jc42.c

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/*
 * jc42.c - driver for Jedec JC42.4 compliant temperature sensors
 *
 * Copyright (c) 2010  Ericsson AB.
 *
 * Derived from lm77.c by Andras BALI <[email protected]>.
 *
 * JC42.4 compliant temperature sensors are typically used on memory modules.
 *
 * 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>

/* Addresses to scan */
static const unsigned short normal_i2c[] = {
    0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, I2C_CLIENT_END };

/* JC42 registers. All registers are 16 bit. */
#define JC42_REG_CAP        0x00
#define JC42_REG_CONFIG     0x01
#define JC42_REG_TEMP_UPPER 0x02
#define JC42_REG_TEMP_LOWER 0x03
#define JC42_REG_TEMP_CRITICAL  0x04
#define JC42_REG_TEMP       0x05
#define JC42_REG_MANID      0x06
#define JC42_REG_DEVICEID   0x07

/* Status bits in temperature register */
#define JC42_ALARM_CRIT_BIT 15
#define JC42_ALARM_MAX_BIT  14
#define JC42_ALARM_MIN_BIT  13

/* Configuration register defines */
#define JC42_CFG_CRIT_ONLY  (1 << 2)
#define JC42_CFG_TCRIT_LOCK (1 << 6)
#define JC42_CFG_EVENT_LOCK (1 << 7)
#define JC42_CFG_SHUTDOWN   (1 << 8)
#define JC42_CFG_HYST_SHIFT 9
#define JC42_CFG_HYST_MASK  (0x03 << 9)

/* Capabilities */
#define JC42_CAP_RANGE      (1 << 2)

/* Manufacturer IDs */
#define ADT_MANID       0x11d4  /* Analog Devices */
#define ATMEL_MANID     0x001f  /* Atmel */
#define MAX_MANID       0x004d  /* Maxim */
#define IDT_MANID       0x00b3  /* IDT */
#define MCP_MANID       0x0054  /* Microchip */
#define NXP_MANID       0x1131  /* NXP Semiconductors */
#define ONS_MANID       0x1b09  /* ON Semiconductor */
#define STM_MANID       0x104a  /* ST Microelectronics */

/* Supported chips */

/* Analog Devices */
#define ADT7408_DEVID       0x0801
#define ADT7408_DEVID_MASK  0xffff

/* Atmel */
#define AT30TS00_DEVID      0x8201
#define AT30TS00_DEVID_MASK 0xffff

/* IDT */
#define TS3000B3_DEVID      0x2903  /* Also matches TSE2002B3 */
#define TS3000B3_DEVID_MASK 0xffff

#define TS3000GB2_DEVID     0x2912  /* Also matches TSE2002GB2 */
#define TS3000GB2_DEVID_MASK    0xffff

/* Maxim */
#define MAX6604_DEVID       0x3e00
#define MAX6604_DEVID_MASK  0xffff

/* Microchip */
#define MCP9804_DEVID       0x0200
#define MCP9804_DEVID_MASK  0xfffc

#define MCP98242_DEVID      0x2000
#define MCP98242_DEVID_MASK 0xfffc

#define MCP98243_DEVID      0x2100
#define MCP98243_DEVID_MASK 0xfffc

#define MCP9843_DEVID       0x0000  /* Also matches mcp9805 */
#define MCP9843_DEVID_MASK  0xfffe

/* NXP */
#define SE97_DEVID      0xa200
#define SE97_DEVID_MASK     0xfffc

#define SE98_DEVID      0xa100
#define SE98_DEVID_MASK     0xfffc

/* ON Semiconductor */
#define CAT6095_DEVID       0x0800  /* Also matches CAT34TS02 */
#define CAT6095_DEVID_MASK  0xffe0

/* ST Microelectronics */
#define STTS424_DEVID       0x0101
#define STTS424_DEVID_MASK  0xffff

#define STTS424E_DEVID      0x0000
#define STTS424E_DEVID_MASK 0xfffe

#define STTS2002_DEVID      0x0300
#define STTS2002_DEVID_MASK 0xffff

#define STTS3000_DEVID      0x0200
#define STTS3000_DEVID_MASK 0xffff

static u16 jc42_hysteresis[] = { 0, 1500, 3000, 6000 };

struct jc42_chips {
    u16 manid;
    u16 devid;
    u16 devid_mask;
};

static struct jc42_chips jc42_chips[] = {
    { ADT_MANID, ADT7408_DEVID, ADT7408_DEVID_MASK },
    { ATMEL_MANID, AT30TS00_DEVID, AT30TS00_DEVID_MASK },
    { IDT_MANID, TS3000B3_DEVID, TS3000B3_DEVID_MASK },
    { IDT_MANID, TS3000GB2_DEVID, TS3000GB2_DEVID_MASK },
    { MAX_MANID, MAX6604_DEVID, MAX6604_DEVID_MASK },
    { MCP_MANID, MCP9804_DEVID, MCP9804_DEVID_MASK },
    { MCP_MANID, MCP98242_DEVID, MCP98242_DEVID_MASK },
    { MCP_MANID, MCP98243_DEVID, MCP98243_DEVID_MASK },
    { MCP_MANID, MCP9843_DEVID, MCP9843_DEVID_MASK },
    { NXP_MANID, SE97_DEVID, SE97_DEVID_MASK },
    { ONS_MANID, CAT6095_DEVID, CAT6095_DEVID_MASK },
    { NXP_MANID, SE98_DEVID, SE98_DEVID_MASK },
    { STM_MANID, STTS424_DEVID, STTS424_DEVID_MASK },
    { STM_MANID, STTS424E_DEVID, STTS424E_DEVID_MASK },
    { STM_MANID, STTS2002_DEVID, STTS2002_DEVID_MASK },
    { STM_MANID, STTS3000_DEVID, STTS3000_DEVID_MASK },
};

/* Each client has this additional data */
struct jc42_data {
    struct device   *hwmon_dev;
    struct mutex    update_lock;    /* protect register access */
    bool        extended;   /* true if extended range supported */
    bool        valid;
    unsigned long   last_updated;   /* In jiffies */
    u16     orig_config;    /* original configuration */
    u16     config;     /* current configuration */
    u16     temp_input; /* Temperatures */
    u16     temp_crit;
    u16     temp_min;
    u16     temp_max;
};

static int jc42_probe(struct i2c_client *client,
              const struct i2c_device_id *id);
static int jc42_detect(struct i2c_client *client, struct i2c_board_info *info);
static int jc42_remove(struct i2c_client *client);

static struct jc42_data *jc42_update_device(struct device *dev);

static const struct i2c_device_id jc42_id[] = {
    { "jc42", 0 },
    { }
};
MODULE_DEVICE_TABLE(i2c, jc42_id);

#ifdef CONFIG_PM

static int jc42_suspend(struct device *dev)
{
    struct i2c_client *client = to_i2c_client(dev);
    struct jc42_data *data = i2c_get_clientdata(client);

    data->config |= JC42_CFG_SHUTDOWN;
    i2c_smbus_write_word_swapped(client, JC42_REG_CONFIG, data->config);
    return 0;
}

static int jc42_resume(struct device *dev)
{
    struct i2c_client *client = to_i2c_client(dev);
    struct jc42_data *data = i2c_get_clientdata(client);

    data->config &= ~JC42_CFG_SHUTDOWN;
    i2c_smbus_write_word_swapped(client, JC42_REG_CONFIG, data->config);
    return 0;
}

static const struct dev_pm_ops jc42_dev_pm_ops = {
    .suspend = jc42_suspend,
    .resume = jc42_resume,
};

#define JC42_DEV_PM_OPS (&jc42_dev_pm_ops)
#else
#define JC42_DEV_PM_OPS NULL
#endif /* CONFIG_PM */

/* This is the driver that will be inserted */
static struct i2c_driver jc42_driver = {
    .class      = I2C_CLASS_SPD,
    .driver = {
        .name   = "jc42",
        .pm = JC42_DEV_PM_OPS,
    },
    .probe      = jc42_probe,
    .remove     = jc42_remove,
    .id_table   = jc42_id,
    .detect     = jc42_detect,
    .address_list   = normal_i2c,
};

#define JC42_TEMP_MIN_EXTENDED  (-40000)
#define JC42_TEMP_MIN       0
#define JC42_TEMP_MAX       125000

static u16 jc42_temp_to_reg(int temp, bool extended)
{
    int ntemp = SENSORS_LIMIT(temp,
                  extended ? JC42_TEMP_MIN_EXTENDED :
                  JC42_TEMP_MIN, JC42_TEMP_MAX);

    /* convert from 0.001 to 0.0625 resolution */
    return (ntemp * 2 / 125) & 0x1fff;
}

static int jc42_temp_from_reg(s16 reg)
{
    reg &= 0x1fff;

    /* sign extend register */
    if (reg & 0x1000)
        reg |= 0xf000;

    /* convert from 0.0625 to 0.001 resolution */
    return reg * 125 / 2;
}

/* sysfs stuff */

/* read routines for temperature limits */
#define show(value) \
static ssize_t show_##value(struct device *dev,             \
                struct device_attribute *attr,      \
                char *buf)                  \
{                                   \
    struct jc42_data *data = jc42_update_device(dev);       \
    if (IS_ERR(data))                       \
        return PTR_ERR(data);                   \
    return sprintf(buf, "%d\n", jc42_temp_from_reg(data->value));   \
}

show(temp_input);
show(temp_crit);
show(temp_min);
show(temp_max);

/* read routines for hysteresis values */
static ssize_t show_temp_crit_hyst(struct device *dev,
                   struct device_attribute *attr, char *buf)
{
    struct jc42_data *data = jc42_update_device(dev);
    int temp, hyst;

    if (IS_ERR(data))
        return PTR_ERR(data);

    temp = jc42_temp_from_reg(data->temp_crit);
    hyst = jc42_hysteresis[(data->config & JC42_CFG_HYST_MASK)
                   >> JC42_CFG_HYST_SHIFT];
    return sprintf(buf, "%d\n", temp - hyst);
}

static ssize_t show_temp_max_hyst(struct device *dev,
                  struct device_attribute *attr, char *buf)
{
    struct jc42_data *data = jc42_update_device(dev);
    int temp, hyst;

    if (IS_ERR(data))
        return PTR_ERR(data);

    temp = jc42_temp_from_reg(data->temp_max);
    hyst = jc42_hysteresis[(data->config & JC42_CFG_HYST_MASK)
                   >> JC42_CFG_HYST_SHIFT];
    return sprintf(buf, "%d\n", temp - hyst);
}

/* write routines */
#define set(value, reg) \
static ssize_t set_##value(struct device *dev,              \
               struct device_attribute *attr,       \
               const char *buf, size_t count)       \
{                                   \
    struct i2c_client *client = to_i2c_client(dev);         \
    struct jc42_data *data = i2c_get_clientdata(client);        \
    int err, ret = count;                       \
    long val;                           \
    if (kstrtol(buf, 10, &val) < 0)             \
        return -EINVAL;                     \
    mutex_lock(&data->update_lock);                 \
    data->value = jc42_temp_to_reg(val, data->extended);        \
    err = i2c_smbus_write_word_swapped(client, reg, data->value);   \
    if (err < 0)                            \
        ret = err;                      \
    mutex_unlock(&data->update_lock);               \
    return ret;                         \
}

set(temp_min, JC42_REG_TEMP_LOWER);
set(temp_max, JC42_REG_TEMP_UPPER);
set(temp_crit, JC42_REG_TEMP_CRITICAL);

/*
 * JC42.4 compliant chips only support four hysteresis values.
 * Pick best choice and go from there.
 */
static ssize_t set_temp_crit_hyst(struct device *dev,
                  struct device_attribute *attr,
                  const char *buf, size_t count)
{
    struct i2c_client *client = to_i2c_client(dev);
    struct jc42_data *data = i2c_get_clientdata(client);
    unsigned long val;
    int diff, hyst;
    int err;
    int ret = count;

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

    diff = jc42_temp_from_reg(data->temp_crit) - val;
    hyst = 0;
    if (diff > 0) {
        if (diff < 2250)
            hyst = 1;   /* 1.5 degrees C */
        else if (diff < 4500)
            hyst = 2;   /* 3.0 degrees C */
        else
            hyst = 3;   /* 6.0 degrees C */
    }

    mutex_lock(&data->update_lock);
    data->config = (data->config & ~JC42_CFG_HYST_MASK)
      | (hyst << JC42_CFG_HYST_SHIFT);
    err = i2c_smbus_write_word_swapped(client, JC42_REG_CONFIG,
                       data->config);
    if (err < 0)
        ret = err;
    mutex_unlock(&data->update_lock);
    return ret;
}

static ssize_t show_alarm(struct device *dev,
              struct device_attribute *attr, char *buf)
{
    u16 bit = to_sensor_dev_attr(attr)->index;
    struct jc42_data *data = jc42_update_device(dev);
    u16 val;

    if (IS_ERR(data))
        return PTR_ERR(data);

    val = data->temp_input;
    if (bit != JC42_ALARM_CRIT_BIT && (data->config & JC42_CFG_CRIT_ONLY))
        val = 0;
    return sprintf(buf, "%u\n", (val >> bit) & 1);
}

static DEVICE_ATTR(temp1_input, S_IRUGO,
           show_temp_input, NULL);
static DEVICE_ATTR(temp1_crit, S_IRUGO,
           show_temp_crit, set_temp_crit);
static DEVICE_ATTR(temp1_min, S_IRUGO,
           show_temp_min, set_temp_min);
static DEVICE_ATTR(temp1_max, S_IRUGO,
           show_temp_max, set_temp_max);

static DEVICE_ATTR(temp1_crit_hyst, S_IRUGO,
           show_temp_crit_hyst, set_temp_crit_hyst);
static DEVICE_ATTR(temp1_max_hyst, S_IRUGO,
           show_temp_max_hyst, NULL);

static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL,
              JC42_ALARM_CRIT_BIT);
static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL,
              JC42_ALARM_MIN_BIT);
static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL,
              JC42_ALARM_MAX_BIT);

static struct attribute *jc42_attributes[] = {
    &dev_attr_temp1_input.attr,
    &dev_attr_temp1_crit.attr,
    &dev_attr_temp1_min.attr,
    &dev_attr_temp1_max.attr,
    &dev_attr_temp1_crit_hyst.attr,
    &dev_attr_temp1_max_hyst.attr,
    &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
    &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
    &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
    NULL
};

static umode_t jc42_attribute_mode(struct kobject *kobj,
                  struct attribute *attr, int index)
{
    struct device *dev = container_of(kobj, struct device, kobj);
    struct i2c_client *client = to_i2c_client(dev);
    struct jc42_data *data = i2c_get_clientdata(client);
    unsigned int config = data->config;
    bool readonly;

    if (attr == &dev_attr_temp1_crit.attr)
        readonly = config & JC42_CFG_TCRIT_LOCK;
    else if (attr == &dev_attr_temp1_min.attr ||
         attr == &dev_attr_temp1_max.attr)
        readonly = config & JC42_CFG_EVENT_LOCK;
    else if (attr == &dev_attr_temp1_crit_hyst.attr)
        readonly = config & (JC42_CFG_EVENT_LOCK | JC42_CFG_TCRIT_LOCK);
    else
        readonly = true;

    return S_IRUGO | (readonly ? 0 : S_IWUSR);
}

static const struct attribute_group jc42_group = {
    .attrs = jc42_attributes,
    .is_visible = jc42_attribute_mode,
};

/* Return 0 if detection is successful, -ENODEV otherwise */
static int jc42_detect(struct i2c_client *client, struct i2c_board_info *info)
{
    struct i2c_adapter *adapter = client->adapter;
    int i, config, cap, manid, devid;

    if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
                     I2C_FUNC_SMBUS_WORD_DATA))
        return -ENODEV;

    cap = i2c_smbus_read_word_swapped(client, JC42_REG_CAP);
    config = i2c_smbus_read_word_swapped(client, JC42_REG_CONFIG);
    manid = i2c_smbus_read_word_swapped(client, JC42_REG_MANID);
    devid = i2c_smbus_read_word_swapped(client, JC42_REG_DEVICEID);

    if (cap < 0 || config < 0 || manid < 0 || devid < 0)
        return -ENODEV;

    if ((cap & 0xff00) || (config & 0xf800))
        return -ENODEV;

    for (i = 0; i < ARRAY_SIZE(jc42_chips); i++) {
        struct jc42_chips *chip = &jc42_chips[i];
        if (manid == chip->manid &&
            (devid & chip->devid_mask) == chip->devid) {
            strlcpy(info->type, "jc42", I2C_NAME_SIZE);
            return 0;
        }
    }
    return -ENODEV;
}

static int jc42_probe(struct i2c_client *client, const struct i2c_device_id *id)
{
    struct jc42_data *data;
    int config, cap, err;
    struct device *dev = &client->dev;

    data = devm_kzalloc(dev, sizeof(struct jc42_data), GFP_KERNEL);
    if (!data)
        return -ENOMEM;

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

    cap = i2c_smbus_read_word_swapped(client, JC42_REG_CAP);
    if (cap < 0)
        return cap;

    data->extended = !!(cap & JC42_CAP_RANGE);

    config = i2c_smbus_read_word_swapped(client, JC42_REG_CONFIG);
    if (config < 0)
        return config;

    data->orig_config = config;
    if (config & JC42_CFG_SHUTDOWN) {
        config &= ~JC42_CFG_SHUTDOWN;
        i2c_smbus_write_word_swapped(client, JC42_REG_CONFIG, config);
    }
    data->config = config;

    /* Register sysfs hooks */
    err = sysfs_create_group(&dev->kobj, &jc42_group);
    if (err)
        return err;

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

    return 0;

exit_remove:
    sysfs_remove_group(&dev->kobj, &jc42_group);
    return err;
}

static int jc42_remove(struct i2c_client *client)
{
    struct jc42_data *data = i2c_get_clientdata(client);
    hwmon_device_unregister(data->hwmon_dev);
    sysfs_remove_group(&client->dev.kobj, &jc42_group);

    /* Restore original configuration except hysteresis */
    if ((data->config & ~JC42_CFG_HYST_MASK) !=
        (data->orig_config & ~JC42_CFG_HYST_MASK)) {
        int config;

        config = (data->orig_config & ~JC42_CFG_HYST_MASK)
          | (data->config & JC42_CFG_HYST_MASK);
        i2c_smbus_write_word_swapped(client, JC42_REG_CONFIG, config);
    }
    return 0;
}

static struct jc42_data *jc42_update_device(struct device *dev)
{
    struct i2c_client *client = to_i2c_client(dev);
    struct jc42_data *data = i2c_get_clientdata(client);
    struct jc42_data *ret = data;
    int val;

    mutex_lock(&data->update_lock);

    if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
        val = i2c_smbus_read_word_swapped(client, JC42_REG_TEMP);
        if (val < 0) {
            ret = ERR_PTR(val);
            goto abort;
        }
        data->temp_input = val;

        val = i2c_smbus_read_word_swapped(client,
                          JC42_REG_TEMP_CRITICAL);
        if (val < 0) {
            ret = ERR_PTR(val);
            goto abort;
        }
        data->temp_crit = val;

        val = i2c_smbus_read_word_swapped(client, JC42_REG_TEMP_LOWER);
        if (val < 0) {
            ret = ERR_PTR(val);
            goto abort;
        }
        data->temp_min = val;

        val = i2c_smbus_read_word_swapped(client, JC42_REG_TEMP_UPPER);
        if (val < 0) {
            ret = ERR_PTR(val);
            goto abort;
        }
        data->temp_max = val;

        data->last_updated = jiffies;
        data->valid = true;
    }
abort:
    mutex_unlock(&data->update_lock);
    return ret;
}

module_i2c_driver(jc42_driver);

MODULE_AUTHOR("Guenter Roeck <[email protected]>");
MODULE_DESCRIPTION("JC42 driver");
MODULE_LICENSE("GPL");