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/*

    ds1621.c - Part of lm_sensors, Linux kernel modules for hardware

             monitoring

    Christian W. Zuckschwerdt  <zany@triq.net>  2000-11-23

    based on lm75.c by Frodo Looijaard <frodol@dds.nl>

    Ported to Linux 2.6 by Aurelien Jarno <aurelien@aurel32.net> with

    the help of Jean Delvare <khali@linux-fr.org>

    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 unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,

                                        0x4d, 0x4e, 0x4f, I2C_CLIENT_END };

/* Insmod parameters */

I2C_CLIENT_INSMOD_1(ds1621);

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 i2c_client client;

        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 int ds1621_attach_adapter(struct i2c_adapter *adapter);

static int ds1621_detect(struct i2c_adapter *adapter, int address,

                         int kind);

static void ds1621_init_client(struct i2c_client *client);

static int ds1621_detach_client(struct i2c_client *client);

static struct ds1621_data *ds1621_update_client(struct device *dev);

/* This is the driver that will be inserted */

static struct i2c_driver ds1621_driver = {

        .driver = {

                .name   = "ds1621",

        },

        .id             = I2C_DRIVERID_DS1621,

        .attach_adapter = ds1621_attach_adapter,

        .detach_client  = ds1621_detach_client,

};

/* All registers are word-sized, except for the configuration register.

   DS1621 uses a high-byte first convention, which is exactly opposite to

   the SMBus standard. */

static int ds1621_read_value(struct i2c_client *client, u8 reg)

{

        if (reg == DS1621_REG_CONF)

                return i2c_smbus_read_byte_data(client, reg);

        else

                return swab16(i2c_smbus_read_word_data(client, reg));

}

static int ds1621_write_value(struct i2c_client *client, u8 reg, u16 value)

{

        if (reg == DS1621_REG_CONF)

                return i2c_smbus_write_byte_data(client, reg, value);

        else

                return i2c_smbus_write_word_data(client, reg, swab16(value));

}

static void ds1621_init_client(struct i2c_client *client)

{

        int reg = ds1621_read_value(client, DS1621_REG_CONF);

        /* switch to continuous conversion mode */

        reg &= ~ DS1621_REG_CONFIG_1SHOT;

        /* setup output polarity */

        if (polarity == 0)

                reg &= ~DS1621_REG_CONFIG_POLARITY;

        else if (polarity == 1)

                reg |= DS1621_REG_CONFIG_POLARITY;

        ds1621_write_value(client, DS1621_REG_CONF, reg);

        /* start conversion */

        i2c_smbus_write_byte(client, DS1621_COM_START);

}

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 = ds1621_update_client(dev);

        u16 val = LM75_TEMP_TO_REG(simple_strtol(buf, NULL, 10));

        mutex_lock(&data->update_lock);

        data->temp[attr->index] = val;

        ds1621_write_value(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,

};

static int ds1621_attach_adapter(struct i2c_adapter *adapter)

{

        if (!(adapter->class & I2C_CLASS_HWMON))

                return 0;

        return i2c_probe(adapter, &addr_data, ds1621_detect);

}

/* This function is called by i2c_probe */

static int ds1621_detect(struct i2c_adapter *adapter, int address,

                         int kind)

{

        int conf, temp;

        struct i2c_client *client;

        struct ds1621_data *data;

        int i, err = 0;

        if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA

                                     | I2C_FUNC_SMBUS_WORD_DATA

                                     | I2C_FUNC_SMBUS_WRITE_BYTE))

                goto exit;

        /* OK. For now, we presume we have a valid client. We now create the

           client structure, even though we cannot fill it completely yet.

           But it allows us to access ds1621_{read,write}_value. */

        if (!(data = kzalloc(sizeof(struct ds1621_data), GFP_KERNEL))) {

                err = -ENOMEM;

                goto exit;

        }

        client = &data->client;

        i2c_set_clientdata(client, data);

        client->addr = address;

        client->adapter = adapter;

        client->driver = &ds1621_driver;

        /* Now, we do the remaining detection. It is lousy. */

        if (kind < 0) {

                /* 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 = ds1621_read_value(client, DS1621_REG_CONF);

                if (conf & DS1621_REG_CONFIG_NVB)

                        goto exit_free;

                /* The 7 lowest bits of a temperature should always be 0. */

                for (i = 0; i < ARRAY_SIZE(data->temp); i++) {

                        temp = ds1621_read_value(client, DS1621_REG_TEMP[i]);

                        if (temp & 0x007f)

                                goto exit_free;

                }

        }

        /* Fill in remaining client fields and put it into the global list */

        strlcpy(client->name, "ds1621", I2C_NAME_SIZE);

        mutex_init(&data->update_lock);

        /* Tell the I2C layer a new client has arrived */

        if ((err = i2c_attach_client(client)))

                goto exit_free;

        /* Initialize the DS1621 chip */

        ds1621_init_client(client);

        /* Register sysfs hooks */

        if ((err = sysfs_create_group(&client->dev.kobj, &ds1621_group)))

                goto exit_detach;

        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);

      exit_detach:

        i2c_detach_client(client);

      exit_free:

        kfree(data);

      exit:

        return err;

}

static int ds1621_detach_client(struct i2c_client *client)

{

        struct ds1621_data *data = i2c_get_clientdata(client);

        int err;

        hwmon_device_unregister(data->hwmon_dev);

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

        if ((err = i2c_detach_client(client)))

                return err;

        kfree(data);

        return 0;

}

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 = ds1621_read_value(client, DS1621_REG_CONF);

                for (i = 0; i < ARRAY_SIZE(data->temp); i++)

                        data->temp[i] = ds1621_read_value(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)

                        ds1621_write_value(client, DS1621_REG_CONF,

                                           new_conf);

                data->last_updated = jiffies;

                data->valid = 1;

        }

        mutex_unlock(&data->update_lock);

        return data;

}

static int __init ds1621_init(void)

{

        return i2c_add_driver(&ds1621_driver);

}

static void __exit ds1621_exit(void)

{

        i2c_del_driver(&ds1621_driver);

}

MODULE_AUTHOR("Christian W. Zuckschwerdt <zany@triq.net>");

MODULE_DESCRIPTION("DS1621 driver");

MODULE_LICENSE("GPL");

module_init(ds1621_init);

module_exit(ds1621_exit);