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/*

    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.

*/

/* #define DEBUG 1 */

#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[] = { I2C_CLIENT_END };

static unsigned short normal_i2c_range[] = { 0x48, 0x4f, I2C_CLIENT_END };

static unsigned int normal_isa[] = { I2C_CLIENT_ISA_END };

static unsigned int normal_isa_range[] = { I2C_CLIENT_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

/* Conversions. Rounding and limit checking is only done on the TO_REG

   variants. Note that you should be a bit careful with which arguments

   these macros are called: arguments may be evaluated more than once.

   Fixing this is just not worth it. */

#define TEMP_FROM_REG(val)      ((((val & 0x7fff) >> 7) * 5) | ((val & 0x8000)?-256:0))

#define TEMP_TO_REG(val)        (SENSORS_LIMIT((val<0?(0x200+((val)/5))<<7:(((val) + 2) / 5) << 7),0,0xffff))

/* Initial values */

#define LM75_INIT_TEMP_OS       600

#define LM75_INIT_TEMP_HYST     500

/* Each client has this additional data */

struct lm75_data {

        struct semaphore        update_lock;

        char                    valid;          /* !=0 if following fields are valid */

        unsigned long           last_updated;   /* In jiffies */

        u16                     temp_input;     /* Register values */

        u16                     temp_max;

        u16                     temp_hyst;

};

static int lm75_attach_adapter(struct i2c_adapter *adapter);

static int lm75_detect(struct i2c_adapter *adapter, int address, 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_update_client(struct i2c_client *client);

/* This is the driver that will be inserted */

static struct i2c_driver lm75_driver = {

        .owner          = THIS_MODULE,

        .name           = "lm75",

        .id             = I2C_DRIVERID_LM75,

        .flags          = I2C_DF_NOTIFY,

        .attach_adapter = lm75_attach_adapter,

        .detach_client  = lm75_detach_client,

};

static int lm75_id = 0;

#define show(value)     \

static ssize_t show_##value(struct device *dev, char *buf)      \

{                                                               \

        struct i2c_client *client = to_i2c_client(dev);         \

        struct lm75_data *data = i2c_get_clientdata(client);    \

        int temp;                                               \

                                                                \

        lm75_update_client(client);                             \

        temp = TEMP_FROM_REG(data->value);                      \

        return sprintf(buf, "%d\n", temp * 100);                \

}

show(temp_max);

show(temp_hyst);

show(temp_input);

#define set(value, reg) \

static ssize_t set_##value(struct device *dev, const char *buf, size_t count)   \

{                                                               \

        struct i2c_client *client = to_i2c_client(dev);         \

        struct lm75_data *data = i2c_get_clientdata(client);    \

        int temp = simple_strtoul(buf, NULL, 10) / 100;         \

                                                                \

        data->value = TEMP_TO_REG(temp);                        \

        lm75_write_value(client, reg, data->value);             \

        return count;                                           \

}

set(temp_max, LM75_REG_TEMP_OS);

set(temp_hyst, LM75_REG_TEMP_HYST);

static DEVICE_ATTR(temp_max, S_IWUSR | S_IRUGO, show_temp_max, set_temp_max);

static DEVICE_ATTR(temp_min, S_IWUSR | S_IRUGO, show_temp_hyst, set_temp_hyst);

static DEVICE_ATTR(temp_input, S_IRUGO, show_temp_input, NULL);

static int lm75_attach_adapter(struct i2c_adapter *adapter)

{

        if (!(adapter->class & I2C_ADAP_CLASS_SMBUS))

                return 0;

        return i2c_detect(adapter, &addr_data, lm75_detect);

}

/* This function is called by i2c_detect */

static int lm75_detect(struct i2c_adapter *adapter, int address, int kind)

{

        int i, cur, conf, hyst, os;

        struct i2c_client *new_client;

        struct lm75_data *data;

        int err = 0;

        const char *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)) {

                dev_dbg(&adapter->dev,

                        "lm75_detect called for an ISA bus adapter?!?\n");

                goto exit;

        }

#endif

        if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |

                                     I2C_FUNC_SMBUS_WORD_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.

           But it allows us to access lm75_{read,write}_value. */

        if (!(new_client = kmalloc(sizeof(struct i2c_client) +

                                   sizeof(struct lm75_data),

                                   GFP_KERNEL))) {

                err = -ENOMEM;

                goto exit;

        }

        memset(new_client, 0x00, sizeof(struct i2c_client) +

                                 sizeof(struct lm75_data));

        data = (struct lm75_data *) (new_client + 1);

        i2c_set_clientdata(new_client, data);

        new_client->addr = address;

        new_client->adapter = adapter;

        new_client->driver = &lm75_driver;

        new_client->flags = 0;

        /* Now, we do the remaining detection. It is lousy. */

        if (kind < 0) {

                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);

                os = i2c_smbus_read_word_data(new_client, 3);

                for (i = 0; i <= 0x1f; i++)

                        if ((i2c_smbus_read_byte_data(new_client, i * 8 + 1) != conf) ||

                            (i2c_smbus_read_word_data(new_client, i * 8 + 2) != hyst) ||

                            (i2c_smbus_read_word_data(new_client, i * 8 + 3) != os))

                                goto exit_free;

        }

        /* Determine the chip type - only one kind supported! */

        if (kind <= 0)

                kind = lm75;

        if (kind == lm75) {

                name = "lm75";

        } else {

                dev_dbg(&adapter->dev, "Internal error: unknown kind (%d)?!?",

                        kind);

                goto exit_free;

        }

        /* Fill in the remaining client fields and put it into the global list */

        strlcpy(new_client->name, name, I2C_NAME_SIZE);

        new_client->id = lm75_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)))

                goto exit_free;

        /* Initialize the LM75 chip */

        lm75_init_client(new_client);

        /* Register sysfs hooks */

        device_create_file(&new_client->dev, &dev_attr_temp_max);

        device_create_file(&new_client->dev, &dev_attr_temp_min);

        device_create_file(&new_client->dev, &dev_attr_temp_input);

        return 0;

exit_free:

        kfree(new_client);

exit:

        return err;

}

static int lm75_detach_client(struct i2c_client *client)

{

        i2c_detach_client(client);

        kfree(client);

        return 0;

}

static u16 swap_bytes(u16 val)

{

        return (val >> 8) | (val << 8);

}

/* 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 swap_bytes(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,

                                                 swap_bytes(value));

}

static void lm75_init_client(struct i2c_client *client)

{

        /* Initialize the LM75 chip */

        lm75_write_value(client, LM75_REG_TEMP_OS,

                         TEMP_TO_REG(LM75_INIT_TEMP_OS));

        lm75_write_value(client, LM75_REG_TEMP_HYST,

                         TEMP_TO_REG(LM75_INIT_TEMP_HYST));

        lm75_write_value(client, LM75_REG_CONF, 0);

}

static void lm75_update_client(struct i2c_client *client)

{

        struct lm75_data *data = i2c_get_clientdata(client);

        down(&data->update_lock);

        if ((jiffies - data->last_updated > HZ + HZ / 2) ||

            (jiffies < data->last_updated) || !data->valid) {

                dev_dbg(&client->dev, "Starting lm75 update\n");

                data->temp_input = lm75_read_value(client, LM75_REG_TEMP);

                data->temp_max = 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);

}

static int __init sensors_lm75_init(void)

{

        return i2c_add_driver(&lm75_driver);

}

static void __exit sensors_lm75_exit(void)

{

        i2c_del_driver(&lm75_driver);

}

MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");

MODULE_DESCRIPTION("LM75 driver");

MODULE_LICENSE("GPL");

module_init(sensors_lm75_init);

module_exit(sensors_lm75_exit);