linux/drivers/hwmon/tmp102.c
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   1/* Texas Instruments TMP102 SMBus temperature sensor driver
   2 *
   3 * Copyright (C) 2010 Steven King <sfking@fdwdc.com>
   4 *
   5 * This program is free software; you can redistribute it and/or modify
   6 * it under the terms of the GNU General Public License as published by
   7 * the Free Software Foundation; either version 2 of the License, or
   8 * (at your option) any later version.
   9 *
  10 * This program is distributed in the hope that it will be useful,
  11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 * GNU General Public License for more details.
  14 *
  15 * You should have received a copy of the GNU General Public License
  16 * along with this program; if not, write to the Free Software
  17 * Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA
  18 */
  19
  20#include <linux/module.h>
  21#include <linux/init.h>
  22#include <linux/slab.h>
  23#include <linux/i2c.h>
  24#include <linux/hwmon.h>
  25#include <linux/hwmon-sysfs.h>
  26#include <linux/err.h>
  27#include <linux/mutex.h>
  28#include <linux/device.h>
  29
  30#define DRIVER_NAME "tmp102"
  31
  32#define TMP102_TEMP_REG                 0x00
  33#define TMP102_CONF_REG                 0x01
  34/* note: these bit definitions are byte swapped */
  35#define         TMP102_CONF_SD          0x0100
  36#define         TMP102_CONF_TM          0x0200
  37#define         TMP102_CONF_POL         0x0400
  38#define         TMP102_CONF_F0          0x0800
  39#define         TMP102_CONF_F1          0x1000
  40#define         TMP102_CONF_R0          0x2000
  41#define         TMP102_CONF_R1          0x4000
  42#define         TMP102_CONF_OS          0x8000
  43#define         TMP102_CONF_EM          0x0010
  44#define         TMP102_CONF_AL          0x0020
  45#define         TMP102_CONF_CR0         0x0040
  46#define         TMP102_CONF_CR1         0x0080
  47#define TMP102_TLOW_REG                 0x02
  48#define TMP102_THIGH_REG                0x03
  49
  50struct tmp102 {
  51        struct device *hwmon_dev;
  52        struct mutex lock;
  53        u16 config_orig;
  54        unsigned long last_update;
  55        int temp[3];
  56};
  57
  58/* convert left adjusted 13-bit TMP102 register value to milliCelsius */
  59static inline int tmp102_reg_to_mC(s16 val)
  60{
  61        return ((val & ~0x01) * 1000) / 128;
  62}
  63
  64/* convert milliCelsius to left adjusted 13-bit TMP102 register value */
  65static inline u16 tmp102_mC_to_reg(int val)
  66{
  67        return (val * 128) / 1000;
  68}
  69
  70static const u8 tmp102_reg[] = {
  71        TMP102_TEMP_REG,
  72        TMP102_TLOW_REG,
  73        TMP102_THIGH_REG,
  74};
  75
  76static struct tmp102 *tmp102_update_device(struct i2c_client *client)
  77{
  78        struct tmp102 *tmp102 = i2c_get_clientdata(client);
  79
  80        mutex_lock(&tmp102->lock);
  81        if (time_after(jiffies, tmp102->last_update + HZ / 3)) {
  82                int i;
  83                for (i = 0; i < ARRAY_SIZE(tmp102->temp); ++i) {
  84                        int status = i2c_smbus_read_word_swapped(client,
  85                                                                 tmp102_reg[i]);
  86                        if (status > -1)
  87                                tmp102->temp[i] = tmp102_reg_to_mC(status);
  88                }
  89                tmp102->last_update = jiffies;
  90        }
  91        mutex_unlock(&tmp102->lock);
  92        return tmp102;
  93}
  94
  95static ssize_t tmp102_show_temp(struct device *dev,
  96                                struct device_attribute *attr,
  97                                char *buf)
  98{
  99        struct sensor_device_attribute *sda = to_sensor_dev_attr(attr);
 100        struct tmp102 *tmp102 = tmp102_update_device(to_i2c_client(dev));
 101
 102        return sprintf(buf, "%d\n", tmp102->temp[sda->index]);
 103}
 104
 105static ssize_t tmp102_set_temp(struct device *dev,
 106                               struct device_attribute *attr,
 107                               const char *buf, size_t count)
 108{
 109        struct sensor_device_attribute *sda = to_sensor_dev_attr(attr);
 110        struct i2c_client *client = to_i2c_client(dev);
 111        struct tmp102 *tmp102 = i2c_get_clientdata(client);
 112        long val;
 113        int status;
 114
 115        if (kstrtol(buf, 10, &val) < 0)
 116                return -EINVAL;
 117        val = SENSORS_LIMIT(val, -256000, 255000);
 118
 119        mutex_lock(&tmp102->lock);
 120        tmp102->temp[sda->index] = val;
 121        status = i2c_smbus_write_word_swapped(client, tmp102_reg[sda->index],
 122                                              tmp102_mC_to_reg(val));
 123        mutex_unlock(&tmp102->lock);
 124        return status ? : count;
 125}
 126
 127static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, tmp102_show_temp, NULL , 0);
 128
 129static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO, tmp102_show_temp,
 130                          tmp102_set_temp, 1);
 131
 132static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, tmp102_show_temp,
 133                          tmp102_set_temp, 2);
 134
 135static struct attribute *tmp102_attributes[] = {
 136        &sensor_dev_attr_temp1_input.dev_attr.attr,
 137        &sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
 138        &sensor_dev_attr_temp1_max.dev_attr.attr,
 139        NULL
 140};
 141
 142static const struct attribute_group tmp102_attr_group = {
 143        .attrs = tmp102_attributes,
 144};
 145
 146#define TMP102_CONFIG  (TMP102_CONF_TM | TMP102_CONF_EM | TMP102_CONF_CR1)
 147#define TMP102_CONFIG_RD_ONLY (TMP102_CONF_R0 | TMP102_CONF_R1 | TMP102_CONF_AL)
 148
 149static int __devinit tmp102_probe(struct i2c_client *client,
 150                                  const struct i2c_device_id *id)
 151{
 152        struct tmp102 *tmp102;
 153        int status;
 154
 155        if (!i2c_check_functionality(client->adapter,
 156                                     I2C_FUNC_SMBUS_WORD_DATA)) {
 157                dev_err(&client->dev, "adapter doesn't support SMBus word "
 158                        "transactions\n");
 159                return -ENODEV;
 160        }
 161
 162        tmp102 = devm_kzalloc(&client->dev, sizeof(*tmp102), GFP_KERNEL);
 163        if (!tmp102)
 164                return -ENOMEM;
 165
 166        i2c_set_clientdata(client, tmp102);
 167
 168        status = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
 169        if (status < 0) {
 170                dev_err(&client->dev, "error reading config register\n");
 171                return status;
 172        }
 173        tmp102->config_orig = status;
 174        status = i2c_smbus_write_word_swapped(client, TMP102_CONF_REG,
 175                                              TMP102_CONFIG);
 176        if (status < 0) {
 177                dev_err(&client->dev, "error writing config register\n");
 178                goto fail_restore_config;
 179        }
 180        status = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
 181        if (status < 0) {
 182                dev_err(&client->dev, "error reading config register\n");
 183                goto fail_restore_config;
 184        }
 185        status &= ~TMP102_CONFIG_RD_ONLY;
 186        if (status != TMP102_CONFIG) {
 187                dev_err(&client->dev, "config settings did not stick\n");
 188                status = -ENODEV;
 189                goto fail_restore_config;
 190        }
 191        tmp102->last_update = jiffies - HZ;
 192        mutex_init(&tmp102->lock);
 193
 194        status = sysfs_create_group(&client->dev.kobj, &tmp102_attr_group);
 195        if (status) {
 196                dev_dbg(&client->dev, "could not create sysfs files\n");
 197                goto fail_restore_config;
 198        }
 199        tmp102->hwmon_dev = hwmon_device_register(&client->dev);
 200        if (IS_ERR(tmp102->hwmon_dev)) {
 201                dev_dbg(&client->dev, "unable to register hwmon device\n");
 202                status = PTR_ERR(tmp102->hwmon_dev);
 203                goto fail_remove_sysfs;
 204        }
 205
 206        dev_info(&client->dev, "initialized\n");
 207
 208        return 0;
 209
 210fail_remove_sysfs:
 211        sysfs_remove_group(&client->dev.kobj, &tmp102_attr_group);
 212fail_restore_config:
 213        i2c_smbus_write_word_swapped(client, TMP102_CONF_REG,
 214                                     tmp102->config_orig);
 215        return status;
 216}
 217
 218static int __devexit tmp102_remove(struct i2c_client *client)
 219{
 220        struct tmp102 *tmp102 = i2c_get_clientdata(client);
 221
 222        hwmon_device_unregister(tmp102->hwmon_dev);
 223        sysfs_remove_group(&client->dev.kobj, &tmp102_attr_group);
 224
 225        /* Stop monitoring if device was stopped originally */
 226        if (tmp102->config_orig & TMP102_CONF_SD) {
 227                int config;
 228
 229                config = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
 230                if (config >= 0)
 231                        i2c_smbus_write_word_swapped(client, TMP102_CONF_REG,
 232                                                     config | TMP102_CONF_SD);
 233        }
 234
 235        return 0;
 236}
 237
 238#ifdef CONFIG_PM
 239static int tmp102_suspend(struct device *dev)
 240{
 241        struct i2c_client *client = to_i2c_client(dev);
 242        int config;
 243
 244        config = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
 245        if (config < 0)
 246                return config;
 247
 248        config |= TMP102_CONF_SD;
 249        return i2c_smbus_write_word_swapped(client, TMP102_CONF_REG, config);
 250}
 251
 252static int tmp102_resume(struct device *dev)
 253{
 254        struct i2c_client *client = to_i2c_client(dev);
 255        int config;
 256
 257        config = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
 258        if (config < 0)
 259                return config;
 260
 261        config &= ~TMP102_CONF_SD;
 262        return i2c_smbus_write_word_swapped(client, TMP102_CONF_REG, config);
 263}
 264
 265static const struct dev_pm_ops tmp102_dev_pm_ops = {
 266        .suspend        = tmp102_suspend,
 267        .resume         = tmp102_resume,
 268};
 269
 270#define TMP102_DEV_PM_OPS (&tmp102_dev_pm_ops)
 271#else
 272#define TMP102_DEV_PM_OPS NULL
 273#endif /* CONFIG_PM */
 274
 275static const struct i2c_device_id tmp102_id[] = {
 276        { "tmp102", 0 },
 277        { }
 278};
 279MODULE_DEVICE_TABLE(i2c, tmp102_id);
 280
 281static struct i2c_driver tmp102_driver = {
 282        .driver.name    = DRIVER_NAME,
 283        .driver.pm      = TMP102_DEV_PM_OPS,
 284        .probe          = tmp102_probe,
 285        .remove         = __devexit_p(tmp102_remove),
 286        .id_table       = tmp102_id,
 287};
 288
 289module_i2c_driver(tmp102_driver);
 290
 291MODULE_AUTHOR("Steven King <sfking@fdwdc.com>");
 292MODULE_DESCRIPTION("Texas Instruments TMP102 temperature sensor driver");
 293MODULE_LICENSE("GPL");
 294
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