/*
      via686a.c - Part of lm_sensors, Linux kernel modules

  		for hardware monitoring

      Copyright (c) 1998 - 2002  Frodo Looijaard <frodol@dds.nl>,

  			Kyösti Mälkki <kmalkki@cc.hut.fi>,

  			Mark Studebaker <mdsxyz123@yahoo.com>,
  			and Bob Dougherty <bobd@stanford.edu>

      (Some conversion-factor data were contributed by Jonathan Teh Soon Yew

      <j.teh@iname.com> and Alex van Kaam <darkside@chello.nl>.)
  
      This program is free software; you can redistribute it and/or modify
      it under the terms of the GNU General Public License as published by
      the Free Software Foundation; either version 2 of the License, or
      (at your option) any later version.
  
      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., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
  
  /*
      Supports the Via VT82C686A, VT82C686B south bridges.
      Reports all as a 686A.
      Warning - only supports a single device.
  */

  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

  #include <linux/module.h>
  #include <linux/slab.h>
  #include <linux/pci.h>

  #include <linux/jiffies.h>

  #include <linux/platform_device.h>

  #include <linux/hwmon.h>

  #include <linux/hwmon-sysfs.h>

  #include <linux/err.h>

  #include <linux/init.h>

  #include <linux/mutex.h>

  #include <linux/sysfs.h>

  #include <linux/acpi.h>

  #include <linux/io.h>

  
  
  /* If force_addr is set to anything different from 0, we forcibly enable
     the device at the given address. */

  static unsigned short force_addr;

  module_param(force_addr, ushort, 0);
  MODULE_PARM_DESC(force_addr,
  		 "Initialize the base address of the sensors");

  static struct platform_device *pdev;

  
  /*
     The Via 686a southbridge has a LM78-like chip integrated on the same IC.
     This driver is a customized copy of lm78.c
  */
  
  /* Many VIA686A constants specified below */
  
  /* Length of ISA address segment */

  #define VIA686A_EXTENT		0x80
  #define VIA686A_BASE_REG	0x70
  #define VIA686A_ENABLE_REG	0x74

  
  /* The VIA686A registers */
  /* ins numbered 0-4 */

  #define VIA686A_REG_IN_MAX(nr)	(0x2b + ((nr) * 2))
  #define VIA686A_REG_IN_MIN(nr)	(0x2c + ((nr) * 2))
  #define VIA686A_REG_IN(nr)	(0x22 + (nr))

  
  /* fans numbered 1-2 */

  #define VIA686A_REG_FAN_MIN(nr)	(0x3a + (nr))
  #define VIA686A_REG_FAN(nr)	(0x28 + (nr))

  /* temps numbered 1-3 */

  static const u8 VIA686A_REG_TEMP[]	= { 0x20, 0x21, 0x1f };
  static const u8 VIA686A_REG_TEMP_OVER[]	= { 0x39, 0x3d, 0x1d };
  static const u8 VIA686A_REG_TEMP_HYST[]	= { 0x3a, 0x3e, 0x1e };

  /* bits 7-6 */
  #define VIA686A_REG_TEMP_LOW1	0x4b
  /* 2 = bits 5-4, 3 = bits 7-6 */
  #define VIA686A_REG_TEMP_LOW23	0x49
  
  #define VIA686A_REG_ALARM1	0x41
  #define VIA686A_REG_ALARM2	0x42
  #define VIA686A_REG_FANDIV	0x47
  #define VIA686A_REG_CONFIG	0x40
  /* The following register sets temp interrupt mode (bits 1-0 for temp1,

   3-2 for temp2, 5-4 for temp3).  Modes are:
      00 interrupt stays as long as value is out-of-range
      01 interrupt is cleared once register is read (default)
      10 comparator mode- like 00, but ignores hysteresis
      11 same as 00 */

  #define VIA686A_REG_TEMP_MODE		0x4b

  /* We'll just assume that you want to set all 3 simultaneously: */

  #define VIA686A_TEMP_MODE_MASK		0x3F
  #define VIA686A_TEMP_MODE_CONTINUOUS	0x00

  
  /* Conversions. Limit checking is only done on the TO_REG

     variants.

  
  ********* VOLTAGE CONVERSIONS (Bob Dougherty) ********
   From HWMon.cpp (Copyright 1998-2000 Jonathan Teh Soon Yew):
   voltagefactor[0]=1.25/2628; (2628/1.25=2102.4)   // Vccp
   voltagefactor[1]=1.25/2628; (2628/1.25=2102.4)   // +2.5V
   voltagefactor[2]=1.67/2628; (2628/1.67=1573.7)   // +3.3V
   voltagefactor[3]=2.6/2628;  (2628/2.60=1010.8)   // +5V
   voltagefactor[4]=6.3/2628;  (2628/6.30=417.14)   // +12V
   in[i]=(data[i+2]*25.0+133)*voltagefactor[i];
   That is:
   volts = (25*regVal+133)*factor
   regVal = (volts/factor-133)/25

   (These conversions were contributed by Jonathan Teh Soon Yew

   <j.teh@iname.com>) */
  static inline u8 IN_TO_REG(long val, int inNum)
  {
  	/* To avoid floating point, we multiply constants by 10 (100 for +12V).
  	   Rounding is done (120500 is actually 133000 - 12500).
  	   Remember that val is expressed in 0.001V/bit, which is why we divide
  	   by an additional 10000 (100000 for +12V): 1000 for val and 10 (100)
  	   for the constants. */
  	if (inNum <= 1)
  		return (u8)
  		    SENSORS_LIMIT((val * 21024 - 1205000) / 250000, 0, 255);
  	else if (inNum == 2)
  		return (u8)
  		    SENSORS_LIMIT((val * 15737 - 1205000) / 250000, 0, 255);
  	else if (inNum == 3)
  		return (u8)
  		    SENSORS_LIMIT((val * 10108 - 1205000) / 250000, 0, 255);
  	else
  		return (u8)
  		    SENSORS_LIMIT((val * 41714 - 12050000) / 2500000, 0, 255);
  }
  
  static inline long IN_FROM_REG(u8 val, int inNum)
  {
  	/* To avoid floating point, we multiply constants by 10 (100 for +12V).
  	   We also multiply them by 1000 because we want 0.001V/bit for the
  	   output value. Rounding is done. */
  	if (inNum <= 1)
  		return (long) ((250000 * val + 1330000 + 21024 / 2) / 21024);
  	else if (inNum == 2)
  		return (long) ((250000 * val + 1330000 + 15737 / 2) / 15737);
  	else if (inNum == 3)
  		return (long) ((250000 * val + 1330000 + 10108 / 2) / 10108);
  	else
  		return (long) ((2500000 * val + 13300000 + 41714 / 2) / 41714);
  }
  
  /********* FAN RPM CONVERSIONS ********/
  /* Higher register values = slower fans (the fan's strobe gates a counter).
   But this chip saturates back at 0, not at 255 like all the other chips.
   So, 0 means 0 RPM */
  static inline u8 FAN_TO_REG(long rpm, int div)
  {
  	if (rpm == 0)
  		return 0;
  	rpm = SENSORS_LIMIT(rpm, 1, 1000000);
  	return SENSORS_LIMIT((1350000 + rpm * div / 2) / (rpm * div), 1, 255);
  }
  
  #define FAN_FROM_REG(val,div) ((val)==0?0:(val)==255?0:1350000/((val)*(div)))
  
  /******** TEMP CONVERSIONS (Bob Dougherty) *********/
  /* linear fits from HWMon.cpp (Copyright 1998-2000 Jonathan Teh Soon Yew)
        if(temp<169)

  	      return double(temp)*0.427-32.08;

        else if(temp>=169 && temp<=202)

  	      return double(temp)*0.582-58.16;

        else

  	      return double(temp)*0.924-127.33;

   A fifth-order polynomial fits the unofficial data (provided by Alex van
   Kaam <darkside@chello.nl>) a bit better.  It also give more reasonable
   numbers on my machine (ie. they agree with what my BIOS tells me).

   Here's the fifth-order fit to the 8-bit data:

   temp = 1.625093e-10*val^5 - 1.001632e-07*val^4 + 2.457653e-05*val^3 -

  	2.967619e-03*val^2 + 2.175144e-01*val - 7.090067e+0.

   (2000-10-25- RFD: thanks to Uwe Andersen <uandersen@mayah.com> for

   finding my typos in this formula!)

   Alas, none of the elegant function-fit solutions will work because we
   aren't allowed to use floating point in the kernel and doing it with
   integers doesn't provide enough precision.  So we'll do boring old
   look-up table stuff.  The unofficial data (see below) have effectively
   7-bit resolution (they are rounded to the nearest degree).  I'm assuming
   that the transfer function of the device is monotonic and smooth, so a
   smooth function fit to the data will allow us to get better precision.

   I used the 5th-order poly fit described above and solved for

   VIA register values 0-255.  I *10 before rounding, so we get tenth-degree
   precision.  (I could have done all 1024 values for our 10-bit readings,
   but the function is very linear in the useful range (0-80 deg C), so
   we'll just use linear interpolation for 10-bit readings.)  So, tempLUT

   is the temp at via register values 0-255: */

  static const s16 tempLUT[] =

  { -709, -688, -667, -646, -627, -607, -589, -570, -553, -536, -519,
  	-503, -487, -471, -456, -442, -428, -414, -400, -387, -375,
  	-362, -350, -339, -327, -316, -305, -295, -285, -275, -265,
  	-255, -246, -237, -229, -220, -212, -204, -196, -188, -180,
  	-173, -166, -159, -152, -145, -139, -132, -126, -120, -114,
  	-108, -102, -96, -91, -85, -80, -74, -69, -64, -59, -54, -49,
  	-44, -39, -34, -29, -25, -20, -15, -11, -6, -2, 3, 7, 12, 16,
  	20, 25, 29, 33, 37, 42, 46, 50, 54, 59, 63, 67, 71, 75, 79, 84,
  	88, 92, 96, 100, 104, 109, 113, 117, 121, 125, 130, 134, 138,
  	142, 146, 151, 155, 159, 163, 168, 172, 176, 181, 185, 189,
  	193, 198, 202, 206, 211, 215, 219, 224, 228, 232, 237, 241,
  	245, 250, 254, 259, 263, 267, 272, 276, 281, 285, 290, 294,
  	299, 303, 307, 312, 316, 321, 325, 330, 334, 339, 344, 348,
  	353, 357, 362, 366, 371, 376, 380, 385, 390, 395, 399, 404,
  	409, 414, 419, 423, 428, 433, 438, 443, 449, 454, 459, 464,
  	469, 475, 480, 486, 491, 497, 502, 508, 514, 520, 526, 532,
  	538, 544, 551, 557, 564, 571, 578, 584, 592, 599, 606, 614,
  	621, 629, 637, 645, 654, 662, 671, 680, 689, 698, 708, 718,
  	728, 738, 749, 759, 770, 782, 793, 805, 818, 830, 843, 856,
  	870, 883, 898, 912, 927, 943, 958, 975, 991, 1008, 1026, 1044,
  	1062, 1081, 1101, 1121, 1141, 1162, 1184, 1206, 1229, 1252,
  	1276, 1301, 1326, 1352, 1378, 1406, 1434, 1462

  };

  /* the original LUT values from Alex van Kaam <darkside@chello.nl>

     (for via register values 12-240):
  {-50,-49,-47,-45,-43,-41,-39,-38,-37,-35,-34,-33,-32,-31,
  -30,-29,-28,-27,-26,-25,-24,-24,-23,-22,-21,-20,-20,-19,-18,-17,-17,-16,-15,
  -15,-14,-14,-13,-12,-12,-11,-11,-10,-9,-9,-8,-8,-7,-7,-6,-6,-5,-5,-4,-4,-3,
  -3,-2,-2,-1,-1,0,0,1,1,1,3,3,3,4,4,4,5,5,5,6,6,7,7,8,8,9,9,9,10,10,11,11,12,
  12,12,13,13,13,14,14,15,15,16,16,16,17,17,18,18,19,19,20,20,21,21,21,22,22,
  22,23,23,24,24,25,25,26,26,26,27,27,27,28,28,29,29,30,30,30,31,31,32,32,33,
  33,34,34,35,35,35,36,36,37,37,38,38,39,39,40,40,41,41,42,42,43,43,44,44,45,
  45,46,46,47,48,48,49,49,50,51,51,52,52,53,53,54,55,55,56,57,57,58,59,59,60,
  61,62,62,63,64,65,66,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,83,84,
  85,86,88,89,91,92,94,96,97,99,101,103,105,107,109,110};
  
  
   Here's the reverse LUT.  I got it by doing a 6-th order poly fit (needed

   an extra term for a good fit to these inverse data!) and then
   solving for each temp value from -50 to 110 (the useable range for
   this chip).  Here's the fit:
   viaRegVal = -1.160370e-10*val^6 +3.193693e-08*val^5 - 1.464447e-06*val^4

   - 2.525453e-04*val^3 + 1.424593e-02*val^2 + 2.148941e+00*val +7.275808e+01)
   Note that n=161: */
  static const u8 viaLUT[] =

  { 12, 12, 13, 14, 14, 15, 16, 16, 17, 18, 18, 19, 20, 20, 21, 22, 23,
  	23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 39, 40,
  	41, 43, 45, 46, 48, 49, 51, 53, 55, 57, 59, 60, 62, 64, 66,
  	69, 71, 73, 75, 77, 79, 82, 84, 86, 88, 91, 93, 95, 98, 100,
  	103, 105, 107, 110, 112, 115, 117, 119, 122, 124, 126, 129,
  	131, 134, 136, 138, 140, 143, 145, 147, 150, 152, 154, 156,
  	158, 160, 162, 164, 166, 168, 170, 172, 174, 176, 178, 180,
  	182, 183, 185, 187, 188, 190, 192, 193, 195, 196, 198, 199,
  	200, 202, 203, 205, 206, 207, 208, 209, 210, 211, 212, 213,
  	214, 215, 216, 217, 218, 219, 220, 221, 222, 222, 223, 224,
  	225, 226, 226, 227, 228, 228, 229, 230, 230, 231, 232, 232,
  	233, 233, 234, 235, 235, 236, 236, 237, 237, 238, 238, 239,
  	239, 240

  };
  
  /* Converting temps to (8-bit) hyst and over registers
     No interpolation here.
     The +50 is because the temps start at -50 */
  static inline u8 TEMP_TO_REG(long val)
  {

  	return viaLUT[val <= -50000 ? 0 : val >= 110000 ? 160 :

  		      (val < 0 ? val - 500 : val + 500) / 1000 + 50];
  }
  
  /* for 8-bit temperature hyst and over registers */

  #define TEMP_FROM_REG(val)	((long)tempLUT[val] * 100)

  
  /* for 10-bit temperature readings */
  static inline long TEMP_FROM_REG10(u16 val)
  {
  	u16 eightBits = val >> 2;
  	u16 twoBits = val & 3;
  
  	/* no interpolation for these */
  	if (twoBits == 0 || eightBits == 255)
  		return TEMP_FROM_REG(eightBits);
  
  	/* do some linear interpolation */
  	return (tempLUT[eightBits] * (4 - twoBits) +

  		tempLUT[eightBits + 1] * twoBits) * 25;

  }

  #define DIV_FROM_REG(val) (1 << (val))
  #define DIV_TO_REG(val) ((val)==8?3:(val)==4?2:(val)==1?0:1)

  /* For each registered chip, we need to keep some data in memory.
     The structure is dynamically allocated. */

  struct via686a_data {

  	unsigned short addr;
  	const char *name;

  	struct device *hwmon_dev;

  	struct mutex update_lock;

  	char valid;		/* !=0 if following fields are valid */
  	unsigned long last_updated;	/* In jiffies */
  
  	u8 in[5];		/* Register value */
  	u8 in_max[5];		/* Register value */
  	u8 in_min[5];		/* Register value */
  	u8 fan[2];		/* Register value */
  	u8 fan_min[2];		/* Register value */
  	u16 temp[3];		/* Register value 10 bit */
  	u8 temp_over[3];	/* Register value */
  	u8 temp_hyst[3];	/* Register value */
  	u8 fan_div[2];		/* Register encoding, shifted right */
  	u16 alarms;		/* Register encoding, combined */
  };
  
  static struct pci_dev *s_bridge;	/* pointer to the (only) via686a */

  static int via686a_probe(struct platform_device *pdev);

  static int __devexit via686a_remove(struct platform_device *pdev);

  static inline int via686a_read_value(struct via686a_data *data, u8 reg)

  {

  	return inb_p(data->addr + reg);

  }

  static inline void via686a_write_value(struct via686a_data *data, u8 reg,

  				       u8 value)
  {

  	outb_p(value, data->addr + reg);

  }
  
  static struct via686a_data *via686a_update_device(struct device *dev);

  static void via686a_init_device(struct via686a_data *data);

  
  /* following are the sysfs callback functions */
  
  /* 7 voltage sensors */

  static ssize_t show_in(struct device *dev, struct device_attribute *da,
  		char *buf) {

  	struct via686a_data *data = via686a_update_device(dev);

  	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
  	int nr = attr->index;

  	return sprintf(buf, "%ld
  ", IN_FROM_REG(data->in[nr], nr));
  }

  static ssize_t show_in_min(struct device *dev, struct device_attribute *da,
  		char *buf) {

  	struct via686a_data *data = via686a_update_device(dev);

  	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
  	int nr = attr->index;

  	return sprintf(buf, "%ld
  ", IN_FROM_REG(data->in_min[nr], nr));
  }

  static ssize_t show_in_max(struct device *dev, struct device_attribute *da,
  		char *buf) {

  	struct via686a_data *data = via686a_update_device(dev);

  	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
  	int nr = attr->index;

  	return sprintf(buf, "%ld
  ", IN_FROM_REG(data->in_max[nr], nr));
  }

  static ssize_t set_in_min(struct device *dev, struct device_attribute *da,
  		const char *buf, size_t count) {

  	struct via686a_data *data = dev_get_drvdata(dev);

  	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
  	int nr = attr->index;

  	unsigned long val = simple_strtoul(buf, NULL, 10);

  	mutex_lock(&data->update_lock);

  	data->in_min[nr] = IN_TO_REG(val, nr);

  	via686a_write_value(data, VIA686A_REG_IN_MIN(nr),

  			data->in_min[nr]);

  	mutex_unlock(&data->update_lock);

  	return count;
  }

  static ssize_t set_in_max(struct device *dev, struct device_attribute *da,
  		const char *buf, size_t count) {

  	struct via686a_data *data = dev_get_drvdata(dev);

  	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
  	int nr = attr->index;

  	unsigned long val = simple_strtoul(buf, NULL, 10);

  	mutex_lock(&data->update_lock);

  	data->in_max[nr] = IN_TO_REG(val, nr);

  	via686a_write_value(data, VIA686A_REG_IN_MAX(nr),

  			data->in_max[nr]);

  	mutex_unlock(&data->update_lock);

  	return count;
  }
  #define show_in_offset(offset)					\

  static SENSOR_DEVICE_ATTR(in##offset##_input, S_IRUGO,		\
  		show_in, NULL, offset);				\
  static SENSOR_DEVICE_ATTR(in##offset##_min, S_IRUGO | S_IWUSR,	\
  		show_in_min, set_in_min, offset);		\
  static SENSOR_DEVICE_ATTR(in##offset##_max, S_IRUGO | S_IWUSR,	\
  		show_in_max, set_in_max, offset);

  
  show_in_offset(0);
  show_in_offset(1);
  show_in_offset(2);
  show_in_offset(3);
  show_in_offset(4);
  
  /* 3 temperatures */

  static ssize_t show_temp(struct device *dev, struct device_attribute *da,
  		char *buf) {

  	struct via686a_data *data = via686a_update_device(dev);

  	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
  	int nr = attr->index;

  	return sprintf(buf, "%ld
  ", TEMP_FROM_REG10(data->temp[nr]));
  }

  static ssize_t show_temp_over(struct device *dev, struct device_attribute *da,
  		char *buf) {

  	struct via686a_data *data = via686a_update_device(dev);

  	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
  	int nr = attr->index;

  	return sprintf(buf, "%ld
  ", TEMP_FROM_REG(data->temp_over[nr]));
  }

  static ssize_t show_temp_hyst(struct device *dev, struct device_attribute *da,
  		char *buf) {

  	struct via686a_data *data = via686a_update_device(dev);

  	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
  	int nr = attr->index;

  	return sprintf(buf, "%ld
  ", TEMP_FROM_REG(data->temp_hyst[nr]));
  }

  static ssize_t set_temp_over(struct device *dev, struct device_attribute *da,
  		const char *buf, size_t count) {

  	struct via686a_data *data = dev_get_drvdata(dev);

  	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
  	int nr = attr->index;

  	int val = simple_strtol(buf, NULL, 10);

  	mutex_lock(&data->update_lock);

  	data->temp_over[nr] = TEMP_TO_REG(val);

  	via686a_write_value(data, VIA686A_REG_TEMP_OVER[nr],

  			    data->temp_over[nr]);

  	mutex_unlock(&data->update_lock);

  	return count;
  }

  static ssize_t set_temp_hyst(struct device *dev, struct device_attribute *da,
  		const char *buf, size_t count) {

  	struct via686a_data *data = dev_get_drvdata(dev);

  	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
  	int nr = attr->index;

  	int val = simple_strtol(buf, NULL, 10);

  	mutex_lock(&data->update_lock);

  	data->temp_hyst[nr] = TEMP_TO_REG(val);

  	via686a_write_value(data, VIA686A_REG_TEMP_HYST[nr],

  			    data->temp_hyst[nr]);

  	mutex_unlock(&data->update_lock);

  	return count;
  }
  #define show_temp_offset(offset)					\

  static SENSOR_DEVICE_ATTR(temp##offset##_input, S_IRUGO,		\
  		show_temp, NULL, offset - 1);				\
  static SENSOR_DEVICE_ATTR(temp##offset##_max, S_IRUGO | S_IWUSR,	\
  		show_temp_over, set_temp_over, offset - 1);		\
  static SENSOR_DEVICE_ATTR(temp##offset##_max_hyst, S_IRUGO | S_IWUSR,	\
  		show_temp_hyst, set_temp_hyst, offset - 1);

  
  show_temp_offset(1);
  show_temp_offset(2);
  show_temp_offset(3);
  
  /* 2 Fans */

  static ssize_t show_fan(struct device *dev, struct device_attribute *da,
  		char *buf) {

  	struct via686a_data *data = via686a_update_device(dev);

  	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
  	int nr = attr->index;

  	return sprintf(buf, "%d
  ", FAN_FROM_REG(data->fan[nr],

  				DIV_FROM_REG(data->fan_div[nr])) );
  }

  static ssize_t show_fan_min(struct device *dev, struct device_attribute *da,
  		char *buf) {

  	struct via686a_data *data = via686a_update_device(dev);

  	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
  	int nr = attr->index;

  	return sprintf(buf, "%d
  ",

  		FAN_FROM_REG(data->fan_min[nr], DIV_FROM_REG(data->fan_div[nr])) );
  }

  static ssize_t show_fan_div(struct device *dev, struct device_attribute *da,
  		char *buf) {

  	struct via686a_data *data = via686a_update_device(dev);

  	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
  	int nr = attr->index;

  	return sprintf(buf, "%d
  ", DIV_FROM_REG(data->fan_div[nr]) );

  }

  static ssize_t set_fan_min(struct device *dev, struct device_attribute *da,
  		const char *buf, size_t count) {

  	struct via686a_data *data = dev_get_drvdata(dev);

  	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
  	int nr = attr->index;

  	int val = simple_strtol(buf, NULL, 10);

  	mutex_lock(&data->update_lock);

  	data->fan_min[nr] = FAN_TO_REG(val, DIV_FROM_REG(data->fan_div[nr]));

  	via686a_write_value(data, VIA686A_REG_FAN_MIN(nr+1), data->fan_min[nr]);

  	mutex_unlock(&data->update_lock);

  	return count;
  }

  static ssize_t set_fan_div(struct device *dev, struct device_attribute *da,
  		const char *buf, size_t count) {

  	struct via686a_data *data = dev_get_drvdata(dev);

  	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
  	int nr = attr->index;

  	int val = simple_strtol(buf, NULL, 10);
  	int old;

  	mutex_lock(&data->update_lock);

  	old = via686a_read_value(data, VIA686A_REG_FANDIV);

  	data->fan_div[nr] = DIV_TO_REG(val);
  	old = (old & 0x0f) | (data->fan_div[1] << 6) | (data->fan_div[0] << 4);

  	via686a_write_value(data, VIA686A_REG_FANDIV, old);

  	mutex_unlock(&data->update_lock);

  	return count;
  }
  
  #define show_fan_offset(offset)						\

  static SENSOR_DEVICE_ATTR(fan##offset##_input, S_IRUGO,			\
  		show_fan, NULL, offset - 1);				\
  static SENSOR_DEVICE_ATTR(fan##offset##_min, S_IRUGO | S_IWUSR,		\
  		show_fan_min, set_fan_min, offset - 1);			\
  static SENSOR_DEVICE_ATTR(fan##offset##_div, S_IRUGO | S_IWUSR,		\
  		show_fan_div, set_fan_div, offset - 1);

  
  show_fan_offset(1);
  show_fan_offset(2);
  
  /* Alarms */

  static ssize_t show_alarms(struct device *dev, struct device_attribute *attr, char *buf) {

  	struct via686a_data *data = via686a_update_device(dev);

  	return sprintf(buf, "%u
  ", data->alarms);

  }

  static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);

  static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
  			  char *buf)
  {
  	int bitnr = to_sensor_dev_attr(attr)->index;
  	struct via686a_data *data = via686a_update_device(dev);
  	return sprintf(buf, "%u
  ", (data->alarms >> bitnr) & 1);
  }
  static SENSOR_DEVICE_ATTR(in0_alarm, S_IRUGO, show_alarm, NULL, 0);
  static SENSOR_DEVICE_ATTR(in1_alarm, S_IRUGO, show_alarm, NULL, 1);
  static SENSOR_DEVICE_ATTR(in2_alarm, S_IRUGO, show_alarm, NULL, 2);
  static SENSOR_DEVICE_ATTR(in3_alarm, S_IRUGO, show_alarm, NULL, 3);
  static SENSOR_DEVICE_ATTR(in4_alarm, S_IRUGO, show_alarm, NULL, 8);
  static SENSOR_DEVICE_ATTR(temp1_alarm, S_IRUGO, show_alarm, NULL, 4);
  static SENSOR_DEVICE_ATTR(temp2_alarm, S_IRUGO, show_alarm, NULL, 11);
  static SENSOR_DEVICE_ATTR(temp3_alarm, S_IRUGO, show_alarm, NULL, 15);
  static SENSOR_DEVICE_ATTR(fan1_alarm, S_IRUGO, show_alarm, NULL, 6);
  static SENSOR_DEVICE_ATTR(fan2_alarm, S_IRUGO, show_alarm, NULL, 7);

  static ssize_t show_name(struct device *dev, struct device_attribute
  			 *devattr, char *buf)
  {
  	struct via686a_data *data = dev_get_drvdata(dev);
  	return sprintf(buf, "%s
  ", data->name);
  }
  static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);

  static struct attribute *via686a_attributes[] = {

  	&sensor_dev_attr_in0_input.dev_attr.attr,
  	&sensor_dev_attr_in1_input.dev_attr.attr,
  	&sensor_dev_attr_in2_input.dev_attr.attr,
  	&sensor_dev_attr_in3_input.dev_attr.attr,
  	&sensor_dev_attr_in4_input.dev_attr.attr,
  	&sensor_dev_attr_in0_min.dev_attr.attr,
  	&sensor_dev_attr_in1_min.dev_attr.attr,
  	&sensor_dev_attr_in2_min.dev_attr.attr,
  	&sensor_dev_attr_in3_min.dev_attr.attr,
  	&sensor_dev_attr_in4_min.dev_attr.attr,
  	&sensor_dev_attr_in0_max.dev_attr.attr,
  	&sensor_dev_attr_in1_max.dev_attr.attr,
  	&sensor_dev_attr_in2_max.dev_attr.attr,
  	&sensor_dev_attr_in3_max.dev_attr.attr,
  	&sensor_dev_attr_in4_max.dev_attr.attr,

  	&sensor_dev_attr_in0_alarm.dev_attr.attr,
  	&sensor_dev_attr_in1_alarm.dev_attr.attr,
  	&sensor_dev_attr_in2_alarm.dev_attr.attr,
  	&sensor_dev_attr_in3_alarm.dev_attr.attr,
  	&sensor_dev_attr_in4_alarm.dev_attr.attr,

  
  	&sensor_dev_attr_temp1_input.dev_attr.attr,
  	&sensor_dev_attr_temp2_input.dev_attr.attr,
  	&sensor_dev_attr_temp3_input.dev_attr.attr,
  	&sensor_dev_attr_temp1_max.dev_attr.attr,
  	&sensor_dev_attr_temp2_max.dev_attr.attr,
  	&sensor_dev_attr_temp3_max.dev_attr.attr,
  	&sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
  	&sensor_dev_attr_temp2_max_hyst.dev_attr.attr,
  	&sensor_dev_attr_temp3_max_hyst.dev_attr.attr,

  	&sensor_dev_attr_temp1_alarm.dev_attr.attr,
  	&sensor_dev_attr_temp2_alarm.dev_attr.attr,
  	&sensor_dev_attr_temp3_alarm.dev_attr.attr,

  
  	&sensor_dev_attr_fan1_input.dev_attr.attr,
  	&sensor_dev_attr_fan2_input.dev_attr.attr,
  	&sensor_dev_attr_fan1_min.dev_attr.attr,
  	&sensor_dev_attr_fan2_min.dev_attr.attr,
  	&sensor_dev_attr_fan1_div.dev_attr.attr,
  	&sensor_dev_attr_fan2_div.dev_attr.attr,

  	&sensor_dev_attr_fan1_alarm.dev_attr.attr,
  	&sensor_dev_attr_fan2_alarm.dev_attr.attr,

  
  	&dev_attr_alarms.attr,

  	&dev_attr_name.attr,

  	NULL
  };
  
  static const struct attribute_group via686a_group = {
  	.attrs = via686a_attributes,
  };

  static struct platform_driver via686a_driver = {

  	.driver = {

  		.owner	= THIS_MODULE,

  		.name	= "via686a",
  	},

  	.probe		= via686a_probe,
  	.remove		= __devexit_p(via686a_remove),

  };
  
  
  /* This is called when the module is loaded */

  static int __devinit via686a_probe(struct platform_device *pdev)

  {

  	struct via686a_data *data;

  	struct resource *res;
  	int err;

  
  	/* Reserve the ISA region */

  	res = platform_get_resource(pdev, IORESOURCE_IO, 0);
  	if (!request_region(res->start, VIA686A_EXTENT,

  			    via686a_driver.driver.name)) {

  		dev_err(&pdev->dev, "Region 0x%lx-0x%lx already in use!
  ",
  			(unsigned long)res->start, (unsigned long)res->end);

  		return -ENODEV;
  	}

  	if (!(data = kzalloc(sizeof(struct via686a_data), GFP_KERNEL))) {

  		err = -ENOMEM;

  		goto exit_release;

  	}

  	platform_set_drvdata(pdev, data);
  	data->addr = res->start;
  	data->name = "via686a";

  	mutex_init(&data->update_lock);

  	/* Initialize the VIA686A chip */

  	via686a_init_device(data);

  
  	/* Register sysfs hooks */

  	if ((err = sysfs_create_group(&pdev->dev.kobj, &via686a_group)))
  		goto exit_free;

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

  		goto exit_remove_files;

  	}

  	return 0;

  exit_remove_files:

  	sysfs_remove_group(&pdev->dev.kobj, &via686a_group);

  exit_free:

  	kfree(data);

  exit_release:

  	release_region(res->start, VIA686A_EXTENT);

  	return err;
  }

  static int __devexit via686a_remove(struct platform_device *pdev)

  {

  	struct via686a_data *data = platform_get_drvdata(pdev);

  	hwmon_device_unregister(data->hwmon_dev);

  	sysfs_remove_group(&pdev->dev.kobj, &via686a_group);

  	release_region(data->addr, VIA686A_EXTENT);
  	platform_set_drvdata(pdev, NULL);

  	kfree(data);

  
  	return 0;
  }

  static void via686a_update_fan_div(struct via686a_data *data)
  {
  	int reg = via686a_read_value(data, VIA686A_REG_FANDIV);
  	data->fan_div[0] = (reg >> 4) & 0x03;
  	data->fan_div[1] = reg >> 6;
  }

  static void __devinit via686a_init_device(struct via686a_data *data)

  {
  	u8 reg;
  
  	/* Start monitoring */

  	reg = via686a_read_value(data, VIA686A_REG_CONFIG);
  	via686a_write_value(data, VIA686A_REG_CONFIG, (reg | 0x01) & 0x7F);

  
  	/* Configure temp interrupt mode for continuous-interrupt operation */

  	reg = via686a_read_value(data, VIA686A_REG_TEMP_MODE);
  	via686a_write_value(data, VIA686A_REG_TEMP_MODE,

  			    (reg & ~VIA686A_TEMP_MODE_MASK)
  			    | VIA686A_TEMP_MODE_CONTINUOUS);

  
  	/* Pre-read fan clock divisor values */
  	via686a_update_fan_div(data);

  }
  
  static struct via686a_data *via686a_update_device(struct device *dev)
  {

  	struct via686a_data *data = dev_get_drvdata(dev);

  	int i;

  	mutex_lock(&data->update_lock);

  
  	if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
  	    || !data->valid) {
  		for (i = 0; i <= 4; i++) {
  			data->in[i] =

  			    via686a_read_value(data, VIA686A_REG_IN(i));
  			data->in_min[i] = via686a_read_value(data,

  							     VIA686A_REG_IN_MIN
  							     (i));
  			data->in_max[i] =

  			    via686a_read_value(data, VIA686A_REG_IN_MAX(i));

  		}
  		for (i = 1; i <= 2; i++) {
  			data->fan[i - 1] =

  			    via686a_read_value(data, VIA686A_REG_FAN(i));
  			data->fan_min[i - 1] = via686a_read_value(data,

  						     VIA686A_REG_FAN_MIN(i));
  		}
  		for (i = 0; i <= 2; i++) {

  			data->temp[i] = via686a_read_value(data,

  						 VIA686A_REG_TEMP[i]) << 2;

  			data->temp_over[i] =

  			    via686a_read_value(data,

  					       VIA686A_REG_TEMP_OVER[i]);

  			data->temp_hyst[i] =

  			    via686a_read_value(data,

  					       VIA686A_REG_TEMP_HYST[i]);

  		}

  		/* add in lower 2 bits

  		   temp1 uses bits 7-6 of VIA686A_REG_TEMP_LOW1
  		   temp2 uses bits 5-4 of VIA686A_REG_TEMP_LOW23
  		   temp3 uses bits 7-6 of VIA686A_REG_TEMP_LOW23
  		 */

  		data->temp[0] |= (via686a_read_value(data,

  						     VIA686A_REG_TEMP_LOW1)
  				  & 0xc0) >> 6;
  		data->temp[1] |=

  		    (via686a_read_value(data, VIA686A_REG_TEMP_LOW23) &

  		     0x30) >> 4;
  		data->temp[2] |=

  		    (via686a_read_value(data, VIA686A_REG_TEMP_LOW23) &

  		     0xc0) >> 6;

  		via686a_update_fan_div(data);

  		data->alarms =

  		    via686a_read_value(data,

  				       VIA686A_REG_ALARM1) |

  		    (via686a_read_value(data, VIA686A_REG_ALARM2) << 8);

  		data->last_updated = jiffies;
  		data->valid = 1;
  	}

  	mutex_unlock(&data->update_lock);

  
  	return data;
  }

  static const struct pci_device_id via686a_pci_ids[] = {

  	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C686_4) },
  	{ 0, }

  };
  
  MODULE_DEVICE_TABLE(pci, via686a_pci_ids);

  static int __devinit via686a_device_add(unsigned short address)
  {
  	struct resource res = {
  		.start	= address,
  		.end	= address + VIA686A_EXTENT - 1,
  		.name	= "via686a",
  		.flags	= IORESOURCE_IO,
  	};
  	int err;

  	err = acpi_check_resource_conflict(&res);
  	if (err)
  		goto exit;

  	pdev = platform_device_alloc("via686a", address);
  	if (!pdev) {
  		err = -ENOMEM;

  		pr_err("Device allocation failed
  ");

  		goto exit;
  	}
  
  	err = platform_device_add_resources(pdev, &res, 1);
  	if (err) {

  		pr_err("Device resource addition failed (%d)
  ", err);

  		goto exit_device_put;
  	}
  
  	err = platform_device_add(pdev);
  	if (err) {

  		pr_err("Device addition failed (%d)
  ", err);

  		goto exit_device_put;
  	}
  
  	return 0;
  
  exit_device_put:
  	platform_device_put(pdev);
  exit:
  	return err;
  }

  static int __devinit via686a_pci_probe(struct pci_dev *dev,

  				       const struct pci_device_id *id)

  {

  	u16 address, val;

  	if (force_addr) {
  		address = force_addr & ~(VIA686A_EXTENT - 1);
  		dev_warn(&dev->dev, "Forcing ISA address 0x%x
  ", address);
  		if (PCIBIOS_SUCCESSFUL !=
  		    pci_write_config_word(dev, VIA686A_BASE_REG, address | 1))
  			return -ENODEV;
  	}

  	if (PCIBIOS_SUCCESSFUL !=
  	    pci_read_config_word(dev, VIA686A_BASE_REG, &val))
  		return -ENODEV;

  	address = val & ~(VIA686A_EXTENT - 1);

  	if (address == 0) {

  		dev_err(&dev->dev, "base address not set - upgrade BIOS "
  			"or use force_addr=0xaddr
  ");
  		return -ENODEV;
  	}

  	if (PCIBIOS_SUCCESSFUL !=
  	    pci_read_config_word(dev, VIA686A_ENABLE_REG, &val))
  		return -ENODEV;
  	if (!(val & 0x0001)) {
  		if (!force_addr) {
  			dev_warn(&dev->dev, "Sensors disabled, enable "
  				 "with force_addr=0x%x
  ", address);
  			return -ENODEV;
  		}
  
  		dev_warn(&dev->dev, "Enabling sensors
  ");
  		if (PCIBIOS_SUCCESSFUL !=
  		    pci_write_config_word(dev, VIA686A_ENABLE_REG,
  					  val | 0x0001))
  			return -ENODEV;

  	}

  	if (platform_driver_register(&via686a_driver))
  		goto exit;
  
  	/* Sets global pdev as a side effect */
  	if (via686a_device_add(address))
  		goto exit_unregister;

  	/* Always return failure here.  This is to allow other drivers to bind
  	 * to this pci device.  We don't really want to have control over the
  	 * pci device, we only wanted to read as few register values from it.
  	 */

  	s_bridge = pci_dev_get(dev);
  	return -ENODEV;
  
  exit_unregister:
  	platform_driver_unregister(&via686a_driver);
  exit:

  	return -ENODEV;
  }
  
  static struct pci_driver via686a_pci_driver = {

  	.name		= "via686a",
  	.id_table	= via686a_pci_ids,
  	.probe		= via686a_pci_probe,

  };
  
  static int __init sm_via686a_init(void)
  {

  	return pci_register_driver(&via686a_pci_driver);

  }
  
  static void __exit sm_via686a_exit(void)
  {
  	pci_unregister_driver(&via686a_pci_driver);
  	if (s_bridge != NULL) {

  		platform_device_unregister(pdev);
  		platform_driver_unregister(&via686a_driver);

  		pci_dev_put(s_bridge);
  		s_bridge = NULL;
  	}
  }

  MODULE_AUTHOR("Kyösti Mälkki <kmalkki@cc.hut.fi>, "

  	      "Mark Studebaker <mdsxyz123@yahoo.com> "
  	      "and Bob Dougherty <bobd@stanford.edu>");

  MODULE_DESCRIPTION("VIA 686A Sensor device");
  MODULE_LICENSE("GPL");
  
  module_init(sm_via686a_init);
  module_exit(sm_via686a_exit);