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