ds620.c

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/*
 *  ds620.c - Support for temperature sensor and thermostat DS620
 *
 *  Copyright (C) 2010, 2011 Roland Stigge <[email protected]>
 *
 *  based on ds1621.c by Christian W. Zuckschwerdt  <[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 <linux/i2c/ds620.h>

/*
 * Many DS620 constants specified below
 *  15   14   13   12   11   10   09    08
 * |Done|NVB |THF |TLF |R1  |R0  |AUTOC|1SHOT|
 *
 *  07   06   05   04   03   02   01    00
 * |PO2 |PO1 |A2  |A1  |A0  |    |     |     |
 */
#define DS620_REG_CONFIG_DONE       0x8000
#define DS620_REG_CONFIG_NVB        0x4000
#define DS620_REG_CONFIG_THF        0x2000
#define DS620_REG_CONFIG_TLF        0x1000
#define DS620_REG_CONFIG_R1     0x0800
#define DS620_REG_CONFIG_R0     0x0400
#define DS620_REG_CONFIG_AUTOC      0x0200
#define DS620_REG_CONFIG_1SHOT      0x0100
#define DS620_REG_CONFIG_PO2        0x0080
#define DS620_REG_CONFIG_PO1        0x0040
#define DS620_REG_CONFIG_A2     0x0020
#define DS620_REG_CONFIG_A1     0x0010
#define DS620_REG_CONFIG_A0     0x0008

/* The DS620 registers */
static const u8 DS620_REG_TEMP[3] = {
    0xAA,           /* input, word, RO */
    0xA2,           /* min, word, RW */
    0xA0,           /* max, word, RW */
};

#define DS620_REG_CONF      0xAC    /* word, RW */
#define DS620_COM_START     0x51    /* no data */
#define DS620_COM_STOP      0x22    /* no data */

/* Each client has this additional data */
struct ds620_data {
    struct device *hwmon_dev;
    struct mutex update_lock;
    char valid;     /* !=0 if following fields are valid */
    unsigned long last_updated; /* In jiffies */

    s16 temp[3];        /* Register values, word */
};

static void ds620_init_client(struct i2c_client *client)
{
    struct ds620_platform_data *ds620_info = client->dev.platform_data;
    u16 conf, new_conf;

    new_conf = conf =
        i2c_smbus_read_word_swapped(client, DS620_REG_CONF);

    /* switch to continuous conversion mode */
    new_conf &= ~DS620_REG_CONFIG_1SHOT;
    /* already high at power-on, but don't trust the BIOS! */
    new_conf |= DS620_REG_CONFIG_PO2;
    /* thermostat mode according to platform data */
    if (ds620_info && ds620_info->pomode == 1)
        new_conf &= ~DS620_REG_CONFIG_PO1; /* PO_LOW */
    else if (ds620_info && ds620_info->pomode == 2)
        new_conf |= DS620_REG_CONFIG_PO1; /* PO_HIGH */
    else
        new_conf &= ~DS620_REG_CONFIG_PO2; /* always low */
    /* with highest precision */
    new_conf |= DS620_REG_CONFIG_R1 | DS620_REG_CONFIG_R0;

    if (conf != new_conf)
        i2c_smbus_write_word_swapped(client, DS620_REG_CONF, new_conf);

    /* start conversion */
    i2c_smbus_write_byte(client, DS620_COM_START);
}

static struct ds620_data *ds620_update_client(struct device *dev)
{
    struct i2c_client *client = to_i2c_client(dev);
    struct ds620_data *data = i2c_get_clientdata(client);
    struct ds620_data *ret = data;

    mutex_lock(&data->update_lock);

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

        dev_dbg(&client->dev, "Starting ds620 update\n");

        for (i = 0; i < ARRAY_SIZE(data->temp); i++) {
            res = i2c_smbus_read_word_swapped(client,
                              DS620_REG_TEMP[i]);
            if (res < 0) {
                ret = ERR_PTR(res);
                goto abort;
            }

            data->temp[i] = res;
        }

        data->last_updated = jiffies;
        data->valid = 1;
    }
abort:
    mutex_unlock(&data->update_lock);

    return ret;
}

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 ds620_data *data = ds620_update_client(dev);

    if (IS_ERR(data))
        return PTR_ERR(data);

    return sprintf(buf, "%d\n", ((data->temp[attr->index] / 8) * 625) / 10);
}

static ssize_t set_temp(struct device *dev, struct device_attribute *da,
            const char *buf, size_t count)
{
    int res;
    long val;

    struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
    struct i2c_client *client = to_i2c_client(dev);
    struct ds620_data *data = i2c_get_clientdata(client);

    res = kstrtol(buf, 10, &val);

    if (res)
        return res;

    val = (val * 10 / 625) * 8;

    mutex_lock(&data->update_lock);
    data->temp[attr->index] = val;
    i2c_smbus_write_word_swapped(client, DS620_REG_TEMP[attr->index],
                     data->temp[attr->index]);
    mutex_unlock(&data->update_lock);
    return count;
}

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 ds620_data *data = ds620_update_client(dev);
    struct i2c_client *client = to_i2c_client(dev);
    u16 conf, new_conf;
    int res;

    if (IS_ERR(data))
        return PTR_ERR(data);

    /* reset alarms if necessary */
    res = i2c_smbus_read_word_swapped(client, DS620_REG_CONF);
    if (res < 0)
        return res;

    new_conf = conf = res;
    new_conf &= ~attr->index;
    if (conf != new_conf) {
        res = i2c_smbus_write_word_swapped(client, DS620_REG_CONF,
                           new_conf);
        if (res < 0)
            return res;
    }

    return sprintf(buf, "%d\n", !!(conf & attr->index));
}

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,
              DS620_REG_CONFIG_TLF);
static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL,
              DS620_REG_CONFIG_THF);

static struct attribute *ds620_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,
    NULL
};

static const struct attribute_group ds620_group = {
    .attrs = ds620_attributes,
};

static int ds620_probe(struct i2c_client *client,
               const struct i2c_device_id *id)
{
    struct ds620_data *data;
    int err;

    data = devm_kzalloc(&client->dev, sizeof(struct ds620_data),
                GFP_KERNEL);
    if (!data)
        return -ENOMEM;

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

    /* Initialize the DS620 chip */
    ds620_init_client(client);

    /* Register sysfs hooks */
    err = sysfs_create_group(&client->dev.kobj, &ds620_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;
    }

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

    return 0;

exit_remove_files:
    sysfs_remove_group(&client->dev.kobj, &ds620_group);
    return err;
}

static int ds620_remove(struct i2c_client *client)
{
    struct ds620_data *data = i2c_get_clientdata(client);

    hwmon_device_unregister(data->hwmon_dev);
    sysfs_remove_group(&client->dev.kobj, &ds620_group);

    return 0;
}

static const struct i2c_device_id ds620_id[] = {
    {"ds620", 0},
    {}
};

MODULE_DEVICE_TABLE(i2c, ds620_id);

/* This is the driver that will be inserted */
static struct i2c_driver ds620_driver = {
    .class = I2C_CLASS_HWMON,
    .driver = {
           .name = "ds620",
    },
    .probe = ds620_probe,
    .remove = ds620_remove,
    .id_table = ds620_id,
};

module_i2c_driver(ds620_driver);

MODULE_AUTHOR("Roland Stigge <[email protected]>");
MODULE_DESCRIPTION("DS620 driver");
MODULE_LICENSE("GPL");