lm95245.c

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/*
 * Copyright (C) 2011 Alexander Stein <[email protected]>
 *
 * The LM95245 is a sensor chip made by National Semiconductors.
 * It reports up to two temperatures (its own plus an external one).
 * Complete datasheet can be obtained from National's website at:
 *   http://www.national.com/ds.cgi/LM/LM95245.pdf
 *
 * This driver is based on lm95241.c
 *
 * 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>

#define DEVNAME "lm95245"

static const unsigned short normal_i2c[] = {
    0x18, 0x19, 0x29, 0x4c, 0x4d, I2C_CLIENT_END };

/* LM95245 registers */
/* general registers */
#define LM95245_REG_RW_CONFIG1      0x03
#define LM95245_REG_RW_CONVERS_RATE 0x04
#define LM95245_REG_W_ONE_SHOT      0x0F

/* diode configuration */
#define LM95245_REG_RW_CONFIG2      0xBF
#define LM95245_REG_RW_REMOTE_OFFH  0x11
#define LM95245_REG_RW_REMOTE_OFFL  0x12

/* status registers */
#define LM95245_REG_R_STATUS1       0x02
#define LM95245_REG_R_STATUS2       0x33

/* limit registers */
#define LM95245_REG_RW_REMOTE_OS_LIMIT      0x07
#define LM95245_REG_RW_LOCAL_OS_TCRIT_LIMIT 0x20
#define LM95245_REG_RW_REMOTE_TCRIT_LIMIT   0x19
#define LM95245_REG_RW_COMMON_HYSTERESIS    0x21

/* temperature signed */
#define LM95245_REG_R_LOCAL_TEMPH_S 0x00
#define LM95245_REG_R_LOCAL_TEMPL_S 0x30
#define LM95245_REG_R_REMOTE_TEMPH_S    0x01
#define LM95245_REG_R_REMOTE_TEMPL_S    0x10
/* temperature unsigned */
#define LM95245_REG_R_REMOTE_TEMPH_U    0x31
#define LM95245_REG_R_REMOTE_TEMPL_U    0x32

/* id registers */
#define LM95245_REG_R_MAN_ID        0xFE
#define LM95245_REG_R_CHIP_ID       0xFF

/* LM95245 specific bitfields */
#define CFG_STOP        0x40
#define CFG_REMOTE_TCRIT_MASK   0x10
#define CFG_REMOTE_OS_MASK  0x08
#define CFG_LOCAL_TCRIT_MASK    0x04
#define CFG_LOCAL_OS_MASK   0x02

#define CFG2_OS_A0      0x40
#define CFG2_DIODE_FAULT_OS 0x20
#define CFG2_DIODE_FAULT_TCRIT  0x10
#define CFG2_REMOTE_TT      0x08
#define CFG2_REMOTE_FILTER_DIS  0x00
#define CFG2_REMOTE_FILTER_EN   0x06

/* conversation rate in ms */
#define RATE_CR0063 0x00
#define RATE_CR0364 0x01
#define RATE_CR1000 0x02
#define RATE_CR2500 0x03

#define STATUS1_DIODE_FAULT 0x04
#define STATUS1_RTCRIT      0x02
#define STATUS1_LOC     0x01

#define MANUFACTURER_ID     0x01
#define DEFAULT_REVISION    0xB3

static const u8 lm95245_reg_address[] = {
    LM95245_REG_R_LOCAL_TEMPH_S,
    LM95245_REG_R_LOCAL_TEMPL_S,
    LM95245_REG_R_REMOTE_TEMPH_S,
    LM95245_REG_R_REMOTE_TEMPL_S,
    LM95245_REG_R_REMOTE_TEMPH_U,
    LM95245_REG_R_REMOTE_TEMPL_U,
    LM95245_REG_RW_LOCAL_OS_TCRIT_LIMIT,
    LM95245_REG_RW_REMOTE_TCRIT_LIMIT,
    LM95245_REG_RW_COMMON_HYSTERESIS,
    LM95245_REG_R_STATUS1,
};

/* Client data (each client gets its own) */
struct lm95245_data {
    struct device *hwmon_dev;
    struct mutex update_lock;
    unsigned long last_updated; /* in jiffies */
    unsigned long interval; /* in msecs */
    bool valid;     /* zero until following fields are valid */
    /* registers values */
    u8 regs[ARRAY_SIZE(lm95245_reg_address)];
    u8 config1, config2;
};

/* Conversions */
static int temp_from_reg_unsigned(u8 val_h, u8 val_l)
{
    return val_h * 1000 + val_l * 1000 / 256;
}

static int temp_from_reg_signed(u8 val_h, u8 val_l)
{
    if (val_h & 0x80)
        return (val_h - 0x100) * 1000;
    return temp_from_reg_unsigned(val_h, val_l);
}

static struct lm95245_data *lm95245_update_device(struct device *dev)
{
    struct i2c_client *client = to_i2c_client(dev);
    struct lm95245_data *data = i2c_get_clientdata(client);

    mutex_lock(&data->update_lock);

    if (time_after(jiffies, data->last_updated
        + msecs_to_jiffies(data->interval)) || !data->valid) {
        int i;

        dev_dbg(&client->dev, "Updating lm95245 data.\n");
        for (i = 0; i < ARRAY_SIZE(lm95245_reg_address); i++)
            data->regs[i]
              = i2c_smbus_read_byte_data(client,
                             lm95245_reg_address[i]);
        data->last_updated = jiffies;
        data->valid = 1;
    }

    mutex_unlock(&data->update_lock);

    return data;
}

static unsigned long lm95245_read_conversion_rate(struct i2c_client *client)
{
    int rate;
    unsigned long interval;

    rate = i2c_smbus_read_byte_data(client, LM95245_REG_RW_CONVERS_RATE);

    switch (rate) {
    case RATE_CR0063:
        interval = 63;
        break;
    case RATE_CR0364:
        interval = 364;
        break;
    case RATE_CR1000:
        interval = 1000;
        break;
    case RATE_CR2500:
    default:
        interval = 2500;
        break;
    }

    return interval;
}

static unsigned long lm95245_set_conversion_rate(struct i2c_client *client,
            unsigned long interval)
{
    int rate;

    if (interval <= 63) {
        interval = 63;
        rate = RATE_CR0063;
    } else if (interval <= 364) {
        interval = 364;
        rate = RATE_CR0364;
    } else if (interval <= 1000) {
        interval = 1000;
        rate = RATE_CR1000;
    } else {
        interval = 2500;
        rate = RATE_CR2500;
    }

    i2c_smbus_write_byte_data(client, LM95245_REG_RW_CONVERS_RATE, rate);

    return interval;
}

/* Sysfs stuff */
static ssize_t show_input(struct device *dev, struct device_attribute *attr,
              char *buf)
{
    struct lm95245_data *data = lm95245_update_device(dev);
    int temp;
    int index = to_sensor_dev_attr(attr)->index;

    /*
     * Index 0 (Local temp) is always signed
     * Index 2 (Remote temp) has both signed and unsigned data
     * use signed calculation for remote if signed bit is set
     */
    if (index == 0 || data->regs[index] & 0x80)
        temp = temp_from_reg_signed(data->regs[index],
                data->regs[index + 1]);
    else
        temp = temp_from_reg_unsigned(data->regs[index + 2],
                data->regs[index + 3]);

    return snprintf(buf, PAGE_SIZE - 1, "%d\n", temp);
}

static ssize_t show_limit(struct device *dev, struct device_attribute *attr,
             char *buf)
{
    struct lm95245_data *data = lm95245_update_device(dev);
    int index = to_sensor_dev_attr(attr)->index;

    return snprintf(buf, PAGE_SIZE - 1, "%d\n",
            data->regs[index] * 1000);
}

static ssize_t set_limit(struct device *dev, struct device_attribute *attr,
            const char *buf, size_t count)
{
    struct i2c_client *client = to_i2c_client(dev);
    struct lm95245_data *data = i2c_get_clientdata(client);
    int index = to_sensor_dev_attr(attr)->index;
    unsigned long val;

    if (kstrtoul(buf, 10, &val) < 0)
        return -EINVAL;

    val /= 1000;

    val = SENSORS_LIMIT(val, 0, (index == 6 ? 127 : 255));

    mutex_lock(&data->update_lock);

    data->valid = 0;

    i2c_smbus_write_byte_data(client, lm95245_reg_address[index], val);

    mutex_unlock(&data->update_lock);

    return count;
}

static ssize_t set_crit_hyst(struct device *dev, struct device_attribute *attr,
            const char *buf, size_t count)
{
    struct i2c_client *client = to_i2c_client(dev);
    struct lm95245_data *data = i2c_get_clientdata(client);
    unsigned long val;

    if (kstrtoul(buf, 10, &val) < 0)
        return -EINVAL;

    val /= 1000;

    val = SENSORS_LIMIT(val, 0, 31);

    mutex_lock(&data->update_lock);

    data->valid = 0;

    /* shared crit hysteresis */
    i2c_smbus_write_byte_data(client, LM95245_REG_RW_COMMON_HYSTERESIS,
        val);

    mutex_unlock(&data->update_lock);

    return count;
}

static ssize_t show_type(struct device *dev, struct device_attribute *attr,
             char *buf)
{
    struct i2c_client *client = to_i2c_client(dev);
    struct lm95245_data *data = i2c_get_clientdata(client);

    return snprintf(buf, PAGE_SIZE - 1,
        data->config2 & CFG2_REMOTE_TT ? "1\n" : "2\n");
}

static ssize_t set_type(struct device *dev, struct device_attribute *attr,
            const char *buf, size_t count)
{
    struct i2c_client *client = to_i2c_client(dev);
    struct lm95245_data *data = i2c_get_clientdata(client);
    unsigned long val;

    if (kstrtoul(buf, 10, &val) < 0)
        return -EINVAL;
    if (val != 1 && val != 2)
        return -EINVAL;

    mutex_lock(&data->update_lock);

    if (val == 1)
        data->config2 |= CFG2_REMOTE_TT;
    else
        data->config2 &= ~CFG2_REMOTE_TT;

    data->valid = 0;

    i2c_smbus_write_byte_data(client, LM95245_REG_RW_CONFIG2,
                  data->config2);

    mutex_unlock(&data->update_lock);

    return count;
}

static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
             char *buf)
{
    struct lm95245_data *data = lm95245_update_device(dev);
    int index = to_sensor_dev_attr(attr)->index;

    return snprintf(buf, PAGE_SIZE - 1, "%d\n",
            !!(data->regs[9] & index));
}

static ssize_t show_interval(struct device *dev, struct device_attribute *attr,
                 char *buf)
{
    struct lm95245_data *data = lm95245_update_device(dev);

    return snprintf(buf, PAGE_SIZE - 1, "%lu\n", data->interval);
}

static ssize_t set_interval(struct device *dev, struct device_attribute *attr,
                const char *buf, size_t count)
{
    struct i2c_client *client = to_i2c_client(dev);
    struct lm95245_data *data = i2c_get_clientdata(client);
    unsigned long val;

    if (kstrtoul(buf, 10, &val) < 0)
        return -EINVAL;

    mutex_lock(&data->update_lock);

    data->interval = lm95245_set_conversion_rate(client, val);

    mutex_unlock(&data->update_lock);

    return count;
}

static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_input, NULL, 0);
static SENSOR_DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_limit,
        set_limit, 6);
static SENSOR_DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_limit,
        set_crit_hyst, 8);
static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL,
        STATUS1_LOC);

static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_input, NULL, 2);
static SENSOR_DEVICE_ATTR(temp2_crit, S_IWUSR | S_IRUGO, show_limit,
        set_limit, 7);
static SENSOR_DEVICE_ATTR(temp2_crit_hyst, S_IWUSR | S_IRUGO, show_limit,
        set_crit_hyst, 8);
static SENSOR_DEVICE_ATTR(temp2_crit_alarm, S_IRUGO, show_alarm, NULL,
        STATUS1_RTCRIT);
static SENSOR_DEVICE_ATTR(temp2_type, S_IWUSR | S_IRUGO, show_type,
        set_type, 0);
static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO, show_alarm, NULL,
        STATUS1_DIODE_FAULT);

static DEVICE_ATTR(update_interval, S_IWUSR | S_IRUGO, show_interval,
        set_interval);

static struct attribute *lm95245_attributes[] = {
    &sensor_dev_attr_temp1_input.dev_attr.attr,
    &sensor_dev_attr_temp1_crit.dev_attr.attr,
    &sensor_dev_attr_temp1_crit_hyst.dev_attr.attr,
    &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
    &sensor_dev_attr_temp2_input.dev_attr.attr,
    &sensor_dev_attr_temp2_crit.dev_attr.attr,
    &sensor_dev_attr_temp2_crit_hyst.dev_attr.attr,
    &sensor_dev_attr_temp2_crit_alarm.dev_attr.attr,
    &sensor_dev_attr_temp2_type.dev_attr.attr,
    &sensor_dev_attr_temp2_fault.dev_attr.attr,
    &dev_attr_update_interval.attr,
    NULL
};

static const struct attribute_group lm95245_group = {
    .attrs = lm95245_attributes,
};

/* Return 0 if detection is successful, -ENODEV otherwise */
static int lm95245_detect(struct i2c_client *new_client,
              struct i2c_board_info *info)
{
    struct i2c_adapter *adapter = new_client->adapter;

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

    if (i2c_smbus_read_byte_data(new_client, LM95245_REG_R_MAN_ID)
            != MANUFACTURER_ID
        || i2c_smbus_read_byte_data(new_client, LM95245_REG_R_CHIP_ID)
            != DEFAULT_REVISION)
        return -ENODEV;

    strlcpy(info->type, DEVNAME, I2C_NAME_SIZE);
    return 0;
}

static void lm95245_init_client(struct i2c_client *client)
{
    struct lm95245_data *data = i2c_get_clientdata(client);

    data->valid = 0;
    data->interval = lm95245_read_conversion_rate(client);

    data->config1 = i2c_smbus_read_byte_data(client,
        LM95245_REG_RW_CONFIG1);
    data->config2 = i2c_smbus_read_byte_data(client,
        LM95245_REG_RW_CONFIG2);

    if (data->config1 & CFG_STOP) {
        /* Clear the standby bit */
        data->config1 &= ~CFG_STOP;
        i2c_smbus_write_byte_data(client, LM95245_REG_RW_CONFIG1,
            data->config1);
    }
}

static int lm95245_probe(struct i2c_client *new_client,
             const struct i2c_device_id *id)
{
    struct lm95245_data *data;
    int err;

    data = devm_kzalloc(&new_client->dev, sizeof(struct lm95245_data),
                GFP_KERNEL);
    if (!data)
        return -ENOMEM;

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

    /* Initialize the LM95245 chip */
    lm95245_init_client(new_client);

    /* Register sysfs hooks */
    err = sysfs_create_group(&new_client->dev.kobj, &lm95245_group);
    if (err)
        return err;

    data->hwmon_dev = hwmon_device_register(&new_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(&new_client->dev.kobj, &lm95245_group);
    return err;
}

static int lm95245_remove(struct i2c_client *client)
{
    struct lm95245_data *data = i2c_get_clientdata(client);

    hwmon_device_unregister(data->hwmon_dev);
    sysfs_remove_group(&client->dev.kobj, &lm95245_group);

    return 0;
}

/* Driver data (common to all clients) */
static const struct i2c_device_id lm95245_id[] = {
    { DEVNAME, 0 },
    { }
};
MODULE_DEVICE_TABLE(i2c, lm95245_id);

static struct i2c_driver lm95245_driver = {
    .class      = I2C_CLASS_HWMON,
    .driver = {
        .name   = DEVNAME,
    },
    .probe      = lm95245_probe,
    .remove     = lm95245_remove,
    .id_table   = lm95245_id,
    .detect     = lm95245_detect,
    .address_list   = normal_i2c,
};

module_i2c_driver(lm95245_driver);

MODULE_AUTHOR("Alexander Stein <[email protected]>");
MODULE_DESCRIPTION("LM95245 sensor driver");
MODULE_LICENSE("GPL");