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