drivers/hwmon/tmp102.c

   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
  50 struct 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 /* SMBus specifies low byte first, but the TMP102 returns high byte first,
  59  * so we have to swab16 the values */
  60 static inline int tmp102_read_reg(struct i2c_client *client, u8 reg)
  61 {
  62         int result = i2c_smbus_read_word_data(client, reg);
  63         return result < 0 ? result : swab16(result);
  64 }
  65
  66 static inline int tmp102_write_reg(struct i2c_client *client, u8 reg, u16 val)
  67 {
  68         return i2c_smbus_write_word_data(client, reg, swab16(val));
  69 }
  70
  71 /* convert left adjusted 13-bit TMP102 register value to milliCelsius */
  72 static inline int tmp102_reg_to_mC(s16 val)
  73 {
  74         return ((val & ~0x01) * 1000) / 128;
  75 }
  76
  77 /* convert milliCelsius to left adjusted 13-bit TMP102 register value */
  78 static inline u16 tmp102_mC_to_reg(int val)
  79 {
  80         return (val * 128) / 1000;
  81 }
  82
  83 static const u8 tmp102_reg[] = {
  84         TMP102_TEMP_REG,
  85         TMP102_TLOW_REG,
  86         TMP102_THIGH_REG,
  87 };
  88
  89 static struct tmp102 *tmp102_update_device(struct i2c_client *client)
  90 {
  91         struct tmp102 *tmp102 = i2c_get_clientdata(client);
  92
  93         mutex_lock(&tmp102->lock);
  94         if (time_after(jiffies, tmp102->last_update + HZ / 3)) {
  95                 int i;
  96                 for (i = 0; i < ARRAY_SIZE(tmp102->temp); ++i) {
  97                         int status = tmp102_read_reg(client, tmp102_reg[i]);
  98                         if (status > -1)
  99                                 tmp102->temp[i] = tmp102_reg_to_mC(status);
 100                 }
 101                 tmp102->last_update = jiffies;
 102         }
 103         mutex_unlock(&tmp102->lock);
 104         return tmp102;
 105 }
 106
 107 static ssize_t tmp102_show_temp(struct device *dev,
 108                                 struct device_attribute *attr,
 109                                 char *buf)
 110 {
 111         struct sensor_device_attribute *sda = to_sensor_dev_attr(attr);
 112         struct tmp102 *tmp102 = tmp102_update_device(to_i2c_client(dev));
 113
 114         return sprintf(buf, "%d\n", tmp102->temp[sda->index]);
 115 }
 116
 117 static ssize_t tmp102_set_temp(struct device *dev,
 118                                struct device_attribute *attr,
 119                                const char *buf, size_t count)
 120 {
 121         struct sensor_device_attribute *sda = to_sensor_dev_attr(attr);
 122         struct i2c_client *client = to_i2c_client(dev);
 123         struct tmp102 *tmp102 = i2c_get_clientdata(client);
 124         long val;
 125         int status;
 126
 127         if (strict_strtol(buf, 10, &val) < 0)
 128                 return -EINVAL;
 129         val = SENSORS_LIMIT(val, -256000, 255000);
 130
 131         mutex_lock(&tmp102->lock);
 132         tmp102->temp[sda->index] = val;
 133         status = tmp102_write_reg(client, tmp102_reg[sda->index],
 134                                   tmp102_mC_to_reg(val));
 135         mutex_unlock(&tmp102->lock);
 136         return status ? : count;
 137 }
 138
 139 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, tmp102_show_temp, NULL , 0);
 140
 141 static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO, tmp102_show_temp,
 142                           tmp102_set_temp, 1);
 143
 144 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, tmp102_show_temp,
 145                           tmp102_set_temp, 2);
 146
 147 static struct attribute *tmp102_attributes[] = {
 148         &sensor_dev_attr_temp1_input.dev_attr.attr,
 149         &sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
 150         &sensor_dev_attr_temp1_max.dev_attr.attr,
 151         NULL
 152 };
 153
 154 static const struct attribute_group tmp102_attr_group = {
 155         .attrs = tmp102_attributes,
 156 };
 157
 158 #define TMP102_CONFIG  (TMP102_CONF_TM | TMP102_CONF_EM | TMP102_CONF_CR1)
 159 #define TMP102_CONFIG_RD_ONLY (TMP102_CONF_R0 | TMP102_CONF_R1 | TMP102_CONF_AL)
 160
 161 static int __devinit tmp102_probe(struct i2c_client *client,
 162                                   const struct i2c_device_id *id)
 163 {
 164         struct tmp102 *tmp102;
 165         int status;
 166
 167         if (!i2c_check_functionality(client->adapter,
 168                                      I2C_FUNC_SMBUS_WORD_DATA)) {
 169                 dev_err(&client->dev, "adapter doesn't support SMBus word "
 170                         "transactions\n");
 171                 return -ENODEV;
 172         }
 173
 174         tmp102 = kzalloc(sizeof(*tmp102), GFP_KERNEL);
 175         if (!tmp102) {
 176                 dev_dbg(&client->dev, "kzalloc failed\n");
 177                 return -ENOMEM;
 178         }
 179         i2c_set_clientdata(client, tmp102);
 180
 181         status = tmp102_read_reg(client, TMP102_CONF_REG);
 182         if (status < 0) {
 183                 dev_err(&client->dev, "error reading config register\n");
 184                 goto fail_free;
 185         }
 186         tmp102->config_orig = status;
 187         status = tmp102_write_reg(client, TMP102_CONF_REG, TMP102_CONFIG);
 188         if (status < 0) {
 189                 dev_err(&client->dev, "error writing config register\n");
 190                 goto fail_restore_config;
 191         }
 192         status = tmp102_read_reg(client, TMP102_CONF_REG);
 193         if (status < 0) {
 194                 dev_err(&client->dev, "error reading config register\n");
 195                 goto fail_restore_config;
 196         }
 197         status &= ~TMP102_CONFIG_RD_ONLY;
 198         if (status != TMP102_CONFIG) {
 199                 dev_err(&client->dev, "config settings did not stick\n");
 200                 status = -ENODEV;
 201                 goto fail_restore_config;
 202         }
 203         tmp102->last_update = jiffies - HZ;
 204         mutex_init(&tmp102->lock);
 205
 206         status = sysfs_create_group(&client->dev.kobj, &tmp102_attr_group);
 207         if (status) {
 208                 dev_dbg(&client->dev, "could not create sysfs files\n");
 209                 goto fail_restore_config;
 210         }
 211         tmp102->hwmon_dev = hwmon_device_register(&client->dev);
 212         if (IS_ERR(tmp102->hwmon_dev)) {
 213                 dev_dbg(&client->dev, "unable to register hwmon device\n");
 214                 status = PTR_ERR(tmp102->hwmon_dev);
 215                 goto fail_remove_sysfs;
 216         }
 217
 218         dev_info(&client->dev, "initialized\n");
 219
 220         return 0;
 221
 222 fail_remove_sysfs:
 223         sysfs_remove_group(&client->dev.kobj, &tmp102_attr_group);
 224 fail_restore_config:
 225         tmp102_write_reg(client, TMP102_CONF_REG, tmp102->config_orig);
 226 fail_free:
 227         kfree(tmp102);
 228
 229         return status;
 230 }
 231
 232 static int __devexit tmp102_remove(struct i2c_client *client)
 233 {
 234         struct tmp102 *tmp102 = i2c_get_clientdata(client);
 235
 236         hwmon_device_unregister(tmp102->hwmon_dev);
 237         sysfs_remove_group(&client->dev.kobj, &tmp102_attr_group);
 238
 239         /* Stop monitoring if device was stopped originally */
 240         if (tmp102->config_orig & TMP102_CONF_SD) {
 241                 int config;
 242
 243                 config = tmp102_read_reg(client, TMP102_CONF_REG);
 244                 if (config >= 0)
 245                         tmp102_write_reg(client, TMP102_CONF_REG,
 246                                          config | TMP102_CONF_SD);
 247         }
 248
 249         kfree(tmp102);
 250
 251         return 0;
 252 }
 253
 254 #ifdef CONFIG_PM
 255 static int tmp102_suspend(struct device *dev)
 256 {
 257         struct i2c_client *client = to_i2c_client(dev);
 258         int config;
 259
 260         config = tmp102_read_reg(client, TMP102_CONF_REG);
 261         if (config < 0)
 262                 return config;
 263
 264         config |= TMP102_CONF_SD;
 265         return tmp102_write_reg(client, TMP102_CONF_REG, config);
 266 }
 267
 268 static int tmp102_resume(struct device *dev)
 269 {
 270         struct i2c_client *client = to_i2c_client(dev);
 271         int config;
 272
 273         config = tmp102_read_reg(client, TMP102_CONF_REG);
 274         if (config < 0)
 275                 return config;
 276
 277         config &= ~TMP102_CONF_SD;
 278         return tmp102_write_reg(client, TMP102_CONF_REG, config);
 279 }
 280
 281 static const struct dev_pm_ops tmp102_dev_pm_ops = {
 282         .suspend        = tmp102_suspend,
 283         .resume         = tmp102_resume,
 284 };
 285
 286 #define TMP102_DEV_PM_OPS (&tmp102_dev_pm_ops)
 287 #else
 288 #define TMP102_DEV_PM_OPS NULL
 289 #endif /* CONFIG_PM */
 290
 291 static const struct i2c_device_id tmp102_id[] = {
 292         { "tmp102", 0 },
 293         { }
 294 };
 295 MODULE_DEVICE_TABLE(i2c, tmp102_id);
 296
 297 static struct i2c_driver tmp102_driver = {
 298         .driver.name    = DRIVER_NAME,
 299         .driver.pm      = TMP102_DEV_PM_OPS,
 300         .probe          = tmp102_probe,
 301         .remove         = __devexit_p(tmp102_remove),
 302         .id_table       = tmp102_id,
 303 };
 304
 305 static int __init tmp102_init(void)
 306 {
 307         return i2c_add_driver(&tmp102_driver);
 308 }
 309 module_init(tmp102_init);
 310
 311 static void __exit tmp102_exit(void)
 312 {
 313         i2c_del_driver(&tmp102_driver);
 314 }
 315 module_exit(tmp102_exit);
 316
 317 MODULE_AUTHOR("Steven King <sfking@fdwdc.com>");
 318 MODULE_DESCRIPTION("Texas Instruments TMP102 temperature sensor driver");
 319 MODULE_LICENSE("GPL");