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 i2c_client *client;
  55         struct device *hwmon_dev;
  56         struct thermal_zone_device *tz;
  57         struct mutex lock;
  58         u16 config_orig;
  59         unsigned long last_update;
  60         int temp[3];
  61 };
  62
  63 /* convert left adjusted 13-bit TMP102 register value to milliCelsius */
  64 static inline int tmp102_reg_to_mC(s16 val)
  65 {
  66         return ((val & ~0x01) * 1000) / 128;
  67 }
  68
  69 /* convert milliCelsius to left adjusted 13-bit TMP102 register value */
  70 static inline u16 tmp102_mC_to_reg(int val)
  71 {
  72         return (val * 128) / 1000;
  73 }
  74
  75 static const u8 tmp102_reg[] = {
  76         TMP102_TEMP_REG,
  77         TMP102_TLOW_REG,
  78         TMP102_THIGH_REG,
  79 };
  80
  81 static struct tmp102 *tmp102_update_device(struct device *dev)
  82 {
  83         struct tmp102 *tmp102 = dev_get_drvdata(dev);
  84         struct i2c_client *client = tmp102->client;
  85
  86         mutex_lock(&tmp102->lock);
  87         if (time_after(jiffies, tmp102->last_update + HZ / 3)) {
  88                 int i;
  89                 for (i = 0; i < ARRAY_SIZE(tmp102->temp); ++i) {
  90                         int status = i2c_smbus_read_word_swapped(client,
  91                                                                  tmp102_reg[i]);
  92                         if (status > -1)
  93                                 tmp102->temp[i] = tmp102_reg_to_mC(status);
  94                 }
  95                 tmp102->last_update = jiffies;
  96         }
  97         mutex_unlock(&tmp102->lock);
  98         return tmp102;
  99 }
 100
 101 static int tmp102_read_temp(void *dev, long *temp)
 102 {
 103         struct tmp102 *tmp102 = tmp102_update_device(dev);
 104
 105         *temp = tmp102->temp[0];
 106
 107         return 0;
 108 }
 109
 110 static ssize_t tmp102_show_temp(struct device *dev,
 111                                 struct device_attribute *attr,
 112                                 char *buf)
 113 {
 114         struct sensor_device_attribute *sda = to_sensor_dev_attr(attr);
 115         struct tmp102 *tmp102 = tmp102_update_device(dev);
 116
 117         return sprintf(buf, "%d\n", tmp102->temp[sda->index]);
 118 }
 119
 120 static ssize_t tmp102_set_temp(struct device *dev,
 121                                struct device_attribute *attr,
 122                                const char *buf, size_t count)
 123 {
 124         struct sensor_device_attribute *sda = to_sensor_dev_attr(attr);
 125         struct tmp102 *tmp102 = dev_get_drvdata(dev);
 126         struct i2c_client *client = tmp102->client;
 127         long val;
 128         int status;
 129
 130         if (kstrtol(buf, 10, &val) < 0)
 131                 return -EINVAL;
 132         val = clamp_val(val, -256000, 255000);
 133
 134         mutex_lock(&tmp102->lock);
 135         tmp102->temp[sda->index] = val;
 136         status = i2c_smbus_write_word_swapped(client, tmp102_reg[sda->index],
 137                                               tmp102_mC_to_reg(val));
 138         mutex_unlock(&tmp102->lock);
 139         return status ? : count;
 140 }
 141
 142 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, tmp102_show_temp, NULL , 0);
 143
 144 static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO, tmp102_show_temp,
 145                           tmp102_set_temp, 1);
 146
 147 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, tmp102_show_temp,
 148                           tmp102_set_temp, 2);
 149
 150 static struct attribute *tmp102_attrs[] = {
 151         &sensor_dev_attr_temp1_input.dev_attr.attr,
 152         &sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
 153         &sensor_dev_attr_temp1_max.dev_attr.attr,
 154         NULL
 155 };
 156 ATTRIBUTE_GROUPS(tmp102);
 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 tmp102_probe(struct i2c_client *client,
 162                                   const struct i2c_device_id *id)
 163 {
 164         struct device *dev = &client->dev;
 165         struct device *hwmon_dev;
 166         struct tmp102 *tmp102;
 167         int status;
 168
 169         if (!i2c_check_functionality(client->adapter,
 170                                      I2C_FUNC_SMBUS_WORD_DATA)) {
 171                 dev_err(dev,
 172                         "adapter doesn't support SMBus word transactions\n");
 173                 return -ENODEV;
 174         }
 175
 176         tmp102 = devm_kzalloc(dev, sizeof(*tmp102), GFP_KERNEL);
 177         if (!tmp102)
 178                 return -ENOMEM;
 179
 180         i2c_set_clientdata(client, tmp102);
 181         tmp102->client = client;
 182
 183         status = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
 184         if (status < 0) {
 185                 dev_err(dev, "error reading config register\n");
 186                 return status;
 187         }
 188         tmp102->config_orig = status;
 189         status = i2c_smbus_write_word_swapped(client, TMP102_CONF_REG,
 190                                               TMP102_CONFIG);
 191         if (status < 0) {
 192                 dev_err(dev, "error writing config register\n");
 193                 goto fail_restore_config;
 194         }
 195         status = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
 196         if (status < 0) {
 197                 dev_err(dev, "error reading config register\n");
 198                 goto fail_restore_config;
 199         }
 200         status &= ~TMP102_CONFIG_RD_ONLY;
 201         if (status != TMP102_CONFIG) {
 202                 dev_err(dev, "config settings did not stick\n");
 203                 status = -ENODEV;
 204                 goto fail_restore_config;
 205         }
 206         tmp102->last_update = jiffies - HZ;
 207         mutex_init(&tmp102->lock);
 208
 209         hwmon_dev = hwmon_device_register_with_groups(dev, client->name,
 210                                                       tmp102, tmp102_groups);
 211         if (IS_ERR(hwmon_dev)) {
 212                 dev_dbg(dev, "unable to register hwmon device\n");
 213                 status = PTR_ERR(hwmon_dev);
 214                 goto fail_restore_config;
 215         }
 216         tmp102->hwmon_dev = hwmon_dev;
 217         tmp102->tz = thermal_zone_of_sensor_register(hwmon_dev, 0, hwmon_dev,
 218                                                      tmp102_read_temp, NULL);
 219         if (IS_ERR(tmp102->tz))
 220                 tmp102->tz = NULL;
 221
 222         dev_info(dev, "initialized\n");
 223
 224         return 0;
 225
 226 fail_restore_config:
 227         i2c_smbus_write_word_swapped(client, TMP102_CONF_REG,
 228                                      tmp102->config_orig);
 229         return status;
 230 }
 231
 232 static int tmp102_remove(struct i2c_client *client)
 233 {
 234         struct tmp102 *tmp102 = i2c_get_clientdata(client);
 235
 236         thermal_zone_of_sensor_unregister(tmp102->hwmon_dev, tmp102->tz);
 237         hwmon_device_unregister(tmp102->hwmon_dev);
 238
 239         /* Stop monitoring if device was stopped originally */
 240         if (tmp102->config_orig & TMP102_CONF_SD) {
 241                 int config;
 242
 243                 config = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
 244                 if (config >= 0)
 245                         i2c_smbus_write_word_swapped(client, TMP102_CONF_REG,
 246                                                      config | TMP102_CONF_SD);
 247         }
 248
 249         return 0;
 250 }
 251
 252 #ifdef CONFIG_PM
 253 static int tmp102_suspend(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 int tmp102_resume(struct device *dev)
 267 {
 268         struct i2c_client *client = to_i2c_client(dev);
 269         int config;
 270
 271         config = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
 272         if (config < 0)
 273                 return config;
 274
 275         config &= ~TMP102_CONF_SD;
 276         return i2c_smbus_write_word_swapped(client, TMP102_CONF_REG, config);
 277 }
 278
 279 static const struct dev_pm_ops tmp102_dev_pm_ops = {
 280         .suspend        = tmp102_suspend,
 281         .resume         = tmp102_resume,
 282 };
 283
 284 #define TMP102_DEV_PM_OPS (&tmp102_dev_pm_ops)
 285 #else
 286 #define TMP102_DEV_PM_OPS NULL
 287 #endif /* CONFIG_PM */
 288
 289 static const struct i2c_device_id tmp102_id[] = {
 290         { "tmp102", 0 },
 291         { }
 292 };
 293 MODULE_DEVICE_TABLE(i2c, tmp102_id);
 294
 295 static struct i2c_driver tmp102_driver = {
 296         .driver.name    = DRIVER_NAME,
 297         .driver.pm      = TMP102_DEV_PM_OPS,
 298         .probe          = tmp102_probe,
 299         .remove         = tmp102_remove,
 300         .id_table       = tmp102_id,
 301 };
 302
 303 module_i2c_driver(tmp102_driver);
 304
 305 MODULE_AUTHOR("Steven King <sfking@fdwdc.com>");
 306 MODULE_DESCRIPTION("Texas Instruments TMP102 temperature sensor driver");
 307 MODULE_LICENSE("GPL");