lm73.c

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/*
 * LM73 Sensor driver
 * Based on LM75
 *
 * Copyright (C) 2007, CenoSYS (www.cenosys.com).
 * Copyright (C) 2009, Bollore telecom (www.bolloretelecom.eu).
 *
 * Guillaume Ligneul <[email protected]>
 * Adrien Demarez <[email protected]>
 * Jeremy Laine <[email protected]>
 *
 * This software program is licensed subject to the GNU General Public License
 * (GPL).Version 2,June 1991, available at
 * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/i2c.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/err.h>


/* Addresses scanned */
static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4c,
                    0x4d, 0x4e, I2C_CLIENT_END };

/* LM73 registers */
#define LM73_REG_INPUT      0x00
#define LM73_REG_CONF       0x01
#define LM73_REG_MAX        0x02
#define LM73_REG_MIN        0x03
#define LM73_REG_CTRL       0x04
#define LM73_REG_ID     0x07

#define LM73_ID         0x9001  /* 0x0190, byte-swapped */
#define DRVNAME         "lm73"
#define LM73_TEMP_MIN       (-40)
#define LM73_TEMP_MAX       150

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


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);
    long temp;
    short value;

    int status = kstrtol(buf, 10, &temp);
    if (status < 0)
        return status;

    /* Write value */
    value = (short) SENSORS_LIMIT(temp/250, (LM73_TEMP_MIN*4),
        (LM73_TEMP_MAX*4)) << 5;
    i2c_smbus_write_word_swapped(client, attr->index, value);
    return count;
}

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 i2c_client *client = to_i2c_client(dev);
    /* use integer division instead of equivalent right shift to
       guarantee arithmetic shift and preserve the sign */
    int temp = ((s16) (i2c_smbus_read_word_swapped(client,
            attr->index))*250) / 32;
    return sprintf(buf, "%d\n", temp);
}


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

/* sysfs attributes for hwmon */

static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
            show_temp, set_temp, LM73_REG_MAX);
static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO,
            show_temp, set_temp, LM73_REG_MIN);
static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO,
            show_temp, NULL, LM73_REG_INPUT);


static struct attribute *lm73_attributes[] = {
    &sensor_dev_attr_temp1_input.dev_attr.attr,
    &sensor_dev_attr_temp1_max.dev_attr.attr,
    &sensor_dev_attr_temp1_min.dev_attr.attr,

    NULL
};

static const struct attribute_group lm73_group = {
    .attrs = lm73_attributes,
};

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

/* device probe and removal */

static int
lm73_probe(struct i2c_client *client, const struct i2c_device_id *id)
{
    struct device *hwmon_dev;
    int status;

    /* Register sysfs hooks */
    status = sysfs_create_group(&client->dev.kobj, &lm73_group);
    if (status)
        return status;

    hwmon_dev = hwmon_device_register(&client->dev);
    if (IS_ERR(hwmon_dev)) {
        status = PTR_ERR(hwmon_dev);
        goto exit_remove;
    }
    i2c_set_clientdata(client, hwmon_dev);

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

    return 0;

exit_remove:
    sysfs_remove_group(&client->dev.kobj, &lm73_group);
    return status;
}

static int lm73_remove(struct i2c_client *client)
{
    struct device *hwmon_dev = i2c_get_clientdata(client);

    hwmon_device_unregister(hwmon_dev);
    sysfs_remove_group(&client->dev.kobj, &lm73_group);
    return 0;
}

static const struct i2c_device_id lm73_ids[] = {
    { "lm73", 0 },
    { /* LIST END */ }
};
MODULE_DEVICE_TABLE(i2c, lm73_ids);

/* Return 0 if detection is successful, -ENODEV otherwise */
static int lm73_detect(struct i2c_client *new_client,
            struct i2c_board_info *info)
{
    struct i2c_adapter *adapter = new_client->adapter;
    int id, ctrl, conf;

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

    /*
     * Do as much detection as possible with byte reads first, as word
     * reads can confuse other devices.
     */
    ctrl = i2c_smbus_read_byte_data(new_client, LM73_REG_CTRL);
    if (ctrl < 0 || (ctrl & 0x10))
        return -ENODEV;

    conf = i2c_smbus_read_byte_data(new_client, LM73_REG_CONF);
    if (conf < 0 || (conf & 0x0c))
        return -ENODEV;

    id = i2c_smbus_read_byte_data(new_client, LM73_REG_ID);
    if (id < 0 || id != (LM73_ID & 0xff))
        return -ENODEV;

    /* Check device ID */
    id = i2c_smbus_read_word_data(new_client, LM73_REG_ID);
    if (id < 0 || id != LM73_ID)
        return -ENODEV;

    strlcpy(info->type, "lm73", I2C_NAME_SIZE);

    return 0;
}

static struct i2c_driver lm73_driver = {
    .class      = I2C_CLASS_HWMON,
    .driver = {
        .name   = "lm73",
    },
    .probe      = lm73_probe,
    .remove     = lm73_remove,
    .id_table   = lm73_ids,
    .detect     = lm73_detect,
    .address_list   = normal_i2c,
};

module_i2c_driver(lm73_driver);

MODULE_AUTHOR("Guillaume Ligneul <[email protected]>");
MODULE_DESCRIPTION("LM73 driver");
MODULE_LICENSE("GPL");