ds1621.c

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/*
 * ds1621.c - Part of lm_sensors, Linux kernel modules for hardware
 *        monitoring
 * Christian W. Zuckschwerdt  <[email protected]>  2000-11-23
 * based on lm75.c by Frodo Looijaard <[email protected]>
 * Ported to Linux 2.6 by Aurelien Jarno <[email protected]> with
 * the help of Jean Delvare <[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., 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 <linux/sysfs.h>
#include "lm75.h"

/* Addresses to scan */
static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
                    0x4d, 0x4e, 0x4f, I2C_CLIENT_END };

/* Insmod parameters */
static int polarity = -1;
module_param(polarity, int, 0);
MODULE_PARM_DESC(polarity, "Output's polarity: 0 = active high, 1 = active low");

/* Many DS1621 constants specified below */
/* Config register used for detection         */
/*  7    6    5    4    3    2    1    0      */
/* |Done|THF |TLF |NVB | X  | X  |POL |1SHOT| */
#define DS1621_REG_CONFIG_NVB       0x10
#define DS1621_REG_CONFIG_POLARITY  0x02
#define DS1621_REG_CONFIG_1SHOT     0x01
#define DS1621_REG_CONFIG_DONE      0x80

/* The DS1621 registers */
static const u8 DS1621_REG_TEMP[3] = {
    0xAA,       /* input, word, RO */
    0xA2,       /* min, word, RW */
    0xA1,       /* max, word, RW */
};
#define DS1621_REG_CONF         0xAC /* byte, RW */
#define DS1621_COM_START        0xEE /* no data */
#define DS1621_COM_STOP         0x22 /* no data */

/* The DS1621 configuration register */
#define DS1621_ALARM_TEMP_HIGH      0x40
#define DS1621_ALARM_TEMP_LOW       0x20

/* Conversions */
#define ALARMS_FROM_REG(val) ((val) & \
            (DS1621_ALARM_TEMP_HIGH | DS1621_ALARM_TEMP_LOW))

/* Each client has this additional data */
struct ds1621_data {
    struct device *hwmon_dev;
    struct mutex update_lock;
    char valid;         /* !=0 if following fields are valid */
    unsigned long last_updated; /* In jiffies */

    u16 temp[3];            /* Register values, word */
    u8 conf;            /* Register encoding, combined */
};

static void ds1621_init_client(struct i2c_client *client)
{
    u8 conf, new_conf;

    new_conf = conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);
    /* switch to continuous conversion mode */
    new_conf &= ~DS1621_REG_CONFIG_1SHOT;

    /* setup output polarity */
    if (polarity == 0)
        new_conf &= ~DS1621_REG_CONFIG_POLARITY;
    else if (polarity == 1)
        new_conf |= DS1621_REG_CONFIG_POLARITY;

    if (conf != new_conf)
        i2c_smbus_write_byte_data(client, DS1621_REG_CONF, new_conf);

    /* start conversion */
    i2c_smbus_write_byte(client, DS1621_COM_START);
}

static struct ds1621_data *ds1621_update_client(struct device *dev)
{
    struct i2c_client *client = to_i2c_client(dev);
    struct ds1621_data *data = i2c_get_clientdata(client);
    u8 new_conf;

    mutex_lock(&data->update_lock);

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

        dev_dbg(&client->dev, "Starting ds1621 update\n");

        data->conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);

        for (i = 0; i < ARRAY_SIZE(data->temp); i++)
            data->temp[i] = i2c_smbus_read_word_swapped(client,
                             DS1621_REG_TEMP[i]);

        /* reset alarms if necessary */
        new_conf = data->conf;
        if (data->temp[0] > data->temp[1])  /* input > min */
            new_conf &= ~DS1621_ALARM_TEMP_LOW;
        if (data->temp[0] < data->temp[2])  /* input < max */
            new_conf &= ~DS1621_ALARM_TEMP_HIGH;
        if (data->conf != new_conf)
            i2c_smbus_write_byte_data(client, DS1621_REG_CONF,
                          new_conf);

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

    mutex_unlock(&data->update_lock);

    return data;
}

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 ds1621_data *data = ds1621_update_client(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 ds1621_data *data = i2c_get_clientdata(client);
    long val;
    int err;

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

    mutex_lock(&data->update_lock);
    data->temp[attr->index] = LM75_TEMP_TO_REG(val);
    i2c_smbus_write_word_swapped(client, DS1621_REG_TEMP[attr->index],
                     data->temp[attr->index]);
    mutex_unlock(&data->update_lock);
    return count;
}

static ssize_t show_alarms(struct device *dev, struct device_attribute *da,
               char *buf)
{
    struct ds1621_data *data = ds1621_update_client(dev);
    return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->conf));
}

static ssize_t show_alarm(struct device *dev, struct device_attribute *da,
              char *buf)
{
    struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
    struct ds1621_data *data = ds1621_update_client(dev);
    return sprintf(buf, "%d\n", !!(data->conf & attr->index));
}

static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp, set_temp, 1);
static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp, set_temp, 2);
static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL,
        DS1621_ALARM_TEMP_LOW);
static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL,
        DS1621_ALARM_TEMP_HIGH);

static struct attribute *ds1621_attributes[] = {
    &sensor_dev_attr_temp1_input.dev_attr.attr,
    &sensor_dev_attr_temp1_min.dev_attr.attr,
    &sensor_dev_attr_temp1_max.dev_attr.attr,
    &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
    &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
    &dev_attr_alarms.attr,
    NULL
};

static const struct attribute_group ds1621_group = {
    .attrs = ds1621_attributes,
};


/* Return 0 if detection is successful, -ENODEV otherwise */
static int ds1621_detect(struct i2c_client *client,
             struct i2c_board_info *info)
{
    struct i2c_adapter *adapter = client->adapter;
    int conf, temp;
    int i;

    if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
                     | I2C_FUNC_SMBUS_WORD_DATA
                     | I2C_FUNC_SMBUS_WRITE_BYTE))
        return -ENODEV;

    /*
     * Now, we do the remaining detection. It is lousy.
     *
     * The NVB bit should be low if no EEPROM write has been requested
     * during the latest 10ms, which is highly improbable in our case.
     */
    conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);
    if (conf < 0 || conf & DS1621_REG_CONFIG_NVB)
        return -ENODEV;
    /* The 7 lowest bits of a temperature should always be 0. */
    for (i = 0; i < ARRAY_SIZE(DS1621_REG_TEMP); i++) {
        temp = i2c_smbus_read_word_data(client, DS1621_REG_TEMP[i]);
        if (temp < 0 || (temp & 0x7f00))
            return -ENODEV;
    }

    strlcpy(info->type, "ds1621", I2C_NAME_SIZE);

    return 0;
}

static int ds1621_probe(struct i2c_client *client,
            const struct i2c_device_id *id)
{
    struct ds1621_data *data;
    int err;

    data = devm_kzalloc(&client->dev, sizeof(struct ds1621_data),
                GFP_KERNEL);
    if (!data)
        return -ENOMEM;

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

    /* Initialize the DS1621 chip */
    ds1621_init_client(client);

    /* Register sysfs hooks */
    err = sysfs_create_group(&client->dev.kobj, &ds1621_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_files;
    }

    return 0;

 exit_remove_files:
    sysfs_remove_group(&client->dev.kobj, &ds1621_group);
    return err;
}

static int ds1621_remove(struct i2c_client *client)
{
    struct ds1621_data *data = i2c_get_clientdata(client);

    hwmon_device_unregister(data->hwmon_dev);
    sysfs_remove_group(&client->dev.kobj, &ds1621_group);

    return 0;
}

static const struct i2c_device_id ds1621_id[] = {
    { "ds1621", 0 },
    { "ds1625", 0 },
    { }
};
MODULE_DEVICE_TABLE(i2c, ds1621_id);

/* This is the driver that will be inserted */
static struct i2c_driver ds1621_driver = {
    .class      = I2C_CLASS_HWMON,
    .driver = {
        .name   = "ds1621",
    },
    .probe      = ds1621_probe,
    .remove     = ds1621_remove,
    .id_table   = ds1621_id,
    .detect     = ds1621_detect,
    .address_list   = normal_i2c,
};

module_i2c_driver(ds1621_driver);

MODULE_AUTHOR("Christian W. Zuckschwerdt <[email protected]>");
MODULE_DESCRIPTION("DS1621 driver");
MODULE_LICENSE("GPL");