adt7411.c

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/*
 *  Driver for the ADT7411 (I2C/SPI 8 channel 10 bit ADC & temperature-sensor)
 *
 *  Copyright (C) 2008, 2010 Pengutronix
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2 as
 *  published by the Free Software Foundation.
 *
 *  TODO: SPI, support for external temperature sensor
 *    use power-down mode for suspend?, interrupt handling?
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/jiffies.h>
#include <linux/i2c.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/slab.h>

#define ADT7411_REG_INT_TEMP_VDD_LSB        0x03
#define ADT7411_REG_EXT_TEMP_AIN14_LSB      0x04
#define ADT7411_REG_VDD_MSB         0x06
#define ADT7411_REG_INT_TEMP_MSB        0x07
#define ADT7411_REG_EXT_TEMP_AIN1_MSB       0x08

#define ADT7411_REG_CFG1            0x18
#define ADT7411_CFG1_START_MONITOR      (1 << 0)

#define ADT7411_REG_CFG2            0x19
#define ADT7411_CFG2_DISABLE_AVG        (1 << 5)

#define ADT7411_REG_CFG3            0x1a
#define ADT7411_CFG3_ADC_CLK_225        (1 << 0)
#define ADT7411_CFG3_REF_VDD            (1 << 4)

#define ADT7411_REG_DEVICE_ID           0x4d
#define ADT7411_REG_MANUFACTURER_ID     0x4e

#define ADT7411_DEVICE_ID           0x2
#define ADT7411_MANUFACTURER_ID         0x41

static const unsigned short normal_i2c[] = { 0x48, 0x4a, 0x4b, I2C_CLIENT_END };

struct adt7411_data {
    struct mutex device_lock;   /* for "atomic" device accesses */
    struct mutex update_lock;
    unsigned long next_update;
    int vref_cached;
    struct device *hwmon_dev;
};

/*
 * When reading a register containing (up to 4) lsb, all associated
 * msb-registers get locked by the hardware. After _one_ of those msb is read,
 * _all_ are unlocked. In order to use this locking correctly, reading lsb/msb
 * is protected here with a mutex, too.
 */
static int adt7411_read_10_bit(struct i2c_client *client, u8 lsb_reg,
                u8 msb_reg, u8 lsb_shift)
{
    struct adt7411_data *data = i2c_get_clientdata(client);
    int val, tmp;

    mutex_lock(&data->device_lock);

    val = i2c_smbus_read_byte_data(client, lsb_reg);
    if (val < 0)
        goto exit_unlock;

    tmp = (val >> lsb_shift) & 3;
    val = i2c_smbus_read_byte_data(client, msb_reg);

    if (val >= 0)
        val = (val << 2) | tmp;

 exit_unlock:
    mutex_unlock(&data->device_lock);

    return val;
}

static int adt7411_modify_bit(struct i2c_client *client, u8 reg, u8 bit,
                bool flag)
{
    struct adt7411_data *data = i2c_get_clientdata(client);
    int ret, val;

    mutex_lock(&data->device_lock);

    ret = i2c_smbus_read_byte_data(client, reg);
    if (ret < 0)
        goto exit_unlock;

    if (flag)
        val = ret | bit;
    else
        val = ret & ~bit;

    ret = i2c_smbus_write_byte_data(client, reg, val);

 exit_unlock:
    mutex_unlock(&data->device_lock);
    return ret;
}

static ssize_t adt7411_show_vdd(struct device *dev,
                struct device_attribute *attr, char *buf)
{
    struct i2c_client *client = to_i2c_client(dev);
    int ret = adt7411_read_10_bit(client, ADT7411_REG_INT_TEMP_VDD_LSB,
            ADT7411_REG_VDD_MSB, 2);

    return ret < 0 ? ret : sprintf(buf, "%u\n", ret * 7000 / 1024);
}

static ssize_t adt7411_show_temp(struct device *dev,
            struct device_attribute *attr, char *buf)
{
    struct i2c_client *client = to_i2c_client(dev);
    int val = adt7411_read_10_bit(client, ADT7411_REG_INT_TEMP_VDD_LSB,
            ADT7411_REG_INT_TEMP_MSB, 0);

    if (val < 0)
        return val;

    val = val & 0x200 ? val - 0x400 : val; /* 10 bit signed */

    return sprintf(buf, "%d\n", val * 250);
}

static ssize_t adt7411_show_input(struct device *dev,
                  struct device_attribute *attr, char *buf)
{
    int nr = to_sensor_dev_attr(attr)->index;
    struct i2c_client *client = to_i2c_client(dev);
    struct adt7411_data *data = i2c_get_clientdata(client);
    int val;
    u8 lsb_reg, lsb_shift;

    mutex_lock(&data->update_lock);
    if (time_after_eq(jiffies, data->next_update)) {
        val = i2c_smbus_read_byte_data(client, ADT7411_REG_CFG3);
        if (val < 0)
            goto exit_unlock;

        if (val & ADT7411_CFG3_REF_VDD) {
            val = adt7411_read_10_bit(client,
                    ADT7411_REG_INT_TEMP_VDD_LSB,
                    ADT7411_REG_VDD_MSB, 2);
            if (val < 0)
                goto exit_unlock;

            data->vref_cached = val * 7000 / 1024;
        } else {
            data->vref_cached = 2250;
        }

        data->next_update = jiffies + HZ;
    }

    lsb_reg = ADT7411_REG_EXT_TEMP_AIN14_LSB + (nr >> 2);
    lsb_shift = 2 * (nr & 0x03);
    val = adt7411_read_10_bit(client, lsb_reg,
            ADT7411_REG_EXT_TEMP_AIN1_MSB + nr, lsb_shift);
    if (val < 0)
        goto exit_unlock;

    val = sprintf(buf, "%u\n", val * data->vref_cached / 1024);
 exit_unlock:
    mutex_unlock(&data->update_lock);
    return val;
}

static ssize_t adt7411_show_bit(struct device *dev,
                struct device_attribute *attr, char *buf)
{
    struct sensor_device_attribute_2 *attr2 = to_sensor_dev_attr_2(attr);
    struct i2c_client *client = to_i2c_client(dev);
    int ret = i2c_smbus_read_byte_data(client, attr2->index);

    return ret < 0 ? ret : sprintf(buf, "%u\n", !!(ret & attr2->nr));
}

static ssize_t adt7411_set_bit(struct device *dev,
                   struct device_attribute *attr, const char *buf,
                   size_t count)
{
    struct sensor_device_attribute_2 *s_attr2 = to_sensor_dev_attr_2(attr);
    struct i2c_client *client = to_i2c_client(dev);
    struct adt7411_data *data = i2c_get_clientdata(client);
    int ret;
    unsigned long flag;

    ret = kstrtoul(buf, 0, &flag);
    if (ret || flag > 1)
        return -EINVAL;

    ret = adt7411_modify_bit(client, s_attr2->index, s_attr2->nr, flag);

    /* force update */
    mutex_lock(&data->update_lock);
    data->next_update = jiffies;
    mutex_unlock(&data->update_lock);

    return ret < 0 ? ret : count;
}

#define ADT7411_BIT_ATTR(__name, __reg, __bit) \
    SENSOR_DEVICE_ATTR_2(__name, S_IRUGO | S_IWUSR, adt7411_show_bit, \
    adt7411_set_bit, __bit, __reg)

static DEVICE_ATTR(temp1_input, S_IRUGO, adt7411_show_temp, NULL);
static DEVICE_ATTR(in0_input, S_IRUGO, adt7411_show_vdd, NULL);
static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, adt7411_show_input, NULL, 0);
static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, adt7411_show_input, NULL, 1);
static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO, adt7411_show_input, NULL, 2);
static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO, adt7411_show_input, NULL, 3);
static SENSOR_DEVICE_ATTR(in5_input, S_IRUGO, adt7411_show_input, NULL, 4);
static SENSOR_DEVICE_ATTR(in6_input, S_IRUGO, adt7411_show_input, NULL, 5);
static SENSOR_DEVICE_ATTR(in7_input, S_IRUGO, adt7411_show_input, NULL, 6);
static SENSOR_DEVICE_ATTR(in8_input, S_IRUGO, adt7411_show_input, NULL, 7);
static ADT7411_BIT_ATTR(no_average, ADT7411_REG_CFG2, ADT7411_CFG2_DISABLE_AVG);
static ADT7411_BIT_ATTR(fast_sampling, ADT7411_REG_CFG3, ADT7411_CFG3_ADC_CLK_225);
static ADT7411_BIT_ATTR(adc_ref_vdd, ADT7411_REG_CFG3, ADT7411_CFG3_REF_VDD);

static struct attribute *adt7411_attrs[] = {
    &dev_attr_temp1_input.attr,
    &dev_attr_in0_input.attr,
    &sensor_dev_attr_in1_input.dev_attr.attr,
    &sensor_dev_attr_in2_input.dev_attr.attr,
    &sensor_dev_attr_in3_input.dev_attr.attr,
    &sensor_dev_attr_in4_input.dev_attr.attr,
    &sensor_dev_attr_in5_input.dev_attr.attr,
    &sensor_dev_attr_in6_input.dev_attr.attr,
    &sensor_dev_attr_in7_input.dev_attr.attr,
    &sensor_dev_attr_in8_input.dev_attr.attr,
    &sensor_dev_attr_no_average.dev_attr.attr,
    &sensor_dev_attr_fast_sampling.dev_attr.attr,
    &sensor_dev_attr_adc_ref_vdd.dev_attr.attr,
    NULL
};

static const struct attribute_group adt7411_attr_grp = {
    .attrs = adt7411_attrs,
};

static int adt7411_detect(struct i2c_client *client,
              struct i2c_board_info *info)
{
    int val;

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

    val = i2c_smbus_read_byte_data(client, ADT7411_REG_MANUFACTURER_ID);
    if (val < 0 || val != ADT7411_MANUFACTURER_ID) {
        dev_dbg(&client->dev, "Wrong manufacturer ID. Got %d, "
            "expected %d\n", val, ADT7411_MANUFACTURER_ID);
        return -ENODEV;
    }

    val = i2c_smbus_read_byte_data(client, ADT7411_REG_DEVICE_ID);
    if (val < 0 || val != ADT7411_DEVICE_ID) {
        dev_dbg(&client->dev, "Wrong device ID. Got %d, "
            "expected %d\n", val, ADT7411_DEVICE_ID);
        return -ENODEV;
    }

    strlcpy(info->type, "adt7411", I2C_NAME_SIZE);

    return 0;
}

static int __devinit adt7411_probe(struct i2c_client *client,
                   const struct i2c_device_id *id)
{
    struct adt7411_data *data;
    int ret;

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

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

    ret = adt7411_modify_bit(client, ADT7411_REG_CFG1,
                 ADT7411_CFG1_START_MONITOR, 1);
    if (ret < 0)
        return ret;

    /* force update on first occasion */
    data->next_update = jiffies;

    ret = sysfs_create_group(&client->dev.kobj, &adt7411_attr_grp);
    if (ret)
        return ret;

    data->hwmon_dev = hwmon_device_register(&client->dev);
    if (IS_ERR(data->hwmon_dev)) {
        ret = PTR_ERR(data->hwmon_dev);
        goto exit_remove;
    }

    dev_info(&client->dev, "successfully registered\n");

    return 0;

 exit_remove:
    sysfs_remove_group(&client->dev.kobj, &adt7411_attr_grp);
    return ret;
}

static int __devexit adt7411_remove(struct i2c_client *client)
{
    struct adt7411_data *data = i2c_get_clientdata(client);

    hwmon_device_unregister(data->hwmon_dev);
    sysfs_remove_group(&client->dev.kobj, &adt7411_attr_grp);
    return 0;
}

static const struct i2c_device_id adt7411_id[] = {
    { "adt7411", 0 },
    { }
};
MODULE_DEVICE_TABLE(i2c, adt7411_id);

static struct i2c_driver adt7411_driver = {
    .driver     = {
        .name       = "adt7411",
    },
    .probe  = adt7411_probe,
    .remove = __devexit_p(adt7411_remove),
    .id_table = adt7411_id,
    .detect = adt7411_detect,
    .address_list = normal_i2c,
    .class = I2C_CLASS_HWMON,
};

module_i2c_driver(adt7411_driver);

MODULE_AUTHOR("Sascha Hauer <[email protected]> and "
    "Wolfram Sang <[email protected]>");
MODULE_DESCRIPTION("ADT7411 driver");
MODULE_LICENSE("GPL v2");