lm95241.c

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/*
 * Copyright (C) 2008, 2010 Davide Rizzo <[email protected]>
 *
 * The LM95241 is a sensor chip made by National Semiconductors.
 * It reports up to three temperatures (its own plus up to two external ones).
 * Complete datasheet can be obtained from National's website at:
 *   http://www.national.com/ds.cgi/LM/LM95241.pdf
 *
 * 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 "lm95241"

static const unsigned short normal_i2c[] = {
    0x19, 0x2a, 0x2b, I2C_CLIENT_END };

/* LM95241 registers */
#define LM95241_REG_R_MAN_ID        0xFE
#define LM95241_REG_R_CHIP_ID       0xFF
#define LM95241_REG_R_STATUS        0x02
#define LM95241_REG_RW_CONFIG       0x03
#define LM95241_REG_RW_REM_FILTER   0x06
#define LM95241_REG_RW_TRUTHERM     0x07
#define LM95241_REG_W_ONE_SHOT      0x0F
#define LM95241_REG_R_LOCAL_TEMPH   0x10
#define LM95241_REG_R_REMOTE1_TEMPH 0x11
#define LM95241_REG_R_REMOTE2_TEMPH 0x12
#define LM95241_REG_R_LOCAL_TEMPL   0x20
#define LM95241_REG_R_REMOTE1_TEMPL 0x21
#define LM95241_REG_R_REMOTE2_TEMPL 0x22
#define LM95241_REG_RW_REMOTE_MODEL 0x30

/* LM95241 specific bitfields */
#define CFG_STOP 0x40
#define CFG_CR0076 0x00
#define CFG_CR0182 0x10
#define CFG_CR1000 0x20
#define CFG_CR2700 0x30
#define R1MS_SHIFT 0
#define R2MS_SHIFT 2
#define R1MS_MASK (0x01 << (R1MS_SHIFT))
#define R2MS_MASK (0x01 << (R2MS_SHIFT))
#define R1DF_SHIFT 1
#define R2DF_SHIFT 2
#define R1DF_MASK (0x01 << (R1DF_SHIFT))
#define R2DF_MASK (0x01 << (R2DF_SHIFT))
#define R1FE_MASK 0x01
#define R2FE_MASK 0x05
#define TT1_SHIFT 0
#define TT2_SHIFT 4
#define TT_OFF 0
#define TT_ON 1
#define TT_MASK 7
#define NATSEMI_MAN_ID  0x01
#define LM95231_CHIP_ID 0xA1
#define LM95241_CHIP_ID 0xA4

static const u8 lm95241_reg_address[] = {
    LM95241_REG_R_LOCAL_TEMPH,
    LM95241_REG_R_LOCAL_TEMPL,
    LM95241_REG_R_REMOTE1_TEMPH,
    LM95241_REG_R_REMOTE1_TEMPL,
    LM95241_REG_R_REMOTE2_TEMPH,
    LM95241_REG_R_REMOTE2_TEMPL
};

/* Client data (each client gets its own) */
struct lm95241_data {
    struct device *hwmon_dev;
    struct mutex update_lock;
    unsigned long last_updated, interval;   /* in jiffies */
    char valid;     /* zero until following fields are valid */
    /* registers values */
    u8 temp[ARRAY_SIZE(lm95241_reg_address)];
    u8 config, model, trutherm;
};

/* Conversions */
static int temp_from_reg_signed(u8 val_h, u8 val_l)
{
    s16 val_hl = (val_h << 8) | val_l;
    return val_hl * 1000 / 256;
}

static int temp_from_reg_unsigned(u8 val_h, u8 val_l)
{
    u16 val_hl = (val_h << 8) | val_l;
    return val_hl * 1000 / 256;
}

static struct lm95241_data *lm95241_update_device(struct device *dev)
{
    struct i2c_client *client = to_i2c_client(dev);
    struct lm95241_data *data = i2c_get_clientdata(client);

    mutex_lock(&data->update_lock);

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

        dev_dbg(&client->dev, "Updating lm95241 data.\n");
        for (i = 0; i < ARRAY_SIZE(lm95241_reg_address); i++)
            data->temp[i]
              = i2c_smbus_read_byte_data(client,
                             lm95241_reg_address[i]);
        data->last_updated = jiffies;
        data->valid = 1;
    }

    mutex_unlock(&data->update_lock);

    return data;
}

/* Sysfs stuff */
static ssize_t show_input(struct device *dev, struct device_attribute *attr,
              char *buf)
{
    struct lm95241_data *data = lm95241_update_device(dev);
    int index = to_sensor_dev_attr(attr)->index;

    return snprintf(buf, PAGE_SIZE - 1, "%d\n",
            index == 0 || (data->config & (1 << (index / 2))) ?
        temp_from_reg_signed(data->temp[index], data->temp[index + 1]) :
        temp_from_reg_unsigned(data->temp[index],
                       data->temp[index + 1]));
}

static ssize_t show_type(struct device *dev, struct device_attribute *attr,
             char *buf)
{
    struct i2c_client *client = to_i2c_client(dev);
    struct lm95241_data *data = i2c_get_clientdata(client);

    return snprintf(buf, PAGE_SIZE - 1,
        data->model & to_sensor_dev_attr(attr)->index ? "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 lm95241_data *data = i2c_get_clientdata(client);
    unsigned long val;
    int shift;
    u8 mask = to_sensor_dev_attr(attr)->index;

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

    shift = mask == R1MS_MASK ? TT1_SHIFT : TT2_SHIFT;

    mutex_lock(&data->update_lock);

    data->trutherm &= ~(TT_MASK << shift);
    if (val == 1) {
        data->model |= mask;
        data->trutherm |= (TT_ON << shift);
    } else {
        data->model &= ~mask;
        data->trutherm |= (TT_OFF << shift);
    }
    data->valid = 0;

    i2c_smbus_write_byte_data(client, LM95241_REG_RW_REMOTE_MODEL,
                  data->model);
    i2c_smbus_write_byte_data(client, LM95241_REG_RW_TRUTHERM,
                  data->trutherm);

    mutex_unlock(&data->update_lock);

    return count;
}

static ssize_t show_min(struct device *dev, struct device_attribute *attr,
            char *buf)
{
    struct i2c_client *client = to_i2c_client(dev);
    struct lm95241_data *data = i2c_get_clientdata(client);

    return snprintf(buf, PAGE_SIZE - 1,
            data->config & to_sensor_dev_attr(attr)->index ?
            "-127000\n" : "0\n");
}

static ssize_t set_min(struct device *dev, struct device_attribute *attr,
               const char *buf, size_t count)
{
    struct i2c_client *client = to_i2c_client(dev);
    struct lm95241_data *data = i2c_get_clientdata(client);
    long val;

    if (kstrtol(buf, 10, &val) < 0)
        return -EINVAL;
    if (val < -128000)
        return -EINVAL;

    mutex_lock(&data->update_lock);

    if (val < 0)
        data->config |= to_sensor_dev_attr(attr)->index;
    else
        data->config &= ~to_sensor_dev_attr(attr)->index;
    data->valid = 0;

    i2c_smbus_write_byte_data(client, LM95241_REG_RW_CONFIG, data->config);

    mutex_unlock(&data->update_lock);

    return count;
}

static ssize_t show_max(struct device *dev, struct device_attribute *attr,
            char *buf)
{
    struct i2c_client *client = to_i2c_client(dev);
    struct lm95241_data *data = i2c_get_clientdata(client);

    return snprintf(buf, PAGE_SIZE - 1,
            data->config & to_sensor_dev_attr(attr)->index ?
            "127000\n" : "255000\n");
}

static ssize_t set_max(struct device *dev, struct device_attribute *attr,
               const char *buf, size_t count)
{
    struct i2c_client *client = to_i2c_client(dev);
    struct lm95241_data *data = i2c_get_clientdata(client);
    long val;

    if (kstrtol(buf, 10, &val) < 0)
        return -EINVAL;
    if (val >= 256000)
        return -EINVAL;

    mutex_lock(&data->update_lock);

    if (val <= 127000)
        data->config |= to_sensor_dev_attr(attr)->index;
    else
        data->config &= ~to_sensor_dev_attr(attr)->index;
    data->valid = 0;

    i2c_smbus_write_byte_data(client, LM95241_REG_RW_CONFIG, data->config);

    mutex_unlock(&data->update_lock);

    return count;
}

static ssize_t show_interval(struct device *dev, struct device_attribute *attr,
                 char *buf)
{
    struct lm95241_data *data = lm95241_update_device(dev);

    return snprintf(buf, PAGE_SIZE - 1, "%lu\n", 1000 * data->interval
            / HZ);
}

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 lm95241_data *data = i2c_get_clientdata(client);
    unsigned long val;

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

    data->interval = val * HZ / 1000;

    return count;
}

static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_input, NULL, 0);
static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_input, NULL, 2);
static SENSOR_DEVICE_ATTR(temp3_input, S_IRUGO, show_input, NULL, 4);
static SENSOR_DEVICE_ATTR(temp2_type, S_IWUSR | S_IRUGO, show_type, set_type,
              R1MS_MASK);
static SENSOR_DEVICE_ATTR(temp3_type, S_IWUSR | S_IRUGO, show_type, set_type,
              R2MS_MASK);
static SENSOR_DEVICE_ATTR(temp2_min, S_IWUSR | S_IRUGO, show_min, set_min,
              R1DF_MASK);
static SENSOR_DEVICE_ATTR(temp3_min, S_IWUSR | S_IRUGO, show_min, set_min,
              R2DF_MASK);
static SENSOR_DEVICE_ATTR(temp2_max, S_IWUSR | S_IRUGO, show_max, set_max,
              R1DF_MASK);
static SENSOR_DEVICE_ATTR(temp3_max, S_IWUSR | S_IRUGO, show_max, set_max,
              R2DF_MASK);
static DEVICE_ATTR(update_interval, S_IWUSR | S_IRUGO, show_interval,
           set_interval);

static struct attribute *lm95241_attributes[] = {
    &sensor_dev_attr_temp1_input.dev_attr.attr,
    &sensor_dev_attr_temp2_input.dev_attr.attr,
    &sensor_dev_attr_temp3_input.dev_attr.attr,
    &sensor_dev_attr_temp2_type.dev_attr.attr,
    &sensor_dev_attr_temp3_type.dev_attr.attr,
    &sensor_dev_attr_temp2_min.dev_attr.attr,
    &sensor_dev_attr_temp3_min.dev_attr.attr,
    &sensor_dev_attr_temp2_max.dev_attr.attr,
    &sensor_dev_attr_temp3_max.dev_attr.attr,
    &dev_attr_update_interval.attr,
    NULL
};

static const struct attribute_group lm95241_group = {
    .attrs = lm95241_attributes,
};

/* Return 0 if detection is successful, -ENODEV otherwise */
static int lm95241_detect(struct i2c_client *new_client,
              struct i2c_board_info *info)
{
    struct i2c_adapter *adapter = new_client->adapter;
    const char *name;
    int mfg_id, chip_id;

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

    mfg_id = i2c_smbus_read_byte_data(new_client, LM95241_REG_R_MAN_ID);
    if (mfg_id != NATSEMI_MAN_ID)
        return -ENODEV;

    chip_id = i2c_smbus_read_byte_data(new_client, LM95241_REG_R_CHIP_ID);
    switch (chip_id) {
    case LM95231_CHIP_ID:
        name = "lm95231";
        break;
    case LM95241_CHIP_ID:
        name = "lm95241";
        break;
    default:
        return -ENODEV;
    }

    /* Fill the i2c board info */
    strlcpy(info->type, name, I2C_NAME_SIZE);
    return 0;
}

static void lm95241_init_client(struct i2c_client *client)
{
    struct lm95241_data *data = i2c_get_clientdata(client);

    data->interval = HZ;    /* 1 sec default */
    data->valid = 0;
    data->config = CFG_CR0076;
    data->model = 0;
    data->trutherm = (TT_OFF << TT1_SHIFT) | (TT_OFF << TT2_SHIFT);

    i2c_smbus_write_byte_data(client, LM95241_REG_RW_CONFIG, data->config);
    i2c_smbus_write_byte_data(client, LM95241_REG_RW_REM_FILTER,
                  R1FE_MASK | R2FE_MASK);
    i2c_smbus_write_byte_data(client, LM95241_REG_RW_TRUTHERM,
                  data->trutherm);
    i2c_smbus_write_byte_data(client, LM95241_REG_RW_REMOTE_MODEL,
                  data->model);
}

static int lm95241_probe(struct i2c_client *new_client,
             const struct i2c_device_id *id)
{
    struct lm95241_data *data;
    int err;

    data = devm_kzalloc(&new_client->dev, sizeof(struct lm95241_data),
                GFP_KERNEL);
    if (!data)
        return -ENOMEM;

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

    /* Initialize the LM95241 chip */
    lm95241_init_client(new_client);

    /* Register sysfs hooks */
    err = sysfs_create_group(&new_client->dev.kobj, &lm95241_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, &lm95241_group);
    return err;
}

static int lm95241_remove(struct i2c_client *client)
{
    struct lm95241_data *data = i2c_get_clientdata(client);

    hwmon_device_unregister(data->hwmon_dev);
    sysfs_remove_group(&client->dev.kobj, &lm95241_group);

    return 0;
}

/* Driver data (common to all clients) */
static const struct i2c_device_id lm95241_id[] = {
    { "lm95231", 0 },
    { "lm95241", 0 },
    { }
};
MODULE_DEVICE_TABLE(i2c, lm95241_id);

static struct i2c_driver lm95241_driver = {
    .class      = I2C_CLASS_HWMON,
    .driver = {
        .name   = DEVNAME,
    },
    .probe      = lm95241_probe,
    .remove     = lm95241_remove,
    .id_table   = lm95241_id,
    .detect     = lm95241_detect,
    .address_list   = normal_i2c,
};

module_i2c_driver(lm95241_driver);

MODULE_AUTHOR("Davide Rizzo <[email protected]>");
MODULE_DESCRIPTION("LM95241 sensor driver");
MODULE_LICENSE("GPL");