/*
    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.
    See doc/chips/via686a for details.
    Warning - only supports a single device.
*/

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/pci.h>
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/i2c-sensor.h>
#include <linux/init.h>
#include <asm/io.h>


/* If force_addr is set to anything different from 0, we forcibly enable
   the device at the given address. */
static int force_addr = 0;
MODULE_PARM(force_addr, "i");
MODULE_PARM_DESC(force_addr,
		 "Initialize the base address of the sensors");

/* Addresses to scan.
   Note that we can't determine the ISA address until we have initialized
   our module */
static unsigned short normal_i2c[] = { I2C_CLIENT_END };
static unsigned short normal_i2c_range[] = { I2C_CLIENT_END };
static unsigned int normal_isa[] = { 0x0000, I2C_CLIENT_ISA_END };
static unsigned int normal_isa_range[] = { I2C_CLIENT_ISA_END };

/* Insmod parameters */
SENSORS_INSMOD_1(via686a);

/*
   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))

/* the following values are as speced by VIA: */
static const u8 regtemp[] = { 0x20, 0x21, 0x1f };
static const u8 regover[] = { 0x39, 0x3d, 0x1d };
static const u8 reghyst[] = { 0x3a, 0x3e, 0x1e };

/* temps numbered 1-3 */
#define VIA686A_REG_TEMP(nr)		(regtemp[nr])
#define VIA686A_REG_TEMP_OVER(nr)	(regover[nr])
#define VIA686A_REG_TEMP_HYST(nr)	(reghyst[nr])
#define VIA686A_REG_TEMP_LOW1	0x4b	// bits 7-6
#define VIA686A_REG_TEMP_LOW23	0x49	// 2 = bits 5-4, 3 = bits 7-6

#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. Rounding and 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>)
 
 These get us close, but they don't completely agree with what my BIOS 
 says- they are all a bit low.  But, it all we have to go on... */
static inline u8 IN_TO_REG(long val, int inNum)
{
	/* to avoid floating point, we multiply everything by 100.
	 val is guaranteed to be positive, so we can achieve the effect of 
	 rounding by (...*10+5)/10.  Note that the *10 is hidden in the 
	 /250 (which should really be /2500).
	 At the end, we need to /100 because we *100 everything and we need
	 to /10 because of the rounding thing, so we /1000.   */
	if (inNum <= 1)
		return (u8)
		    SENSORS_LIMIT(((val * 210240 - 13300) / 250 + 5) / 1000, 
				  0, 255);
	else if (inNum == 2)
		return (u8)
		    SENSORS_LIMIT(((val * 157370 - 13300) / 250 + 5) / 1000, 
				  0, 255);
	else if (inNum == 3)
		return (u8)
		    SENSORS_LIMIT(((val * 101080 - 13300) / 250 + 5) / 1000, 
				  0, 255);
	else
		return (u8) SENSORS_LIMIT(((val * 41714 - 13300) / 250 + 5)
					  / 1000, 0, 255);
}

static inline long IN_FROM_REG(u8 val, int inNum)
{
	/* to avoid floating point, we multiply everything by 100.
	 val is guaranteed to be positive, so we can achieve the effect of
	 rounding by adding 0.5.  Or, to avoid fp math, we do (...*10+5)/10.
	 We need to scale with *100 anyway, so no need to /100 at the end. */
	if (inNum <= 1)
		return (long) (((250000 * val + 13300) / 210240 * 10 + 5) /10);
	else if (inNum == 2)
		return (long) (((250000 * val + 13300) / 157370 * 10 + 5) /10);
	else if (inNum == 3)
		return (long) (((250000 * val + 13300) / 101080 * 10 + 5) /10);
	else
		return (long) (((250000 * val + 13300) / 41714 * 10 + 5) /10);
}

/********* 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 rpovide 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 long 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.  Just check the limits and go.
 The +5 effectively rounds off properly and the +50 is because 
 the temps start at -50 */
static inline u8 TEMP_TO_REG(long val)
{
	return (u8)
	    SENSORS_LIMIT(viaLUT[((val <= -500) ? 0 : (val >= 1100) ? 160 : 
				  ((val + 5) / 10 + 50))], 0, 255);
}

/* for 8-bit temperature hyst and over registers 
 The temp values are already *10, so we don't need to do that.
 But we _will_ round these off to the nearest degree with (...*10+5)/10 */
#define TEMP_FROM_REG(val) ((tempLUT[(val)]*10+5)/10)

/* for 10-bit temperature readings 
 You might _think_ this is too long to inline, but's it's really only
 called once... */
static inline long TEMP_FROM_REG10(u16 val)
{
	/* the temp values are already *10, so we don't need to do that. */
	long temp;
	u16 eightBits = val >> 2;
	u16 twoBits = val & 3;

	/* handle the extremes first (they won't interpolate well! ;-) */
	if (val == 0)
		return (long) tempLUT[0];
	if (val == 1023)
		return (long) tempLUT[255];

	if (twoBits == 0)
		return (long) tempLUT[eightBits];
	else {
		/* do some interpolation by multipying the lower and upper
		 bounds by 25, 50 or 75, then /100. */
		temp = ((25 * (4 - twoBits)) * tempLUT[eightBits]
			+ (25 * twoBits) * tempLUT[eightBits + 1]);
		/* increase the magnitude by 50 to achieve rounding. */
		if (temp > 0)
			temp += 50;
		else
			temp -= 50;
		return (temp / 100);
	}
}

#define ALARMS_FROM_REG(val) (val)

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

/* Initial limits */
#define VIA686A_INIT_IN_0 200
#define VIA686A_INIT_IN_1 250
#define VIA686A_INIT_IN_2 330
#define VIA686A_INIT_IN_3 500
#define VIA686A_INIT_IN_4 1200

#define VIA686A_INIT_IN_PERCENTAGE 10

#define VIA686A_INIT_IN_MIN_0 (VIA686A_INIT_IN_0 - VIA686A_INIT_IN_0 \
        * VIA686A_INIT_IN_PERCENTAGE / 100)
#define VIA686A_INIT_IN_MAX_0 (VIA686A_INIT_IN_0 + VIA686A_INIT_IN_0 \
        * VIA686A_INIT_IN_PERCENTAGE / 100)
#define VIA686A_INIT_IN_MIN_1 (VIA686A_INIT_IN_1 - VIA686A_INIT_IN_1 \
        * VIA686A_INIT_IN_PERCENTAGE / 100)
#define VIA686A_INIT_IN_MAX_1 (VIA686A_INIT_IN_1 + VIA686A_INIT_IN_1 \
        * VIA686A_INIT_IN_PERCENTAGE / 100)
#define VIA686A_INIT_IN_MIN_2 (VIA686A_INIT_IN_2 - VIA686A_INIT_IN_2 \
        * VIA686A_INIT_IN_PERCENTAGE / 100)
#define VIA686A_INIT_IN_MAX_2 (VIA686A_INIT_IN_2 + VIA686A_INIT_IN_2 \
        * VIA686A_INIT_IN_PERCENTAGE / 100)
#define VIA686A_INIT_IN_MIN_3 (VIA686A_INIT_IN_3 - VIA686A_INIT_IN_3 \
        * VIA686A_INIT_IN_PERCENTAGE / 100)
#define VIA686A_INIT_IN_MAX_3 (VIA686A_INIT_IN_3 + VIA686A_INIT_IN_3 \
        * VIA686A_INIT_IN_PERCENTAGE / 100)
#define VIA686A_INIT_IN_MIN_4 (VIA686A_INIT_IN_4 - VIA686A_INIT_IN_4 \
        * VIA686A_INIT_IN_PERCENTAGE / 100)
#define VIA686A_INIT_IN_MAX_4 (VIA686A_INIT_IN_4 + VIA686A_INIT_IN_4 \
        * VIA686A_INIT_IN_PERCENTAGE / 100)

#define VIA686A_INIT_FAN_MIN	3000

#define VIA686A_INIT_TEMP_OVER 600
#define VIA686A_INIT_TEMP_HYST 500

/* For the VIA686A, we need to keep some data in memory. That
   data is pointed to by via686a_list[NR]->data. The structure itself is
   dynamically allocated, at the same time when a new via686a client is
   allocated. */
struct via686a_data {
	int sysctl_id;

	struct semaphore 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_attach_adapter(struct i2c_adapter *adapter);
static int via686a_detect(struct i2c_adapter *adapter, int address, int kind);
static int via686a_detach_client(struct i2c_client *client);

static inline int via686a_read_value(struct i2c_client *client, u8 reg)
{
	return (inb_p(client->addr + reg));
}

static inline void via686a_write_value(struct i2c_client *client, u8 reg,
				       u8 value)
{
	outb_p(value, client->addr + reg);
}

static void via686a_update_client(struct i2c_client *client);
static void via686a_init_client(struct i2c_client *client);

/* following are the sysfs callback functions */

/* 7 voltage sensors */
static ssize_t show_in(struct device *dev, char *buf, int nr) {
	struct i2c_client *client = to_i2c_client(dev);
	struct via686a_data *data = i2c_get_clientdata(client);
	via686a_update_client(client);
	return sprintf(buf, "%ld\n", IN_FROM_REG(data->in[nr], nr)*10 );
}

static ssize_t show_in_min(struct device *dev, char *buf, int nr) {
	struct i2c_client *client = to_i2c_client(dev);
	struct via686a_data *data = i2c_get_clientdata(client);
	via686a_update_client(client);
	return sprintf(buf, "%ld\n", IN_FROM_REG(data->in_min[nr], nr)*10 );
}

static ssize_t show_in_max(struct device *dev, char *buf, int nr) {
	struct i2c_client *client = to_i2c_client(dev);
	struct via686a_data *data = i2c_get_clientdata(client);
	via686a_update_client(client);
	return sprintf(buf, "%ld\n", IN_FROM_REG(data->in_max[nr], nr)*10 );
}

static ssize_t set_in_min(struct device *dev, const char *buf, 
		size_t count, int nr) {
	struct i2c_client *client = to_i2c_client(dev);
	struct via686a_data *data = i2c_get_clientdata(client);
	unsigned long val = simple_strtoul(buf, NULL, 10)/10;
	data->in_min[nr] = IN_TO_REG(val,nr);
	via686a_write_value(client, VIA686A_REG_IN_MIN(nr), 
			data->in_min[nr]);
	return count;
}
static ssize_t set_in_max(struct device *dev, const char *buf, 
		size_t count, int nr) {
	struct i2c_client *client = to_i2c_client(dev);
	struct via686a_data *data = i2c_get_clientdata(client);
	unsigned long val = simple_strtoul(buf, NULL, 10)/10;
	data->in_max[nr] = IN_TO_REG(val,nr);
	via686a_write_value(client, VIA686A_REG_IN_MAX(nr), 
			data->in_max[nr]);
	return count;
}
#define show_in_offset(offset)					\
static ssize_t 							\
	show_in##offset (struct device *dev, char *buf)		\
{								\
	return show_in(dev, buf, 0x##offset);			\
}								\
static ssize_t 							\
	show_in##offset##_min (struct device *dev, char *buf)	\
{								\
	return show_in_min(dev, buf, 0x##offset);		\
}								\
static ssize_t 							\
	show_in##offset##_max (struct device *dev, char *buf)	\
{								\
	return show_in_max(dev, buf, 0x##offset);		\
}								\
static ssize_t set_in##offset##_min (struct device *dev, 	\
		const char *buf, size_t count) 			\
{								\
	return set_in_min(dev, buf, count, 0x##offset);		\
}								\
static ssize_t set_in##offset##_max (struct device *dev,	\
			const char *buf, size_t count)		\
{								\
	return set_in_max(dev, buf, count, 0x##offset);		\
}								\
static DEVICE_ATTR(in_input##offset, S_IRUGO, show_in##offset, NULL) 	\
static DEVICE_ATTR(in_min##offset, S_IRUGO | S_IWUSR, 		\
		show_in##offset##_min, set_in##offset##_min)	\
static DEVICE_ATTR(in_max##offset, S_IRUGO | S_IWUSR, 		\
		show_in##offset##_max, set_in##offset##_max)

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, char *buf, int nr) {
	struct i2c_client *client = to_i2c_client(dev);
	struct via686a_data *data = i2c_get_clientdata(client);
	via686a_update_client(client);
	return sprintf(buf, "%ld\n", TEMP_FROM_REG10(data->temp[nr])*10 );
}
/* more like overshoot temperature */
static ssize_t show_temp_max(struct device *dev, char *buf, int nr) {
	struct i2c_client *client = to_i2c_client(dev);
	struct via686a_data *data = i2c_get_clientdata(client);
	via686a_update_client(client);
	return sprintf(buf, "%ld\n", TEMP_FROM_REG(data->temp_over[nr])*10);
}
/* more like hysteresis temperature */
static ssize_t show_temp_min(struct device *dev, char *buf, int nr) {
	struct i2c_client *client = to_i2c_client(dev);
	struct via686a_data *data = i2c_get_clientdata(client);
	via686a_update_client(client);
	return sprintf(buf, "%ld\n", TEMP_FROM_REG(data->temp_hyst[nr])*10);
}
static ssize_t set_temp_max(struct device *dev, const char *buf, 
		size_t count, int nr) {
	struct i2c_client *client = to_i2c_client(dev);
	struct via686a_data *data = i2c_get_clientdata(client);
	int val = simple_strtol(buf, NULL, 10)/10;
	data->temp_over[nr] = TEMP_TO_REG(val);
	via686a_write_value(client, VIA686A_REG_TEMP_OVER(nr), data->temp_over[nr]);
	return count;
}
static ssize_t set_temp_min(struct device *dev, const char *buf, 
		size_t count, int nr) {
	struct i2c_client *client = to_i2c_client(dev);
	struct via686a_data *data = i2c_get_clientdata(client);
	int val = simple_strtol(buf, NULL, 10)/10;
	data->temp_hyst[nr] = TEMP_TO_REG(val);
	via686a_write_value(client, VIA686A_REG_TEMP_HYST(nr), data->temp_hyst[nr]);
	return count;
}
#define show_temp_offset(offset)					\
static ssize_t show_temp_##offset (struct device *dev, char *buf)	\
{									\
	return show_temp(dev, buf, 0x##offset - 1);			\
}									\
static ssize_t								\
show_temp_##offset##_max (struct device *dev, char *buf)		\
{									\
	return show_temp_max(dev, buf, 0x##offset - 1);			\
}									\
static ssize_t								\
show_temp_##offset##_min (struct device *dev, char *buf)		\
{									\
	return show_temp_min(dev, buf, 0x##offset - 1);			\
}									\
static ssize_t set_temp_##offset##_max (struct device *dev, 		\
		const char *buf, size_t count) 				\
{									\
	return set_temp_max(dev, buf, count, 0x##offset - 1);		\
}									\
static ssize_t set_temp_##offset##_min (struct device *dev, 		\
		const char *buf, size_t count) 				\
{									\
	return set_temp_min(dev, buf, count, 0x##offset - 1);		\
}									\
static DEVICE_ATTR(temp_input##offset, S_IRUGO, show_temp_##offset, NULL) \
static DEVICE_ATTR(temp_max##offset, S_IRUGO | S_IWUSR, 		\
		show_temp_##offset##_max, set_temp_##offset##_max) 	\
static DEVICE_ATTR(temp_min##offset, S_IRUGO | S_IWUSR, 		\
		show_temp_##offset##_min, set_temp_##offset##_min)	

show_temp_offset(1);
show_temp_offset(2);
show_temp_offset(3);

/* 2 Fans */
static ssize_t show_fan(struct device *dev, char *buf, int nr) {
	struct i2c_client *client = to_i2c_client(dev);
	struct via686a_data *data = i2c_get_clientdata(client);
	via686a_update_client(client);
	return sprintf(buf,"%d\n", FAN_FROM_REG(data->fan[nr], 
				DIV_FROM_REG(data->fan_div[nr])) );
}
static ssize_t show_fan_min(struct device *dev, char *buf, int nr) {
	struct i2c_client *client = to_i2c_client(dev);
	struct via686a_data *data = i2c_get_clientdata(client);
	via686a_update_client(client);
	return sprintf(buf,"%d\n",
		FAN_FROM_REG(data->fan_min[nr], DIV_FROM_REG(data->fan_div[nr])) );
}
static ssize_t show_fan_div(struct device *dev, char *buf, int nr) {
	struct i2c_client *client = to_i2c_client(dev);
	struct via686a_data *data = i2c_get_clientdata(client);
	via686a_update_client(client);
	return sprintf(buf,"%d\n", DIV_FROM_REG(data->fan_div[nr]) );
}
static ssize_t set_fan_min(struct device *dev, const char *buf, 
		size_t count, int nr) {
	struct i2c_client *client = to_i2c_client(dev);
	struct via686a_data *data = i2c_get_clientdata(client);
	int val = simple_strtol(buf, NULL, 10);
	data->fan_min[nr] = FAN_TO_REG(val, DIV_FROM_REG(data->fan_div[nr]));
	via686a_write_value(client, VIA686A_REG_FAN_MIN(nr+1), data->fan_min[nr]);
	return count;
}
static ssize_t set_fan_div(struct device *dev, const char *buf, 
		size_t count, int nr) {
	struct i2c_client *client = to_i2c_client(dev);
	struct via686a_data *data = i2c_get_clientdata(client);
	int val = simple_strtol(buf, NULL, 10);
	int old = via686a_read_value(client, 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(client, VIA686A_REG_FANDIV, old);
	return count;
}

#define show_fan_offset(offset)						\
static ssize_t show_fan_##offset (struct device *dev, char *buf)	\
{									\
	return show_fan(dev, buf, 0x##offset - 1);			\
}									\
static ssize_t show_fan_##offset##_min (struct device *dev, char *buf)	\
{									\
	return show_fan_min(dev, buf, 0x##offset - 1);			\
}									\
static ssize_t show_fan_##offset##_div (struct device *dev, char *buf)	\
{									\
	return show_fan_div(dev, buf, 0x##offset - 1);			\
}									\
static ssize_t set_fan_##offset##_min (struct device *dev, 		\
	const char *buf, size_t count) 					\
{									\
	return set_fan_min(dev, buf, count, 0x##offset - 1);		\
}									\
static ssize_t set_fan_##offset##_div (struct device *dev, 		\
		const char *buf, size_t count) 				\
{									\
	return set_fan_div(dev, buf, count, 0x##offset - 1);		\
}									\
static DEVICE_ATTR(fan_input##offset, S_IRUGO, show_fan_##offset, NULL) \
static DEVICE_ATTR(fan_min##offset, S_IRUGO | S_IWUSR, 			\
		show_fan_##offset##_min, set_fan_##offset##_min) 	\
static DEVICE_ATTR(fan_div##offset, S_IRUGO | S_IWUSR, 			\
		show_fan_##offset##_div, set_fan_##offset##_div)

show_fan_offset(1);
show_fan_offset(2);

/* Alarm */
static ssize_t show_alarm(struct device *dev, char *buf) {
	struct i2c_client *client = to_i2c_client(dev);
	struct via686a_data *data = i2c_get_clientdata(client);
	via686a_update_client(client);
	return sprintf(buf,"%d\n", ALARMS_FROM_REG(data->alarms));
}
static DEVICE_ATTR(alarm, S_IRUGO | S_IWUSR, show_alarm, NULL);

/* The driver. I choose to use type i2c_driver, as at is identical to both
   smbus_driver and isa_driver, and clients could be of either kind */
static struct i2c_driver via686a_driver = {
	.owner		= THIS_MODULE,
	.name		= "VIA686A",
	.id		= I2C_DRIVERID_VIA686A,
	.flags		= I2C_DF_NOTIFY,
	.attach_adapter	= via686a_attach_adapter,
	.detach_client	= via686a_detach_client,
};


/* This is called when the module is loaded */
static int via686a_attach_adapter(struct i2c_adapter *adapter)
{
	return i2c_detect(adapter, &addr_data, via686a_detect);
}

static int via686a_detect(struct i2c_adapter *adapter, int address, int kind)
{
	struct i2c_client *new_client;
	struct via686a_data *data;
	int err = 0;
	const char client_name[] = "via686a chip";
	u16 val;

	/* Make sure we are probing the ISA bus!!  */
	if (!i2c_is_isa_adapter(adapter)) {
		dev_err(&adapter->dev,
		"via686a_detect called for an I2C bus adapter?!?\n");
		return 0;
	}

	/* 8231 requires multiple of 256, we enforce that on 686 as well */
	if(force_addr)
		address = force_addr & 0xFF00;

	if(force_addr) {
		dev_warn(&adapter->dev,"forcing ISA address 0x%04X\n", address);
		if (PCIBIOS_SUCCESSFUL !=
		    pci_write_config_word(s_bridge, VIA686A_BASE_REG, address))
			return -ENODEV;
	}
	if (PCIBIOS_SUCCESSFUL !=
	    pci_read_config_word(s_bridge, VIA686A_ENABLE_REG, &val))
		return -ENODEV;
	if (!(val & 0x0001)) {
		dev_warn(&adapter->dev,"enabling sensors\n");
		if (PCIBIOS_SUCCESSFUL !=
		    pci_write_config_word(s_bridge, VIA686A_ENABLE_REG,
		                      val | 0x0001))
			return -ENODEV;
	}

	/* Reserve the ISA region */
	if (!request_region(address, VIA686A_EXTENT, "via686a-sensor")) {
		dev_err(&adapter->dev,"region 0x%x already in use!\n",
		       address);
		return -ENODEV;
	}

	if (!(new_client = kmalloc(sizeof(struct i2c_client) +
				   sizeof(struct via686a_data),
				   GFP_KERNEL))) {
		err = -ENOMEM;
		goto ERROR0;
	}

	memset(new_client,0x00, sizeof(struct i2c_client) +
				sizeof(struct via686a_data));
	data = (struct via686a_data *) (new_client + 1);
	i2c_set_clientdata(new_client, data);
	new_client->addr = address;
	new_client->adapter = adapter;
	new_client->driver = &via686a_driver;
	new_client->flags = 0;
	new_client->dev.parent = &adapter->dev;

	/* Fill in the remaining client fields and put into the global list */
	snprintf(new_client->dev.name, DEVICE_NAME_SIZE, client_name);

	data->valid = 0;
	init_MUTEX(&data->update_lock);
	/* Tell the I2C layer a new client has arrived */
	if ((err = i2c_attach_client(new_client)))
		goto ERROR3;
	
	/* register sysfs hooks */
	device_create_file(&new_client->dev, &dev_attr_in_input0);
	device_create_file(&new_client->dev, &dev_attr_in_input1);
	device_create_file(&new_client->dev, &dev_attr_in_input2);
	device_create_file(&new_client->dev, &dev_attr_in_input3);
	device_create_file(&new_client->dev, &dev_attr_in_input4);
	device_create_file(&new_client->dev, &dev_attr_in_min0);
	device_create_file(&new_client->dev, &dev_attr_in_min1);
	device_create_file(&new_client->dev, &dev_attr_in_min2);
	device_create_file(&new_client->dev, &dev_attr_in_min3);
	device_create_file(&new_client->dev, &dev_attr_in_min4);
	device_create_file(&new_client->dev, &dev_attr_in_max0);
	device_create_file(&new_client->dev, &dev_attr_in_max1);
	device_create_file(&new_client->dev, &dev_attr_in_max2);
	device_create_file(&new_client->dev, &dev_attr_in_max3);
	device_create_file(&new_client->dev, &dev_attr_in_max4);
	device_create_file(&new_client->dev, &dev_attr_temp_input1);
	device_create_file(&new_client->dev, &dev_attr_temp_input2);
	device_create_file(&new_client->dev, &dev_attr_temp_input3);
	device_create_file(&new_client->dev, &dev_attr_temp_max1);
	device_create_file(&new_client->dev, &dev_attr_temp_max2);
	device_create_file(&new_client->dev, &dev_attr_temp_max3);
	device_create_file(&new_client->dev, &dev_attr_temp_min1);
	device_create_file(&new_client->dev, &dev_attr_temp_min2);
	device_create_file(&new_client->dev, &dev_attr_temp_min3);
	device_create_file(&new_client->dev, &dev_attr_fan_input1);
	device_create_file(&new_client->dev, &dev_attr_fan_input2);
	device_create_file(&new_client->dev, &dev_attr_fan_min1);
	device_create_file(&new_client->dev, &dev_attr_fan_min2);
	device_create_file(&new_client->dev, &dev_attr_fan_div1);
	device_create_file(&new_client->dev, &dev_attr_fan_div2);
	device_create_file(&new_client->dev, &dev_attr_alarm);

	/* Initialize the VIA686A chip */
	via686a_init_client(new_client);
	return 0;

      ERROR3:
	release_region(address, VIA686A_EXTENT);
	kfree(new_client);
      ERROR0:
	return err;
}

static int via686a_detach_client(struct i2c_client *client)
{
	int err;

	if ((err = i2c_detach_client(client))) {
		dev_err(&client->dev,
		"Client deregistration failed, client not detached.\n");
		return err;
	}

	release_region(client->addr, VIA686A_EXTENT);
	kfree(client);

	return 0;
}

/* Called when we have found a new VIA686A. Set limits, etc. */
static void via686a_init_client(struct i2c_client *client)
{
	int i;

	/* Reset the device */
	via686a_write_value(client, VIA686A_REG_CONFIG, 0x80);

	/* Have to wait for reset to complete or else the following
	   initializations won't work reliably. The delay was arrived at
	   empirically, the datasheet doesn't tell you.
	   Waiting for the reset bit to clear doesn't work, it
	   clears in about 2-4 udelays and that isn't nearly enough. */
	udelay(50);

	via686a_write_value(client, VIA686A_REG_IN_MIN(0),
			    IN_TO_REG(VIA686A_INIT_IN_MIN_0, 0));
	via686a_write_value(client, VIA686A_REG_IN_MAX(0),
			    IN_TO_REG(VIA686A_INIT_IN_MAX_0, 0));
	via686a_write_value(client, VIA686A_REG_IN_MIN(1),
			    IN_TO_REG(VIA686A_INIT_IN_MIN_1, 1));
	via686a_write_value(client, VIA686A_REG_IN_MAX(1),
			    IN_TO_REG(VIA686A_INIT_IN_MAX_1, 1));
	via686a_write_value(client, VIA686A_REG_IN_MIN(2),
			    IN_TO_REG(VIA686A_INIT_IN_MIN_2, 2));
	via686a_write_value(client, VIA686A_REG_IN_MAX(2),
			    IN_TO_REG(VIA686A_INIT_IN_MAX_2, 2));
	via686a_write_value(client, VIA686A_REG_IN_MIN(3),
			    IN_TO_REG(VIA686A_INIT_IN_MIN_3, 3));
	via686a_write_value(client, VIA686A_REG_IN_MAX(3),
			    IN_TO_REG(VIA686A_INIT_IN_MAX_3, 3));
	via686a_write_value(client, VIA686A_REG_IN_MIN(4),
			    IN_TO_REG(VIA686A_INIT_IN_MIN_4, 4));
	via686a_write_value(client, VIA686A_REG_IN_MAX(4),
			    IN_TO_REG(VIA686A_INIT_IN_MAX_4, 4));
	via686a_write_value(client, VIA686A_REG_FAN_MIN(1),
			    FAN_TO_REG(VIA686A_INIT_FAN_MIN, 2));
	via686a_write_value(client, VIA686A_REG_FAN_MIN(2),
			    FAN_TO_REG(VIA686A_INIT_FAN_MIN, 2));
	for (i = 0; i <= 2; i++) {
		via686a_write_value(client, VIA686A_REG_TEMP_OVER(i),
				    TEMP_TO_REG(VIA686A_INIT_TEMP_OVER));
		via686a_write_value(client, VIA686A_REG_TEMP_HYST(i),
				    TEMP_TO_REG(VIA686A_INIT_TEMP_HYST));
	}

	/* Start monitoring */
	via686a_write_value(client, VIA686A_REG_CONFIG, 0x01);

	/* Cofigure temp interrupt mode for continuous-interrupt operation */
	via686a_write_value(client, VIA686A_REG_TEMP_MODE, 
			    via686a_read_value(client, VIA686A_REG_TEMP_MODE) &
			    !(VIA686A_TEMP_MODE_MASK | VIA686A_TEMP_MODE_CONTINUOUS));
}

static void via686a_update_client(struct i2c_client *client)
{
	struct via686a_data *data = i2c_get_clientdata(client);
	int i;

	down(&data->update_lock);

       if ((jiffies - data->last_updated > HZ + HZ / 2) ||
           (jiffies < data->last_updated) || !data->valid) {

		for (i = 0; i <= 4; i++) {
			data->in[i] =
			    via686a_read_value(client, VIA686A_REG_IN(i));
			data->in_min[i] = via686a_read_value(client,
							     VIA686A_REG_IN_MIN
							     (i));
			data->in_max[i] =
			    via686a_read_value(client, VIA686A_REG_IN_MAX(i));
		}
		for (i = 1; i <= 2; i++) {
			data->fan[i - 1] =
			    via686a_read_value(client, VIA686A_REG_FAN(i));
			data->fan_min[i - 1] = via686a_read_value(client,
						     VIA686A_REG_FAN_MIN(i));
		}
		for (i = 0; i <= 2; i++) {
			data->temp[i] = via686a_read_value(client,
						 VIA686A_REG_TEMP(i)) << 2;
			data->temp_over[i] =
			    via686a_read_value(client,
					       VIA686A_REG_TEMP_OVER(i));
			data->temp_hyst[i] =
			    via686a_read_value(client,
					       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(client,
						     VIA686A_REG_TEMP_LOW1)
				  & 0xc0) >> 6;
		data->temp[1] |=
		    (via686a_read_value(client, VIA686A_REG_TEMP_LOW23) &
		     0x30) >> 4;
		data->temp[2] |=
		    (via686a_read_value(client, VIA686A_REG_TEMP_LOW23) &
		     0xc0) >> 6;

		i = via686a_read_value(client, VIA686A_REG_FANDIV);
		data->fan_div[0] = (i >> 4) & 0x03;
		data->fan_div[1] = i >> 6;
		data->alarms =
		    via686a_read_value(client,
				       VIA686A_REG_ALARM1) |
		    (via686a_read_value(client, VIA686A_REG_ALARM2) << 8);
		data->last_updated = jiffies;
		data->valid = 1;
	}

	up(&data->update_lock);
}

static struct pci_device_id via686a_pci_ids[] __devinitdata = {
       {
	       .vendor 		= PCI_VENDOR_ID_VIA, 
	       .device 		= PCI_DEVICE_ID_VIA_82C686_4, 
	       .subvendor	= PCI_ANY_ID, 
	       .subdevice	= PCI_ANY_ID, 
       },
       { 0, }
};

static int __devinit via686a_pci_probe(struct pci_dev *dev,
                                      const struct pci_device_id *id)
{
       u16 val;
       int addr = 0;

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

       addr = val & ~(VIA686A_EXTENT - 1);
       if (addr == 0 && force_addr == 0) {
               dev_err(&dev->dev,"base address not set - upgrade BIOS or use force_addr=0xaddr\n");
               return -ENODEV;
       }
       if (force_addr)
               addr = force_addr;      /* so detect will get called */

       if (!addr) {
               dev_err(&dev->dev,"No Via 686A sensors found.\n");
               return -ENODEV;
       }
       normal_isa[0] = addr;
       s_bridge = dev;
       return i2c_add_driver(&via686a_driver);
}

static void __devexit via686a_pci_remove(struct pci_dev *dev)
{
       i2c_del_driver(&via686a_driver);
}

static struct pci_driver via686a_pci_driver = {
       .name		= "via686a",
       .id_table	= via686a_pci_ids,
       .probe		= via686a_pci_probe,
       .remove		= __devexit_p(via686a_pci_remove),
};

static int __init sm_via686a_init(void)
{
       return pci_module_init(&via686a_pci_driver);
}

static void __exit sm_via686a_exit(void)
{
       pci_unregister_driver(&via686a_pci_driver);
}

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);
