tmp102.c

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/* Texas Instruments TMP102 SMBus temperature sensor driver
 *
 * Copyright (C) 2010 Steven King <[email protected]>
 *
 * 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., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/device.h>
#include <linux/jiffies.h>

#define DRIVER_NAME "tmp102"

#define TMP102_TEMP_REG         0x00
#define TMP102_CONF_REG         0x01
/* note: these bit definitions are byte swapped */
#define     TMP102_CONF_SD      0x0100
#define     TMP102_CONF_TM      0x0200
#define     TMP102_CONF_POL     0x0400
#define     TMP102_CONF_F0      0x0800
#define     TMP102_CONF_F1      0x1000
#define     TMP102_CONF_R0      0x2000
#define     TMP102_CONF_R1      0x4000
#define     TMP102_CONF_OS      0x8000
#define     TMP102_CONF_EM      0x0010
#define     TMP102_CONF_AL      0x0020
#define     TMP102_CONF_CR0     0x0040
#define     TMP102_CONF_CR1     0x0080
#define TMP102_TLOW_REG         0x02
#define TMP102_THIGH_REG        0x03

struct tmp102 {
    struct device *hwmon_dev;
    struct mutex lock;
    u16 config_orig;
    unsigned long last_update;
    int temp[3];
};

/* convert left adjusted 13-bit TMP102 register value to milliCelsius */
static inline int tmp102_reg_to_mC(s16 val)
{
    return ((val & ~0x01) * 1000) / 128;
}

/* convert milliCelsius to left adjusted 13-bit TMP102 register value */
static inline u16 tmp102_mC_to_reg(int val)
{
    return (val * 128) / 1000;
}

static const u8 tmp102_reg[] = {
    TMP102_TEMP_REG,
    TMP102_TLOW_REG,
    TMP102_THIGH_REG,
};

static struct tmp102 *tmp102_update_device(struct i2c_client *client)
{
    struct tmp102 *tmp102 = i2c_get_clientdata(client);

    mutex_lock(&tmp102->lock);
    if (time_after(jiffies, tmp102->last_update + HZ / 3)) {
        int i;
        for (i = 0; i < ARRAY_SIZE(tmp102->temp); ++i) {
            int status = i2c_smbus_read_word_swapped(client,
                                 tmp102_reg[i]);
            if (status > -1)
                tmp102->temp[i] = tmp102_reg_to_mC(status);
        }
        tmp102->last_update = jiffies;
    }
    mutex_unlock(&tmp102->lock);
    return tmp102;
}

static ssize_t tmp102_show_temp(struct device *dev,
                struct device_attribute *attr,
                char *buf)
{
    struct sensor_device_attribute *sda = to_sensor_dev_attr(attr);
    struct tmp102 *tmp102 = tmp102_update_device(to_i2c_client(dev));

    return sprintf(buf, "%d\n", tmp102->temp[sda->index]);
}

static ssize_t tmp102_set_temp(struct device *dev,
                   struct device_attribute *attr,
                   const char *buf, size_t count)
{
    struct sensor_device_attribute *sda = to_sensor_dev_attr(attr);
    struct i2c_client *client = to_i2c_client(dev);
    struct tmp102 *tmp102 = i2c_get_clientdata(client);
    long val;
    int status;

    if (kstrtol(buf, 10, &val) < 0)
        return -EINVAL;
    val = SENSORS_LIMIT(val, -256000, 255000);

    mutex_lock(&tmp102->lock);
    tmp102->temp[sda->index] = val;
    status = i2c_smbus_write_word_swapped(client, tmp102_reg[sda->index],
                          tmp102_mC_to_reg(val));
    mutex_unlock(&tmp102->lock);
    return status ? : count;
}

static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, tmp102_show_temp, NULL , 0);

static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO, tmp102_show_temp,
              tmp102_set_temp, 1);

static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, tmp102_show_temp,
              tmp102_set_temp, 2);

static struct attribute *tmp102_attributes[] = {
    &sensor_dev_attr_temp1_input.dev_attr.attr,
    &sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
    &sensor_dev_attr_temp1_max.dev_attr.attr,
    NULL
};

static const struct attribute_group tmp102_attr_group = {
    .attrs = tmp102_attributes,
};

#define TMP102_CONFIG  (TMP102_CONF_TM | TMP102_CONF_EM | TMP102_CONF_CR1)
#define TMP102_CONFIG_RD_ONLY (TMP102_CONF_R0 | TMP102_CONF_R1 | TMP102_CONF_AL)

static int __devinit tmp102_probe(struct i2c_client *client,
                  const struct i2c_device_id *id)
{
    struct tmp102 *tmp102;
    int status;

    if (!i2c_check_functionality(client->adapter,
                     I2C_FUNC_SMBUS_WORD_DATA)) {
        dev_err(&client->dev, "adapter doesn't support SMBus word "
            "transactions\n");
        return -ENODEV;
    }

    tmp102 = devm_kzalloc(&client->dev, sizeof(*tmp102), GFP_KERNEL);
    if (!tmp102)
        return -ENOMEM;

    i2c_set_clientdata(client, tmp102);

    status = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
    if (status < 0) {
        dev_err(&client->dev, "error reading config register\n");
        return status;
    }
    tmp102->config_orig = status;
    status = i2c_smbus_write_word_swapped(client, TMP102_CONF_REG,
                          TMP102_CONFIG);
    if (status < 0) {
        dev_err(&client->dev, "error writing config register\n");
        goto fail_restore_config;
    }
    status = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
    if (status < 0) {
        dev_err(&client->dev, "error reading config register\n");
        goto fail_restore_config;
    }
    status &= ~TMP102_CONFIG_RD_ONLY;
    if (status != TMP102_CONFIG) {
        dev_err(&client->dev, "config settings did not stick\n");
        status = -ENODEV;
        goto fail_restore_config;
    }
    tmp102->last_update = jiffies - HZ;
    mutex_init(&tmp102->lock);

    status = sysfs_create_group(&client->dev.kobj, &tmp102_attr_group);
    if (status) {
        dev_dbg(&client->dev, "could not create sysfs files\n");
        goto fail_restore_config;
    }
    tmp102->hwmon_dev = hwmon_device_register(&client->dev);
    if (IS_ERR(tmp102->hwmon_dev)) {
        dev_dbg(&client->dev, "unable to register hwmon device\n");
        status = PTR_ERR(tmp102->hwmon_dev);
        goto fail_remove_sysfs;
    }

    dev_info(&client->dev, "initialized\n");

    return 0;

fail_remove_sysfs:
    sysfs_remove_group(&client->dev.kobj, &tmp102_attr_group);
fail_restore_config:
    i2c_smbus_write_word_swapped(client, TMP102_CONF_REG,
                     tmp102->config_orig);
    return status;
}

static int __devexit tmp102_remove(struct i2c_client *client)
{
    struct tmp102 *tmp102 = i2c_get_clientdata(client);

    hwmon_device_unregister(tmp102->hwmon_dev);
    sysfs_remove_group(&client->dev.kobj, &tmp102_attr_group);

    /* Stop monitoring if device was stopped originally */
    if (tmp102->config_orig & TMP102_CONF_SD) {
        int config;

        config = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
        if (config >= 0)
            i2c_smbus_write_word_swapped(client, TMP102_CONF_REG,
                             config | TMP102_CONF_SD);
    }

    return 0;
}

#ifdef CONFIG_PM
static int tmp102_suspend(struct device *dev)
{
    struct i2c_client *client = to_i2c_client(dev);
    int config;

    config = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
    if (config < 0)
        return config;

    config |= TMP102_CONF_SD;
    return i2c_smbus_write_word_swapped(client, TMP102_CONF_REG, config);
}

static int tmp102_resume(struct device *dev)
{
    struct i2c_client *client = to_i2c_client(dev);
    int config;

    config = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
    if (config < 0)
        return config;

    config &= ~TMP102_CONF_SD;
    return i2c_smbus_write_word_swapped(client, TMP102_CONF_REG, config);
}

static const struct dev_pm_ops tmp102_dev_pm_ops = {
    .suspend    = tmp102_suspend,
    .resume     = tmp102_resume,
};

#define TMP102_DEV_PM_OPS (&tmp102_dev_pm_ops)
#else
#define TMP102_DEV_PM_OPS NULL
#endif /* CONFIG_PM */

static const struct i2c_device_id tmp102_id[] = {
    { "tmp102", 0 },
    { }
};
MODULE_DEVICE_TABLE(i2c, tmp102_id);

static struct i2c_driver tmp102_driver = {
    .driver.name    = DRIVER_NAME,
    .driver.pm  = TMP102_DEV_PM_OPS,
    .probe      = tmp102_probe,
    .remove     = __devexit_p(tmp102_remove),
    .id_table   = tmp102_id,
};

module_i2c_driver(tmp102_driver);

MODULE_AUTHOR("Steven King <[email protected]>");
MODULE_DESCRIPTION("Texas Instruments TMP102 temperature sensor driver");
MODULE_LICENSE("GPL");