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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.
 */
 
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/slab.h>
 #include <linux/jiffies.h>
 #include <linux/i2c.h>
 #include <linux/hwmon.h>
 #include <linux/hwmon-sysfs.h>
 #include <linux/err.h>
 #include <linux/mutex.h>
 #include "lm75.h"
 
 
 /*
  * This driver handles the LM75 and compatible digital temperature sensors.
  * Only types which are _not_ listed in I2C_CLIENT_INSMOD_*() need to be
  * listed here.  We start at 9 since I2C_CLIENT_INSMOD_*() currently allow
  * definition of up to 8 chip types (plus zero).
  */
 
 enum lm75_type {                /* keep sorted in alphabetical order */
         ds1775 = 9,
         ds75,
         /* lm75 -- in I2C_CLIENT_INSMOD_1() */
         lm75a,
         max6625,
         max6626,
         mcp980x,
         stds75,
         tcn75,
         tmp100,
         tmp101,
         tmp175,
         tmp275,
         tmp75,
 };
 
 /* Addresses scanned */
 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
                                         0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
 
 /* Insmod parameters */
 I2C_CLIENT_INSMOD_1(lm75);
 
 
 /* The LM75 registers */
 #define LM75_REG_CONF                0x01
 static const u8 LM75_REG_TEMP[3] = {
         0x00,                /* input */
         0x03,                /* max */
         0x02,                /* hyst */
 };
 
 /* Each client has this additional data */
 struct lm75_data {
         struct device                *hwmon_dev;
         struct mutex                update_lock;
         u8                        orig_conf;
         char                        valid;                /* !=0 if registers are valid */
         unsigned long                last_updated;        /* In jiffies */
         u16                        temp[3];        /* Register values,
                                                    0 = input
                                                    1 = max
                                                    2 = hyst */
 };
 
 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 struct lm75_data *lm75_update_device(struct device *dev);
 
 
 /*-----------------------------------------------------------------------*/
 
 /* sysfs attributes for hwmon */
 
 static ssize_t show_temp(struct device *dev, struct device_attribute *da,
                          char *buf)
 {
         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
         struct lm75_data *data = lm75_update_device(dev);
        return sprintf(buf, "%d\n",
                       LM75_TEMP_FROM_REG(data->temp[attr->index]));
}

static ssize_t set_temp(struct device *dev, struct device_attribute *da,
                        const char *buf, size_t count)
{
        struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
        struct i2c_client *client = to_i2c_client(dev);
        struct lm75_data *data = i2c_get_clientdata(client);
        int nr = attr->index;
        long temp = simple_strtol(buf, NULL, 10);

        mutex_lock(&data->update_lock);
        data->temp[nr] = LM75_TEMP_TO_REG(temp);
        lm75_write_value(client, LM75_REG_TEMP[nr], data->temp[nr]);
        mutex_unlock(&data->update_lock);
        return count;
}

static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
                        show_temp, set_temp, 1);
static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO,
                        show_temp, set_temp, 2);
static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);

static struct attribute *lm75_attributes[] = {
        &sensor_dev_attr_temp1_input.dev_attr.attr,
        &sensor_dev_attr_temp1_max.dev_attr.attr,
        &sensor_dev_attr_temp1_max_hyst.dev_attr.attr,

        NULL
};

static const struct attribute_group lm75_group = {
        .attrs = lm75_attributes,
};

/*-----------------------------------------------------------------------*/

/* device probe and removal */

static int
lm75_probe(struct i2c_client *client, const struct i2c_device_id *id)
{
        struct lm75_data *data;
        int status;
        u8 set_mask, clr_mask;
        int new;

        if (!i2c_check_functionality(client->adapter,
                        I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
                return -EIO;

        data = kzalloc(sizeof(struct lm75_data), GFP_KERNEL);
        if (!data)
                return -ENOMEM;

        i2c_set_clientdata(client, data);
        mutex_init(&data->update_lock);

        /* Set to LM75 resolution (9 bits, 1/2 degree C) and range.
         * Then tweak to be more precise when appropriate.
         */
        set_mask = 0;
        clr_mask = (1 << 0)                        /* continuous conversions */
                | (1 << 6) | (1 << 5);                /* 9-bit mode */

        /* configure as specified */
        status = lm75_read_value(client, LM75_REG_CONF);
        if (status < 0) {
                dev_dbg(&client->dev, "Can't read config? %d\n", status);
                goto exit_free;
        }
        data->orig_conf = status;
        new = status & ~clr_mask;
        new |= set_mask;
        if (status != new)
                lm75_write_value(client, LM75_REG_CONF, new);
        dev_dbg(&client->dev, "Config %02x\n", new);

        /* Register sysfs hooks */
        status = sysfs_create_group(&client->dev.kobj, &lm75_group);
        if (status)
                goto exit_free;

        data->hwmon_dev = hwmon_device_register(&client->dev);
        if (IS_ERR(data->hwmon_dev)) {
                status = PTR_ERR(data->hwmon_dev);
                goto exit_remove;
        }

        dev_info(&client->dev, "%s: sensor '%s'\n",
                data->hwmon_dev->bus_id, client->name);

        return 0;

exit_remove:
        sysfs_remove_group(&client->dev.kobj, &lm75_group);
exit_free:
        i2c_set_clientdata(client, NULL);
        kfree(data);
        return status;
}

static int lm75_remove(struct i2c_client *client)
{
        struct lm75_data *data = i2c_get_clientdata(client);

        hwmon_device_unregister(data->hwmon_dev);
        sysfs_remove_group(&client->dev.kobj, &lm75_group);
        lm75_write_value(client, LM75_REG_CONF, data->orig_conf);
        i2c_set_clientdata(client, NULL);
        kfree(data);
        return 0;
}

static const struct i2c_device_id lm75_ids[] = {
        { "ds1775", ds1775, },
        { "ds75", ds75, },
        { "lm75", lm75, },
        { "lm75a", lm75a, },
        { "max6625", max6625, },
        { "max6626", max6626, },
        { "mcp980x", mcp980x, },
        { "stds75", stds75, },
        { "tcn75", tcn75, },
        { "tmp100", tmp100, },
        { "tmp101", tmp101, },
        { "tmp175", tmp175, },
        { "tmp275", tmp275, },
        { "tmp75", tmp75, },
        { /* LIST END */ }
};
MODULE_DEVICE_TABLE(i2c, lm75_ids);

/* Return 0 if detection is successful, -ENODEV otherwise */
static int lm75_detect(struct i2c_client *new_client, int kind,
                       struct i2c_board_info *info)
{
        struct i2c_adapter *adapter = new_client->adapter;
        int i;

        if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
                                     I2C_FUNC_SMBUS_WORD_DATA))
                return -ENODEV;

        /* 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)
                        return -ENODEV;
                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)
                        return -ENODEV;

                /* Unused bits */
                if (conf & 0xe0)
                        return -ENODEV;

                /* 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)
                                return -ENODEV;
        }

        /* NOTE: we treat "force=..." and "force_lm75=..." the same.
         * Only new-style driver binding distinguishes chip types.
         */
        strlcpy(info->type, "lm75", I2C_NAME_SIZE);

        return 0;
}

static struct i2c_driver lm75_driver = {
        .class                = I2C_CLASS_HWMON,
        .driver = {
                .name        = "lm75",
        },
        .probe                = lm75_probe,
        .remove                = lm75_remove,
        .id_table        = lm75_ids,
        .detect                = lm75_detect,
        .address_data        = &addr_data,
};

/*-----------------------------------------------------------------------*/

/* register access */

/* All registers are word-sized, except for the configuration register.
   LM75 uses a high-byte first convention, which is exactly opposite to
   the SMBus standard. */
static int lm75_read_value(struct i2c_client *client, u8 reg)
{
        int value;

        if (reg == LM75_REG_CONF)
                return i2c_smbus_read_byte_data(client, reg);

        value = i2c_smbus_read_word_data(client, reg);
        return (value < 0) ? value : swab16(value);
}

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 struct lm75_data *lm75_update_device(struct device *dev)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct lm75_data *data = i2c_get_clientdata(client);

        mutex_lock(&data->update_lock);

        if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
            || !data->valid) {
                int i;
                dev_dbg(&client->dev, "Starting lm75 update\n");

                for (i = 0; i < ARRAY_SIZE(data->temp); i++) {
                        int status;

                        status = lm75_read_value(client, LM75_REG_TEMP[i]);
                        if (status < 0)
                                dev_dbg(&client->dev, "reg %d, err %d\n",
                                                LM75_REG_TEMP[i], status);
                        else
                                data->temp[i] = status;
                }
                data->last_updated = jiffies;
                data->valid = 1;
        }

        mutex_unlock(&data->update_lock);

        return data;
}

/*-----------------------------------------------------------------------*/

/* module glue */

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);