lm83.c

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/*
 * lm83.c - Part of lm_sensors, Linux kernel modules for hardware
 *          monitoring
 * Copyright (C) 2003-2009  Jean Delvare <[email protected]>
 *
 * Heavily inspired from the lm78, lm75 and adm1021 drivers. The LM83 is
 * a sensor chip made by National Semiconductor. It reports up to four
 * temperatures (its own plus up to three external ones) with a 1 deg
 * resolution and a 3-4 deg accuracy. Complete datasheet can be obtained
 * from National's website at:
 *   http://www.national.com/pf/LM/LM83.html
 * Since the datasheet omits to give the chip stepping code, I give it
 * here: 0x03 (at register 0xff).
 *
 * Also supports the LM82 temp sensor, which is basically a stripped down
 * model of the LM83.  Datasheet is here:
 * http://www.national.com/pf/LM/LM82.html
 *
 * 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-sysfs.h>
#include <linux/hwmon.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/sysfs.h>

/*
 * Addresses to scan
 * Address is selected using 2 three-level pins, resulting in 9 possible
 * addresses.
 */

static const unsigned short normal_i2c[] = {
    0x18, 0x19, 0x1a, 0x29, 0x2a, 0x2b, 0x4c, 0x4d, 0x4e, I2C_CLIENT_END };

enum chips { lm83, lm82 };

/*
 * The LM83 registers
 * Manufacturer ID is 0x01 for National Semiconductor.
 */

#define LM83_REG_R_MAN_ID       0xFE
#define LM83_REG_R_CHIP_ID      0xFF
#define LM83_REG_R_CONFIG       0x03
#define LM83_REG_W_CONFIG       0x09
#define LM83_REG_R_STATUS1      0x02
#define LM83_REG_R_STATUS2      0x35
#define LM83_REG_R_LOCAL_TEMP       0x00
#define LM83_REG_R_LOCAL_HIGH       0x05
#define LM83_REG_W_LOCAL_HIGH       0x0B
#define LM83_REG_R_REMOTE1_TEMP     0x30
#define LM83_REG_R_REMOTE1_HIGH     0x38
#define LM83_REG_W_REMOTE1_HIGH     0x50
#define LM83_REG_R_REMOTE2_TEMP     0x01
#define LM83_REG_R_REMOTE2_HIGH     0x07
#define LM83_REG_W_REMOTE2_HIGH     0x0D
#define LM83_REG_R_REMOTE3_TEMP     0x31
#define LM83_REG_R_REMOTE3_HIGH     0x3A
#define LM83_REG_W_REMOTE3_HIGH     0x52
#define LM83_REG_R_TCRIT        0x42
#define LM83_REG_W_TCRIT        0x5A

/*
 * Conversions and various macros
 * The LM83 uses signed 8-bit values with LSB = 1 degree Celsius.
 */

#define TEMP_FROM_REG(val)  ((val) * 1000)
#define TEMP_TO_REG(val)    ((val) <= -128000 ? -128 : \
                 (val) >= 127000 ? 127 : \
                 (val) < 0 ? ((val) - 500) / 1000 : \
                 ((val) + 500) / 1000)

static const u8 LM83_REG_R_TEMP[] = {
    LM83_REG_R_LOCAL_TEMP,
    LM83_REG_R_REMOTE1_TEMP,
    LM83_REG_R_REMOTE2_TEMP,
    LM83_REG_R_REMOTE3_TEMP,
    LM83_REG_R_LOCAL_HIGH,
    LM83_REG_R_REMOTE1_HIGH,
    LM83_REG_R_REMOTE2_HIGH,
    LM83_REG_R_REMOTE3_HIGH,
    LM83_REG_R_TCRIT,
};

static const u8 LM83_REG_W_HIGH[] = {
    LM83_REG_W_LOCAL_HIGH,
    LM83_REG_W_REMOTE1_HIGH,
    LM83_REG_W_REMOTE2_HIGH,
    LM83_REG_W_REMOTE3_HIGH,
    LM83_REG_W_TCRIT,
};

/*
 * Functions declaration
 */

static int lm83_detect(struct i2c_client *new_client,
               struct i2c_board_info *info);
static int lm83_probe(struct i2c_client *client,
              const struct i2c_device_id *id);
static int lm83_remove(struct i2c_client *client);
static struct lm83_data *lm83_update_device(struct device *dev);

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

static const struct i2c_device_id lm83_id[] = {
    { "lm83", lm83 },
    { "lm82", lm82 },
    { }
};
MODULE_DEVICE_TABLE(i2c, lm83_id);

static struct i2c_driver lm83_driver = {
    .class      = I2C_CLASS_HWMON,
    .driver = {
        .name   = "lm83",
    },
    .probe      = lm83_probe,
    .remove     = lm83_remove,
    .id_table   = lm83_id,
    .detect     = lm83_detect,
    .address_list   = normal_i2c,
};

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

struct lm83_data {
    struct device *hwmon_dev;
    struct mutex update_lock;
    char valid; /* zero until following fields are valid */
    unsigned long last_updated; /* in jiffies */

    /* registers values */
    s8 temp[9]; /* 0..3: input 1-4,
               4..7: high limit 1-4,
               8   : critical limit */
    u16 alarms; /* bitvector, combined */
};

/*
 * Sysfs stuff
 */

static ssize_t show_temp(struct device *dev, struct device_attribute *devattr,
             char *buf)
{
    struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
    struct lm83_data *data = lm83_update_device(dev);
    return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[attr->index]));
}

static ssize_t set_temp(struct device *dev, struct device_attribute *devattr,
            const char *buf, size_t count)
{
    struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
    struct i2c_client *client = to_i2c_client(dev);
    struct lm83_data *data = i2c_get_clientdata(client);
    long val;
    int nr = attr->index;
    int err;

    err = kstrtol(buf, 10, &val);
    if (err < 0)
        return err;

    mutex_lock(&data->update_lock);
    data->temp[nr] = TEMP_TO_REG(val);
    i2c_smbus_write_byte_data(client, LM83_REG_W_HIGH[nr - 4],
                  data->temp[nr]);
    mutex_unlock(&data->update_lock);
    return count;
}

static ssize_t show_alarms(struct device *dev, struct device_attribute *dummy,
               char *buf)
{
    struct lm83_data *data = lm83_update_device(dev);
    return sprintf(buf, "%d\n", data->alarms);
}

static ssize_t show_alarm(struct device *dev, struct device_attribute
              *devattr, char *buf)
{
    struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
    struct lm83_data *data = lm83_update_device(dev);
    int bitnr = attr->index;

    return sprintf(buf, "%d\n", (data->alarms >> bitnr) & 1);
}

static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_temp, NULL, 1);
static SENSOR_DEVICE_ATTR(temp3_input, S_IRUGO, show_temp, NULL, 2);
static SENSOR_DEVICE_ATTR(temp4_input, S_IRUGO, show_temp, NULL, 3);
static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp,
    set_temp, 4);
static SENSOR_DEVICE_ATTR(temp2_max, S_IWUSR | S_IRUGO, show_temp,
    set_temp, 5);
static SENSOR_DEVICE_ATTR(temp3_max, S_IWUSR | S_IRUGO, show_temp,
    set_temp, 6);
static SENSOR_DEVICE_ATTR(temp4_max, S_IWUSR | S_IRUGO, show_temp,
    set_temp, 7);
static SENSOR_DEVICE_ATTR(temp1_crit, S_IRUGO, show_temp, NULL, 8);
static SENSOR_DEVICE_ATTR(temp2_crit, S_IRUGO, show_temp, NULL, 8);
static SENSOR_DEVICE_ATTR(temp3_crit, S_IWUSR | S_IRUGO, show_temp,
    set_temp, 8);
static SENSOR_DEVICE_ATTR(temp4_crit, S_IRUGO, show_temp, NULL, 8);

/* Individual alarm files */
static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 0);
static SENSOR_DEVICE_ATTR(temp3_crit_alarm, S_IRUGO, show_alarm, NULL, 1);
static SENSOR_DEVICE_ATTR(temp3_fault, S_IRUGO, show_alarm, NULL, 2);
static SENSOR_DEVICE_ATTR(temp3_max_alarm, S_IRUGO, show_alarm, NULL, 4);
static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 6);
static SENSOR_DEVICE_ATTR(temp2_crit_alarm, S_IRUGO, show_alarm, NULL, 8);
static SENSOR_DEVICE_ATTR(temp4_crit_alarm, S_IRUGO, show_alarm, NULL, 9);
static SENSOR_DEVICE_ATTR(temp4_fault, S_IRUGO, show_alarm, NULL, 10);
static SENSOR_DEVICE_ATTR(temp4_max_alarm, S_IRUGO, show_alarm, NULL, 12);
static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO, show_alarm, NULL, 13);
static SENSOR_DEVICE_ATTR(temp2_max_alarm, S_IRUGO, show_alarm, NULL, 15);
/* Raw alarm file for compatibility */
static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);

static struct attribute *lm83_attributes[] = {
    &sensor_dev_attr_temp1_input.dev_attr.attr,
    &sensor_dev_attr_temp3_input.dev_attr.attr,
    &sensor_dev_attr_temp1_max.dev_attr.attr,
    &sensor_dev_attr_temp3_max.dev_attr.attr,
    &sensor_dev_attr_temp1_crit.dev_attr.attr,
    &sensor_dev_attr_temp3_crit.dev_attr.attr,

    &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
    &sensor_dev_attr_temp3_crit_alarm.dev_attr.attr,
    &sensor_dev_attr_temp3_fault.dev_attr.attr,
    &sensor_dev_attr_temp3_max_alarm.dev_attr.attr,
    &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
    &dev_attr_alarms.attr,
    NULL
};

static const struct attribute_group lm83_group = {
    .attrs = lm83_attributes,
};

static struct attribute *lm83_attributes_opt[] = {
    &sensor_dev_attr_temp2_input.dev_attr.attr,
    &sensor_dev_attr_temp4_input.dev_attr.attr,
    &sensor_dev_attr_temp2_max.dev_attr.attr,
    &sensor_dev_attr_temp4_max.dev_attr.attr,
    &sensor_dev_attr_temp2_crit.dev_attr.attr,
    &sensor_dev_attr_temp4_crit.dev_attr.attr,

    &sensor_dev_attr_temp2_crit_alarm.dev_attr.attr,
    &sensor_dev_attr_temp4_crit_alarm.dev_attr.attr,
    &sensor_dev_attr_temp4_fault.dev_attr.attr,
    &sensor_dev_attr_temp4_max_alarm.dev_attr.attr,
    &sensor_dev_attr_temp2_fault.dev_attr.attr,
    &sensor_dev_attr_temp2_max_alarm.dev_attr.attr,
    NULL
};

static const struct attribute_group lm83_group_opt = {
    .attrs = lm83_attributes_opt,
};

/*
 * Real code
 */

/* Return 0 if detection is successful, -ENODEV otherwise */
static int lm83_detect(struct i2c_client *new_client,
               struct i2c_board_info *info)
{
    struct i2c_adapter *adapter = new_client->adapter;
    const char *name;
    u8 man_id, chip_id;

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

    /* Detection */
    if ((i2c_smbus_read_byte_data(new_client, LM83_REG_R_STATUS1) & 0xA8) ||
        (i2c_smbus_read_byte_data(new_client, LM83_REG_R_STATUS2) & 0x48) ||
        (i2c_smbus_read_byte_data(new_client, LM83_REG_R_CONFIG) & 0x41)) {
        dev_dbg(&adapter->dev, "LM83 detection failed at 0x%02x\n",
            new_client->addr);
        return -ENODEV;
    }

    /* Identification */
    man_id = i2c_smbus_read_byte_data(new_client, LM83_REG_R_MAN_ID);
    if (man_id != 0x01) /* National Semiconductor */
        return -ENODEV;

    chip_id = i2c_smbus_read_byte_data(new_client, LM83_REG_R_CHIP_ID);
    switch (chip_id) {
    case 0x03:
        name = "lm83";
        break;
    case 0x01:
        name = "lm82";
        break;
    default:
        /* identification failed */
        dev_info(&adapter->dev,
             "Unsupported chip (man_id=0x%02X, chip_id=0x%02X)\n",
             man_id, chip_id);
        return -ENODEV;
    }

    strlcpy(info->type, name, I2C_NAME_SIZE);

    return 0;
}

static int lm83_probe(struct i2c_client *new_client,
              const struct i2c_device_id *id)
{
    struct lm83_data *data;
    int err;

    data = devm_kzalloc(&new_client->dev, sizeof(struct lm83_data),
                GFP_KERNEL);
    if (!data)
        return -ENOMEM;

    i2c_set_clientdata(new_client, data);
    data->valid = 0;
    mutex_init(&data->update_lock);

    /*
     * Register sysfs hooks
     * The LM82 can only monitor one external diode which is
     * at the same register as the LM83 temp3 entry - so we
     * declare 1 and 3 common, and then 2 and 4 only for the LM83.
     */

    err = sysfs_create_group(&new_client->dev.kobj, &lm83_group);
    if (err)
        return err;

    if (id->driver_data == lm83) {
        err = sysfs_create_group(&new_client->dev.kobj,
                     &lm83_group_opt);
        if (err)
            goto exit_remove_files;
    }

    data->hwmon_dev = hwmon_device_register(&new_client->dev);
    if (IS_ERR(data->hwmon_dev)) {
        err = PTR_ERR(data->hwmon_dev);
        goto exit_remove_files;
    }

    return 0;

exit_remove_files:
    sysfs_remove_group(&new_client->dev.kobj, &lm83_group);
    sysfs_remove_group(&new_client->dev.kobj, &lm83_group_opt);
    return err;
}

static int lm83_remove(struct i2c_client *client)
{
    struct lm83_data *data = i2c_get_clientdata(client);

    hwmon_device_unregister(data->hwmon_dev);
    sysfs_remove_group(&client->dev.kobj, &lm83_group);
    sysfs_remove_group(&client->dev.kobj, &lm83_group_opt);

    return 0;
}

static struct lm83_data *lm83_update_device(struct device *dev)
{
    struct i2c_client *client = to_i2c_client(dev);
    struct lm83_data *data = i2c_get_clientdata(client);

    mutex_lock(&data->update_lock);

    if (time_after(jiffies, data->last_updated + HZ * 2) || !data->valid) {
        int nr;

        dev_dbg(&client->dev, "Updating lm83 data.\n");
        for (nr = 0; nr < 9; nr++) {
            data->temp[nr] =
                i2c_smbus_read_byte_data(client,
                LM83_REG_R_TEMP[nr]);
        }
        data->alarms =
            i2c_smbus_read_byte_data(client, LM83_REG_R_STATUS1)
            + (i2c_smbus_read_byte_data(client, LM83_REG_R_STATUS2)
            << 8);

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

    mutex_unlock(&data->update_lock);

    return data;
}

module_i2c_driver(lm83_driver);

MODULE_AUTHOR("Jean Delvare <[email protected]>");
MODULE_DESCRIPTION("LM83 driver");
MODULE_LICENSE("GPL");