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/*

 * w83l785ts.c - Part of lm_sensors, Linux kernel modules for hardware

 *               monitoring

 * Copyright (C) 2003-2004  Jean Delvare <khali@linux-fr.org>

 *

 * Inspired from the lm83 driver. The W83L785TS-S is a sensor chip made

 * by Winbond. It reports a single external temperature with a 1 deg

 * resolution and a 3 deg accuracy. Datasheet can be obtained from

 * Winbond's website at:

 *   http://www.winbond-usa.com/products/winbond_products/pdfs/PCIC/W83L785TS-S.pdf

 *

 * Ported to Linux 2.6 by Wolfgang Ziegler <nuppla@gmx.at> and Jean Delvare

 * <khali@linux-fr.org>.

 *

 * Thanks to James Bolt <james@evilpenguin.com> for benchmarking the read

 * error handling mechanism.

 *

 * 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/delay.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>

/* How many retries on register read error */

#define MAX_RETRIES     5

/*

 * Address to scan

 * Address is fully defined internally and cannot be changed.

 */

static unsigned short normal_i2c[] = { 0x2e, I2C_CLIENT_END };

/*

 * Insmod parameters

 */

I2C_CLIENT_INSMOD_1(w83l785ts);

/*

 * The W83L785TS-S registers

 * Manufacturer ID is 0x5CA3 for Winbond.

 */

#define W83L785TS_REG_MAN_ID1           0x4D

#define W83L785TS_REG_MAN_ID2           0x4C

#define W83L785TS_REG_CHIP_ID           0x4E

#define W83L785TS_REG_CONFIG            0x40

#define W83L785TS_REG_TYPE              0x52

#define W83L785TS_REG_TEMP              0x27

#define W83L785TS_REG_TEMP_OVER         0x53 /* not sure about this one */

/*

 * Conversions

 * The W83L785TS-S uses signed 8-bit values.

 */

#define TEMP_FROM_REG(val)      ((val) * 1000)

/*

 * Functions declaration

 */

static int w83l785ts_attach_adapter(struct i2c_adapter *adapter);

static int w83l785ts_detect(struct i2c_adapter *adapter, int address,

        int kind);

static int w83l785ts_detach_client(struct i2c_client *client);

static u8 w83l785ts_read_value(struct i2c_client *client, u8 reg, u8 defval);

static struct w83l785ts_data *w83l785ts_update_device(struct device *dev);

/*

 * Driver data (common to all clients)

 */

static struct i2c_driver w83l785ts_driver = {

        .driver = {

                .name   = "w83l785ts",

        },

        .id             = I2C_DRIVERID_W83L785TS,

        .attach_adapter = w83l785ts_attach_adapter,

        .detach_client  = w83l785ts_detach_client,

};

/*

 * Client data (each client gets its own)

 */

struct w83l785ts_data {

        struct i2c_client client;

        struct device *hwmon_dev;

        struct mutex update_lock;

        char valid; /* zero until following fields are valid */

        unsigned long last_updated; /* in jiffies */

        /* registers values */

        s8 temp[2]; /* 0: input

                       1: critical limit */

};

/*

 * Sysfs stuff

 */

static ssize_t show_temp(struct device *dev, struct device_attribute *devattr,

        char *buf)

{

        struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);

        struct w83l785ts_data *data = w83l785ts_update_device(dev);

        return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[attr->index]));

}

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

static SENSOR_DEVICE_ATTR(temp1_max, S_IRUGO, show_temp, NULL, 1);

/*

 * Real code

 */

static int w83l785ts_attach_adapter(struct i2c_adapter *adapter)

{

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

                return 0;

        return i2c_probe(adapter, &addr_data, w83l785ts_detect);

}

/*

 * The following function does more than just detection. If detection

 * succeeds, it also registers the new chip.

 */

static int w83l785ts_detect(struct i2c_adapter *adapter, int address, int kind)

{

        struct i2c_client *new_client;

        struct w83l785ts_data *data;

        int err = 0;

        if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))

                goto exit;

        if (!(data = kzalloc(sizeof(struct w83l785ts_data), GFP_KERNEL))) {

                err = -ENOMEM;

                goto exit;

        }

        /* The common I2C client data is placed right before the

         * W83L785TS-specific data. */

        new_client = &data->client;

        i2c_set_clientdata(new_client, data);

        new_client->addr = address;

        new_client->adapter = adapter;

        new_client->driver = &w83l785ts_driver;

        new_client->flags = 0;

        /*

         * Now we do the remaining detection. A negative kind means that

         * the driver was loaded with no force parameter (default), so we

         * must both detect and identify the chip (actually there is only

         * one possible kind of chip for now, W83L785TS-S). A zero kind means

         * that the driver was loaded with the force parameter, the detection

         * step shall be skipped. A positive kind means that the driver

         * was loaded with the force parameter and a given kind of chip is

         * requested, so both the detection and the identification steps

         * are skipped.

         */

        if (kind < 0) { /* detection */

                if (((w83l785ts_read_value(new_client,

                      W83L785TS_REG_CONFIG, 0) & 0x80) != 0x00)

                 || ((w83l785ts_read_value(new_client,

                      W83L785TS_REG_TYPE, 0) & 0xFC) != 0x00)) {

                        dev_dbg(&adapter->dev,

                                "W83L785TS-S detection failed at 0x%02x.\n",

                                address);

                        goto exit_free;

                }

        }

        if (kind <= 0) { /* identification */

                u16 man_id;

                u8 chip_id;

                man_id = (w83l785ts_read_value(new_client,

                         W83L785TS_REG_MAN_ID1, 0) << 8) +

                         w83l785ts_read_value(new_client,

                         W83L785TS_REG_MAN_ID2, 0);

                chip_id = w83l785ts_read_value(new_client,

                          W83L785TS_REG_CHIP_ID, 0);

                if (man_id == 0x5CA3) { /* Winbond */

                        if (chip_id == 0x70) { /* W83L785TS-S */

                                kind = w83l785ts;

                        }

                }

                if (kind <= 0) { /* identification failed */

                        dev_info(&adapter->dev,

                                 "Unsupported chip (man_id=0x%04X, "

                                 "chip_id=0x%02X).\n", man_id, chip_id);

                        goto exit_free;

                }

        }

        /* We can fill in the remaining client fields. */

        strlcpy(new_client->name, "w83l785ts", I2C_NAME_SIZE);

        data->valid = 0;

        mutex_init(&data->update_lock);

        /* Default values in case the first read fails (unlikely). */

        data->temp[1] = data->temp[0] = 0;

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

        if ((err = i2c_attach_client(new_client)))

                goto exit_free;

        /*

         * Initialize the W83L785TS chip

         * Nothing yet, assume it is already started.

         */

        err = device_create_file(&new_client->dev,

                                 &sensor_dev_attr_temp1_input.dev_attr);

        if (err)

                goto exit_remove;

        err = device_create_file(&new_client->dev,

                                 &sensor_dev_attr_temp1_max.dev_attr);

        if (err)

                goto exit_remove;

        /* Register sysfs hooks */

        data->hwmon_dev = hwmon_device_register(&new_client->dev);

        if (IS_ERR(data->hwmon_dev)) {

                err = PTR_ERR(data->hwmon_dev);

                goto exit_remove;

        }

        return 0;

exit_remove:

        device_remove_file(&new_client->dev,

                           &sensor_dev_attr_temp1_input.dev_attr);

        device_remove_file(&new_client->dev,

                           &sensor_dev_attr_temp1_max.dev_attr);

        i2c_detach_client(new_client);

exit_free:

        kfree(data);

exit:

        return err;

}

static int w83l785ts_detach_client(struct i2c_client *client)

{

        struct w83l785ts_data *data = i2c_get_clientdata(client);

        int err;

        hwmon_device_unregister(data->hwmon_dev);

        device_remove_file(&client->dev,

                           &sensor_dev_attr_temp1_input.dev_attr);

        device_remove_file(&client->dev,

                           &sensor_dev_attr_temp1_max.dev_attr);

        if ((err = i2c_detach_client(client)))

                return err;

        kfree(data);

        return 0;

}

static u8 w83l785ts_read_value(struct i2c_client *client, u8 reg, u8 defval)

{

        int value, i;

        /* Frequent read errors have been reported on Asus boards, so we

         * retry on read errors. If it still fails (unlikely), return the

         * default value requested by the caller. */

        for (i = 1; i <= MAX_RETRIES; i++) {

                value = i2c_smbus_read_byte_data(client, reg);

                if (value >= 0) {

                        dev_dbg(&client->dev, "Read 0x%02x from register "

                                "0x%02x.\n", value, reg);

                        return value;

                }

                dev_dbg(&client->dev, "Read failed, will retry in %d.\n", i);

                msleep(i);

        }

        dev_err(&client->dev, "Couldn't read value from register 0x%02x. "

                "Please report.\n", reg);

        return defval;

}

static struct w83l785ts_data *w83l785ts_update_device(struct device *dev)

{

        struct i2c_client *client = to_i2c_client(dev);

        struct w83l785ts_data *data = i2c_get_clientdata(client);

        mutex_lock(&data->update_lock);

        if (!data->valid || time_after(jiffies, data->last_updated + HZ * 2)) {

                dev_dbg(&client->dev, "Updating w83l785ts data.\n");

                data->temp[0] = w83l785ts_read_value(client,

                                W83L785TS_REG_TEMP, data->temp[0]);

                data->temp[1] = w83l785ts_read_value(client,

                                W83L785TS_REG_TEMP_OVER, data->temp[1]);

                data->last_updated = jiffies;

                data->valid = 1;

        }

        mutex_unlock(&data->update_lock);

        return data;

}

static int __init sensors_w83l785ts_init(void)

{

        return i2c_add_driver(&w83l785ts_driver);

}

static void __exit sensors_w83l785ts_exit(void)

{

        i2c_del_driver(&w83l785ts_driver);

}

MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");

MODULE_DESCRIPTION("W83L785TS-S driver");

MODULE_LICENSE("GPL");

module_init(sensors_w83l785ts_init);

module_exit(sensors_w83l785ts_exit);