ad7414.c

Go to the documentation of this file.

/*
 * An hwmon driver for the Analog Devices AD7414
 *
 * Copyright 2006 Stefan Roese <sr at denx.de>, DENX Software Engineering
 *
 * Copyright (c) 2008 PIKA Technologies
 *   Sean MacLennan <[email protected]>
 *
 * Copyright (c) 2008 Spansion Inc.
 *   Frank Edelhaeuser <frank.edelhaeuser at spansion.com>
 *   (converted to "new style" I2C driver model, removed checkpatch.pl warnings)
 *
 * Based on ad7418.c
 * Copyright 2006 Tower Technologies, Alessandro Zummo <a.zummo at towertech.it>
 *
 * 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.
 */

#include <linux/module.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 <linux/sysfs.h>
#include <linux/slab.h>


/* AD7414 registers */
#define AD7414_REG_TEMP     0x00
#define AD7414_REG_CONF     0x01
#define AD7414_REG_T_HIGH   0x02
#define AD7414_REG_T_LOW    0x03

static u8 AD7414_REG_LIMIT[] = { AD7414_REG_T_HIGH, AD7414_REG_T_LOW };

struct ad7414_data {
    struct device       *hwmon_dev;
    struct mutex        lock;   /* atomic read data updates */
    char            valid;  /* !=0 if following fields are valid */
    unsigned long       next_update;    /* In jiffies */
    s16         temp_input; /* Register values */
    s8          temps[ARRAY_SIZE(AD7414_REG_LIMIT)];
};

/* REG: (0.25C/bit, two's complement) << 6 */
static inline int ad7414_temp_from_reg(s16 reg)
{
    /*
     * use integer division instead of equivalent right shift to
     * guarantee arithmetic shift and preserve the sign
     */
    return ((int)reg / 64) * 250;
}

static inline int ad7414_read(struct i2c_client *client, u8 reg)
{
    if (reg == AD7414_REG_TEMP)
        return i2c_smbus_read_word_swapped(client, reg);
    else
        return i2c_smbus_read_byte_data(client, reg);
}

static inline int ad7414_write(struct i2c_client *client, u8 reg, u8 value)
{
    return i2c_smbus_write_byte_data(client, reg, value);
}

static struct ad7414_data *ad7414_update_device(struct device *dev)
{
    struct i2c_client *client = to_i2c_client(dev);
    struct ad7414_data *data = i2c_get_clientdata(client);

    mutex_lock(&data->lock);

    if (time_after(jiffies, data->next_update) || !data->valid) {
        int value, i;

        dev_dbg(&client->dev, "starting ad7414 update\n");

        value = ad7414_read(client, AD7414_REG_TEMP);
        if (value < 0)
            dev_dbg(&client->dev, "AD7414_REG_TEMP err %d\n",
                value);
        else
            data->temp_input = value;

        for (i = 0; i < ARRAY_SIZE(AD7414_REG_LIMIT); ++i) {
            value = ad7414_read(client, AD7414_REG_LIMIT[i]);
            if (value < 0)
                dev_dbg(&client->dev, "AD7414 reg %d err %d\n",
                    AD7414_REG_LIMIT[i], value);
            else
                data->temps[i] = value;
        }

        data->next_update = jiffies + HZ + HZ / 2;
        data->valid = 1;
    }

    mutex_unlock(&data->lock);

    return data;
}

static ssize_t show_temp_input(struct device *dev,
                   struct device_attribute *attr, char *buf)
{
    struct ad7414_data *data = ad7414_update_device(dev);
    return sprintf(buf, "%d\n", ad7414_temp_from_reg(data->temp_input));
}
static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp_input, NULL, 0);

static ssize_t show_max_min(struct device *dev, struct device_attribute *attr,
              char *buf)
{
    int index = to_sensor_dev_attr(attr)->index;
    struct ad7414_data *data = ad7414_update_device(dev);
    return sprintf(buf, "%d\n", data->temps[index] * 1000);
}

static ssize_t set_max_min(struct device *dev,
               struct device_attribute *attr,
               const char *buf, size_t count)
{
    struct i2c_client *client = to_i2c_client(dev);
    struct ad7414_data *data = i2c_get_clientdata(client);
    int index = to_sensor_dev_attr(attr)->index;
    u8 reg = AD7414_REG_LIMIT[index];
    long temp;
    int ret = kstrtol(buf, 10, &temp);

    if (ret < 0)
        return ret;

    temp = SENSORS_LIMIT(temp, -40000, 85000);
    temp = (temp + (temp < 0 ? -500 : 500)) / 1000;

    mutex_lock(&data->lock);
    data->temps[index] = temp;
    ad7414_write(client, reg, temp);
    mutex_unlock(&data->lock);
    return count;
}

static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
              show_max_min, set_max_min, 0);
static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO,
              show_max_min, set_max_min, 1);

static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
              char *buf)
{
    int bitnr = to_sensor_dev_attr(attr)->index;
    struct ad7414_data *data = ad7414_update_device(dev);
    int value = (data->temp_input >> bitnr) & 1;
    return sprintf(buf, "%d\n", value);
}

static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 3);
static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 4);

static struct attribute *ad7414_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,
    &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
    &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
    NULL
};

static const struct attribute_group ad7414_group = {
    .attrs = ad7414_attributes,
};

static int ad7414_probe(struct i2c_client *client,
            const struct i2c_device_id *dev_id)
{
    struct ad7414_data *data;
    int conf;
    int err;

    if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA |
                     I2C_FUNC_SMBUS_READ_WORD_DATA))
        return -EOPNOTSUPP;

    data = devm_kzalloc(&client->dev, sizeof(struct ad7414_data),
                GFP_KERNEL);
    if (!data)
        return -ENOMEM;

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

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

    /* Make sure the chip is powered up. */
    conf = i2c_smbus_read_byte_data(client, AD7414_REG_CONF);
    if (conf < 0)
        dev_warn(&client->dev,
             "ad7414_probe unable to read config register.\n");
    else {
        conf &= ~(1 << 7);
        i2c_smbus_write_byte_data(client, AD7414_REG_CONF, conf);
    }

    /* Register sysfs hooks */
    err = sysfs_create_group(&client->dev.kobj, &ad7414_group);
    if (err)
        return err;

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

    return 0;

exit_remove:
    sysfs_remove_group(&client->dev.kobj, &ad7414_group);
    return err;
}

static int __devexit ad7414_remove(struct i2c_client *client)
{
    struct ad7414_data *data = i2c_get_clientdata(client);

    hwmon_device_unregister(data->hwmon_dev);
    sysfs_remove_group(&client->dev.kobj, &ad7414_group);
    return 0;
}

static const struct i2c_device_id ad7414_id[] = {
    { "ad7414", 0 },
    {}
};
MODULE_DEVICE_TABLE(i2c, ad7414_id);

static struct i2c_driver ad7414_driver = {
    .driver = {
        .name   = "ad7414",
    },
    .probe  = ad7414_probe,
    .remove = __devexit_p(ad7414_remove),
    .id_table = ad7414_id,
};

module_i2c_driver(ad7414_driver);

MODULE_AUTHOR("Stefan Roese <sr at denx.de>, "
          "Frank Edelhaeuser <frank.edelhaeuser at spansion.com>");

MODULE_DESCRIPTION("AD7414 driver");
MODULE_LICENSE("GPL");