root/lm-sensors/trunk/kernel/chips/lm90.c @ 2784

/*
 * lm90.c - Part of lm_sensors, Linux kernel modules for hardware
 *          monitoring
 * Copyright (C) 2003-2004  Jean Delvare <khali@linux-fr.org>
 *
 * Based on the lm83 driver. The LM90 is a sensor chip made by National
 * Semiconductor. It reports up to two temperatures (its own plus up to
 * one external one) with a 0.125 deg resolution (1 deg for local
 * temperature) and a 3-4 deg accuracy. Complete datasheet can be
 * obtained from National's website at:
 *   http://www.national.com/pf/LM/LM90.html
 *
 * This driver also supports the LM89 and LM99, two other sensor chips
 * made by National Semiconductor. Both have an increased remote
 * temperature measurement accuracy (1 degree), and the LM99
 * additionally shifts remote temperatures (measured and limits) by 16
 * degrees, which allows for higher temperatures measurement. The
 * driver doesn't handle it since it can be done easily in user-space.
 * Complete datasheets can be obtained from National's website at:
 *   http://www.national.com/pf/LM/LM89.html
 *   http://www.national.com/pf/LM/LM99.html
 * Note that there is no way to differenciate between both chips.
 *
 * This driver also supports the LM86, another sensor chip made by
 * National Semiconductor. It is exactly similar to the LM90 except it
 * has a higher accuracy.
 * Complete datasheet can be obtained from National's website at:
 *   http://www.national.com/pf/LM/LM86.html
 *
 * This driver also supports the ADM1032, a sensor chip made by Analog
 * Devices. That chip is similar to the LM90, with a few differences
 * that are not handled by this driver. Complete datasheet can be
 * obtained from Analog's website at:
 *   http://products.analog.com/products/info.asp?product=ADM1032
 * Among others, it has a higher accuracy than the LM90, much like the
 * LM86 does.
 *
 * This driver also supports the MAX6657 and MAX6658, sensor chips made
 * by Maxim. These chips are similar to the LM86. Complete datasheet
 * can be obtained at Maxim's website at:
 *   http://www.maxim-ic.com/quick_view2.cfm/qv_pk/2578
 * Note that there is no way to differenciate between both chips (but
 * no need either).
 *
 * Since the LM90 was the first chipset supported by this driver, most
 * comments will refer to this chipset, but are actually general and
 * concern all supported chipsets, unless mentioned otherwise.
 *
 * 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/slab.h>
#include <linux/i2c.h>
#include <linux/i2c-proc.h>
#include <linux/init.h>
#include "version.h"

#ifndef I2C_DRIVERID_LM90
#define I2C_DRIVERID_LM90       1042
#endif

/*
 * Addresses to scan
 * Address is fully defined internally and cannot be changed.
 * LM86, LM89, LM90, LM99, ADM1032, MAX6657 and MAX6658 have address 0x4c.
 * LM89-1, and LM99-1 have address 0x4d.
 */

static unsigned short normal_i2c[] = { 0x4c, 0x4d, SENSORS_I2C_END };
static unsigned short normal_i2c_range[] = { SENSORS_I2C_END };
static unsigned int normal_isa[] = { SENSORS_ISA_END };
static unsigned int normal_isa_range[] = { SENSORS_ISA_END };

/*
 * Insmod parameters
 */

SENSORS_INSMOD_5(lm90, adm1032, lm99, lm86, max6657);

/*
 * The LM90 registers
 */

#define LM90_REG_R_MAN_ID        0xFE
#define LM90_REG_R_CHIP_ID       0xFF
#define LM90_REG_R_CONFIG1       0x03
#define LM90_REG_W_CONFIG1       0x09
#define LM90_REG_R_CONFIG2       0xBF
#define LM90_REG_W_CONFIG2       0xBF
#define LM90_REG_R_CONVRATE      0x04
#define LM90_REG_W_CONVRATE      0x0A
#define LM90_REG_R_STATUS        0x02
#define LM90_REG_R_LOCAL_TEMP    0x00
#define LM90_REG_R_LOCAL_HIGH    0x05
#define LM90_REG_W_LOCAL_HIGH    0x0B
#define LM90_REG_R_LOCAL_LOW     0x06
#define LM90_REG_W_LOCAL_LOW     0x0C
#define LM90_REG_R_LOCAL_CRIT    0x20
#define LM90_REG_W_LOCAL_CRIT    0x20
#define LM90_REG_R_REMOTE_TEMPH  0x01
#define LM90_REG_R_REMOTE_TEMPL  0x10
#define LM90_REG_R_REMOTE_OFFSH  0x11
#define LM90_REG_W_REMOTE_OFFSH  0x11
#define LM90_REG_R_REMOTE_OFFSL  0x12
#define LM90_REG_W_REMOTE_OFFSL  0x12
#define LM90_REG_R_REMOTE_HIGHH  0x07
#define LM90_REG_W_REMOTE_HIGHH  0x0D
#define LM90_REG_R_REMOTE_HIGHL  0x13
#define LM90_REG_W_REMOTE_HIGHL  0x13
#define LM90_REG_R_REMOTE_LOWH   0x08
#define LM90_REG_W_REMOTE_LOWH   0x0E
#define LM90_REG_R_REMOTE_LOWL   0x14
#define LM90_REG_W_REMOTE_LOWL   0x14
#define LM90_REG_R_REMOTE_CRIT   0x19
#define LM90_REG_W_REMOTE_CRIT   0x19
#define LM90_REG_R_TCRIT_HYST    0x21
#define LM90_REG_W_TCRIT_HYST    0x21

/*
 * Conversions and various macros
 * For local temperatures and limits, critical limits and the hysteresis
 * value, the LM90 uses signed 8-bit values with LSB = 1 degree Celcius.
 * For remote temperatures and limits, it uses signed 11-bit values with
 * LSB = 0.125 degree Celcius, left-justified in 16-bit registers.
 */

#define TEMP1_FROM_REG(val)     (val)
#define TEMP1_TO_REG(val)       ((val) <= -128 ? -128 : \
                                 (val) >= 127 ? 127 : (val))
#define TEMP2_FROM_REG(val)     ((val) / 32 * 125 / 100)
#define TEMP2_TO_REG(val)       ((val) <= -1280 ? 0x8000 : \
                                 (val) >= 1270 ? 0x7FE0 : \
                                 ((val) * 100 / 125 * 32))
#define HYST_TO_REG(val)        ((val) <= 0 ? 0 : \
                                 (val) >= 31 ? 31 : (val))

/*
 * Functions declaration
 */

static int lm90_attach_adapter(struct i2c_adapter *adapter);
static int lm90_detect(struct i2c_adapter *adapter, int address,
        unsigned short flags, int kind);
static void lm90_init_client(struct i2c_client *client);
static int lm90_detach_client(struct i2c_client *client);
static void lm90_local_temp(struct i2c_client *client, int operation,
        int ctl_name, int *nrels_mag, long *results);
static void lm90_remote_temp(struct i2c_client *client, int operation,
        int ctl_name, int *nrels_mag, long *results);
static void lm90_local_tcrit(struct i2c_client *client, int operation,
        int ctl_name, int *nrels_mag, long *results);
static void lm90_remote_tcrit(struct i2c_client *client, int operation,
        int ctl_name, int *nrels_mag, long *results);
static void lm90_local_hyst(struct i2c_client *client, int operation,
        int ctl_name, int *nrels_mag, long *results);
static void lm90_remote_hyst(struct i2c_client *client, int operation,
        int ctl_name, int *nrels_mag, long *results);
static void lm90_alarms(struct i2c_client *client, int operation,
        int ctl_name, int *nrels_mag, long *results);

/*
 * Driver data (common to all clients)
 */

static struct i2c_driver lm90_driver = {
        .name           = "LM90/ADM1032 sensor driver",
        .id             = I2C_DRIVERID_LM90,
        .flags          = I2C_DF_NOTIFY,
        .attach_adapter = lm90_attach_adapter,
        .detach_client  = lm90_detach_client
};

/*
 * Client data (each client gets its own)
 */

struct lm90_data
{
        struct i2c_client client;
        int sysctl_id;

        struct semaphore update_lock;
        char valid; /* zero until following fields are valid */
        unsigned long last_updated; /* in jiffies */

        /* registers values */
        s8 local_temp, local_high, local_low;
        s16 remote_temp, remote_high, remote_low; /* combined */
        s8 local_crit, remote_crit;
        u8 hyst; /* linked to two sysctl files (hyst1 RW, hyst2 RO) */
        u8 alarms; /* bitvector */
};

/*
 * Proc entries
 * These files are created for each detected LM90.
 */

/* -- SENSORS SYSCTL START -- */

#define LM90_SYSCTL_LOCAL_TEMP    1200
#define LM90_SYSCTL_REMOTE_TEMP   1201
#define LM90_SYSCTL_LOCAL_TCRIT   1204
#define LM90_SYSCTL_REMOTE_TCRIT  1205
#define LM90_SYSCTL_LOCAL_HYST    1207
#define LM90_SYSCTL_REMOTE_HYST   1208
#define LM90_SYSCTL_ALARMS        1210

#define LM90_ALARM_LOCAL_HIGH     0x40
#define LM90_ALARM_LOCAL_LOW      0x20
#define LM90_ALARM_LOCAL_CRIT     0x01
#define LM90_ALARM_REMOTE_HIGH    0x10
#define LM90_ALARM_REMOTE_LOW     0x08
#define LM90_ALARM_REMOTE_CRIT    0x02
#define LM90_ALARM_REMOTE_OPEN    0x04

/* -- SENSORS SYSCTL END -- */


static ctl_table lm90_dir_table_template[] =
{
        {LM90_SYSCTL_LOCAL_TEMP, "temp1", NULL, 0, 0644, NULL,
         &i2c_proc_real, &i2c_sysctl_real, NULL, &lm90_local_temp},
        {LM90_SYSCTL_REMOTE_TEMP, "temp2", NULL, 0, 0644, NULL,
         &i2c_proc_real, &i2c_sysctl_real, NULL, &lm90_remote_temp},
        {LM90_SYSCTL_LOCAL_TCRIT, "tcrit1", NULL, 0, 0644, NULL,
         &i2c_proc_real, &i2c_sysctl_real, NULL, &lm90_local_tcrit},
        {LM90_SYSCTL_REMOTE_TCRIT, "tcrit2", NULL, 0, 0644, NULL,
         &i2c_proc_real, &i2c_sysctl_real, NULL, &lm90_remote_tcrit},
        {LM90_SYSCTL_LOCAL_HYST, "hyst1", NULL, 0, 0644, NULL,
         &i2c_proc_real, &i2c_sysctl_real, NULL, &lm90_local_hyst},
        {LM90_SYSCTL_REMOTE_HYST, "hyst2", NULL, 0, 0444, NULL,
         &i2c_proc_real, &i2c_sysctl_real, NULL, &lm90_remote_hyst},
        {LM90_SYSCTL_ALARMS, "alarms", NULL, 0, 0444, NULL,
         &i2c_proc_real, &i2c_sysctl_real, NULL, &lm90_alarms},
        {0}
};

/*
 * Internal variables
 */

static int lm90_id = 0;

/*
 * Real code
 */

static int lm90_attach_adapter(struct i2c_adapter *adapter)
{
        return i2c_detect(adapter, &addr_data, lm90_detect);
}

/*
 * The following function does more than just detection. If detection
 * succeeds, it also registers the new chip.
 */
static int lm90_detect(struct i2c_adapter *adapter, int address,
        unsigned short flags, int kind)
{
        struct i2c_client *new_client;
        struct lm90_data *data;
        int err = 0;
        const char *type_name = "";
        const char *client_name = "";

#ifdef DEBUG
        if (i2c_is_isa_adapter(adapter))
        {
                printk("lm90.o: Called for an ISA bus adapter, aborting.\n");
                return 0;
        }
#endif

        if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
        {
#ifdef DEBUG
                printk("lm90.o: I2C bus doesn't support byte read mode, "
                       "skipping.\n");
#endif
                return 0;
        }

        if (!(data = kmalloc(sizeof(struct lm90_data), GFP_KERNEL)))
        {
                printk("lm90.o: Out of memory in lm90_detect (new_client).\n");
                return -ENOMEM;
        }

        /*
         * The common I2C client data is placed right before the
         * LM90-specific data. The LM90-specific data is pointed to by the
         * data field from the I2C client data.
         */

        new_client = &data->client;
        new_client->addr = address;
        new_client->data = data;
        new_client->adapter = adapter;
        new_client->driver = &lm90_driver;
        new_client->flags = 0;

        /*
         * Now we do the remaining detection. A negative kind means that
         * the driver was loaded with no force parameter (default), so we
         * must both detect and identify the chip. A zero kind means that
         * the driver was loaded with the force parameter, the detection
         * step shall be skipped. A positive kind means that the driver
         * was loaded with the force parameter and a given kind of chip is
         * requested, so both the detection and the identification steps
         * are skipped.
         */

        /* Default to an LM90 if forced */
        if (kind == 0)
                kind = lm90;

        if (kind < 0) /* detection and identification */
        {
                u8 man_id, chip_id, reg_config1, reg_convrate;

                man_id = i2c_smbus_read_byte_data(new_client,
                        LM90_REG_R_MAN_ID);
                chip_id = i2c_smbus_read_byte_data(new_client,
                        LM90_REG_R_CHIP_ID);
                reg_config1 = i2c_smbus_read_byte_data(new_client,
                        LM90_REG_R_CONFIG1);
                reg_convrate = i2c_smbus_read_byte_data(new_client,
                        LM90_REG_R_CONVRATE);
                
                if (man_id == 0x01) /* National Semiconductor */
                {
                        u8 reg_config2;

                        reg_config2 = i2c_smbus_read_byte_data(new_client,
                                LM90_REG_R_CONFIG2);

                        if ((reg_config1 & 0x2A) == 0x00
                         && (reg_config2 & 0xF8) == 0x00
                         && reg_convrate <= 0x09)
                        {
                                if (address == 0x4C
                                 && (chip_id & 0xF0) == 0x20) /* LM90 */
                                        kind = lm90;
                                else if ((chip_id & 0xF0) == 0x30) /* LM89/LM99 */
                                        kind = lm99;
                                else if (address == 0x4C
                                 && (chip_id & 0xF0) == 0x10) /* LM86 */
                                        kind = lm99;
                        }
                }
                else if (man_id == 0x41) /* Analog Devices */
                {
                        if (address == 0x4C
                         && (chip_id & 0xF0) == 0x40 /* ADM1032 */
                         && (reg_config1 & 0x3F) == 0x00
                         && reg_convrate <= 0x0A)
                                kind = adm1032;
                }
                else if (man_id == 0x4D) /* Maxim */
                {
                        if (address == 0x4C
                         && (reg_config1 & 0x1F) == 0
                         && reg_convrate <= 0x09)
                                kind = max6657;
                }
        }

        if (kind <= 0) /* identification failed */
        {
                printk("lm90.o: Unsupported chip.\n");
                goto ERROR1;
        }

        if (kind == lm90)
        {
                type_name = "lm90";
                client_name = "LM90 chip";
        }
        else if (kind == adm1032)
        {
                type_name = "adm1032";
                client_name = "ADM1032 chip";
        }
        else if (kind == lm99)
        {
                type_name = "lm99";
                client_name = "LM99 chip";
        }
        else if (kind == lm86)
        {
                type_name = "lm86";
                client_name = "LM86 chip";
        }
        else if (kind == max6657)
        {
                type_name = "max6657";
                client_name = "MAX6657 chip";
        }
        else
        {
                printk("lm90.o: Unknown kind %d.\n", kind);
                goto ERROR1;
        }

        /*
         * OK, we got a valid chip so we can fill in the remaining client
         * fields.
         */

        strcpy(new_client->name, client_name);
        new_client->id = lm90_id++;
        data->valid = 0;
        init_MUTEX(&data->update_lock);

        /*
         * Tell the I2C layer a new client has arrived.
         */

        if ((err = i2c_attach_client(new_client)))
        {
#ifdef DEBUG
                printk("lm90.o: Failed attaching client.\n");
#endif
                goto ERROR1;
        }

        /*
         * Register a new directory entry.
         */

        if ((err = i2c_register_entry(new_client, type_name,
             lm90_dir_table_template, THIS_MODULE)) < 0)
        {
#ifdef DEBUG
                printk("lm90.o: Failed registering directory entry.\n");
#endif
                goto ERROR2;
        }
        data->sysctl_id = err;

        /*
         * Initialize the LM90 chip.
         */

        lm90_init_client(new_client);
        return 0;

        ERROR2:
        i2c_detach_client(new_client);
        ERROR1:
        kfree(data);
        return err;
}

static void lm90_init_client(struct i2c_client *client)
{
        u8 config;

        /*
         * Start the conversions.
         */

        i2c_smbus_write_byte_data(client, LM90_REG_W_CONVRATE,
                5); /* 2 Hz */
        config = i2c_smbus_read_byte_data(client, LM90_REG_R_CONFIG1);
        if (config & 0x40)
                i2c_smbus_write_byte_data(client, LM90_REG_W_CONFIG1,
                        config & 0xBF); /* run */
}


static int lm90_detach_client(struct i2c_client *client)
{
        int err;

        i2c_deregister_entry(((struct lm90_data *) (client->data))->sysctl_id);
        if ((err = i2c_detach_client(client)))
        {
                printk("lm90.o: Client deregistration failed, client not "
                       "detached.\n");
                return err;
        }

        kfree(client->data);
        return 0;
}

static void lm90_update_client(struct i2c_client *client)
{
        struct lm90_data *data = client->data;

        down(&data->update_lock);

        if ((jiffies - data->last_updated > HZ * 2) ||
            (jiffies < data->last_updated) || !data->valid)
        {
                u8 oldh, newh;
#ifdef DEBUG
                printk("lm90.o: Updating data.\n");
#endif

                data->local_temp =
                        i2c_smbus_read_byte_data(client, LM90_REG_R_LOCAL_TEMP);
                data->local_high =
                        i2c_smbus_read_byte_data(client, LM90_REG_R_LOCAL_HIGH);
                data->local_low =
                        i2c_smbus_read_byte_data(client, LM90_REG_R_LOCAL_LOW);
                data->local_crit =
                        i2c_smbus_read_byte_data(client, LM90_REG_R_LOCAL_CRIT);

                /*
                 * There is a trick here. We have to read two registers to
                 * have the remote sensor temperature, but we have to beware
                 * a conversion could occur inbetween the readings. The
                 * datasheet says we should either use the one-shot
                 * conversion register, which we don't want to do (disables
                 * hardware monitoring) or monitor the busy bit, which is
                 * impossible (we can't read the values and monitor that bit
                 * at the exact same time). So the solution used here is to
                 * read the high byte once, then the low byte, then the high
                 * byte again. If the new high byte matches the old one,
                 * then we have a valid reading. Else we have to read the low
                 * byte again, and now we believe we have a correct reading.
                 */

                oldh =
                        i2c_smbus_read_byte_data(client, LM90_REG_R_REMOTE_TEMPH);
                data->remote_temp =
                        i2c_smbus_read_byte_data(client, LM90_REG_R_REMOTE_TEMPL);
                newh =
                        i2c_smbus_read_byte_data(client, LM90_REG_R_REMOTE_TEMPH);
                if (newh != oldh)
                {
                        data->remote_temp =
                                i2c_smbus_read_byte_data(client, LM90_REG_R_REMOTE_TEMPL);
#ifdef DEBUG
                        oldh = /* actually newer */
                                i2c_smbus_read_byte_data(client, LM90_REG_R_REMOTE_TEMPH);
                        if (newh != oldh)
                                printk("lm90.o: Remote temperature may be wrong.\n");
#endif
                }
                data->remote_temp |= (newh << 8);
                data->remote_high =
                        (i2c_smbus_read_byte_data(client, LM90_REG_R_REMOTE_HIGHH) << 8)
                        + i2c_smbus_read_byte_data(client, LM90_REG_R_REMOTE_HIGHL);
                data->remote_low =
                        (i2c_smbus_read_byte_data(client, LM90_REG_R_REMOTE_LOWH) << 8)
                        + i2c_smbus_read_byte_data(client, LM90_REG_R_REMOTE_LOWL);
                data->remote_crit =
                        i2c_smbus_read_byte_data(client, LM90_REG_R_REMOTE_CRIT);

                data->hyst =
                        i2c_smbus_read_byte_data(client, LM90_REG_R_TCRIT_HYST);
                data->alarms =
                        i2c_smbus_read_byte_data(client, LM90_REG_R_STATUS);

                data->last_updated = jiffies;
                data->valid = 1;
        }

        up(&data->update_lock);
}

static void lm90_local_temp(struct i2c_client *client, int operation,
        int ctl_name, int *nrels_mag, long *results)
{
        struct lm90_data *data = client->data;

        if (operation == SENSORS_PROC_REAL_INFO)
                *nrels_mag = 0; /* magnitude */
        else if (operation == SENSORS_PROC_REAL_READ)
        {
                lm90_update_client(client);
                results[0] = TEMP1_FROM_REG(data->local_high);
                results[1] = TEMP1_FROM_REG(data->local_low);
                results[2] = TEMP1_FROM_REG(data->local_temp);
                *nrels_mag = 3;
        }
        else if (operation == SENSORS_PROC_REAL_WRITE)
        {
                if (*nrels_mag >= 1)
                {
                        data->local_high = TEMP1_TO_REG(results[0]);
                        i2c_smbus_write_byte_data(client, LM90_REG_W_LOCAL_HIGH,
                                data->local_high);
                }
                if (*nrels_mag >= 2)
                {
                        data->local_low = TEMP1_TO_REG(results[1]);
                        i2c_smbus_write_byte_data(client, LM90_REG_W_LOCAL_LOW,
                                data->local_low);
                }
        }
}

static void lm90_remote_temp(struct i2c_client *client, int operation,
        int ctl_name, int *nrels_mag, long *results)
{
        struct lm90_data *data = client->data;

        if (operation == SENSORS_PROC_REAL_INFO)
                *nrels_mag = 1; /* magnitude */
        else if (operation == SENSORS_PROC_REAL_READ)
        {
                lm90_update_client(client);
                results[0] = TEMP2_FROM_REG(data->remote_high);
                results[1] = TEMP2_FROM_REG(data->remote_low);
                results[2] = TEMP2_FROM_REG(data->remote_temp);
                *nrels_mag = 3;
        }
        else if (operation == SENSORS_PROC_REAL_WRITE)
        {
                if (*nrels_mag >= 1)
                {
                        data->remote_high = TEMP2_TO_REG(results[0]);
                        i2c_smbus_write_byte_data(client, LM90_REG_W_REMOTE_HIGHH,
                                data->remote_high >> 8);
                        i2c_smbus_write_byte_data(client, LM90_REG_W_REMOTE_HIGHL,
                                data->remote_high & 0xFF);
                }
                if (*nrels_mag >= 2)
                {
                        data->remote_low = TEMP2_TO_REG(results[1]);
                        i2c_smbus_write_byte_data(client, LM90_REG_W_REMOTE_LOWH,
                                data->remote_low >> 8);
                        i2c_smbus_write_byte_data(client, LM90_REG_W_REMOTE_LOWL,
                                data->remote_low & 0xFF);
                }
        }
}

static void lm90_local_tcrit(struct i2c_client *client, int operation,
        int ctl_name, int *nrels_mag, long *results)
{
        struct lm90_data *data = client->data;

        if (operation == SENSORS_PROC_REAL_INFO)
                *nrels_mag = 0; /* magnitude */
        else if (operation == SENSORS_PROC_REAL_READ)
        {
                lm90_update_client(client);
                results[0] = TEMP1_FROM_REG(data->local_crit);
                *nrels_mag = 1;
        }
        else if (operation == SENSORS_PROC_REAL_WRITE)
        {
                if (*nrels_mag >= 1)
                {
                        data->local_crit = TEMP1_TO_REG(results[0]);
                        i2c_smbus_write_byte_data(client, LM90_REG_W_LOCAL_CRIT,
                                data->local_crit);
                }
        }
}

static void lm90_remote_tcrit(struct i2c_client *client, int operation,
        int ctl_name, int *nrels_mag, long *results)
{
        struct lm90_data *data = client->data;

        if (operation == SENSORS_PROC_REAL_INFO)
                *nrels_mag = 0; /* magnitude */
        else if (operation == SENSORS_PROC_REAL_READ)
        {
                lm90_update_client(client);
                results[0] = TEMP1_FROM_REG(data->remote_crit);
                *nrels_mag = 1;
        }
        else if (operation == SENSORS_PROC_REAL_WRITE)
        {
                if (*nrels_mag >= 1)
                {
                        data->remote_crit = TEMP1_TO_REG(results[0]);
                        i2c_smbus_write_byte_data(client, LM90_REG_W_REMOTE_CRIT,
                                data->remote_crit);
                }
        }
}

/*
 * One quick note about hysteresis. Internally, the hysteresis value
 * is held in a single register by the LM90, as a relative value.
 * This relative value applies to both the local critical temperature
 * and the remote critical temperature. Since all temperatures exported
 * through procfs have to be absolute, we have to do some conversions.
 * The solution retained here is to export two absolute values, one for
 * each critical temperature. In order not to confuse the users too
 * much, only one file is writable. Would we fail to do so, users
 * would probably attempt to write to both files, as if they were
 * independant, and since they aren't, they wouldn't understand why
 * setting one affects the other one (and would probably claim there's
 * a bug in the driver).
 */

static void lm90_local_hyst(struct i2c_client *client, int operation,
        int ctl_name, int *nrels_mag, long *results)
{
        struct lm90_data *data = client->data;

        if (operation == SENSORS_PROC_REAL_INFO)
                *nrels_mag = 0; /* magnitude */
        else if (operation == SENSORS_PROC_REAL_READ)
        {
                lm90_update_client(client);
                results[0] = TEMP1_FROM_REG(data->local_crit) -
                        TEMP1_FROM_REG(data->hyst);
                *nrels_mag = 1;
        }
        else if (operation == SENSORS_PROC_REAL_WRITE)
        {
                if (*nrels_mag >= 1)
                {
                        data->hyst = HYST_TO_REG(data->local_crit - results[0]);
                        i2c_smbus_write_byte_data(client, LM90_REG_W_TCRIT_HYST,
                                data->hyst);
                }
        }
}

static void lm90_remote_hyst(struct i2c_client *client, int operation,
        int ctl_name, int *nrels_mag, long *results)
{
        struct lm90_data *data = client->data;

        if (operation == SENSORS_PROC_REAL_INFO)
                *nrels_mag = 0; /* magnitude */
        else if (operation == SENSORS_PROC_REAL_READ)
        {
                lm90_update_client(client);
                results[0] = TEMP1_FROM_REG(data->remote_crit) -
                        TEMP1_FROM_REG(data->hyst);
                *nrels_mag = 1;
        }
}

static void lm90_alarms(struct i2c_client *client, int operation,
        int ctl_name, int *nrels_mag, long *results)
{
        struct lm90_data *data = client->data;

        if (operation == SENSORS_PROC_REAL_INFO)
                *nrels_mag = 0; /* magnitude */
        else if (operation == SENSORS_PROC_REAL_READ)
        {
                lm90_update_client(client);
                results[0] = data->alarms;
                *nrels_mag = 1;
        }
}

static int __init sm_lm90_init(void)
{
        printk(KERN_INFO "lm90.o version %s (%s)\n", LM_VERSION, LM_DATE);
        return i2c_add_driver(&lm90_driver);
}

static void __exit sm_lm90_exit(void)
{
        i2c_del_driver(&lm90_driver);
}

MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
MODULE_DESCRIPTION("LM90/ADM1032 sensor driver");
MODULE_LICENSE("GPL");

module_init(sm_lm90_init);
module_exit(sm_lm90_exit);