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 /* convert left adjusted 13-bit TMP102 register value to milliCelsius */
  59 static 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 */
  65 static inline u16 tmp102_mC_to_reg(int val)
  66 {
  67         return (val * 128) / 1000;
  68 }
  69
  70 static const u8 tmp102_reg[] = {
  71         TMP102_TEMP_REG,
  72         TMP102_TLOW_REG,
  73         TMP102_THIGH_REG,
  74 };
  75
  76 static 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
  95 static 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
 105 static 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
 127 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, tmp102_show_temp, NULL , 0);
 128
 129 static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO, tmp102_show_temp,
 130                           tmp102_set_temp, 1);
 131
 132 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, tmp102_show_temp,
 133                           tmp102_set_temp, 2);
 134
 135 static 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
 142 static 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
 149 static 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
 210 fail_remove_sysfs:
 211         sysfs_remove_group(&client->dev.kobj, &tmp102_attr_group);
 212 fail_restore_config:
 213         i2c_smbus_write_word_swapped(client, TMP102_CONF_REG,
 214                                      tmp102->config_orig);
 215         return status;
 216 }
 217
 218 static 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
 239 static 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
 252 static 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
 265 static 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
 275 static const struct i2c_device_id tmp102_id[] = {
 276         { "tmp102", 0 },
 277         { }
 278 };
 279 MODULE_DEVICE_TABLE(i2c, tmp102_id);
 280
 281 static 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
 289 module_i2c_driver(tmp102_driver);
 290
 291 MODULE_AUTHOR("Steven King <sfking@fdwdc.com>");
 292 MODULE_DESCRIPTION("Texas Instruments TMP102 temperature sensor driver");
 293 MODULE_LICENSE("GPL");