[PATCH] hwmon: New vt8231 driver

Port the vt8231 hardware monitoring driver from lm_sensors CVS to
Linux 2.6.

Signed-off-by: Roger Lucas <roger@planbit.co.uk>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

3 files changed, 874 insertions, 0 deletions

diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index db358cfa7cbf..c58295914365 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -350,6 +350,18 @@ config SENSORS_VIA686A
           This driver can also be built as a module.  If so, the module
           will be called via686a.
 
+config SENSORS_VT8231
+        tristate "VT8231"
+        depends on HWMON && I2C && PCI && EXPERIMENTAL
+        select HWMON_VID
+        select I2C_ISA
+        help
+          If you say yes here then you get support for the integrated sensors
+          in the VIA VT8231 device.
+
+          This driver can also be built as a module.  If so, the module
+          will be called vt8231.
+
 config SENSORS_W83781D
         tristate "Winbond W83781D, W83782D, W83783S, W83627HF, Asus AS99127F"
         depends on HWMON && I2C
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index f7d6a2f61ee7..06d4a1d14105 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -40,6 +40,7 @@ obj-$(CONFIG_SENSORS_SIS5595)	+= sis5595.o
 obj-$(CONFIG_SENSORS_SMSC47B397)+= smsc47b397.o
 obj-$(CONFIG_SENSORS_SMSC47M1)  += smsc47m1.o
 obj-$(CONFIG_SENSORS_VIA686A)   += via686a.o
+obj-$(CONFIG_SENSORS_VT8231)    += vt8231.o
 obj-$(CONFIG_SENSORS_W83627EHF) += w83627ehf.o
 obj-$(CONFIG_SENSORS_W83L785TS) += w83l785ts.o
 
diff --git a/drivers/hwmon/vt8231.c b/drivers/hwmon/vt8231.c
new file mode 100644
index 000000000000..c8556a72a1cd
--- /dev/null
+++ b/drivers/hwmon/vt8231.c
@@ -0,0 +1,861 @@
+/*
+        vt8231.c - Part of lm_sensors, Linux kernel modules
+                                for hardware monitoring
+
+        Copyright (c) 2005 Roger Lucas <roger@planbit.co.uk>
+        Copyright (c) 2002 Mark D. Studebaker <mdsxyz123@yahoo.com>
+                           Aaron M. Marsh <amarsh@sdf.lonestar.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.
+*/
+
+/* Supports VIA VT8231 South Bridge embedded sensors
+*/
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/pci.h>
+#include <linux/jiffies.h>
+#include <linux/i2c.h>
+#include <linux/i2c-isa.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/hwmon-vid.h>
+#include <linux/err.h>
+#include <asm/io.h>
+
+static int force_addr;
+module_param(force_addr, int, 0);
+MODULE_PARM_DESC(force_addr, "Initialize the base address of the sensors");
+
+/* Device address
+   Note that we can't determine the ISA address until we have initialized
+   our module */
+static unsigned short isa_address;
+
+#define VT8231_EXTENT 0x80
+#define VT8231_BASE_REG 0x70
+#define VT8231_ENABLE_REG 0x74
+
+/* The VT8231 registers
+
+   The reset value for the input channel configuration is used (Reg 0x4A=0x07)
+   which sets the selected inputs marked with '*' below if multiple options are
+   possible:
+
+                    Voltage Mode          Temperature Mode
+        Sensor        Linux Id        Linux Id        VIA Id
+        --------      --------        --------        ------
+        CPU Diode       N/A             temp1           0
+        UIC1            in0             temp2 *         1
+        UIC2            in1 *           temp3           2
+        UIC3            in2 *           temp4           3
+        UIC4            in3 *           temp5           4
+        UIC5            in4 *           temp6           5
+        3.3V            in5             N/A
+
+   Note that the BIOS may set the configuration register to a different value
+   to match the motherboard configuration.
+*/
+
+/* fans numbered 0-1 */
+#define VT8231_REG_FAN_MIN(nr)  (0x3b + (nr))
+#define VT8231_REG_FAN(nr)      (0x29 + (nr))
+
+/* Voltage inputs numbered 0-5 */
+
+static const u8 regvolt[]    = { 0x21, 0x22, 0x23, 0x24, 0x25, 0x26 };
+static const u8 regvoltmax[] = { 0x3d, 0x2b, 0x2d, 0x2f, 0x31, 0x33 };
+static const u8 regvoltmin[] = { 0x3e, 0x2c, 0x2e, 0x30, 0x32, 0x34 };
+
+/* Temperatures are numbered 1-6 according to the Linux kernel specification.
+**
+** In the VIA datasheet, however, the temperatures are numbered from zero.
+** Since it is important that this driver can easily be compared to the VIA
+** datasheet, we will use the VIA numbering within this driver and map the
+** kernel sysfs device name to the VIA number in the sysfs callback.
+*/
+
+#define VT8231_REG_TEMP_LOW01   0x49
+#define VT8231_REG_TEMP_LOW25   0x4d
+
+static const u8 regtemp[]    = { 0x1f, 0x21, 0x22, 0x23, 0x24, 0x25 };
+static const u8 regtempmax[] = { 0x39, 0x3d, 0x2b, 0x2d, 0x2f, 0x31 };
+static const u8 regtempmin[] = { 0x3a, 0x3e, 0x2c, 0x2e, 0x30, 0x32 };
+
+#define TEMP_FROM_REG(reg)              (((253 * 4 - (reg)) * 550 + 105) / 210)
+#define TEMP_MAXMIN_FROM_REG(reg)       (((253 - (reg)) * 2200 + 105) / 210)
+#define TEMP_MAXMIN_TO_REG(val)         (253 - ((val) * 210 + 1100) / 2200)
+
+#define VT8231_REG_CONFIG 0x40
+#define VT8231_REG_ALARM1 0x41
+#define VT8231_REG_ALARM2 0x42
+#define VT8231_REG_FANDIV 0x47
+#define VT8231_REG_UCH_CONFIG 0x4a
+#define VT8231_REG_TEMP1_CONFIG 0x4b
+#define VT8231_REG_TEMP2_CONFIG 0x4c
+
+/* temps 0-5 as numbered in VIA datasheet - see later for mapping to Linux
+** numbering
+*/
+#define ISTEMP(i, ch_config) ((i) == 0 ? 1 : \
+                              ((ch_config) >> ((i)+1)) & 0x01)
+/* voltages 0-5 */
+#define ISVOLT(i, ch_config) ((i) == 5 ? 1 : \
+                              !(((ch_config) >> ((i)+2)) & 0x01))
+
+#define DIV_FROM_REG(val) (1 << (val))
+
+/* NB  The values returned here are NOT temperatures.  The calibration curves
+**     for the thermistor curves are board-specific and must go in the
+**     sensors.conf file.  Temperature sensors are actually ten bits, but the
+**     VIA datasheet only considers the 8 MSBs obtained from the regtemp[]
+**     register.  The temperature value returned should have a magnitude of 3,
+**     so we use the VIA scaling as the "true" scaling and use the remaining 2
+**     LSBs as fractional precision.
+**
+**     All the on-chip hardware temperature comparisons for the alarms are only
+**     8-bits wide, and compare against the 8 MSBs of the temperature.  The bits
+**     in the registers VT8231_REG_TEMP_LOW01 and VT8231_REG_TEMP_LOW25 are
+**     ignored.
+*/
+
+/******** FAN RPM CONVERSIONS ********
+** This chip saturates back at 0, not at 255 like many the other chips.
+** So, 0 means 0 RPM
+*/
+static inline u8 FAN_TO_REG(long rpm, int div)
+{
+        if (rpm == 0)
+                return 0;
+        return SENSORS_LIMIT(1310720 / (rpm * div), 1, 255);
+}
+
+#define FAN_FROM_REG(val, div) ((val) == 0 ? 0 : 1310720 / ((val) * (div)))
+
+struct vt8231_data {
+        struct i2c_client client;
+        struct semaphore update_lock;
+        struct class_device *class_dev;
+        char valid;             /* !=0 if following fields are valid */
+        unsigned long last_updated;     /* In jiffies */
+
+        u8 in[6];               /* Register value */
+        u8 in_max[6];           /* Register value */
+        u8 in_min[6];           /* Register value */
+        u16 temp[6];            /* Register value 10 bit, right aligned */
+        u8 temp_max[6];         /* Register value */
+        u8 temp_min[6];         /* Register value */
+        u8 fan[2];              /* Register value */
+        u8 fan_min[2];          /* Register value */
+        u8 fan_div[2];          /* Register encoding, shifted right */
+        u16 alarms;             /* Register encoding */
+        u8 uch_config;
+};
+
+static struct pci_dev *s_bridge;
+static int vt8231_detect(struct i2c_adapter *adapter);
+static int vt8231_detach_client(struct i2c_client *client);
+static struct vt8231_data *vt8231_update_device(struct device *dev);
+static void vt8231_init_client(struct i2c_client *client);
+
+static inline int vt8231_read_value(struct i2c_client *client, u8 reg)
+{
+        return inb_p(client->addr + reg);
+}
+
+static inline void vt8231_write_value(struct i2c_client *client, u8 reg,
+                                        u8 value)
+{
+        outb_p(value, client->addr + reg);
+}
+
+/* following are the sysfs callback functions */
+static ssize_t show_in(struct device *dev, struct device_attribute *attr,
+                char *buf)
+{
+        struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
+        int nr = sensor_attr->index;
+        struct vt8231_data *data = vt8231_update_device(dev);
+
+        return sprintf(buf, "%d\n", ((data->in[nr] - 3) * 10000) / 958);
+}
+
+static ssize_t show_in_min(struct device *dev, struct device_attribute *attr,
+                char *buf)
+{
+        struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
+        int nr = sensor_attr->index;
+        struct vt8231_data *data = vt8231_update_device(dev);
+
+        return sprintf(buf, "%d\n", ((data->in_min[nr] - 3) * 10000) / 958);
+}
+
+static ssize_t show_in_max(struct device *dev, struct device_attribute *attr,
+                char *buf)
+{
+        struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
+        int nr = sensor_attr->index;
+        struct vt8231_data *data = vt8231_update_device(dev);
+
+        return sprintf(buf, "%d\n", (((data->in_max[nr] - 3) * 10000) / 958));
+}
+
+static ssize_t set_in_min(struct device *dev, struct device_attribute *attr,
+                const char *buf, size_t count)
+{
+        struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
+        int nr = sensor_attr->index;
+        struct i2c_client *client = to_i2c_client(dev);
+        struct vt8231_data *data = i2c_get_clientdata(client);
+        unsigned long val = simple_strtoul(buf, NULL, 10);
+
+        down(&data->update_lock);
+        data->in_min[nr] = SENSORS_LIMIT(((val * 958) / 10000) + 3, 0, 255);
+        vt8231_write_value(client, regvoltmin[nr], data->in_min[nr]);
+        up(&data->update_lock);
+        return count;
+}
+
+static ssize_t set_in_max(struct device *dev, struct device_attribute *attr,
+                const char *buf, size_t count)
+{
+        struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
+        int nr = sensor_attr->index;
+        struct i2c_client *client = to_i2c_client(dev);
+        struct vt8231_data *data = i2c_get_clientdata(client);
+        unsigned long val = simple_strtoul(buf, NULL, 10);
+
+        down(&data->update_lock);
+        data->in_max[nr] = SENSORS_LIMIT(((val * 958) / 10000) + 3, 0, 255);
+        vt8231_write_value(client, regvoltmax[nr], data->in_max[nr]);
+        up(&data->update_lock);
+        return count;
+}
+
+/* Special case for input 5 as this has 3.3V scaling built into the chip */
+static ssize_t show_in5(struct device *dev, struct device_attribute *attr,
+                char *buf)
+{
+        struct vt8231_data *data = vt8231_update_device(dev);
+
+        return sprintf(buf, "%d\n",
+                (((data->in[5] - 3) * 10000 * 54) / (958 * 34)));
+}
+
+static ssize_t show_in5_min(struct device *dev, struct device_attribute *attr,
+                char *buf)
+{
+        struct vt8231_data *data = vt8231_update_device(dev);
+
+        return sprintf(buf, "%d\n",
+                (((data->in_min[5] - 3) * 10000 * 54) / (958 * 34)));
+}
+
+static ssize_t show_in5_max(struct device *dev, struct device_attribute *attr,
+                char *buf)
+{
+        struct vt8231_data *data = vt8231_update_device(dev);
+
+        return sprintf(buf, "%d\n",
+                (((data->in_max[5] - 3) * 10000 * 54) / (958 * 34)));
+}
+
+static ssize_t set_in5_min(struct device *dev, struct device_attribute *attr,
+                const char *buf, size_t count)
+{
+        struct i2c_client *client = to_i2c_client(dev);
+        struct vt8231_data *data = i2c_get_clientdata(client);
+        unsigned long val = simple_strtoul(buf, NULL, 10);
+
+        down(&data->update_lock);
+        data->in_min[5] = SENSORS_LIMIT(((val * 958 * 34) / (10000 * 54)) + 3,
+                                        0, 255);
+        vt8231_write_value(client, regvoltmin[5], data->in_min[5]);
+        up(&data->update_lock);
+        return count;
+}
+
+static ssize_t set_in5_max(struct device *dev, struct device_attribute *attr,
+                const char *buf, size_t count)
+{
+        struct i2c_client *client = to_i2c_client(dev);
+        struct vt8231_data *data = i2c_get_clientdata(client);
+        unsigned long val = simple_strtoul(buf, NULL, 10);
+
+        down(&data->update_lock);
+        data->in_max[5] = SENSORS_LIMIT(((val * 958 * 34) / (10000 * 54)) + 3,
+                                        0, 255);
+        vt8231_write_value(client, regvoltmax[5], data->in_max[5]);
+        up(&data->update_lock);
+        return count;
+}
+
+#define define_voltage_sysfs(offset)                            \
+static SENSOR_DEVICE_ATTR(in##offset##_input, S_IRUGO,          \
+                show_in, NULL, offset);                         \
+static SENSOR_DEVICE_ATTR(in##offset##_min, S_IRUGO | S_IWUSR,  \
+                show_in_min, set_in_min, offset);               \
+static SENSOR_DEVICE_ATTR(in##offset##_max, S_IRUGO | S_IWUSR,  \
+                show_in_max, set_in_max, offset)
+
+define_voltage_sysfs(0);
+define_voltage_sysfs(1);
+define_voltage_sysfs(2);
+define_voltage_sysfs(3);
+define_voltage_sysfs(4);
+
+static DEVICE_ATTR(in5_input, S_IRUGO, show_in5, NULL);
+static DEVICE_ATTR(in5_min, S_IRUGO | S_IWUSR, show_in5_min, set_in5_min);
+static DEVICE_ATTR(in5_max, S_IRUGO | S_IWUSR, show_in5_max, set_in5_max);
+
+/* Temperatures */
+static ssize_t show_temp0(struct device *dev, struct device_attribute *attr,
+                char *buf)
+{
+        struct vt8231_data *data = vt8231_update_device(dev);
+        return sprintf(buf, "%d\n", data->temp[0] * 250);
+}
+
+static ssize_t show_temp0_max(struct device *dev, struct device_attribute *attr,
+                char *buf)
+{
+        struct vt8231_data *data = vt8231_update_device(dev);
+        return sprintf(buf, "%d\n", data->temp_max[0] * 1000);
+}
+
+static ssize_t show_temp0_min(struct device *dev, struct device_attribute *attr,
+                char *buf)
+{
+        struct vt8231_data *data = vt8231_update_device(dev);
+        return sprintf(buf, "%d\n", data->temp_min[0] * 1000);
+}
+
+static ssize_t set_temp0_max(struct device *dev, struct device_attribute *attr,
+                const char *buf, size_t count)
+{
+        struct i2c_client *client = to_i2c_client(dev);
+        struct vt8231_data *data = i2c_get_clientdata(client);
+        int val = simple_strtol(buf, NULL, 10);
+
+        down(&data->update_lock);
+        data->temp_max[0] = SENSORS_LIMIT((val + 500) / 1000, 0, 255);
+        vt8231_write_value(client, regtempmax[0], data->temp_max[0]);
+        up(&data->update_lock);
+        return count;
+}
+static ssize_t set_temp0_min(struct device *dev, struct device_attribute *attr,
+                const char *buf, size_t count)
+{
+        struct i2c_client *client = to_i2c_client(dev);
+        struct vt8231_data *data = i2c_get_clientdata(client);
+        int val = simple_strtol(buf, NULL, 10);
+
+        down(&data->update_lock);
+        data->temp_min[0] = SENSORS_LIMIT((val + 500) / 1000, 0, 255);
+        vt8231_write_value(client, regtempmin[0], data->temp_min[0]);
+        up(&data->update_lock);
+        return count;
+}
+
+static ssize_t show_temp(struct device *dev, struct device_attribute *attr,
+                char *buf)
+{
+        struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
+        int nr = sensor_attr->index;
+        struct vt8231_data *data = vt8231_update_device(dev);
+        return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[nr]));
+}
+
+static ssize_t show_temp_max(struct device *dev, struct device_attribute *attr,
+                char *buf)
+{
+        struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
+        int nr = sensor_attr->index;
+        struct vt8231_data *data = vt8231_update_device(dev);
+        return sprintf(buf, "%d\n", TEMP_MAXMIN_FROM_REG(data->temp_max[nr]));
+}
+
+static ssize_t show_temp_min(struct device *dev, struct device_attribute *attr,
+                char *buf)
+{
+        struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
+        int nr = sensor_attr->index;
+        struct vt8231_data *data = vt8231_update_device(dev);
+        return sprintf(buf, "%d\n", TEMP_MAXMIN_FROM_REG(data->temp_min[nr]));
+}
+
+static ssize_t set_temp_max(struct device *dev, struct device_attribute *attr,
+                const char *buf, size_t count)
+{
+        struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
+        int nr = sensor_attr->index;
+        struct i2c_client *client = to_i2c_client(dev);
+        struct vt8231_data *data = i2c_get_clientdata(client);
+        int val = simple_strtol(buf, NULL, 10);
+
+        down(&data->update_lock);
+        data->temp_max[nr] = SENSORS_LIMIT(TEMP_MAXMIN_TO_REG(val), 0, 255);
+        vt8231_write_value(client, regtempmax[nr], data->temp_max[nr]);
+        up(&data->update_lock);
+        return count;
+}
+static ssize_t set_temp_min(struct device *dev, struct device_attribute *attr,
+                const char *buf, size_t count)
+{
+        struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
+        int nr = sensor_attr->index;
+        struct i2c_client *client = to_i2c_client(dev);
+        struct vt8231_data *data = i2c_get_clientdata(client);
+        int val = simple_strtol(buf, NULL, 10);
+
+        down(&data->update_lock);
+        data->temp_min[nr] = SENSORS_LIMIT(TEMP_MAXMIN_TO_REG(val), 0, 255);
+        vt8231_write_value(client, regtempmin[nr], data->temp_min[nr]);
+        up(&data->update_lock);
+        return count;
+}
+
+/* Note that these map the Linux temperature sensor numbering (1-6) to the VIA
+** temperature sensor numbering (0-5)
+*/
+#define define_temperature_sysfs(offset)                                \
+static SENSOR_DEVICE_ATTR(temp##offset##_input, S_IRUGO,                \
+                show_temp, NULL, offset - 1);                           \
+static SENSOR_DEVICE_ATTR(temp##offset##_max, S_IRUGO | S_IWUSR,        \
+                show_temp_max, set_temp_max, offset - 1);               \
+static SENSOR_DEVICE_ATTR(temp##offset##_min, S_IRUGO | S_IWUSR,        \
+                show_temp_min, set_temp_min, offset - 1)
+
+static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp0, NULL);
+static DEVICE_ATTR(temp1_max, S_IRUGO | S_IWUSR, show_temp0_max, set_temp0_max);
+static DEVICE_ATTR(temp1_min, S_IRUGO | S_IWUSR, show_temp0_min, set_temp0_min);
+
+define_temperature_sysfs(2);
+define_temperature_sysfs(3);
+define_temperature_sysfs(4);
+define_temperature_sysfs(5);
+define_temperature_sysfs(6);
+
+#define CFG_INFO_TEMP(id)       { &sensor_dev_attr_temp##id##_input.dev_attr, \
+                                &sensor_dev_attr_temp##id##_min.dev_attr, \
+                                &sensor_dev_attr_temp##id##_max.dev_attr }
+#define CFG_INFO_VOLT(id)       { &sensor_dev_attr_in##id##_input.dev_attr, \
+                                &sensor_dev_attr_in##id##_min.dev_attr, \
+                                &sensor_dev_attr_in##id##_max.dev_attr }
+
+struct str_device_attr_table {
+        struct device_attribute *input;
+        struct device_attribute *min;
+        struct device_attribute *max;
+};
+
+static struct str_device_attr_table cfg_info_temp[] = {
+        { &dev_attr_temp1_input, &dev_attr_temp1_min, &dev_attr_temp1_max },
+        CFG_INFO_TEMP(2),
+        CFG_INFO_TEMP(3),
+        CFG_INFO_TEMP(4),
+        CFG_INFO_TEMP(5),
+        CFG_INFO_TEMP(6)
+};
+
+static struct str_device_attr_table cfg_info_volt[] = {
+        CFG_INFO_VOLT(0),
+        CFG_INFO_VOLT(1),
+        CFG_INFO_VOLT(2),
+        CFG_INFO_VOLT(3),
+        CFG_INFO_VOLT(4),
+        { &dev_attr_in5_input, &dev_attr_in5_min, &dev_attr_in5_max }
+};
+
+/* Fans */
+static ssize_t show_fan(struct device *dev, struct device_attribute *attr,
+                char *buf)
+{
+        struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
+        int nr = sensor_attr->index;
+        struct vt8231_data *data = vt8231_update_device(dev);
+        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, struct device_attribute *attr,
+                char *buf)
+{
+        struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
+        int nr = sensor_attr->index;
+        struct vt8231_data *data = vt8231_update_device(dev);
+        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, struct device_attribute *attr,
+                char *buf)
+{
+        struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
+        int nr = sensor_attr->index;
+        struct vt8231_data *data = vt8231_update_device(dev);
+        return sprintf(buf, "%d\n", DIV_FROM_REG(data->fan_div[nr]));
+}
+
+static ssize_t set_fan_min(struct device *dev, struct device_attribute *attr,
+                const char *buf, size_t count)
+{
+        struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
+        int nr = sensor_attr->index;
+        struct i2c_client *client = to_i2c_client(dev);
+        struct vt8231_data *data = i2c_get_clientdata(client);
+        int val = simple_strtoul(buf, NULL, 10);
+
+        down(&data->update_lock);
+        data->fan_min[nr] = FAN_TO_REG(val, DIV_FROM_REG(data->fan_div[nr]));
+        vt8231_write_value(client, VT8231_REG_FAN_MIN(nr), data->fan_min[nr]);
+        up(&data->update_lock);
+        return count;
+}
+
+static ssize_t set_fan_div(struct device *dev, struct device_attribute *attr,
+                const char *buf, size_t count)
+{
+        struct i2c_client *client = to_i2c_client(dev);
+        struct vt8231_data *data = i2c_get_clientdata(client);
+        struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
+        unsigned long val = simple_strtoul(buf, NULL, 10);
+        int nr = sensor_attr->index;
+        int old = vt8231_read_value(client, VT8231_REG_FANDIV);
+        long min = FAN_FROM_REG(data->fan_min[nr],
+                                 DIV_FROM_REG(data->fan_div[nr]));
+
+        down(&data->update_lock);
+        switch (val) {
+        case 1: data->fan_div[nr] = 0; break;
+        case 2: data->fan_div[nr] = 1; break;
+        case 4: data->fan_div[nr] = 2; break;
+        case 8: data->fan_div[nr] = 3; break;
+        default:
+                dev_err(&client->dev, "fan_div value %ld not supported."
+                        "Choose one of 1, 2, 4 or 8!\n", val);
+                up(&data->update_lock);
+                return -EINVAL;
+        }
+
+        /* Correct the fan minimum speed */
+        data->fan_min[nr] = FAN_TO_REG(min, DIV_FROM_REG(data->fan_div[nr]));
+        vt8231_write_value(client, VT8231_REG_FAN_MIN(nr), data->fan_min[nr]);
+
+        old = (old & 0x0f) | (data->fan_div[1] << 6) | (data->fan_div[0] << 4);
+        vt8231_write_value(client, VT8231_REG_FANDIV, old);
+        up(&data->update_lock);
+        return count;
+}
+
+
+#define define_fan_sysfs(offset)                                        \
+static SENSOR_DEVICE_ATTR(fan##offset##_input, S_IRUGO,                 \
+                show_fan, NULL, offset - 1);                            \
+static SENSOR_DEVICE_ATTR(fan##offset##_div, S_IRUGO | S_IWUSR,         \
+                show_fan_div, set_fan_div, offset - 1);                 \
+static SENSOR_DEVICE_ATTR(fan##offset##_min, S_IRUGO | S_IWUSR,         \
+                show_fan_min, set_fan_min, offset - 1)
+
+define_fan_sysfs(1);
+define_fan_sysfs(2);
+
+/* Alarms */
+static ssize_t show_alarms(struct device *dev, struct device_attribute *attr,
+                           char *buf)
+{
+        struct vt8231_data *data = vt8231_update_device(dev);
+        return sprintf(buf, "%d\n", data->alarms);
+}
+
+static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
+
+static struct i2c_driver vt8231_driver = {
+        .owner          = THIS_MODULE,
+        .name           = "vt8231",
+        .attach_adapter = vt8231_detect,
+        .detach_client  = vt8231_detach_client,
+};
+
+static struct pci_device_id vt8231_pci_ids[] = {
+        { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8231_4) },
+        { 0, }
+};
+
+MODULE_DEVICE_TABLE(pci, vt8231_pci_ids);
+
+static int __devinit vt8231_pci_probe(struct pci_dev *dev,
+                                      const struct pci_device_id *id);
+
+static struct pci_driver vt8231_pci_driver = {
+        .name           = "vt8231",
+        .id_table       = vt8231_pci_ids,
+        .probe          = vt8231_pci_probe,
+};
+
+int vt8231_detect(struct i2c_adapter *adapter)
+{
+        struct i2c_client *client;
+        struct vt8231_data *data;
+        int err = 0, i;
+        u16 val;
+
+        /* 8231 requires multiple of 256 */
+        if (force_addr) {
+                isa_address = force_addr & 0xFF00;
+                dev_warn(&adapter->dev, "forcing ISA address 0x%04X\n",
+                                 isa_address);
+                if (PCIBIOS_SUCCESSFUL != pci_write_config_word(s_bridge,
+                                                VT8231_BASE_REG, isa_address))
+                        return -ENODEV;
+        }
+
+        if (PCIBIOS_SUCCESSFUL !=
+                pci_read_config_word(s_bridge, VT8231_ENABLE_REG, &val))
+                return -ENODEV;
+
+        if (!(val & 0x0001)) {
+                dev_warn(&adapter->dev, "enabling sensors\n");
+                if (PCIBIOS_SUCCESSFUL !=
+                        pci_write_config_word(s_bridge, VT8231_ENABLE_REG,
+                                                          val | 0x0001))
+                        return -ENODEV;
+        }
+
+        /* Reserve the ISA region */
+        if (!request_region(isa_address, VT8231_EXTENT,
+                            vt8231_pci_driver.name)) {
+                dev_err(&adapter->dev, "region 0x%x already in use!\n",
+                           isa_address);
+                return -ENODEV;
+        }
+
+        if (!(data = kzalloc(sizeof(struct vt8231_data), GFP_KERNEL))) {
+                err = -ENOMEM;
+                goto exit_release;
+        }
+
+        client = &data->client;
+        i2c_set_clientdata(client, data);
+        client->addr = isa_address;
+        client->adapter = adapter;
+        client->driver = &vt8231_driver;
+        client->dev.parent = &adapter->dev;
+
+        /* Fill in the remaining client fields and put into the global list */
+        strlcpy(client->name, "vt8231", I2C_NAME_SIZE);
+
+        init_MUTEX(&data->update_lock);
+
+        /* Tell the I2C layer a new client has arrived */
+        if ((err = i2c_attach_client(client)))
+                goto exit_free;
+
+        vt8231_init_client(client);
+
+        /* Register sysfs hooks */
+        data->class_dev = hwmon_device_register(&client->dev);
+        if (IS_ERR(data->class_dev)) {
+                err = PTR_ERR(data->class_dev);
+                goto exit_detach;
+        }
+
+        /* Must update device information to find out the config field */
+        data->uch_config = vt8231_read_value(client, VT8231_REG_UCH_CONFIG);
+
+        for (i = 0; i < ARRAY_SIZE(cfg_info_temp); i++) {
+                if (ISTEMP(i, data->uch_config)) {
+                        device_create_file(&client->dev,
+                                           cfg_info_temp[i].input);
+                        device_create_file(&client->dev, cfg_info_temp[i].max);
+                        device_create_file(&client->dev, cfg_info_temp[i].min);
+                }
+        }
+
+        for (i = 0; i < ARRAY_SIZE(cfg_info_volt); i++) {
+                if (ISVOLT(i, data->uch_config)) {
+                        device_create_file(&client->dev,
+                                           cfg_info_volt[i].input);
+                        device_create_file(&client->dev, cfg_info_volt[i].max);
+                        device_create_file(&client->dev, cfg_info_volt[i].min);
+                }
+        }
+
+        device_create_file(&client->dev, &sensor_dev_attr_fan1_input.dev_attr);
+        device_create_file(&client->dev, &sensor_dev_attr_fan2_input.dev_attr);
+        device_create_file(&client->dev, &sensor_dev_attr_fan1_min.dev_attr);
+        device_create_file(&client->dev, &sensor_dev_attr_fan2_min.dev_attr);
+        device_create_file(&client->dev, &sensor_dev_attr_fan1_div.dev_attr);
+        device_create_file(&client->dev, &sensor_dev_attr_fan2_div.dev_attr);
+
+        device_create_file(&client->dev, &dev_attr_alarms);
+        return 0;
+
+exit_detach:
+        i2c_detach_client(client);
+exit_free:
+        kfree(data);
+exit_release:
+        release_region(isa_address, VT8231_EXTENT);
+        return err;
+}
+
+static int vt8231_detach_client(struct i2c_client *client)
+{
+        struct vt8231_data *data = i2c_get_clientdata(client);
+        int err;
+
+        hwmon_device_unregister(data->class_dev);
+
+        if ((err = i2c_detach_client(client))) {
+                return err;
+        }
+
+        release_region(client->addr, VT8231_EXTENT);
+        kfree(data);
+
+        return 0;
+}
+
+static void vt8231_init_client(struct i2c_client *client)
+{
+        vt8231_write_value(client, VT8231_REG_TEMP1_CONFIG, 0);
+        vt8231_write_value(client, VT8231_REG_TEMP2_CONFIG, 0);
+}
+
+static struct vt8231_data *vt8231_update_device(struct device *dev)
+{
+        struct i2c_client *client = to_i2c_client(dev);
+        struct vt8231_data *data = i2c_get_clientdata(client);
+        int i;
+        u16 low;
+
+        down(&data->update_lock);
+
+        if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
+            || !data->valid) {
+                for (i = 0; i < 6; i++) {
+                        if (ISVOLT(i, data->uch_config)) {
+                                data->in[i] = vt8231_read_value(client,
+                                                regvolt[i]);
+                                data->in_min[i] = vt8231_read_value(client,
+                                                regvoltmin[i]);
+                                data->in_max[i] = vt8231_read_value(client,
+                                                regvoltmax[i]);
+                        }
+                }
+                for (i = 0; i < 2; i++) {
+                        data->fan[i] = vt8231_read_value(client,
+                                                VT8231_REG_FAN(i));
+                        data->fan_min[i] = vt8231_read_value(client,
+                                                VT8231_REG_FAN_MIN(i));
+                }
+
+                low = vt8231_read_value(client, VT8231_REG_TEMP_LOW01);
+                low = (low >> 6) | ((low & 0x30) >> 2)
+                    | (vt8231_read_value(client, VT8231_REG_TEMP_LOW25) << 4);
+                for (i = 0; i < 6; i++) {
+                        if (ISTEMP(i, data->uch_config)) {
+                                data->temp[i] = (vt8231_read_value(client,
+                                                       regtemp[i]) << 2)
+                                                | ((low >> (2 * i)) & 0x03);
+                                data->temp_max[i] = vt8231_read_value(client,
+                                                      regtempmax[i]);
+                                data->temp_min[i] = vt8231_read_value(client,
+                                                      regtempmin[i]);
+                        }
+                }
+
+                i = vt8231_read_value(client, VT8231_REG_FANDIV);
+                data->fan_div[0] = (i >> 4) & 0x03;
+                data->fan_div[1] = i >> 6;
+                data->alarms = vt8231_read_value(client, VT8231_REG_ALARM1) |
+                        (vt8231_read_value(client, VT8231_REG_ALARM2) << 8);
+
+                /* Set alarm flags correctly */
+                if (!data->fan[0] && data->fan_min[0]) {
+                        data->alarms |= 0x40;
+                } else if (data->fan[0] && !data->fan_min[0]) {
+                        data->alarms &= ~0x40;
+                }
+
+                if (!data->fan[1] && data->fan_min[1]) {
+                        data->alarms |= 0x80;
+                } else if (data->fan[1] && !data->fan_min[1]) {
+                        data->alarms &= ~0x80;
+                }
+
+                data->last_updated = jiffies;
+                data->valid = 1;
+        }
+
+        up(&data->update_lock);
+
+        return data;
+}
+
+static int __devinit vt8231_pci_probe(struct pci_dev *dev,
+                                const struct pci_device_id *id)
+{
+        u16 val;
+
+        if (PCIBIOS_SUCCESSFUL != pci_read_config_word(dev, VT8231_BASE_REG,
+                                                        &val))
+                return -ENODEV;
+
+        isa_address = val & ~(VT8231_EXTENT - 1);
+        if (isa_address == 0 && force_addr == 0) {
+                dev_err(&dev->dev, "base address not set -\
+                                 upgrade BIOS or use force_addr=0xaddr\n");
+                return -ENODEV;
+        }
+
+        s_bridge = pci_dev_get(dev);
+
+        if (i2c_isa_add_driver(&vt8231_driver)) {
+                pci_dev_put(s_bridge);
+                s_bridge = NULL;
+        }
+
+        /* Always return failure here.  This is to allow other drivers to bind
+         * to this pci device.  We don't really want to have control over the
+         * pci device, we only wanted to read as few register values from it.
+         */
+        return -ENODEV;
+}
+
+static int __init sm_vt8231_init(void)
+{
+        return pci_module_init(&vt8231_pci_driver);
+}
+
+static void __exit sm_vt8231_exit(void)
+{
+        pci_unregister_driver(&vt8231_pci_driver);
+        if (s_bridge != NULL) {
+                i2c_isa_del_driver(&vt8231_driver);
+                pci_dev_put(s_bridge);
+                s_bridge = NULL;
+        }
+}
+
+MODULE_AUTHOR("Roger Lucas <roger@planbit.co.uk>");
+MODULE_DESCRIPTION("VT8231 sensors");
+MODULE_LICENSE("GPL");
+
+module_init(sm_vt8231_init);
+module_exit(sm_vt8231_exit);