path: root/drivers/hwmon/lm78.c

/*
    lm78.c - Part of lm_sensors, Linux kernel modules for hardware
             monitoring
    Copyright (c) 1998, 1999  Frodo Looijaard <frodol@dds.nl> 
    Copyright (c) 2007        Jean Delvare <khali@linux-fr.org>

    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.
*/

#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/jiffies.h>
#include <linux/i2c.h>
#include <linux/platform_device.h>
#include <linux/ioport.h>
#include <linux/hwmon.h>
#include <linux/hwmon-vid.h>
#include <linux/hwmon-sysfs.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <asm/io.h>

/* ISA device, if found */
static struct platform_device *pdev;

/* Addresses to scan */
static const unsigned short normal_i2c[] = { 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d,
						0x2e, 0x2f, I2C_CLIENT_END };
static unsigned short isa_address = 0x290;

/* Insmod parameters */
I2C_CLIENT_INSMOD_2(lm78, lm79);

/* Many LM78 constants specified below */

/* Length of ISA address segment */
#define LM78_EXTENT 8

/* Where are the ISA address/data registers relative to the base address */
#define LM78_ADDR_REG_OFFSET 5
#define LM78_DATA_REG_OFFSET 6

/* The LM78 registers */
#define LM78_REG_IN_MAX(nr) (0x2b + (nr) * 2)
#define LM78_REG_IN_MIN(nr) (0x2c + (nr) * 2)
#define LM78_REG_IN(nr) (0x20 + (nr))

#define LM78_REG_FAN_MIN(nr) (0x3b + (nr))
#define LM78_REG_FAN(nr) (0x28 + (nr))

#define LM78_REG_TEMP 0x27
#define LM78_REG_TEMP_OVER 0x39
#define LM78_REG_TEMP_HYST 0x3a

#define LM78_REG_ALARM1 0x41
#define LM78_REG_ALARM2 0x42

#define LM78_REG_VID_FANDIV 0x47

#define LM78_REG_CONFIG 0x40
#define LM78_REG_CHIPID 0x49
#define LM78_REG_I2C_ADDR 0x48


/* Conversions. Rounding and limit checking is only done on the TO_REG 
   variants. */

/* IN: mV, (0V to 4.08V)
   REG: 16mV/bit */
static inline u8 IN_TO_REG(unsigned long val)
{
	unsigned long nval = SENSORS_LIMIT(val, 0, 4080);
	return (nval + 8) / 16;
}
#define IN_FROM_REG(val) ((val) *  16)

static inline u8 FAN_TO_REG(long rpm, int div)
{
	if (rpm <= 0)
		return 255;
	return SENSORS_LIMIT((1350000 + rpm * div / 2) / (rpm * div), 1, 254);
}

static inline int FAN_FROM_REG(u8 val, int div)
{
	return val==0 ? -1 : val==255 ? 0 : 1350000/(val*div);
}

/* TEMP: mC (-128C to +127C)
   REG: 1C/bit, two's complement */
static inline s8 TEMP_TO_REG(int val)
{
	int nval = SENSORS_LIMIT(val, -128000, 127000) ;
	return nval<0 ? (nval-500)/1000 : (nval+500)/1000;
}

static inline int TEMP_FROM_REG(s8 val)
{
	return val * 1000;
}

#define DIV_FROM_REG(val) (1 << (val))

/* There are some complications in a module like this. First off, LM78 chips
   may be both present on the SMBus and the ISA bus, and we have to handle
   those cases separately at some places. Second, there might be several
   LM78 chips available (well, actually, that is probably never done; but
   it is a clean illustration of how to handle a case like that). Finally,
   a specific chip may be attached to *both* ISA and SMBus, and we would
   not like to detect it double. */

/* For ISA chips, we abuse the i2c_client addr and name fields. We also use
   the driver field to differentiate between I2C and ISA chips. */
struct lm78_data {
	struct i2c_client client;
	struct device *hwmon_dev;
	struct mutex lock;
	enum chips type;

	struct mutex update_lock;
	char valid;		/* !=0 if following fields are valid */
	unsigned long last_updated;	/* In jiffies */

	u8 in[7];		/* Register value */
	u8 in_max[7];		/* Register value */
	u8 in_min[7];		/* Register value */
	u8 fan[3];		/* Register value */
	u8 fan_min[3];		/* Register value */
	s8 temp;		/* Register value */
	s8 temp_over;		/* Register value */
	s8 temp_hyst;		/* Register value */
	u8 fan_div[3];		/* Register encoding, shifted right */
	u8 vid;			/* Register encoding, combined */
	u16 alarms;		/* Register encoding, combined */
};


static int lm78_attach_adapter(struct i2c_adapter *adapter);
static int lm78_detect(struct i2c_adapter *adapter, int address, int kind);
static int lm78_detach_client(struct i2c_client *client);

static int __devinit lm78_isa_probe(struct platform_device *pdev);
static int __devexit lm78_isa_remove(struct platform_device *pdev);

static int lm78_read_value(struct lm78_data *data, u8 reg);
static int lm78_write_value(struct lm78_data *data, u8 reg, u8 value);