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         bool first_time;
  62 };
  63
  64 /* convert left adjusted 13-bit TMP102 register value to milliCelsius */
  65 static inline int tmp102_reg_to_mC(s16 val)
  66 {
  67         return ((val & ~0x01) * 1000) / 128;
  68 }
  69
  70 /* convert milliCelsius to left adjusted 13-bit TMP102 register value */
  71 static inline u16 tmp102_mC_to_reg(int val)
  72 {
  73         return (val * 128) / 1000;
  74 }
  75
  76 static const u8 tmp102_reg[] = {
  77         TMP102_TEMP_REG,
  78         TMP102_TLOW_REG,
  79         TMP102_THIGH_REG,
  80 };
  81
  82 static struct tmp102 *tmp102_update_device(struct device *dev)
  83 {
  84         struct tmp102 *tmp102 = dev_get_drvdata(dev);
  85         struct i2c_client *client = tmp102->client;
  86
  87         mutex_lock(&tmp102->lock);
  88         if (time_after(jiffies, tmp102->last_update + HZ / 3)) {
  89                 int i;
  90                 for (i = 0; i < ARRAY_SIZE(tmp102->temp); ++i) {
  91                         int status = i2c_smbus_read_word_swapped(client,
  92                                                                  tmp102_reg[i]);
  93                         if (status > -1)
  94                                 tmp102->temp[i] = tmp102_reg_to_mC(status);
  95                 }
  96                 tmp102->last_update = jiffies;
  97                 tmp102->first_time = false;
  98         }
  99         mutex_unlock(&tmp102->lock);
 100         return tmp102;
 101 }
 102
 103 static int tmp102_read_temp(void *dev, int *temp)
 104 {
 105         struct tmp102 *tmp102 = tmp102_update_device(dev);
 106
 107         /* Is it too early even to return a conversion? */
 108         if (tmp102->first_time) {
 109                 dev_dbg(dev, "%s: Conversion not ready yet..\n", __func__);
 110                 return -EAGAIN;
 111         }
 112
 113         *temp = tmp102->temp[0];
 114
 115         return 0;
 116 }
 117
 118 static ssize_t tmp102_show_temp(struct device *dev,
 119                                 struct device_attribute *attr,
 120                                 char *buf)
 121 {
 122         struct sensor_device_attribute *sda = to_sensor_dev_attr(attr);
 123         struct tmp102 *tmp102 = tmp102_update_device(dev);
 124
 125         /* Is it too early even to return a read? */
 126         if (tmp102->first_time)
 127                 return -EAGAIN;
 128
 129         return sprintf(buf, "%d\n", tmp102->temp[sda->index]);
 130 }
 131
 132 static ssize_t tmp102_set_temp(struct device *dev,
 133                                struct device_attribute *attr,
 134                                const char *buf, size_t count)
 135 {
 136         struct sensor_device_attribute *sda = to_sensor_dev_attr(attr);
 137         struct tmp102 *tmp102 = dev_get_drvdata(dev);
 138         struct i2c_client *client = tmp102->client;
 139         long val;
 140         int status;
 141
 142         if (kstrtol(buf, 10, &val) < 0)
 143                 return -EINVAL;
 144         val = clamp_val(val, -256000, 255000);
 145
 146         mutex_lock(&tmp102->lock);
 147         tmp102->temp[sda->index] = val;
 148         status = i2c_smbus_write_word_swapped(client, tmp102_reg[sda->index],
 149                                               tmp102_mC_to_reg(val));
 150         mutex_unlock(&tmp102->lock);
 151         return status ? : count;
 152 }
 153
 154 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, tmp102_show_temp, NULL , 0);
 155
 156 static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO, tmp102_show_temp,
 157                           tmp102_set_temp, 1);
 158
 159 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, tmp102_show_temp,
 160                           tmp102_set_temp, 2);
 161
 162 static struct attribute *tmp102_attrs[] = {
 163         &sensor_dev_attr_temp1_input.dev_attr.attr,
 164         &sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
 165         &sensor_dev_attr_temp1_max.dev_attr.attr,
 166         NULL
 167 };
 168 ATTRIBUTE_GROUPS(tmp102);
 169
 170 #define TMP102_CONFIG  (TMP102_CONF_TM | TMP102_CONF_EM | TMP102_CONF_CR1)
 171 #define TMP102_CONFIG_RD_ONLY (TMP102_CONF_R0 | TMP102_CONF_R1 | TMP102_CONF_AL)
 172
 173 static const struct thermal_zone_of_device_ops tmp102_of_thermal_ops = {
 174         .get_temp = tmp102_read_temp,
 175 };
 176
 177 static int tmp102_probe(struct i2c_client *client,
 178                                   const struct i2c_device_id *id)
 179 {
 180         struct device *dev = &client->dev;
 181         struct device *hwmon_dev;
 182         struct tmp102 *tmp102;
 183         int status;
 184
 185         if (!i2c_check_functionality(client->adapter,
 186                                      I2C_FUNC_SMBUS_WORD_DATA)) {
 187                 dev_err(dev,
 188                         "adapter doesn't support SMBus word transactions\n");
 189                 return -ENODEV;
 190         }
 191
 192         tmp102 = devm_kzalloc(dev, sizeof(*tmp102), GFP_KERNEL);
 193         if (!tmp102)
 194                 return -ENOMEM;
 195
 196         i2c_set_clientdata(client, tmp102);
 197         tmp102->client = client;
 198
 199         status = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
 200         if (status < 0) {
 201                 dev_err(dev, "error reading config register\n");
 202                 return status;
 203         }
 204         tmp102->config_orig = status;
 205         status = i2c_smbus_write_word_swapped(client, TMP102_CONF_REG,
 206                                               TMP102_CONFIG);
 207         if (status < 0) {
 208                 dev_err(dev, "error writing config register\n");
 209                 goto fail_restore_config;
 210         }
 211         status = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
 212         if (status < 0) {
 213                 dev_err(dev, "error reading config register\n");
 214                 goto fail_restore_config;
 215         }
 216         status &= ~TMP102_CONFIG_RD_ONLY;
 217         if (status != TMP102_CONFIG) {
 218                 dev_err(dev, "config settings did not stick\n");
 219                 status = -ENODEV;
 220                 goto fail_restore_config;
 221         }
 222         tmp102->last_update = jiffies;
 223         /* Mark that we are not ready with data until conversion is complete */
 224         tmp102->first_time = true;
 225         mutex_init(&tmp102->lock);
 226
 227         hwmon_dev = hwmon_device_register_with_groups(dev, client->name,
 228                                                       tmp102, tmp102_groups);
 229         if (IS_ERR(hwmon_dev)) {
 230                 dev_dbg(dev, "unable to register hwmon device\n");
 231                 status = PTR_ERR(hwmon_dev);
 232                 goto fail_restore_config;
 233         }
 234         tmp102->hwmon_dev = hwmon_dev;
 235         tmp102->tz = thermal_zone_of_sensor_register(hwmon_dev, 0, hwmon_dev,
 236                                                      &tmp102_of_thermal_ops);
 237         if (IS_ERR(tmp102->tz))
 238                 tmp102->tz = NULL;
 239
 240         dev_info(dev, "initialized\n");
 241
 242         return 0;
 243
 244 fail_restore_config:
 245         i2c_smbus_write_word_swapped(client, TMP102_CONF_REG,
 246                                      tmp102->config_orig);
 247         return status;
 248 }
 249
 250 static int tmp102_remove(struct i2c_client *client)
 251 {
 252         struct tmp102 *tmp102 = i2c_get_clientdata(client);
 253
 254         thermal_zone_of_sensor_unregister(tmp102->hwmon_dev, tmp102->tz);
 255         hwmon_device_unregister(tmp102->hwmon_dev);
 256
 257         /* Stop monitoring if device was stopped originally */
 258         if (tmp102->config_orig & TMP102_CONF_SD) {
 259                 int config;
 260
 261                 config = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
 262                 if (config >= 0)
 263                         i2c_smbus_write_word_swapped(client, TMP102_CONF_REG,
 264                                                      config | TMP102_CONF_SD);
 265         }
 266
 267         return 0;
 268 }
 269
 270 #ifdef CONFIG_PM_SLEEP
 271 static int tmp102_suspend(struct device *dev)
 272 {
 273         struct i2c_client *client = to_i2c_client(dev);
 274         int config;
 275
 276         config = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
 277         if (config < 0)
 278                 return config;
 279
 280         config |= TMP102_CONF_SD;
 281         return i2c_smbus_write_word_swapped(client, TMP102_CONF_REG, config);
 282 }
 283
 284 static int tmp102_resume(struct device *dev)
 285 {
 286         struct i2c_client *client = to_i2c_client(dev);
 287         int config;
 288
 289         config = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
 290         if (config < 0)
 291                 return config;
 292
 293         config &= ~TMP102_CONF_SD;
 294         return i2c_smbus_write_word_swapped(client, TMP102_CONF_REG, config);
 295 }
 296 #endif /* CONFIG_PM */
 297
 298 static SIMPLE_DEV_PM_OPS(tmp102_dev_pm_ops, tmp102_suspend, tmp102_resume);
 299
 300 static const struct i2c_device_id tmp102_id[] = {
 301         { "tmp102", 0 },
 302         { }
 303 };
 304 MODULE_DEVICE_TABLE(i2c, tmp102_id);
 305
 306 static struct i2c_driver tmp102_driver = {
 307         .driver.name    = DRIVER_NAME,
 308         .driver.pm      = &tmp102_dev_pm_ops,
 309         .probe          = tmp102_probe,
 310         .remove         = tmp102_remove,
 311         .id_table       = tmp102_id,
 312 };
 313
 314 module_i2c_driver(tmp102_driver);
 315
 316 MODULE_AUTHOR("Steven King <sfking@fdwdc.com>");
 317 MODULE_DESCRIPTION("Texas Instruments TMP102 temperature sensor driver");
 318 MODULE_LICENSE("GPL");