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, 2011  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.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

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

#ifdef CONFIG_ISA
#include <linux/platform_device.h>
#include <linux/ioport.h>
#include <linux/io.h>
#endif

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

struct lm78_data {
	struct i2c_client *client;
	struct device *hwmon_dev;
	struct mutex lock;
	enum chips type;

	/* For ISA device only */
	const char *name;
	int isa_addr;

	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_read_value(struct lm78_data *data, u8 reg);
static int lm78_write_value(struct lm78_data *data, u8 reg, u8 value);
static struct lm78_data *lm78_update_device(struct device *dev