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 #include <linux/thermal.h>
  31 #include <linux/of.h>
  32
  33 #define DRIVER_NAME "tmp102"
  34
  35 #define TMP102_TEMP_REG                 0x00
  36 #define TMP102_CONF_REG                 0x01
  37 /* note: these bit definitions are byte swapped */
  38 #define         TMP102_CONF_SD          0x0100
  39 #define         TMP102_CONF_TM          0x0200
  40 #define         TMP102_CONF_POL         0x0400
  41 #define         TMP102_CONF_F0          0x0800
  42 #define         TMP102_CONF_F1          0x1000
  43 #define         TMP102_CONF_R0          0x2000
  44 #define         TMP102_CONF_R1          0x4000
  45 #define         TMP102_CONF_OS          0x8000
  46 #define         TMP102_CONF_EM          0x0010
  47 #define         TMP102_CONF_AL          0x0020
  48 #define         TMP102_CONF_CR0         0x0040
  49 #define         TMP102_CONF_CR1         0x0080
  50 #define TMP102_TLOW_REG                 0x02
  51 #define TMP102_THIGH_REG                0x03
  52
  53 struct tmp102 {
  54         struct device *hwmon_dev;
  55         struct thermal_zone_device *tz;
  56         struct mutex lock;
  57         u16 config_orig;
  58         unsigned long last_update;
  59         int temp[3];
  60 };
  61
  62 /* convert left adjusted 13-bit TMP102 register value to milliCelsius */
  63 static inline int tmp102_reg_to_mC(s16 val)
  64 {
  65         return ((val & ~0x01) * 1000) / 128;
  66 }
  67
  68 /* convert milliCelsius to left adjusted 13-bit TMP102 register value */
  69 static inline u16 tmp102_mC_to_reg(int val)
  70 {
  71         return (val * 128) / 1000;
  72 }
  73
  74 static const u8 tmp102_reg[] = {
  75         TMP102_TEMP_REG,
  76         TMP102_TLOW_REG,
  77         TMP102_THIGH_REG,
  78 };
  79
  80 static struct tmp102 *tmp102_update_device(struct i2c_client *client)
  81 {
  82         struct tmp102 *tmp102 = i2c_get_clientdata(client);
  83
  84         mutex_lock(&tmp102->lock);
  85         if (time_after(jiffies, tmp102->last_update + HZ / 3)) {
  86                 int i;
  87                 for (i = 0; i < ARRAY_SIZE(tmp102->temp); ++i) {
  88                         int status = i2c_smbus_read_word_swapped(client,
  89                                                                  tmp102_reg[i]);
  90                         if (status > -1)
  91                                 tmp102->temp[i] = tmp102_reg_to_mC(status);
  92                 }
  93                 tmp102->last_update = jiffies;
  94         }
  95         mutex_unlock(&tmp102->lock);
  96         return tmp102;
  97 }
  98
  99 static int tmp102_read_temp(void *dev, long *temp)
 100 {
 101         struct tmp102 *tmp102 = tmp102_update_device(to_i2c_client(dev));
 102
 103         *temp = tmp102->temp[0];
 104
 105         return 0;
 106 }
 107
 108 static ssize_t tmp102_show_temp(struct device *dev,
 109                                 struct device_attribute *attr,
 110                                 char *buf)
 111 {
 112         struct sensor_device_attribute *sda = to_sensor_dev_attr(attr);
 113         struct tmp102 *tmp102 = tmp102_update_device(to_i2c_client(dev));
 114
 115         return sprintf(buf, "%d\n", tmp102->temp[sda->index]);
 116 }
 117
 118 static ssize_t tmp102_set_temp(struct device *dev,
 119                                struct device_attribute *attr,
 120                                const char *buf, size_t count)
 121 {
 122         struct sensor_device_attribute *sda = to_sensor_dev_attr(attr);
 123         struct i2c_client *client = to_i2c_client(dev);
 124         struct tmp102 *tmp102 = i2c_get_clientdata(client);
 125         long val;
 126         int status;
 127
 128         if (kstrtol(buf, 10, &val) < 0)
 129                 return -EINVAL;
 130         val = clamp_val(val, -256000, 255000);
 131
 132         mutex_lock(&tmp102->lock);
 133         tmp102->temp[sda->index] = val;
 134         status = i2c_smbus_write_word_swapped(client, tmp102_reg[sda->index],
 135                                               tmp102_mC_to_reg(val));
 136         mutex_unlock(&tmp102->lock);
 137         return status ? : count;
 138 }
 139
 140 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, tmp102_show_temp, NULL , 0);
 141
 142 static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO, tmp102_show_temp,
 143                           tmp102_set_temp, 1);
 144
 145 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, tmp102_show_temp,
 146                           tmp102_set_temp, 2);
 147
 148 static struct attribute *tmp102_attributes[] = {
 149         &sensor_dev_attr_temp1_input.dev_attr.attr,
 150         &sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
 151         &sensor_dev_attr_temp1_max.dev_attr.attr,
 152         NULL
 153 };
 154
 155 static const struct attribute_group tmp102_attr_group = {
 156         .attrs = tmp102_attributes,
 157 };
 158
 159 #define TMP102_CONFIG  (TMP102_CONF_TM | TMP102_CONF_EM | TMP102_CONF_CR1)
 160 #define TMP102_CONFIG_RD_ONLY (TMP102_CONF_R0 | TMP102_CONF_R1 | TMP102_CONF_AL)
 161
 162 static int tmp102_probe(struct i2c_client *client,
 163                                   const struct i2c_device_id *id)
 164 {
 165         struct tmp102 *tmp102;
 166         int status;
 167
 168         if (!i2c_check_functionality(client->adapter,
 169                                      I2C_FUNC_SMBUS_WORD_DATA)) {
 170                 dev_err(&client->dev,
 171                         "adapter doesn't support SMBus word transactions\n");
 172                 return -ENODEV;
 173         }
 174
 175         tmp102 = devm_kzalloc(&client->dev, sizeof(*tmp102), GFP_KERNEL);
 176         if (!tmp102)
 177                 return -ENOMEM;
 178
 179         i2c_set_clientdata(client, tmp102);
 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                 return status;
 185         }
 186         tmp102->config_orig = status;
 187         status = i2c_smbus_write_word_swapped(client, TMP102_CONF_REG,
 188                                               TMP102_CONFIG);
 189         if (status < 0) {
 190                 dev_err(&client->dev, "error writing config register\n");
 191                 goto fail_restore_config;
 192         }
 193         status = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
 194         if (status < 0) {
 195                 dev_err(&client->dev, "error reading config register\n");
 196                 goto fail_restore_config;
 197         }
 198         status &= ~TMP102_CONFIG_RD_ONLY;
 199         if (status != TMP102_CONFIG) {
 200                 dev_err(&client->dev, "config settings did not stick\n");
 201                 status = -ENODEV;
 202                 goto fail_restore_config;
 203         }
 204         tmp102->last_update = jiffies - HZ;
 205         mutex_init(&tmp102->lock);
 206
 207         status = sysfs_create_group(&client->dev.kobj, &tmp102_attr_group);
 208         if (status) {
 209                 dev_dbg(&client->dev, "could not create sysfs files\n");
 210                 goto fail_restore_config;
 211         }
 212         tmp102->hwmon_dev = hwmon_device_register(&client->dev);
 213         if (IS_ERR(tmp102->hwmon_dev)) {
 214                 dev_dbg(&client->dev, "unable to register hwmon device\n");
 215                 status = PTR_ERR(tmp102->hwmon_dev);
 216                 goto fail_remove_sysfs;
 217         }
 218
 219         tmp102->tz = thermal_zone_of_sensor_register(&client->dev, 0,
 220                                                      &client->dev,
 221                                                      tmp102_read_temp, NULL);
 222         if (IS_ERR(tmp102->tz))
 223                 tmp102->tz = NULL;
 224
 225         dev_info(&client->dev, "initialized\n");
 226
 227         return 0;
 228
 229 fail_remove_sysfs:
 230         sysfs_remove_group(&client->dev.kobj, &tmp102_attr_group);
 231 fail_restore_config:
 232         i2c_smbus_write_word_swapped(client, TMP102_CONF_REG,
 233                                      tmp102->config_orig);
 234         return status;
 235 }
 236
 237 static int tmp102_remove(struct i2c_client *client)
 238 {
 239         struct tmp102 *tmp102 = i2c_get_clientdata(client);
 240
 241         thermal_zone_of_sensor_unregister(&client->dev, tmp102->tz);
 242         hwmon_device_unregister(tmp102->hwmon_dev);
 243         sysfs_remove_group(&client->dev.kobj, &tmp102_attr_group);
 244
 245         /* Stop monitoring if device was stopped originally */
 246         if (tmp102->config_orig & TMP102_CONF_SD) {
 247                 int config;
 248
 249                 config = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
 250                 if (config >= 0)
 251                         i2c_smbus_write_word_swapped(client, TMP102_CONF_REG,
 252                                                      config | TMP102_CONF_SD);
 253         }
 254
 255         return 0;
 256 }
 257
 258 #ifdef CONFIG_PM
 259 static int tmp102_suspend(struct device *dev)
 260 {
 261         struct i2c_client *client = to_i2c_client(dev);
 262         int config;
 263
 264         config = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
 265         if (config < 0)
 266                 return config;
 267
 268         config |= TMP102_CONF_SD;
 269         return i2c_smbus_write_word_swapped(client, TMP102_CONF_REG, config);
 270 }
 271
 272 static int tmp102_resume(struct device *dev)
 273 {
 274         struct i2c_client *client = to_i2c_client(dev);
 275         int config;
 276
 277         config = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
 278         if (config < 0)
 279                 return config;
 280
 281         config &= ~TMP102_CONF_SD;
 282         return i2c_smbus_write_word_swapped(client, TMP102_CONF_REG, config);
 283 }
 284
 285 static const struct dev_pm_ops tmp102_dev_pm_ops = {
 286         .suspend        = tmp102_suspend,
 287         .resume         = tmp102_resume,
 288 };
 289
 290 #define TMP102_DEV_PM_OPS (&tmp102_dev_pm_ops)
 291 #else
 292 #define TMP102_DEV_PM_OPS NULL
 293 #endif /* CONFIG_PM */
 294
 295 static const struct i2c_device_id tmp102_id[] = {
 296         { "tmp102", 0 },
 297         { }
 298 };
 299 MODULE_DEVICE_TABLE(i2c, tmp102_id);
 300
 301 static struct i2c_driver tmp102_driver = {
 302         .driver.name    = DRIVER_NAME,
 303         .driver.pm      = TMP102_DEV_PM_OPS,
 304         .probe          = tmp102_probe,
 305         .remove         = tmp102_remove,
 306         .id_table       = tmp102_id,
 307 };
 308
 309 module_i2c_driver(tmp102_driver);
 310
 311 MODULE_AUTHOR("Steven King <sfking@fdwdc.com>");
 312 MODULE_DESCRIPTION("Texas Instruments TMP102 temperature sensor driver");
 313 MODULE_LICENSE("GPL");