root/lm-sensors/trunk/kernel/chips/lm75.c @ 2867

/*
    lm75.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/slab.h>
#include <linux/i2c.h>
#include <linux/i2c-proc.h>
#include <linux/init.h>
#include "version.h"
#include "lm75.h"

/* Addresses to scan */
static unsigned short normal_i2c[] = { SENSORS_I2C_END };
static unsigned short normal_i2c_range[] = { 0x48, 0x4f, SENSORS_I2C_END };
static unsigned int normal_isa[] = { SENSORS_ISA_END };
static unsigned int normal_isa_range[] = { SENSORS_ISA_END };

/* Insmod parameters */
SENSORS_INSMOD_1(lm75);

/* Many LM75 constants specified below */

/* The LM75 registers */
#define LM75_REG_TEMP 0x00
#define LM75_REG_CONF 0x01
#define LM75_REG_TEMP_HYST 0x02
#define LM75_REG_TEMP_OS 0x03

/* Each client has this additional data */
struct lm75_data {
        struct i2c_client client;
        int sysctl_id;

        struct semaphore update_lock;
        char valid;             /* !=0 if following fields are valid */
        unsigned long last_updated;     /* In jiffies */

        u16 temp, temp_os, temp_hyst;   /* Register values */
};

static int lm75_attach_adapter(struct i2c_adapter *adapter);
static int lm75_detect(struct i2c_adapter *adapter, int address,
                       unsigned short flags, int kind);
static void lm75_init_client(struct i2c_client *client);
static int lm75_detach_client(struct i2c_client *client);

static int lm75_read_value(struct i2c_client *client, u8 reg);
static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value);
static void lm75_temp(struct i2c_client *client, int operation,
                      int ctl_name, int *nrels_mag, long *results);
static void lm75_update_client(struct i2c_client *client);


/* This is the driver that will be inserted */
static struct i2c_driver lm75_driver = {
        .name           = "LM75 sensor chip driver",
        .id             = I2C_DRIVERID_LM75,
        .flags          = I2C_DF_NOTIFY,
        .attach_adapter = lm75_attach_adapter,
        .detach_client  = lm75_detach_client,
};

/* -- SENSORS SYSCTL START -- */

#define LM75_SYSCTL_TEMP 1200   /* Degrees Celcius * 10 */

/* -- SENSORS SYSCTL END -- */

/* These files are created for each detected LM75. This is just a template;
   though at first sight, you might think we could use a statically
   allocated list, we need some way to get back to the parent - which
   is done through one of the 'extra' fields which are initialized
   when a new copy is allocated. */
static ctl_table lm75_dir_table_template[] = {
        {LM75_SYSCTL_TEMP, "temp", NULL, 0, 0644, NULL, &i2c_proc_real,
         &i2c_sysctl_real, NULL, &lm75_temp},
        {0}
};

static int lm75_attach_adapter(struct i2c_adapter *adapter)
{
        return i2c_detect(adapter, &addr_data, lm75_detect);
}

/* This function is called by i2c_detect */
int lm75_detect(struct i2c_adapter *adapter, int address,
                unsigned short flags, int kind)
{
        int i;
        struct i2c_client *new_client;
        struct lm75_data *data;
        int err = 0;
        const char *type_name, *client_name;

        /* Make sure we aren't probing the ISA bus!! This is just a safety check
           at this moment; i2c_detect really won't call us. */
#ifdef DEBUG
        if (i2c_is_isa_adapter(adapter)) {
                printk
                    ("lm75.o: lm75_detect called for an ISA bus adapter?!?\n");
                return 0;
        }
#endif

        if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
                                     I2C_FUNC_SMBUS_WORD_DATA))
                    goto error0;

        /* 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 lm75_{read,write}_value. */
        if (!(data = kmalloc(sizeof(struct lm75_data), GFP_KERNEL))) {
                err = -ENOMEM;
                goto error0;
        }

        new_client = &data->client;
        new_client->addr = address;
        new_client->data = data;
        new_client->adapter = adapter;
        new_client->driver = &lm75_driver;
        new_client->flags = 0;

        /* Now, we do the remaining detection. There is no identification-
           dedicated register so we have to rely on several tricks:
           unused bits, registers cycling over 8-address boundaries,
           addresses 0x04-0x07 returning the last read value.
           The cycling+unused addresses combination is not tested,
           since it would significantly slow the detection down and would
           hardly add any value. */
        if (kind < 0) {
                int cur, conf, hyst, os;

                /* Unused addresses */
                cur = i2c_smbus_read_word_data(new_client, 0);
                conf = i2c_smbus_read_byte_data(new_client, 1);
                hyst = i2c_smbus_read_word_data(new_client, 2);
                if (i2c_smbus_read_word_data(new_client, 4) != hyst
                 || i2c_smbus_read_word_data(new_client, 5) != hyst
                 || i2c_smbus_read_word_data(new_client, 6) != hyst
                 || i2c_smbus_read_word_data(new_client, 7) != hyst)
                        goto error1;
                os = i2c_smbus_read_word_data(new_client, 3);
                if (i2c_smbus_read_word_data(new_client, 4) != os
                 || i2c_smbus_read_word_data(new_client, 5) != os
                 || i2c_smbus_read_word_data(new_client, 6) != os
                 || i2c_smbus_read_word_data(new_client, 7) != os)
                        goto error1;

                /* Unused bits */
                if (conf & 0xe0)
                        goto error1;

                /* Addresses cycling */
                for (i = 8; i < 0xff; i += 8)
                        if (i2c_smbus_read_byte_data(new_client, i + 1) != conf
                         || i2c_smbus_read_word_data(new_client, i + 2) != hyst
                         || i2c_smbus_read_word_data(new_client, i + 3) != os)
                                goto error1;
        }

        /* Determine the chip type - only one kind supported! */
        if (kind <= 0)
                kind = lm75;

        if (kind == lm75) {
                type_name = "lm75";
                client_name = "LM75 chip";
        } else {
                pr_debug("lm75.o: Internal error: unknown kind (%d)?!?", kind);
                goto error1;
        }

        /* Fill in the remaining client fields and put it into the global list */
        strcpy(new_client->name, client_name);
        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 error3;

        /* Register a new directory entry with module sensors */
        if ((i = i2c_register_entry(new_client, type_name,
                                        lm75_dir_table_template,
                                        THIS_MODULE)) < 0) {
                err = i;
                goto error4;
        }
        data->sysctl_id = i;

        lm75_init_client(new_client);
        return 0;

/* OK, this is not exactly good programming practice, usually. But it is
   very code-efficient in this case. */

      error4:
        i2c_detach_client(new_client);
      error3:
      error1:
        kfree(data);
      error0:
        return err;
}

static int lm75_detach_client(struct i2c_client *client)
{
        struct lm75_data *data = client->data;

        i2c_deregister_entry(data->sysctl_id);
        i2c_detach_client(client);
        kfree(client->data);
        return 0;
}

/* All registers are word-sized, except for the configuration register.
   LM75 uses a high-byte first convention, which is exactly opposite to
   the usual practice. */
static int lm75_read_value(struct i2c_client *client, u8 reg)
{
        if (reg == LM75_REG_CONF)
                return i2c_smbus_read_byte_data(client, reg);
        else
                return swab16(i2c_smbus_read_word_data(client, reg));
}

/* All registers are word-sized, except for the configuration register.
   LM75 uses a high-byte first convention, which is exactly opposite to
   the usual practice. */
static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value)
{
        if (reg == LM75_REG_CONF)
                return i2c_smbus_write_byte_data(client, reg, value);
        else
                return i2c_smbus_write_word_data(client, reg, swab16(value));
}

static void lm75_init_client(struct i2c_client *client)
{
        /* Initialize the LM75 chip */
        lm75_write_value(client, LM75_REG_CONF, 0);
}

static void lm75_update_client(struct i2c_client *client)
{
        struct lm75_data *data = client->data;

        down(&data->update_lock);

        if ((jiffies - data->last_updated > HZ + HZ / 2) ||
            (jiffies < data->last_updated) || !data->valid) {
                pr_debug("Starting lm75 update\n");

                data->temp = lm75_read_value(client, LM75_REG_TEMP);
                data->temp_os = lm75_read_value(client, LM75_REG_TEMP_OS);
                data->temp_hyst =
                    lm75_read_value(client, LM75_REG_TEMP_HYST);
                data->last_updated = jiffies;
                data->valid = 1;
        }

        up(&data->update_lock);
}


void lm75_temp(struct i2c_client *client, int operation, int ctl_name,
               int *nrels_mag, long *results)
{
        struct lm75_data *data = client->data;
        if (operation == SENSORS_PROC_REAL_INFO)
                *nrels_mag = 1;
        else if (operation == SENSORS_PROC_REAL_READ) {
                lm75_update_client(client);
                results[0] = LM75_TEMP_FROM_REG(data->temp_os);
                results[1] = LM75_TEMP_FROM_REG(data->temp_hyst);
                results[2] = LM75_TEMP_FROM_REG(data->temp);
                *nrels_mag = 3;
        } else if (operation == SENSORS_PROC_REAL_WRITE) {
                if (*nrels_mag >= 1) {
                        data->temp_os = LM75_TEMP_TO_REG(results[0]);
                        lm75_write_value(client, LM75_REG_TEMP_OS,
                                         data->temp_os);
                }
                if (*nrels_mag >= 2) {
                        data->temp_hyst = LM75_TEMP_TO_REG(results[1]);
                        lm75_write_value(client, LM75_REG_TEMP_HYST,
                                         data->temp_hyst);
                }
        }
}

static int __init sm_lm75_init(void)
{
        printk(KERN_INFO "lm75.o version %s (%s)\n", LM_VERSION, LM_DATE);
        return i2c_add_driver(&lm75_driver);
}

static void __exit sm_lm75_exit(void)
{
        i2c_del_driver(&lm75_driver);
}

MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
MODULE_DESCRIPTION("LM75 driver");
MODULE_LICENSE("GPL");

module_init(sm_lm75_init);
module_exit(sm_lm75_exit);