diff --git a/drivers/i2c/chips/pcf8591.c b/drivers/i2c/chips/pcf8591.c
new file mode 100644
index 0000000..b6b927d
--- /dev/null
+++ b/drivers/i2c/chips/pcf8591.c
@@ -0,0 +1,316 @@
+/*
+    pcf8591.c - Part of lm_sensors, Linux kernel modules for hardware
+                monitoring
+    Copyright (C) 2001-2004 Aurelien Jarno <aurelien@aurel32.net>
+    Ported to Linux 2.6 by Aurelien Jarno <aurelien@aurel32.net> with 
+    the help of 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/i2c.h>
+#include <linux/i2c-sensor.h>
+
+/* Addresses to scan */
+static unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
+					0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
+static unsigned int normal_isa[] = { I2C_CLIENT_ISA_END };
+
+/* Insmod parameters */
+SENSORS_INSMOD_1(pcf8591);
+
+static int input_mode;
+module_param(input_mode, int, 0);
+MODULE_PARM_DESC(input_mode,
+	"Analog input mode:\n"
+	" 0 = four single ended inputs\n"
+	" 1 = three differential inputs\n"
+	" 2 = single ended and differential mixed\n"
+	" 3 = two differential inputs\n");
+
+/* The PCF8591 control byte
+      7    6    5    4    3    2    1    0  
+   |  0 |AOEF|   AIP   |  0 |AINC|  AICH   | */
+
+/* Analog Output Enable Flag (analog output active if 1) */
+#define PCF8591_CONTROL_AOEF		0x40
+					
+/* Analog Input Programming 
+   0x00 = four single ended inputs
+   0x10 = three differential inputs
+   0x20 = single ended and differential mixed
+   0x30 = two differential inputs */
+#define PCF8591_CONTROL_AIP_MASK	0x30
+
+/* Autoincrement Flag (switch on if 1) */
+#define PCF8591_CONTROL_AINC		0x04
+
+/* Channel selection
+   0x00 = channel 0 
+   0x01 = channel 1
+   0x02 = channel 2
+   0x03 = channel 3 */
+#define PCF8591_CONTROL_AICH_MASK	0x03
+
+/* Initial values */
+#define PCF8591_INIT_CONTROL	((input_mode << 4) | PCF8591_CONTROL_AOEF)
+#define PCF8591_INIT_AOUT	0	/* DAC out = 0 */
+
+/* Conversions */
+#define REG_TO_SIGNED(reg)	(((reg) & 0x80)?((reg) - 256):(reg))
+
+struct pcf8591_data {
+	struct i2c_client client;
+	struct semaphore update_lock;
+
+	u8 control;
+	u8 aout;
+};
+
+static int pcf8591_attach_adapter(struct i2c_adapter *adapter);
+static int pcf8591_detect(struct i2c_adapter *adapter, int address, int kind);
+static int pcf8591_detach_client(struct i2c_client *client);
+static void pcf8591_init_client(struct i2c_client *client);
+static int pcf8591_read_channel(struct device *dev, int channel);
+
+/* This is the driver that will be inserted */
+static struct i2c_driver pcf8591_driver = {
+	.owner		= THIS_MODULE,
+	.name		= "pcf8591",
+	.id		= I2C_DRIVERID_PCF8591,
+	.flags		= I2C_DF_NOTIFY,
+	.attach_adapter	= pcf8591_attach_adapter,
+	.detach_client	= pcf8591_detach_client,
+};
+
+/* following are the sysfs callback functions */
+#define show_in_channel(channel)					\
+static ssize_t show_in##channel##_input(struct device *dev, char *buf)	\
+{									\
+	return sprintf(buf, "%d\n", pcf8591_read_channel(dev, channel));\
+}									\
+static DEVICE_ATTR(in##channel##_input, S_IRUGO,			\
+		   show_in##channel##_input, NULL);
+
+show_in_channel(0);
+show_in_channel(1);
+show_in_channel(2);
+show_in_channel(3);
+
+static ssize_t show_out0_ouput(struct device *dev, char *buf)
+{
+	struct pcf8591_data *data = i2c_get_clientdata(to_i2c_client(dev));
+	return sprintf(buf, "%d\n", data->aout * 10);
+}
+
+static ssize_t set_out0_output(struct device *dev, const char *buf, size_t count)
+{
+	unsigned int value;
+	struct i2c_client *client = to_i2c_client(dev);
+	struct pcf8591_data *data = i2c_get_clientdata(client);
+	if ((value = (simple_strtoul(buf, NULL, 10) + 5) / 10) <= 255) {
+		data->aout = value;
+		i2c_smbus_write_byte_data(client, data->control, data->aout);
+		return count;
+	}
+	return -EINVAL;
+}
+
+static DEVICE_ATTR(out0_output, S_IWUSR | S_IRUGO, 
+		   show_out0_ouput, set_out0_output);
+
+static ssize_t show_out0_enable(struct device *dev, char *buf)
+{
+	struct pcf8591_data *data = i2c_get_clientdata(to_i2c_client(dev));
+	return sprintf(buf, "%u\n", !(!(data->control & PCF8591_CONTROL_AOEF)));
+}
+
+static ssize_t set_out0_enable(struct device *dev, const char *buf, size_t count)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct pcf8591_data *data = i2c_get_clientdata(client);
+	unsigned long val = simple_strtoul(buf, NULL, 10);
+
+	down(&data->update_lock);
+	if (val)
+		data->control |= PCF8591_CONTROL_AOEF;
+	else
+		data->control &= ~PCF8591_CONTROL_AOEF;
+	i2c_smbus_write_byte(client, data->control);
+	up(&data->update_lock);
+	return count;
+}
+
+static DEVICE_ATTR(out0_enable, S_IWUSR | S_IRUGO, 
+		   show_out0_enable, set_out0_enable);
+
+/*
+ * Real code
+ */
+static int pcf8591_attach_adapter(struct i2c_adapter *adapter)
+{
+	return i2c_detect(adapter, &addr_data, pcf8591_detect);
+}
+
+/* This function is called by i2c_detect */
+int pcf8591_detect(struct i2c_adapter *adapter, int address, int kind)
+{
+	struct i2c_client *new_client;
+	struct pcf8591_data *data;
+	int err = 0;
+
+	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE
+				     | I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
+		goto exit;
+
+	/* OK. For now, we presume we have a valid client. We now create the
+	   client structure, even though we cannot fill it completely yet. */
+	if (!(data = kmalloc(sizeof(struct pcf8591_data), GFP_KERNEL))) {
+		err = -ENOMEM;
+		goto exit;
+	}
+	memset(data, 0, sizeof(struct pcf8591_data));
+	
+	new_client = &data->client;
+	i2c_set_clientdata(new_client, data);
+	new_client->addr = address;
+	new_client->adapter = adapter;
+	new_client->driver = &pcf8591_driver;
+	new_client->flags = 0;
+
+	/* Now, we would do the remaining detection. But the PCF8591 is plainly
+	   impossible to detect! Stupid chip. */
+
+	/* Determine the chip type - only one kind supported! */
+	if (kind <= 0)
+		kind = pcf8591;
+
+	/* Fill in the remaining client fields and put it into the global 
+	   list */
+	strlcpy(new_client->name, "pcf8591", I2C_NAME_SIZE);
+	init_MUTEX(&data->update_lock);
+
+	/* Tell the I2C layer a new client has arrived */
+	if ((err = i2c_attach_client(new_client)))
+		goto exit_kfree;
+
+	/* Initialize the PCF8591 chip */
+	pcf8591_init_client(new_client);
+
+	/* Register sysfs hooks */
+	device_create_file(&new_client->dev, &dev_attr_out0_enable);
+	device_create_file(&new_client->dev, &dev_attr_out0_output);
+	device_create_file(&new_client->dev, &dev_attr_in0_input);
+	device_create_file(&new_client->dev, &dev_attr_in1_input);
+
+	/* Register input2 if not in "two differential inputs" mode */
+	if (input_mode != 3 )
+		device_create_file(&new_client->dev, &dev_attr_in2_input);
+		
+	/* Register input3 only in "four single ended inputs" mode */
+	if (input_mode == 0)
+		device_create_file(&new_client->dev, &dev_attr_in3_input);
+	
+	return 0;
+	
+	/* OK, this is not exactly good programming practice, usually. But it is
+	   very code-efficient in this case. */
+
+exit_kfree:
+	kfree(data);
+exit:
+	return err;
+}
+
+static int pcf8591_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;
+	}
+
+	kfree(i2c_get_clientdata(client));
+	return 0;
+}
+
+/* Called when we have found a new PCF8591. */
+static void pcf8591_init_client(struct i2c_client *client)
+{
+	struct pcf8591_data *data = i2c_get_clientdata(client);
+	data->control = PCF8591_INIT_CONTROL;
+	data->aout = PCF8591_INIT_AOUT;
+
+	i2c_smbus_write_byte_data(client, data->control, data->aout);
+	
+	/* The first byte transmitted contains the conversion code of the 
+	   previous read cycle. FLUSH IT! */
+	i2c_smbus_read_byte(client);
+}
+
+static int pcf8591_read_channel(struct device *dev, int channel)
+{
+	u8 value;
+	struct i2c_client *client = to_i2c_client(dev);
+	struct pcf8591_data *data = i2c_get_clientdata(client);
+
+	down(&data->update_lock);
+
+	if ((data->control & PCF8591_CONTROL_AICH_MASK) != channel) {
+		data->control = (data->control & ~PCF8591_CONTROL_AICH_MASK)
+			      | channel;
+		i2c_smbus_write_byte(client, data->control);
+	
+		/* The first byte transmitted contains the conversion code of 
+		   the previous read cycle. FLUSH IT! */
+		i2c_smbus_read_byte(client);
+	}
+	value = i2c_smbus_read_byte(client);
+
+	up(&data->update_lock);
+
+	if ((channel == 2 && input_mode == 2) ||
+	    (channel != 3 && (input_mode == 1 || input_mode == 3)))
+		return (10 * REG_TO_SIGNED(value));
+	else
+		return (10 * value);
+}
+
+static int __init pcf8591_init(void)
+{
+	if (input_mode < 0 || input_mode > 3) {
+		printk(KERN_WARNING "pcf8591: invalid input_mode (%d)\n",
+		       input_mode);
+		input_mode = 0;
+	}
+	return i2c_add_driver(&pcf8591_driver);
+}
+
+static void __exit pcf8591_exit(void)
+{
+	i2c_del_driver(&pcf8591_driver);
+}
+
+MODULE_AUTHOR("Aurelien Jarno <aurelien@aurel32.net>");
+MODULE_DESCRIPTION("PCF8591 driver");
+MODULE_LICENSE("GPL");
+
+module_init(pcf8591_init);
+module_exit(pcf8591_exit);