
  			       u8 *buf, u8 len)

  {

  	int ret;

  	if (entry->len != len)
  		return -EINVAL;
  	mutex_lock(&smcreg.mutex);
  	ret = read_smc(APPLESMC_READ_CMD, entry->key, buf, len);
  	mutex_unlock(&smcreg.mutex);

  	return ret;
  }
  
  static int applesmc_write_entry(const struct applesmc_entry *entry,
  				const u8 *buf, u8 len)
  {
  	int ret;
  
  	if (entry->len != len)
  		return -EINVAL;
  	mutex_lock(&smcreg.mutex);
  	ret = write_smc(APPLESMC_WRITE_CMD, entry->key, buf, len);
  	mutex_unlock(&smcreg.mutex);
  	return ret;
  }
  
  static const struct applesmc_entry *applesmc_get_entry_by_index(int index)
  {
  	struct applesmc_entry *cache = &smcreg.cache[index];
  	u8 key[4], info[6];
  	__be32 be;
  	int ret = 0;
  
  	if (cache->valid)
  		return cache;
  
  	mutex_lock(&smcreg.mutex);
  
  	if (cache->valid)
  		goto out;
  	be = cpu_to_be32(index);
  	ret = read_smc(APPLESMC_GET_KEY_BY_INDEX_CMD, (u8 *)&be, key, 4);
  	if (ret)
  		goto out;
  	ret = read_smc(APPLESMC_GET_KEY_TYPE_CMD, key, info, 6);
  	if (ret)
  		goto out;
  
  	memcpy(cache->key, key, 4);
  	cache->len = info[0];
  	memcpy(cache->type, &info[1], 4);
  	cache->flags = info[5];
  	cache->valid = 1;
  
  out:
  	mutex_unlock(&smcreg.mutex);
  	if (ret)
  		return ERR_PTR(ret);
  	return cache;
  }
  
  static int applesmc_get_lower_bound(unsigned int *lo, const char *key)
  {
  	int begin = 0, end = smcreg.key_count;
  	const struct applesmc_entry *entry;
  
  	while (begin != end) {
  		int middle = begin + (end - begin) / 2;
  		entry = applesmc_get_entry_by_index(middle);
  		if (IS_ERR(entry))
  			return PTR_ERR(entry);
  		if (strcmp(entry->key, key) < 0)
  			begin = middle + 1;
  		else
  			end = middle;

  	}

  	*lo = begin;
  	return 0;
  }

  static int applesmc_get_upper_bound(unsigned int *hi, const char *key)
  {
  	int begin = 0, end = smcreg.key_count;
  	const struct applesmc_entry *entry;
  
  	while (begin != end) {
  		int middle = begin + (end - begin) / 2;
  		entry = applesmc_get_entry_by_index(middle);
  		if (IS_ERR(entry))
  			return PTR_ERR(entry);
  		if (strcmp(key, entry->key) < 0)
  			end = middle;
  		else
  			begin = middle + 1;

  	}

  	*hi = begin;

  	return 0;
  }

  static const struct applesmc_entry *applesmc_get_entry_by_key(const char *key)

  {

  	int begin, end;
  	int ret;

  	ret = applesmc_get_lower_bound(&begin, key);
  	if (ret)
  		return ERR_PTR(ret);
  	ret = applesmc_get_upper_bound(&end, key);
  	if (ret)
  		return ERR_PTR(ret);
  	if (end - begin != 1)
  		return ERR_PTR(-EINVAL);

  	return applesmc_get_entry_by_index(begin);
  }

  static int applesmc_read_key(const char *key, u8 *buffer, u8 len)
  {
  	const struct applesmc_entry *entry;

  	entry = applesmc_get_entry_by_key(key);
  	if (IS_ERR(entry))
  		return PTR_ERR(entry);

  	return applesmc_read_entry(entry, buffer, len);
  }
  
  static int applesmc_write_key(const char *key, const u8 *buffer, u8 len)
  {
  	const struct applesmc_entry *entry;
  
  	entry = applesmc_get_entry_by_key(key);
  	if (IS_ERR(entry))
  		return PTR_ERR(entry);
  
  	return applesmc_write_entry(entry, buffer, len);

  }

  static int applesmc_has_key(const char *key, bool *value)
  {
  	const struct applesmc_entry *entry;
  
  	entry = applesmc_get_entry_by_key(key);
  	if (IS_ERR(entry) && PTR_ERR(entry) != -EINVAL)
  		return PTR_ERR(entry);
  
  	*value = !IS_ERR(entry);
  	return 0;
  }

  /*

   * applesmc_read_motion_sensor - Read motion sensor (X, Y or Z).

   */

  static int applesmc_read_motion_sensor(int index, s16 *value)

  {
  	u8 buffer[2];
  	int ret;
  
  	switch (index) {
  	case SENSOR_X:
  		ret = applesmc_read_key(MOTION_SENSOR_X_KEY, buffer, 2);
  		break;
  	case SENSOR_Y:
  		ret = applesmc_read_key(MOTION_SENSOR_Y_KEY, buffer, 2);
  		break;
  	case SENSOR_Z:
  		ret = applesmc_read_key(MOTION_SENSOR_Z_KEY, buffer, 2);
  		break;
  	default:
  		ret = -EINVAL;
  	}
  
  	*value = ((s16)buffer[0] << 8) | buffer[1];
  
  	return ret;
  }
  
  /*

   * applesmc_device_init - initialize the accelerometer.  Can sleep.

   */

  static void applesmc_device_init(void)

  {

  	int total;

  	u8 buffer[2];

  	if (!smcreg.has_accelerometer)

  		return;

  	for (total = INIT_TIMEOUT_MSECS; total > 0; total -= INIT_WAIT_MSECS) {

  		if (!applesmc_read_key(MOTION_SENSOR_KEY, buffer, 2) &&

  				(buffer[0] != 0x00 || buffer[1] != 0x00))

  			return;

  		buffer[0] = 0xe0;
  		buffer[1] = 0x00;
  		applesmc_write_key(MOTION_SENSOR_KEY, buffer, 2);
  		msleep(INIT_WAIT_MSECS);
  	}

  	pr_warn("failed to init the device
  ");

  }
  
  /*

   * applesmc_init_smcreg_try - Try to initialize register cache. Idempotent.
   */
  static int applesmc_init_smcreg_try(void)
  {
  	struct applesmc_registers *s = &smcreg;

  	bool left_light_sensor, right_light_sensor;

  	u8 tmp[1];

  	int ret;
  
  	if (s->init_complete)
  		return 0;
  
  	ret = read_register_count(&s->key_count);
  	if (ret)
  		return ret;
  
  	if (!s->cache)
  		s->cache = kcalloc(s->key_count, sizeof(*s->cache), GFP_KERNEL);
  	if (!s->cache)
  		return -ENOMEM;

  	ret = applesmc_read_key(FANS_COUNT, tmp, 1);
  	if (ret)
  		return ret;
  	s->fan_count = tmp[0];

  	ret = applesmc_get_lower_bound(&s->temp_begin, "T");
  	if (ret)
  		return ret;
  	ret = applesmc_get_lower_bound(&s->temp_end, "U");
  	if (ret)
  		return ret;
  	s->temp_count = s->temp_end - s->temp_begin;

  	ret = applesmc_has_key(LIGHT_SENSOR_LEFT_KEY, &left_light_sensor);
  	if (ret)
  		return ret;
  	ret = applesmc_has_key(LIGHT_SENSOR_RIGHT_KEY, &right_light_sensor);
  	if (ret)
  		return ret;
  	ret = applesmc_has_key(MOTION_SENSOR_KEY, &s->has_accelerometer);
  	if (ret)
  		return ret;
  	ret = applesmc_has_key(BACKLIGHT_KEY, &s->has_key_backlight);
  	if (ret)
  		return ret;
  
  	s->num_light_sensors = left_light_sensor + right_light_sensor;

  	s->init_complete = true;

  	pr_info("key=%d fan=%d temp=%d acc=%d lux=%d kbd=%d
  ",
  	       s->key_count, s->fan_count, s->temp_count,

  	       s->has_accelerometer,
  	       s->num_light_sensors,
  	       s->has_key_backlight);

  
  	return 0;
  }
  
  /*
   * applesmc_init_smcreg - Initialize register cache.
   *
   * Retries until initialization is successful, or the operation times out.
   *
   */
  static int applesmc_init_smcreg(void)
  {
  	int ms, ret;
  
  	for (ms = 0; ms < INIT_TIMEOUT_MSECS; ms += INIT_WAIT_MSECS) {
  		ret = applesmc_init_smcreg_try();
  		if (!ret) {
  			if (ms)
  				pr_info("init_smcreg() took %d ms
  ", ms);
  			return 0;
  		}
  		msleep(INIT_WAIT_MSECS);
  	}
  
  	kfree(smcreg.cache);
  	smcreg.cache = NULL;
  
  	return ret;
  }
  
  static void applesmc_destroy_smcreg(void)
  {
  	kfree(smcreg.cache);
  	smcreg.cache = NULL;
  	smcreg.init_complete = false;
  }

  /* Device model stuff */
  static int applesmc_probe(struct platform_device *dev)
  {

  	int ret;
  
  	ret = applesmc_init_smcreg();
  	if (ret)
  		return ret;

  	applesmc_device_init();

  	return 0;
  }

  /* Synchronize device with memorized backlight state */
  static int applesmc_pm_resume(struct device *dev)
  {

  	if (smcreg.has_key_backlight)

  		applesmc_write_key(BACKLIGHT_KEY, backlight_state, 2);

  	return 0;
  }
  
  /* Reinitialize device on resume from hibernation */
  static int applesmc_pm_restore(struct device *dev)

  {

  	applesmc_device_init();

  	return applesmc_pm_resume(dev);

  }

  static const struct dev_pm_ops applesmc_pm_ops = {

  	.resume = applesmc_pm_resume,
  	.restore = applesmc_pm_restore,
  };

  static struct platform_driver applesmc_driver = {
  	.probe = applesmc_probe,

  	.driver	= {
  		.name = "applesmc",
  		.owner = THIS_MODULE,

  		.pm = &applesmc_pm_ops,

  	},
  };
  
  /*
   * applesmc_calibrate - Set our "resting" values.  Callers must
   * hold applesmc_lock.
   */
  static void applesmc_calibrate(void)
  {
  	applesmc_read_motion_sensor(SENSOR_X, &rest_x);
  	applesmc_read_motion_sensor(SENSOR_Y, &rest_y);
  	rest_x = -rest_x;
  }

  static void applesmc_idev_poll(struct input_polled_dev *dev)

  {

  	struct input_dev *idev = dev->input;

  	s16 x, y;

  	if (applesmc_read_motion_sensor(SENSOR_X, &x))

  		return;

  	if (applesmc_read_motion_sensor(SENSOR_Y, &y))

  		return;

  
  	x = -x;

  	input_report_abs(idev, ABS_X, x - rest_x);
  	input_report_abs(idev, ABS_Y, y - rest_y);
  	input_sync(idev);

  }
  
  /* Sysfs Files */

  static ssize_t applesmc_name_show(struct device *dev,
  				   struct device_attribute *attr, char *buf)
  {
  	return snprintf(buf, PAGE_SIZE, "applesmc
  ");
  }

  static ssize_t applesmc_position_show(struct device *dev,
  				   struct device_attribute *attr, char *buf)
  {
  	int ret;
  	s16 x, y, z;

  	ret = applesmc_read_motion_sensor(SENSOR_X, &x);
  	if (ret)
  		goto out;
  	ret = applesmc_read_motion_sensor(SENSOR_Y, &y);
  	if (ret)
  		goto out;
  	ret = applesmc_read_motion_sensor(SENSOR_Z, &z);
  	if (ret)
  		goto out;
  
  out:

  	if (ret)
  		return ret;
  	else
  		return snprintf(buf, PAGE_SIZE, "(%d,%d,%d)
  ", x, y, z);
  }
  
  static ssize_t applesmc_light_show(struct device *dev,
  				struct device_attribute *attr, char *sysfsbuf)
  {

  	const struct applesmc_entry *entry;

  	static int data_length;

  	int ret;
  	u8 left = 0, right = 0;

  	u8 buffer[10];

  	if (!data_length) {

  		entry = applesmc_get_entry_by_key(LIGHT_SENSOR_LEFT_KEY);
  		if (IS_ERR(entry))
  			return PTR_ERR(entry);
  		if (entry->len > 10)
  			return -ENXIO;
  		data_length = entry->len;

  		pr_info("light sensor data length set to %d
  ", data_length);

  	}
  
  	ret = applesmc_read_key(LIGHT_SENSOR_LEFT_KEY, buffer, data_length);

  	/* newer macbooks report a single 10-bit bigendian value */
  	if (data_length == 10) {
  		left = be16_to_cpu(*(__be16 *)(buffer + 6)) >> 2;
  		goto out;
  	}

  	left = buffer[2];
  	if (ret)
  		goto out;

  	ret = applesmc_read_key(LIGHT_SENSOR_RIGHT_KEY, buffer, data_length);

  	right = buffer[2];
  
  out:

  	if (ret)
  		return ret;
  	else
  		return snprintf(sysfsbuf, PAGE_SIZE, "(%d,%d)
  ", left, right);
  }

  /* Displays sensor key as label */
  static ssize_t applesmc_show_sensor_label(struct device *dev,
  			struct device_attribute *devattr, char *sysfsbuf)
  {

  	int index = smcreg.temp_begin + to_index(devattr);
  	const struct applesmc_entry *entry;

  	entry = applesmc_get_entry_by_index(index);
  	if (IS_ERR(entry))
  		return PTR_ERR(entry);
  
  	return snprintf(sysfsbuf, PAGE_SIZE, "%s
  ", entry->key);

  }

  /* Displays degree Celsius * 1000 */
  static ssize_t applesmc_show_temperature(struct device *dev,
  			struct device_attribute *devattr, char *sysfsbuf)
  {

  	int index = smcreg.temp_begin + to_index(devattr);
  	const struct applesmc_entry *entry;

  	int ret;
  	u8 buffer[2];
  	unsigned int temp;

  	entry = applesmc_get_entry_by_index(index);
  	if (IS_ERR(entry))
  		return PTR_ERR(entry);

  	if (entry->len > 2)
  		return -EINVAL;

  	ret = applesmc_read_entry(entry, buffer, entry->len);

  	if (ret)
  		return ret;

  	if (entry->len == 2) {
  		temp = buffer[0] * 1000;
  		temp += (buffer[1] >> 6) * 250;
  	} else {
  		temp = buffer[0] * 4000;
  	}

  
  	return snprintf(sysfsbuf, PAGE_SIZE, "%u
  ", temp);

  }
  
  static ssize_t applesmc_show_fan_speed(struct device *dev,
  				struct device_attribute *attr, char *sysfsbuf)
  {
  	int ret;
  	unsigned int speed = 0;
  	char newkey[5];
  	u8 buffer[2];

  	sprintf(newkey, fan_speed_fmt[to_option(attr)], to_index(attr));

  	ret = applesmc_read_key(newkey, buffer, 2);
  	speed = ((buffer[0] << 8 | buffer[1]) >> 2);

  	if (ret)
  		return ret;
  	else
  		return snprintf(sysfsbuf, PAGE_SIZE, "%u
  ", speed);
  }
  
  static ssize_t applesmc_store_fan_speed(struct device *dev,
  					struct device_attribute *attr,
  					const char *sysfsbuf, size_t count)
  {
  	int ret;

  	unsigned long speed;

  	char newkey[5];
  	u8 buffer[2];

  	if (kstrtoul(sysfsbuf, 10, &speed) < 0 || speed >= 0x4000)

  		return -EINVAL;		/* Bigger than a 14-bit value */

  	sprintf(newkey, fan_speed_fmt[to_option(attr)], to_index(attr));

  	buffer[0] = (speed >> 6) & 0xff;
  	buffer[1] = (speed << 2) & 0xff;
  	ret = applesmc_write_key(newkey, buffer, 2);

  	if (ret)
  		return ret;
  	else
  		return count;
  }
  
  static ssize_t applesmc_show_fan_manual(struct device *dev,

  			struct device_attribute *attr, char *sysfsbuf)

  {
  	int ret;
  	u16 manual = 0;
  	u8 buffer[2];

  	ret = applesmc_read_key(FANS_MANUAL, buffer, 2);

  	manual = ((buffer[0] << 8 | buffer[1]) >> to_index(attr)) & 0x01;

  	if (ret)
  		return ret;
  	else
  		return snprintf(sysfsbuf, PAGE_SIZE, "%d
  ", manual);
  }
  
  static ssize_t applesmc_store_fan_manual(struct device *dev,

  					 struct device_attribute *attr,

  					 const char *sysfsbuf, size_t count)
  {
  	int ret;
  	u8 buffer[2];

  	unsigned long input;

  	u16 val;

  	if (kstrtoul(sysfsbuf, 10, &input) < 0)

  		return -EINVAL;

  	ret = applesmc_read_key(FANS_MANUAL, buffer, 2);
  	val = (buffer[0] << 8 | buffer[1]);
  	if (ret)
  		goto out;
  
  	if (input)

  		val = val | (0x01 << to_index(attr));

  	else

  		val = val & ~(0x01 << to_index(attr));

  
  	buffer[0] = (val >> 8) & 0xFF;
  	buffer[1] = val & 0xFF;
  
  	ret = applesmc_write_key(FANS_MANUAL, buffer, 2);
  
  out:

  	if (ret)
  		return ret;
  	else
  		return count;
  }
  
  static ssize_t applesmc_show_fan_position(struct device *dev,
  				struct device_attribute *attr, char *sysfsbuf)
  {
  	int ret;
  	char newkey[5];
  	u8 buffer[17];

  	sprintf(newkey, FAN_ID_FMT, to_index(attr));

  	ret = applesmc_read_key(newkey, buffer, 16);
  	buffer[16] = 0;

  	if (ret)
  		return ret;
  	else
  		return snprintf(sysfsbuf, PAGE_SIZE, "%s
  ", buffer+4);
  }
  
  static ssize_t applesmc_calibrate_show(struct device *dev,
  				struct device_attribute *attr, char *sysfsbuf)
  {
  	return snprintf(sysfsbuf, PAGE_SIZE, "(%d,%d)
  ", rest_x, rest_y);
  }
  
  static ssize_t applesmc_calibrate_store(struct device *dev,
  	struct device_attribute *attr, const char *sysfsbuf, size_t count)
  {

  	applesmc_calibrate();

  
  	return count;
  }

  static void applesmc_backlight_set(struct work_struct *work)
  {

  	applesmc_write_key(BACKLIGHT_KEY, backlight_state, 2);

  }
  static DECLARE_WORK(backlight_work, &applesmc_backlight_set);
  
  static void applesmc_brightness_set(struct led_classdev *led_cdev,
  						enum led_brightness value)
  {
  	int ret;

  	backlight_state[0] = value;

  	ret = queue_work(applesmc_led_wq, &backlight_work);
  
  	if (debug && (!ret))
  		printk(KERN_DEBUG "applesmc: work was already on the queue.
  ");
  }
  
  static ssize_t applesmc_key_count_show(struct device *dev,
  				struct device_attribute *attr, char *sysfsbuf)
  {
  	int ret;
  	u8 buffer[4];
  	u32 count;

  	ret = applesmc_read_key(KEY_COUNT_KEY, buffer, 4);
  	count = ((u32)buffer[0]<<24) + ((u32)buffer[1]<<16) +
  						((u32)buffer[2]<<8) + buffer[3];

  	if (ret)
  		return ret;
  	else
  		return snprintf(sysfsbuf, PAGE_SIZE, "%d
  ", count);
  }
  
  static ssize_t applesmc_key_at_index_read_show(struct device *dev,
  				struct device_attribute *attr, char *sysfsbuf)
  {

  	const struct applesmc_entry *entry;

  	int ret;

  	entry = applesmc_get_entry_by_index(key_at_index);
  	if (IS_ERR(entry))
  		return PTR_ERR(entry);
  	ret = applesmc_read_entry(entry, sysfsbuf, entry->len);
  	if (ret)

  		return ret;

  	return entry->len;

  }
  
  static ssize_t applesmc_key_at_index_data_length_show(struct device *dev,
  				struct device_attribute *attr, char *sysfsbuf)
  {

  	const struct applesmc_entry *entry;

  	entry = applesmc_get_entry_by_index(key_at_index);
  	if (IS_ERR(entry))
  		return PTR_ERR(entry);

  	return snprintf(sysfsbuf, PAGE_SIZE, "%d
  ", entry->len);

  }
  
  static ssize_t applesmc_key_at_index_type_show(struct device *dev,
  				struct device_attribute *attr, char *sysfsbuf)
  {

  	const struct applesmc_entry *entry;

  	entry = applesmc_get_entry_by_index(key_at_index);
  	if (IS_ERR(entry))
  		return PTR_ERR(entry);

  	return snprintf(sysfsbuf, PAGE_SIZE, "%s
  ", entry->type);

  }
  
  static ssize_t applesmc_key_at_index_name_show(struct device *dev,
  				struct device_attribute *attr, char *sysfsbuf)
  {

  	const struct applesmc_entry *entry;

  	entry = applesmc_get_entry_by_index(key_at_index);
  	if (IS_ERR(entry))
  		return PTR_ERR(entry);

  	return snprintf(sysfsbuf, PAGE_SIZE, "%s
  ", entry->key);

  }
  
  static ssize_t applesmc_key_at_index_show(struct device *dev,
  				struct device_attribute *attr, char *sysfsbuf)
  {
  	return snprintf(sysfsbuf, PAGE_SIZE, "%d
  ", key_at_index);
  }
  
  static ssize_t applesmc_key_at_index_store(struct device *dev,
  	struct device_attribute *attr, const char *sysfsbuf, size_t count)
  {

  	unsigned long newkey;

  	if (kstrtoul(sysfsbuf, 10, &newkey) < 0

  	    || newkey >= smcreg.key_count)
  		return -EINVAL;

  	key_at_index = newkey;

  	return count;
  }
  
  static struct led_classdev applesmc_backlight = {

  	.name			= "smc::kbd_backlight",

  	.default_trigger	= "nand-disk",
  	.brightness_set		= applesmc_brightness_set,
  };

  static struct applesmc_node_group info_group[] = {
  	{ "name", applesmc_name_show },
  	{ "key_count", applesmc_key_count_show },
  	{ "key_at_index", applesmc_key_at_index_show, applesmc_key_at_index_store },
  	{ "key_at_index_name", applesmc_key_at_index_name_show },
  	{ "key_at_index_type", applesmc_key_at_index_type_show },
  	{ "key_at_index_data_length", applesmc_key_at_index_data_length_show },
  	{ "key_at_index_data", applesmc_key_at_index_read_show },
  	{ }

  };

  static struct applesmc_node_group accelerometer_group[] = {
  	{ "position", applesmc_position_show },
  	{ "calibrate", applesmc_calibrate_show, applesmc_calibrate_store },
  	{ }

  };

  static struct applesmc_node_group light_sensor_group[] = {
  	{ "light", applesmc_light_show },
  	{ }
  };

  static struct applesmc_node_group fan_group[] = {
  	{ "fan%d_label", applesmc_show_fan_position },
  	{ "fan%d_input", applesmc_show_fan_speed, NULL, 0 },
  	{ "fan%d_min", applesmc_show_fan_speed, applesmc_store_fan_speed, 1 },
  	{ "fan%d_max", applesmc_show_fan_speed, NULL, 2 },
  	{ "fan%d_safe", applesmc_show_fan_speed, NULL, 3 },
  	{ "fan%d_output", applesmc_show_fan_speed, applesmc_store_fan_speed, 4 },
  	{ "fan%d_manual", applesmc_show_fan_manual, applesmc_store_fan_manual },
  	{ }

  };

  static struct applesmc_node_group temp_group[] = {
  	{ "temp%d_label", applesmc_show_sensor_label },
  	{ "temp%d_input", applesmc_show_temperature },
  	{ }

  };

  /* Module stuff */
  
  /*

   * applesmc_destroy_nodes - remove files and free associated memory
   */
  static void applesmc_destroy_nodes(struct applesmc_node_group *groups)
  {
  	struct applesmc_node_group *grp;
  	struct applesmc_dev_attr *node;
  
  	for (grp = groups; grp->nodes; grp++) {
  		for (node = grp->nodes; node->sda.dev_attr.attr.name; node++)
  			sysfs_remove_file(&pdev->dev.kobj,
  					  &node->sda.dev_attr.attr);
  		kfree(grp->nodes);
  		grp->nodes = NULL;
  	}
  }
  
  /*
   * applesmc_create_nodes - create a two-dimensional group of sysfs files
   */
  static int applesmc_create_nodes(struct applesmc_node_group *groups, int num)
  {
  	struct applesmc_node_group *grp;
  	struct applesmc_dev_attr *node;
  	struct attribute *attr;
  	int ret, i;
  
  	for (grp = groups; grp->format; grp++) {
  		grp->nodes = kcalloc(num + 1, sizeof(*node), GFP_KERNEL);
  		if (!grp->nodes) {
  			ret = -ENOMEM;
  			goto out;
  		}
  		for (i = 0; i < num; i++) {
  			node = &grp->nodes[i];
  			sprintf(node->name, grp->format, i + 1);

  			node->sda.index = (grp->option << 16) | (i & 0xffff);

  			node->sda.dev_attr.show = grp->show;
  			node->sda.dev_attr.store = grp->store;
  			attr = &node->sda.dev_attr.attr;

  			sysfs_attr_init(attr);

  			attr->name = node->name;
  			attr->mode = S_IRUGO | (grp->store ? S_IWUSR : 0);
  			ret = sysfs_create_file(&pdev->dev.kobj, attr);
  			if (ret) {
  				attr->name = NULL;
  				goto out;
  			}
  		}
  	}
  
  	return 0;
  out:
  	applesmc_destroy_nodes(groups);
  	return ret;
  }

  /* Create accelerometer ressources */
  static int applesmc_create_accelerometer(void)
  {

  	struct input_dev *idev;

  	int ret;

  	if (!smcreg.has_accelerometer)
  		return 0;
  
  	ret = applesmc_create_nodes(accelerometer_group, 1);

  	if (ret)
  		goto out;

  	applesmc_idev = input_allocate_polled_device();

  	if (!applesmc_idev) {
  		ret = -ENOMEM;
  		goto out_sysfs;
  	}

  	applesmc_idev->poll = applesmc_idev_poll;
  	applesmc_idev->poll_interval = APPLESMC_POLL_INTERVAL;

  	/* initial calibrate for the input device */
  	applesmc_calibrate();

  	/* initialize the input device */
  	idev = applesmc_idev->input;
  	idev->name = "applesmc";
  	idev->id.bustype = BUS_HOST;
  	idev->dev.parent = &pdev->dev;

  	idev->evbit[0] = BIT_MASK(EV_ABS);

  	input_set_abs_params(idev, ABS_X,

  			-256, 256, APPLESMC_INPUT_FUZZ, APPLESMC_INPUT_FLAT);

  	input_set_abs_params(idev, ABS_Y,

  			-256, 256, APPLESMC_INPUT_FUZZ, APPLESMC_INPUT_FLAT);

  	ret = input_register_polled_device(applesmc_idev);

  	if (ret)
  		goto out_idev;

  	return 0;
  
  out_idev:

  	input_free_polled_device(applesmc_idev);

  
  out_sysfs:

  	applesmc_destroy_nodes(accelerometer_group);

  
  out:

  	pr_warn("driver init failed (ret=%d)!
  ", ret);

  	return ret;
  }
  
  /* Release all ressources used by the accelerometer */
  static void applesmc_release_accelerometer(void)
  {

  	if (!smcreg.has_accelerometer)
  		return;

  	input_unregister_polled_device(applesmc_idev);
  	input_free_polled_device(applesmc_idev);

  	applesmc_destroy_nodes(accelerometer_group);

  }

  
  static int applesmc_create_light_sensor(void)
  {
  	if (!smcreg.num_light_sensors)
  		return 0;
  	return applesmc_create_nodes(light_sensor_group, 1);
  }
  
  static void applesmc_release_light_sensor(void)
  {
  	if (!smcreg.num_light_sensors)
  		return;
  	applesmc_destroy_nodes(light_sensor_group);
  }
  
  static int applesmc_create_key_backlight(void)
  {
  	if (!smcreg.has_key_backlight)
  		return 0;
  	applesmc_led_wq = create_singlethread_workqueue("applesmc-led");
  	if (!applesmc_led_wq)
  		return -ENOMEM;
  	return led_classdev_register(&pdev->dev, &applesmc_backlight);
  }
  
  static void applesmc_release_key_backlight(void)
  {
  	if (!smcreg.has_key_backlight)
  		return;
  	led_classdev_unregister(&applesmc_backlight);
  	destroy_workqueue(applesmc_led_wq);
  }

  static int applesmc_dmi_match(const struct dmi_system_id *id)
  {
  	return 1;
  }

  
  /* Note that DMI_MATCH(...,"MacBook") will match "MacBookPro1,1".
   * So we need to put "Apple MacBook Pro" before "Apple MacBook". */
  static __initdata struct dmi_system_id applesmc_whitelist[] = {

  	{ applesmc_dmi_match, "Apple MacBook Air", {
  	  DMI_MATCH(DMI_BOARD_VENDOR, "Apple"),
  	  DMI_MATCH(DMI_PRODUCT_NAME, "MacBookAir") },

  	},

  	{ applesmc_dmi_match, "Apple MacBook Pro", {

  	  DMI_MATCH(DMI_BOARD_VENDOR, "Apple"),
  	  DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro") },

  	},

  	{ applesmc_dmi_match, "Apple MacBook", {

  	  DMI_MATCH(DMI_BOARD_VENDOR, "Apple"),
  	  DMI_MATCH(DMI_PRODUCT_NAME, "MacBook") },

  	},

  	{ applesmc_dmi_match, "Apple Macmini", {

  	  DMI_MATCH(DMI_BOARD_VENDOR, "Apple"),
  	  DMI_MATCH(DMI_PRODUCT_NAME, "Macmini") },

  	},

  	{ applesmc_dmi_match, "Apple MacPro", {
  	  DMI_MATCH(DMI_BOARD_VENDOR, "Apple"),
  	  DMI_MATCH(DMI_PRODUCT_NAME, "MacPro") },

  	},

  	{ applesmc_dmi_match, "Apple iMac", {

  	  DMI_MATCH(DMI_BOARD_VENDOR, "Apple"),
  	  DMI_MATCH(DMI_PRODUCT_NAME, "iMac") },

  	},

  	{ .ident = NULL }
  };
  
  static int __init applesmc_init(void)
  {
  	int ret;

  	if (!dmi_check_system(applesmc_whitelist)) {

  		pr_warn("supported laptop not found!
  ");

  		ret = -ENODEV;
  		goto out;
  	}
  
  	if (!request_region(APPLESMC_DATA_PORT, APPLESMC_NR_PORTS,
  								"applesmc")) {
  		ret = -ENXIO;
  		goto out;
  	}
  
  	ret = platform_driver_register(&applesmc_driver);
  	if (ret)
  		goto out_region;

  	pdev = platform_device_register_simple("applesmc", APPLESMC_DATA_PORT,
  					       NULL, 0);

  	if (IS_ERR(pdev)) {
  		ret = PTR_ERR(pdev);
  		goto out_driver;
  	}

  	/* create register cache */
  	ret = applesmc_init_smcreg();

  	if (ret)
  		goto out_device;

  	ret = applesmc_create_nodes(info_group, 1);

  	if (ret)
  		goto out_smcreg;

  	ret = applesmc_create_nodes(fan_group, smcreg.fan_count);
  	if (ret)
  		goto out_info;

  	ret = applesmc_create_nodes(temp_group, smcreg.temp_count);
  	if (ret)
  		goto out_fans;

  	ret = applesmc_create_accelerometer();
  	if (ret)
  		goto out_temperature;

  	ret = applesmc_create_light_sensor();
  	if (ret)
  		goto out_accelerometer;

  	ret = applesmc_create_key_backlight();
  	if (ret)
  		goto out_light_sysfs;

  	hwmon_dev = hwmon_device_register(&pdev->dev);
  	if (IS_ERR(hwmon_dev)) {
  		ret = PTR_ERR(hwmon_dev);

  		goto out_light_ledclass;
  	}

  	return 0;
  
  out_light_ledclass:

  	applesmc_release_key_backlight();

  out_light_sysfs:

  	applesmc_release_light_sensor();

  out_accelerometer:

  	applesmc_release_accelerometer();

  out_temperature:

  	applesmc_destroy_nodes(temp_group);

  out_fans:

  	applesmc_destroy_nodes(fan_group);
  out_info:

  	applesmc_destroy_nodes(info_group);

  out_smcreg:
  	applesmc_destroy_smcreg();

  out_device:
  	platform_device_unregister(pdev);
  out_driver:
  	platform_driver_unregister(&applesmc_driver);
  out_region:
  	release_region(APPLESMC_DATA_PORT, APPLESMC_NR_PORTS);
  out:

  	pr_warn("driver init failed (ret=%d)!
  ", ret);

  	return ret;
  }
  
  static void __exit applesmc_exit(void)
  {

  	hwmon_device_unregister(hwmon_dev);

  	applesmc_release_key_backlight();
  	applesmc_release_light_sensor();
  	applesmc_release_accelerometer();

  	applesmc_destroy_nodes(temp_group);

  	applesmc_destroy_nodes(fan_group);

  	applesmc_destroy_nodes(info_group);

  	applesmc_destroy_smcreg();

  	platform_device_unregister(pdev);
  	platform_driver_unregister(&applesmc_driver);
  	release_region(APPLESMC_DATA_PORT, APPLESMC_NR_PORTS);

  }
  
  module_init(applesmc_init);
  module_exit(applesmc_exit);
  
  MODULE_AUTHOR("Nicolas Boichat");
  MODULE_DESCRIPTION("Apple SMC");
  MODULE_LICENSE("GPL v2");

  MODULE_DEVICE_TABLE(dmi, applesmc_whitelist);