[PATCH] i2c: Add lm78 sensor chip support

This patch vs. 2.5.70 adds support for LM78, LM78-J, and LM79 sensors
chips based on lm_sensors project CVS.  This works on one of my boards.

I want to draw attention to something I did with this driver by
comparing it to it87.c in 2.5.70:

> #define IT87_INIT_TEMP_HIGH_1 600
> #define IT87_INIT_TEMP_LOW_1  200

The hardware uses degrees C, and sysfs uses degrees C * 1000.  But
these #defines are apparently in units of degrees C * 10.  This
arbitrary intermediate representation bugs me.  And given the new 2.5
sysfs standard, it's unnecessary.

In this patch for lm78, I rewrote the conversion routines in terms
of the sysfs units - getting rid of the intermediate nonsense.  If
there are no objections, I'm going to start passing patches to do
this to the other sensor chip drivers in 2.5 as well.  It would be
nice to get some help with this too... especially since I don't
have all that hardware at hand to test the results.

drivers/i2c/chips/Kconfig

@@ -62,6 +62,20 @@ config SENSORS_LM85
 	  in the lm_sensors package, which you can download at 
 	  http://www.lm-sensors.nu
 	  
+config SENSORS_LM78
+	tristate "  National Semiconductors LM78 and compatibles"
+	depends on I2C && EXPERIMENTAL
+	help
+	  If you say yes here you get support for National Semiconductor LM78,
+	  LM78-J and LM79.  This can also be built as a module which can be
+	  inserted and removed while the kernel is running.
+
+	  The module will be called lm78.
+
+	  You will also need the latest user-space utilties: you can find them
+	  in the lm_sensors package, which you can download at 
+	  http://www.lm-sensors.nu
+	  
 config SENSORS_VIA686A
 	tristate "  VIA686A"
 	depends on I2C && EXPERIMENTAL

drivers/i2c/chips/lm78.c

+/*
+    lm78.c - Part of lm_sensors, Linux kernel modules for hardware
+             monitoring
+    Copyright (c) 1998, 1999  Frodo Looijaard <frodol@dds.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.
+*/
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/i2c-sensor.h>
+#include <asm/io.h>
+
+/* Addresses to scan */
+static unsigned short normal_i2c[] = { I2C_CLIENT_END };
+static unsigned short normal_i2c_range[] = { 0x20, 0x2f, I2C_CLIENT_END };
+static unsigned int normal_isa[] = { 0x0290, I2C_CLIENT_ISA_END };
+static unsigned int normal_isa_range[] = { I2C_CLIENT_ISA_END };
+
+/* Insmod parameters */
+SENSORS_INSMOD_3(lm78, lm78j, 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;
+	rpm = SENSORS_LIMIT(rpm, 1, 1000000);
+	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 u8 TEMP_TO_REG(int val)
+{
+	int nval = SENSORS_LIMIT(val, -128000, 127000) ;
+	return nval<0 ? (nval-500)/1000+0x100 : (nval+500)/1000;
+}
+
+static inline int TEMP_FROM_REG(u8 val)
+{
+	return (val>=0x80 ? val-0x100 : val) * 1000;
+}
+
+/* VID: mV
+   REG: (see doc/vid) */
+static inline int VID_FROM_REG(u8 val)
+{
+	return val==0x1f ? 0 : val>=0x10 ? 5100-val*100 : 2050-val*50;
+}
+
+/* ALARMS: chip-specific bitmask
+   REG: (same) */
+#define ALARMS_FROM_REG(val) (val)
+
+/* FAN DIV: 1, 2, 4, or 8 (defaults to 2)
+   REG: 0, 1, 2, or 3 (respectively) (defaults to 1) */
+static inline u8 DIV_TO_REG(int val)
+{
+	return val==8 ? 3 : val==4 ? 2 : val==1 ? 0 : 1;
+}
+#define DIV_FROM_REG(val) (1 << (val))
+
+/* Initial limits. To keep them sane, we use the 'standard' translation as
+   specified in the LM78 sheet. Use the config file to set better limits. */
+#define LM78_INIT_IN_0(vid) ((vid)==3500 ? 2800 : (vid))
+#define LM78_INIT_IN_1(vid) ((vid)==3500 ? 2800 : (vid))
+#define LM78_INIT_IN_2 3300
+#define LM78_INIT_IN_3 (((5000)   * 100)/168)
+#define LM78_INIT_IN_4 (((12000)  * 10)/38)
+#define LM78_INIT_IN_5 (((-12000) * -604)/2100)
+#define LM78_INIT_IN_6 (((-5000)  * -604)/909)
+
+#define LM78_INIT_IN_PERCENTAGE 10
+
+#define LM78_INIT_IN_MIN_0(vid) (LM78_INIT_IN_0(vid) - \
+	LM78_INIT_IN_0(vid) * LM78_INIT_IN_PERCENTAGE / 100)
+#define LM78_INIT_IN_MAX_0(vid) (LM78_INIT_IN_0(vid) + \
+	LM78_INIT_IN_0(vid) * LM78_INIT_IN_PERCENTAGE / 100)
+#define LM78_INIT_IN_MIN_1(vid) (LM78_INIT_IN_1(vid) - \
+	LM78_INIT_IN_1(vid) * LM78_INIT_IN_PERCENTAGE / 100)
+#define LM78_INIT_IN_MAX_1(vid) (LM78_INIT_IN_1(vid) + \
+	LM78_INIT_IN_1(vid) * LM78_INIT_IN_PERCENTAGE / 100)
+
+#define LM78_INIT_IN_MIN_2 \
+        (LM78_INIT_IN_2 - LM78_INIT_IN_2 * LM78_INIT_IN_PERCENTAGE / 100)
+#define LM78_INIT_IN_MAX_2 \
+        (LM78_INIT_IN_2 + LM78_INIT_IN_2 * LM78_INIT_IN_PERCENTAGE / 100)
+#define LM78_INIT_IN_MIN_3 \
+        (LM78_INIT_IN_3 - LM78_INIT_IN_3 * LM78_INIT_IN_PERCENTAGE / 100)
+#define LM78_INIT_IN_MAX_3 \
+        (LM78_INIT_IN_3 + LM78_INIT_IN_3 * LM78_INIT_IN_PERCENTAGE / 100)
+#define LM78_INIT_IN_MIN_4 \
+        (LM78_INIT_IN_4 - LM78_INIT_IN_4 * LM78_INIT_IN_PERCENTAGE / 100)
+#define LM78_INIT_IN_MAX_4 \
+        (LM78_INIT_IN_4 + LM78_INIT_IN_4 * LM78_INIT_IN_PERCENTAGE / 100)
+#define LM78_INIT_IN_MIN_5 \
+        (LM78_INIT_IN_5 - LM78_INIT_IN_5 * LM78_INIT_IN_PERCENTAGE / 100)
+#define LM78_INIT_IN_MAX_5 \
+        (LM78_INIT_IN_5 + LM78_INIT_IN_5 * LM78_INIT_IN_PERCENTAGE / 100)
+#define LM78_INIT_IN_MIN_6 \
+        (LM78_INIT_IN_6 - LM78_INIT_IN_6 * LM78_INIT_IN_PERCENTAGE / 100)
+#define LM78_INIT_IN_MAX_6 \
+        (LM78_INIT_IN_6 + LM78_INIT_IN_6 * LM78_INIT_IN_PERCENTAGE / 100)
+
+#define LM78_INIT_FAN_MIN_1 3000
+#define LM78_INIT_FAN_MIN_2 3000
+#define LM78_INIT_FAN_MIN_3 3000
+
+#define LM78_INIT_TEMP_OVER 60000
+#define LM78_INIT_TEMP_HYST 50000
+
+/* 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. Fortunately, in the case of the LM78 at
+   least, a register tells us what SMBus address we are on, so that helps
+   a bit - except if there could be more than one SMBus. Groan. No solution
+   for this yet. */
+
+/* This module may seem overly long and complicated. In fact, it is not so
+   bad. Quite a lot of bookkeeping is done. A real driver can often cut
+   some corners. */
+
+/* For each registered LM78, we need to keep some data in memory. That
+   data is pointed to by lm78_list[NR]->data. The structure itself is
+   dynamically allocated, at the same time when a new lm78 client is
+   allocated. */
+struct lm78_data {
+	struct semaphore lock;
+	enum chips type;
+
+	struct semaphore 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 */
+	u8 temp;		/* Register value */
+	u8 temp_over;		/* Register value */
+	u8 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 lm78_read_value(struct i2c_client *client, u8 register);
+static int lm78_write_value(struct i2c_client *client, u8 register, u8 value);
+static void lm78_update_client(struct i2c_client *client);
+static void lm78_init_client(struct i2c_client *client);
+
+
+static struct i2c_driver lm78_driver = {
+	.owner		= THIS_MODULE,
+	.name		= "lm78",
+	.id		= I2C_DRIVERID_LM78,
+	.flags		= I2C_DF_NOTIFY,
+	.attach_adapter	= lm78_attach_adapter,
+	.detach_client	= lm78_detach_client,
+};
+
+/* 7 Voltages */
+static ssize_t show_in(struct device *dev, char *buf, int nr)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct lm78_data *data = i2c_get_clientdata(client);
+	lm78_update_client(client);
+	return sprintf(buf, "%d\n", IN_FROM_REG(data->in[nr]));
+}
+
+static ssize_t show_in_min(struct device *dev, char *buf, int nr)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct lm78_data *data = i2c_get_clientdata(client);
+	lm78_update_client(client);
+	return sprintf(buf, "%d\n", IN_FROM_REG(data->in_min[nr]));
+}
+
+static ssize_t show_in_max(struct device *dev, char *buf, int nr)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct lm78_data *data = i2c_get_clientdata(client);
+	lm78_update_client(client);
+	return sprintf(buf, "%d\n", IN_FROM_REG(data->in_max[nr]));
+}
+
+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 lm78_data *data = i2c_get_clientdata(client);
+	unsigned long val = simple_strtoul(buf, NULL, 10);
+	data->in_min[nr] = IN_TO_REG(val);
+	lm78_write_value(client, LM78_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 lm78_data *data = i2c_get_clientdata(client);
+	unsigned long val = simple_strtoul(buf, NULL, 10);
+	data->in_max[nr] = IN_TO_REG(val);
+	lm78_write_value(client, LM78_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 DEVICE_ATTR(in_input##offset, S_IRUGO, 			\
+		show_in##offset, NULL)				\
+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_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);
+show_in_offset(5);
+show_in_offset(6);
+
+/* Temperature */
+static ssize_t show_temp(struct device *dev, char *buf)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct lm78_data *data = i2c_get_clientdata(client);
+	lm78_update_client(client);
+	return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp));
+}
+
+static ssize_t show_temp_over(struct device *dev, char *buf)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct lm78_data *data = i2c_get_clientdata(client);
+	lm78_update_client(client);
+	return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp_over));
+}
+
+static ssize_t set_temp_over(struct device *dev, const char *buf, size_t count)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct lm78_data *data = i2c_get_clientdata(client);
+	long val = simple_strtol(buf, NULL, 10);
+	data->temp_over = TEMP_TO_REG(val);
+	lm78_write_value(client, LM78_REG_TEMP_OVER, data->temp_over);
+	return count;
+}
+
+static ssize_t show_temp_hyst(struct device *dev, char *buf)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct lm78_data *data = i2c_get_clientdata(client);
+	lm78_update_client(client);
+	return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp_hyst));
+}
+
+static ssize_t set_temp_hyst(struct device *dev, const char *buf, size_t count)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct lm78_data *data = i2c_get_clientdata(client);
+	long val = simple_strtol(buf, NULL, 10);
+	data->temp_hyst = TEMP_TO_REG(val);
+	lm78_write_value(client, LM78_REG_TEMP_HYST, data->temp_hyst);
+	return count;
+}
+
+static DEVICE_ATTR(temp_input, S_IRUGO, show_temp, NULL)
+static DEVICE_ATTR(temp_max, S_IRUGO | S_IWUSR,
+		show_temp_over, set_temp_over)
+static DEVICE_ATTR(temp_min, S_IRUGO | S_IWUSR,
+		show_temp_hyst, set_temp_hyst)
+
+/* 3 Fans */
+static ssize_t show_fan(struct device *dev, char *buf, int nr)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct lm78_data *data = i2c_get_clientdata(client);
+	lm78_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 lm78_data *data = i2c_get_clientdata(client);
+	lm78_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 set_fan_min(struct device *dev, const char *buf,
+		size_t count, int nr)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct lm78_data *data = i2c_get_clientdata(client);
+	unsigned long val = simple_strtoul(buf, NULL, 10);
+	data->fan_min[nr] = FAN_TO_REG(val, DIV_FROM_REG(data->fan_div[nr]));
+	lm78_write_value(client, LM78_REG_FAN_MIN(nr), data->fan_min[nr]);
+	return count;
+}
+
+static ssize_t show_fan_div(struct device *dev, char *buf, int nr)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct lm78_data *data = i2c_get_clientdata(client);
+	lm78_update_client(client);
+	return sprintf(buf, "%d\n", DIV_FROM_REG(data->fan_div[nr]) );
+}
+
+/* Note: we save and restore the fan minimum here, because its value is
+   determined in part by the fan divisor.  This follows the principle of
+   least suprise; the user doesn't expect the fan minimum to change just
+   because the divisor changed. */
+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 lm78_data *data = i2c_get_clientdata(client);
+	unsigned long min = FAN_FROM_REG(data->fan_min[nr],
+			DIV_FROM_REG(data->fan_div[nr]));
+	unsigned long val = simple_strtoul(buf, NULL, 10);
+	int reg = lm78_read_value(client, LM78_REG_VID_FANDIV);
+	data->fan_div[nr] = DIV_TO_REG(val);
+	switch (nr) {
+	case 0:
+		reg = (reg & 0xcf) | (data->fan_div[nr] << 4);
+		break;
+	case 1:
+		reg = (reg & 0x3f) | (data->fan_div[nr] << 6);
+		break;
+	}
+	lm78_write_value(client, LM78_REG_VID_FANDIV, reg);
+	data->fan_min[nr] =
+		FAN_TO_REG(min, DIV_FROM_REG(data->fan_div[nr]));
+	lm78_write_value(client, LM78_REG_FAN_MIN(nr), data->fan_min[nr]);
+	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 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 ssize_t set_fan_1_div(struct device *dev, const char *buf,
+		size_t count)
+{
+	return set_fan_div(dev, buf, count, 0) ;
+}
+
+static ssize_t set_fan_2_div(struct device *dev, const char *buf,
+		size_t count)
+{
+	return set_fan_div(dev, buf, count, 1) ;
+}
+
+show_fan_offset(1);
+show_fan_offset(2);
+show_fan_offset(3);
+
+/* Fan 3 divisor is locked in H/W */
+static DEVICE_ATTR(fan_div1, S_IRUGO | S_IWUSR,
+		show_fan_1_div, set_fan_1_div)
+static DEVICE_ATTR(fan_div2, S_IRUGO | S_IWUSR,
+		show_fan_2_div, set_fan_2_div)
+static DEVICE_ATTR(fan_div3, S_IRUGO, show_fan_3_div, NULL)
+
+/* VID */
+static ssize_t show_vid(struct device *dev, char *buf)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct lm78_data *data = i2c_get_clientdata(client);
+	lm78_update_client(client);
+	return sprintf(buf, "%d\n", VID_FROM_REG(data->vid));
+}
+static DEVICE_ATTR(vid, S_IRUGO, show_vid, NULL);
+
+/* Alarms */
+static ssize_t show_alarms(struct device *dev, char *buf)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct lm78_data *data = i2c_get_clientdata(client);
+	lm78_update_client(client);
+	return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->alarms));
+}
+static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
+
+/* This function is called when:
+     * lm78_driver is inserted (when this module is loaded), for each
+       available adapter
+     * when a new adapter is inserted (and lm78_driver is still present) */
+static int lm78_attach_adapter(struct i2c_adapter *adapter)
+{
+	if (!(adapter->class & I2C_ADAP_CLASS_SMBUS))
+		return 0;
+	return i2c_detect(adapter, &addr_data, lm78_detect);
+}
+
+/* This function is called by i2c_detect */
+int lm78_detect(struct i2c_adapter *adapter, int address, int kind)
+{
+	int i, err;
+	struct i2c_client *new_client;
+	struct lm78_data *data;
+	const char *client_name = "";
+	int is_isa = i2c_is_isa_adapter(adapter);
+
+	if (!is_isa &&
+	    !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) {
+		err = -ENODEV;
+		goto ERROR0;
+	}
+
+	/* Reserve the ISA region */
+	if (is_isa)
+		if (!request_region(address, LM78_EXTENT, "lm78")) {
+			err = -EBUSY;
+			goto ERROR0;
+		}
+
+	/* Probe whether there is anything available on this address. Already
+	   done for SMBus clients */
+	if (kind < 0) {
+		if (is_isa) {
+
+#define REALLY_SLOW_IO
+			/* We need the timeouts for at least some LM78-like
+			   chips. But only if we read 'undefined' registers. */
+			i = inb_p(address + 1);
+			if (inb_p(address + 2) != i) {
+				err = -ENODEV;
+				goto ERROR1;
+			}
+			if (inb_p(address + 3) != i) {
+				err = -ENODEV;
+				goto ERROR1;
+			}
+			if (inb_p(address + 7) != i) {
+				err = -ENODEV;
+				goto ERROR1;
+			}
+#undef REALLY_SLOW_IO
+
+			/* Let's just hope nothing breaks here */
+			i = inb_p(address + 5) & 0x7f;
+			outb_p(~i & 0x7f, address + 5);
+			if ((inb_p(address + 5) & 0x7f) != (~i & 0x7f)) {
+				outb_p(i, address + 5);
+				err = -ENODEV;
+				goto ERROR1;
+			}
+		}
+	}
+
+	/* OK. For now, we presume we have a valid client. We now create the
+	   client structure, even though we cannot fill it completely yet.
+	   But it allows us to access lm78_{read,write}_value. */
+
+	if (!(new_client = kmalloc((sizeof(struct i2c_client)) +
+				   sizeof(struct lm78_data),
+				   GFP_KERNEL))) {
+		err = -ENOMEM;
+		goto ERROR1;
+	}
+	memset(new_client, 0, sizeof(struct i2c_client) + 
+			      sizeof(struct lm78_data));
+
+	data = (struct lm78_data *) (new_client + 1);
+	if (is_isa)
+		init_MUTEX(&data->lock);
+	i2c_set_clientdata(new_client, data);
+	new_client->addr = address;
+	new_client->adapter = adapter;
+	new_client->driver = &lm78_driver;
+	new_client->flags = 0;
+
+	/* Now, we do the remaining detection. */
+	if (kind < 0) {
+		if (lm78_read_value(new_client, LM78_REG_CONFIG) & 0x80) {
+			err = -ENODEV;
+			goto ERROR2;
+		}
+		if (!is_isa && (lm78_read_value(
+				new_client, LM78_REG_I2C_ADDR) != address)) {
+			err = -ENODEV;
+			goto ERROR2;
+		}
+	}
+
+	/* Determine the chip type. */
+	if (kind <= 0) {
+		i = lm78_read_value(new_client, LM78_REG_CHIPID);
+		if (i == 0x00 || i == 0x20)
+			kind = lm78;
+		else if (i == 0x40)
+			kind = lm78j;
+		else if ((i & 0xfe) == 0xc0)
+			kind = lm79;
+		else {
+			if (kind == 0)
+				printk(KERN_WARNING "lm78.o: Ignoring 'force' "
+					"parameter for unknown chip at "
+					"adapter %d, address 0x%02x\n",
+					i2c_adapter_id(adapter), address);
+			err = -ENODEV;
+			goto ERROR2;
+		}
+	}
+
+	if (kind == lm78) {
+		client_name = "LM78 chip";
+	} else if (kind == lm78j) {
+		client_name = "LM78-J chip";
+	} else if (kind == lm79) {
+		client_name = "LM79 chip";
+	} else {
+		dev_dbg(&adapter->dev, "Internal error: unknown kind (%d)?!?",
+			kind);
+		err = -ENODEV;
+		goto ERROR2;
+	}
+
+	/* Fill in the remaining client fields and put into the global list */
+	strlcpy(new_client->dev.name, client_name, DEVICE_NAME_SIZE);
+	data->type = kind;
+
+	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 ERROR2;
+
+	/* register sysfs hooks */
+	device_create_file(&new_client->dev, &dev_attr_in_input0);
+	device_create_file(&new_client->dev, &dev_attr_in_min0);
+	device_create_file(&new_client->dev, &dev_attr_in_max0);
+	device_create_file(&new_client->dev, &dev_attr_in_input1);
+	device_create_file(&new_client->dev, &dev_attr_in_min1);
+	device_create_file(&new_client->dev, &dev_attr_in_max1);
+	device_create_file(&new_client->dev, &dev_attr_in_input2);
+	device_create_file(&new_client->dev, &dev_attr_in_min2);
+	device_create_file(&new_client->dev, &dev_attr_in_max2);
+	device_create_file(&new_client->dev, &dev_attr_in_input3);
+	device_create_file(&new_client->dev, &dev_attr_in_min3);
+	device_create_file(&new_client->dev, &dev_attr_in_max3);
+	device_create_file(&new_client->dev, &dev_attr_in_input4);
+	device_create_file(&new_client->dev, &dev_attr_in_min4);
+	device_create_file(&new_client->dev, &dev_attr_in_max4);
+	device_create_file(&new_client->dev, &dev_attr_in_input5);
+	device_create_file(&new_client->dev, &dev_attr_in_min5);
+	device_create_file(&new_client->dev, &dev_attr_in_max5);
+	device_create_file(&new_client->dev, &dev_attr_in_input6);
+	device_create_file(&new_client->dev, &dev_attr_in_min6);
+	device_create_file(&new_client->dev, &dev_attr_in_max6);
+	device_create_file(&new_client->dev, &dev_attr_temp_input);
+	device_create_file(&new_client->dev, &dev_attr_temp_min);
+	device_create_file(&new_client->dev, &dev_attr_temp_max);
+	device_create_file(&new_client->dev, &dev_attr_fan_input1);
+	device_create_file(&new_client->dev, &dev_attr_fan_min1);
+	device_create_file(&new_client->dev, &dev_attr_fan_div1);
+	device_create_file(&new_client->dev, &dev_attr_fan_input2);
+	device_create_file(&new_client->dev, &dev_attr_fan_min2);
+	device_create_file(&new_client->dev, &dev_attr_fan_div2);
+	device_create_file(&new_client->dev, &dev_attr_fan_input3);
+	device_create_file(&new_client->dev, &dev_attr_fan_min3);
+	device_create_file(&new_client->dev, &dev_attr_fan_div3);
+	device_create_file(&new_client->dev, &dev_attr_alarms);
+	device_create_file(&new_client->dev, &dev_attr_vid);
+
+	/* Initialize the LM78 chip */
+	lm78_init_client(new_client);
+	return 0;
+
+ERROR2:
+	kfree(new_client);
+ERROR1:
+	if (is_isa)
+		release_region(address, LM78_EXTENT);
+ERROR0:
+	return err;
+}
+
+static int lm78_detach_client(struct i2c_client *client)
+{
+	int err;
+
+	/* release ISA region first */
+	if(i2c_is_isa_client(client))
+		release_region(client->addr, LM78_EXTENT);
+
+	/* now it's safe to scrap the rest */
+	if ((err = i2c_detach_client(client))) {
+		dev_err(&client->dev,
+		    "Client deregistration failed, client not detached.\n");
+		return err;
+	}
+
+	kfree(client);
+
+	return 0;
+}
+
+/* The SMBus locks itself, but ISA access must be locked explicitely! 
+   We don't want to lock the whole ISA bus, so we lock each client
+   separately.
+   We ignore the LM78 BUSY flag at this moment - it could lead to deadlocks,
+   would slow down the LM78 access and should not be necessary. 
+   There are some ugly typecasts here, but the good new is - they should
+   nowhere else be necessary! */
+static int lm78_read_value(struct i2c_client *client, u8 reg)
+{
+	int res;
+	if (i2c_is_isa_client(client)) {
+		struct lm78_data *data = i2c_get_clientdata(client);
+		down(&data->lock);
+		outb_p(reg, client->addr + LM78_ADDR_REG_OFFSET);
+		res = inb_p(client->addr + LM78_DATA_REG_OFFSET);
+		up(&data->lock);
+		return res;
+	} else
+		return i2c_smbus_read_byte_data(client, reg);
+}
+
+/* The SMBus locks itself, but ISA access muse be locked explicitely! 
+   We don't want to lock the whole ISA bus, so we lock each client
+   separately.
+   We ignore the LM78 BUSY flag at this moment - it could lead to deadlocks,
+   would slow down the LM78 access and should not be necessary. 
+   There are some ugly typecasts here, but the good new is - they should
+   nowhere else be necessary! */
+static int lm78_write_value(struct i2c_client *client, u8 reg, u8 value)
+{
+	if (i2c_is_isa_client(client)) {
+		struct lm78_data *data = i2c_get_clientdata(client);
+		down(&data->lock);
+		outb_p(reg, client->addr + LM78_ADDR_REG_OFFSET);
+		outb_p(value, client->addr + LM78_DATA_REG_OFFSET);
+		up(&data->lock);
+		return 0;
+	} else
+		return i2c_smbus_write_byte_data(client, reg, value);
+}
+
+/* Called when we have found a new LM78. It should set limits, etc. */
+static void lm78_init_client(struct i2c_client *client)
+{
+	struct lm78_data *data = i2c_get_clientdata(client);
+	int vid;
+
+	/* Reset all except Watchdog values and last conversion values
+	   This sets fan-divs to 2, among others */
+	lm78_write_value(client, LM78_REG_CONFIG, 0x80);
+
+	vid = lm78_read_value(client, LM78_REG_VID_FANDIV) & 0x0f;
+	if (data->type == lm79)
+		vid |=
+		    (lm78_read_value(client, LM78_REG_CHIPID) & 0x01) << 4;
+	else
+		vid |= 0x10;
+	vid = VID_FROM_REG(vid);
+
+	lm78_write_value(client, LM78_REG_IN_MIN(0),
+			 IN_TO_REG(LM78_INIT_IN_MIN_0(vid)));
+	lm78_write_value(client, LM78_REG_IN_MAX(0),
+			 IN_TO_REG(LM78_INIT_IN_MAX_0(vid)));
+	lm78_write_value(client, LM78_REG_IN_MIN(1),
+			 IN_TO_REG(LM78_INIT_IN_MIN_1(vid)));
+	lm78_write_value(client, LM78_REG_IN_MAX(1),
+			 IN_TO_REG(LM78_INIT_IN_MAX_1(vid)));
+	lm78_write_value(client, LM78_REG_IN_MIN(2),
+			 IN_TO_REG(LM78_INIT_IN_MIN_2));
+	lm78_write_value(client, LM78_REG_IN_MAX(2),
+			 IN_TO_REG(LM78_INIT_IN_MAX_2));
+	lm78_write_value(client, LM78_REG_IN_MIN(3),
+			 IN_TO_REG(LM78_INIT_IN_MIN_3));
+	lm78_write_value(client, LM78_REG_IN_MAX(3),
+			 IN_TO_REG(LM78_INIT_IN_MAX_3));
+	lm78_write_value(client, LM78_REG_IN_MIN(4),
+			 IN_TO_REG(LM78_INIT_IN_MIN_4));
+	lm78_write_value(client, LM78_REG_IN_MAX(4),
+			 IN_TO_REG(LM78_INIT_IN_MAX_4));
+	lm78_write_value(client, LM78_REG_IN_MIN(5),
+			 IN_TO_REG(LM78_INIT_IN_MIN_5));
+	lm78_write_value(client, LM78_REG_IN_MAX(5),
+			 IN_TO_REG(LM78_INIT_IN_MAX_5));
+	lm78_write_value(client, LM78_REG_IN_MIN(6),
+			 IN_TO_REG(LM78_INIT_IN_MIN_6));
+	lm78_write_value(client, LM78_REG_IN_MAX(6),
+			 IN_TO_REG(LM78_INIT_IN_MAX_6));
+	lm78_write_value(client, LM78_REG_FAN_MIN(0),
+			 FAN_TO_REG(LM78_INIT_FAN_MIN_1, 2));
+	lm78_write_value(client, LM78_REG_FAN_MIN(1),
+			 FAN_TO_REG(LM78_INIT_FAN_MIN_2, 2));
+	lm78_write_value(client, LM78_REG_FAN_MIN(2),
+			 FAN_TO_REG(LM78_INIT_FAN_MIN_3, 2));
+	lm78_write_value(client, LM78_REG_TEMP_OVER,
+			 TEMP_TO_REG(LM78_INIT_TEMP_OVER));
+	lm78_write_value(client, LM78_REG_TEMP_HYST,
+			 TEMP_TO_REG(LM78_INIT_TEMP_HYST));
+
+	/* Start monitoring */
+	lm78_write_value(client, LM78_REG_CONFIG,
+			 (lm78_read_value(client, LM78_REG_CONFIG) & 0xf7)
+			 | 0x01);
+
+}
+
+static void lm78_update_client(struct i2c_client *client)
+{
+	struct lm78_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) {
+
+		dev_dbg(&client->dev, "Starting lm78 update\n");
+
+		for (i = 0; i <= 6; i++) {
+			data->in[i] =
+			    lm78_read_value(client, LM78_REG_IN(i));
+			data->in_min[i] =
+			    lm78_read_value(client, LM78_REG_IN_MIN(i));
+			data->in_max[i] =
+			    lm78_read_value(client, LM78_REG_IN_MAX(i));
+		}
+		for (i = 0; i < 3; i++) {
+			data->fan[i] =
+			    lm78_read_value(client, LM78_REG_FAN(i));
+			data->fan_min[i] =
+			    lm78_read_value(client, LM78_REG_FAN_MIN(i));
+		}
+		data->temp = lm78_read_value(client, LM78_REG_TEMP);
+		data->temp_over =
+		    lm78_read_value(client, LM78_REG_TEMP_OVER);
+		data->temp_hyst =
+		    lm78_read_value(client, LM78_REG_TEMP_HYST);
+		i = lm78_read_value(client, LM78_REG_VID_FANDIV);
+		data->vid = i & 0x0f;
+		if (data->type == lm79)
+			data->vid |=
+			    (lm78_read_value(client, LM78_REG_CHIPID) &
+			     0x01) << 4;
+		else
+			data->vid |= 0x10;
+		data->fan_div[0] = (i >> 4) & 0x03;
+		data->fan_div[1] = i >> 6;
+		data->alarms = lm78_read_value(client, LM78_REG_ALARM1) +
+		    (lm78_read_value(client, LM78_REG_ALARM2) << 8);
+		data->last_updated = jiffies;
+		data->valid = 1;
+
+		data->fan_div[2] = 1;
+	}
+
+	up(&data->update_lock);
+}
+
+static int __init sm_lm78_init(void)
+{
+	return i2c_add_driver(&lm78_driver);
+}
+
+static void __exit sm_lm78_exit(void)
+{
+	i2c_del_driver(&lm78_driver);
+}
+
+
+
+MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
+MODULE_DESCRIPTION("LM78, LM78-J and LM79 driver");
+MODULE_LICENSE("GPL");
+
+module_init(sm_lm78_init);
+module_exit(sm_lm78_exit);