drivers/hwmon/tmp102.c

   1 /* Texas Instruments TMP102 SMBUS temperature sensor driver
   2  *
   3  * Copyright 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
  21
  22 #include <linux/module.h>
  23 #include <linux/init.h>
  24 #include <linux/slab.h>
  25 #include <linux/i2c.h>
  26 #include <linux/hwmon.h>
  27 #include <linux/hwmon-sysfs.h>
  28 #include <linux/err.h>
  29 #include <linux/mutex.h>
  30 #include <linux/delay.h>
  31
  32 #define DRIVER_NAME "tmp102"
  33
  34 #define TMP102_TEMP_REG                 0x00
  35 #define TMP102_CONF_REG                 0x01
  36 /* note: these bit definitions are byte swapped */
  37 #define         TMP102_CONF_SD          0x0100
  38 #define         TMP102_CONF_TM          0x0200
  39 #define         TMP102_CONF_POL         0x0400
  40 #define         TMP102_CONF_F0          0x0800
  41 #define         TMP102_CONF_F1          0x1000
  42 #define         TMP102_CONF_R0          0x2000
  43 #define         TMP102_CONF_R1          0x4000
  44 #define         TMP102_CONF_OS          0x8000
  45 #define         TMP102_CONF_EM          0x0010
  46 #define         TMP102_CONF_AL          0x0020
  47 #define         TMP102_CONF_CR0         0x0040
  48 #define         TMP102_CONF_CR1         0x0080
  49 #define TMP102_TLOW_REG                 0x02
  50 #define TMP102_THIGH_REG                0x03
  51
  52 struct tmp102 {
  53         struct device *hwmon_dev;
  54         struct mutex lock;
  55         unsigned long last_update;
  56         int temp[3];
  57 };
  58
  59 /* the TMP102 registers are big endian so we have to swab16 the values */
  60 static int tmp102_read_reg(struct i2c_client *client, u8 reg)
  61 {
  62         int result = i2c_smbus_read_word_data(client, reg);
  63         return result < 0 ? result : swab16(result);
  64 }
  65
  66 static int tmp102_write_reg(struct i2c_client *client, u8 reg, u16 val)
  67 {
  68         return i2c_smbus_write_word_data(client, reg, swab16(val));
  69 }
  70
  71 /* convert left adjusted 13bit TMP102 register value to miliCelsius */
  72 static int tmp102_reg_to_mC(s16 val)
  73 {
  74         return (val * 1000) / 128;
  75 }
  76
  77 /* convert miliCelsius to left adjusted 13bit TMP102 register value */
  78 static u16 tmp102_mC_to_reg(int val)
  79 {
  80         return (val * 128) / 1000;
  81 }
  82
  83 static const u8 tmp102_reg[] = {
  84         TMP102_TEMP_REG,
  85         TMP102_TLOW_REG,
  86         TMP102_THIGH_REG,
  87 };
  88
  89 static struct tmp102 *tmp102_update_device(struct i2c_client *client)
  90 {
  91         struct tmp102 *tmp102 = i2c_get_clientdata(client);
  92
  93         mutex_lock(&tmp102->lock);
  94         if (time_after(jiffies, tmp102->last_update + HZ / 4)) {
  95                 int i;
  96                 for (i = 0; i < ARRAY_SIZE(tmp102->temp); ++i) {
  97                         int status = tmp102_read_reg(client, tmp102_reg[i]);
  98                         if (status > -1)
  99                                 tmp102->temp[i] = tmp102_reg_to_mC(status);
 100                 }
 101                 tmp102->last_update = jiffies;
 102         }
 103         mutex_unlock(&tmp102->lock);
 104         return tmp102;
 105 }
 106
 107 static ssize_t tmp102_show_temp(struct device *dev,
 108                                 struct device_attribute *attr,
 109                                 char *buf)
 110 {
 111         struct sensor_device_attribute *sda = to_sensor_dev_attr(attr);
 112         struct tmp102 *tmp102 = tmp102_update_device(to_i2c_client(dev));
 113
 114         return sprintf(buf, "%d\n", tmp102->temp[sda->index]);
 115 }
 116
 117 static ssize_t tmp102_set_temp(struct device *dev,
 118                                struct device_attribute *attr,
 119                                const char *buf, size_t count)
 120 {
 121         struct sensor_device_attribute *sda = to_sensor_dev_attr(attr);
 122         struct i2c_client *client = to_i2c_client(dev);
 123         struct tmp102 *tmp102 = i2c_get_clientdata(client);
 124         long val;
 125         int status = 0;
 126
 127         if ((strict_strtol(buf, 10, &val) < 0) || (abs(val) > 150000))
 128                 return -EINVAL;
 129         mutex_lock(&tmp102->lock);
 130         if (tmp102->temp[sda->index] != val) {
 131                 tmp102->temp[sda->index] = val;
 132                 status = tmp102_write_reg(client, tmp102_reg[sda->index],
 133                                           tmp102_mC_to_reg(val));
 134         }
 135         mutex_unlock(&tmp102->lock);
 136         return status ? : count;
 137 }
 138
 139 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, tmp102_show_temp, NULL , 0);
 140
 141 static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO, tmp102_show_temp,
 142                           tmp102_set_temp, 1);
 143
 144 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, tmp102_show_temp,
 145                           tmp102_set_temp, 2);
 146
 147 static struct attribute *tmp102_attributes[] = {
 148         &sensor_dev_attr_temp1_input.dev_attr.attr,
 149         &sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
 150         &sensor_dev_attr_temp1_max.dev_attr.attr,
 151         NULL
 152 };
 153
 154 static const struct attribute_group tmp102_attr_group = {
 155         .attrs = tmp102_attributes,
 156 };
 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 __devinit tmp102_probe(struct i2c_client *client,
 162                                   const struct i2c_device_id *id)
 163 {
 164         struct tmp102 *tmp102;
 165         int status;
 166
 167         if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA |
 168                                      I2C_FUNC_SMBUS_WORD_DATA)) {
 169                 dev_dbg(&client->dev, "adapter doesnt support SMBUS\n");
 170                 return -ENODEV;
 171         }
 172
 173         tmp102 = kzalloc(sizeof(*tmp102), GFP_KERNEL);
 174         if (!tmp102) {
 175                 dev_dbg(&client->dev, "kzalloc failed\n");
 176                 return -ENOMEM;
 177         }
 178         i2c_set_clientdata(client, tmp102);
 179
 180         tmp102_write_reg(client, TMP102_CONF_REG, TMP102_CONFIG);
 181         status = tmp102_read_reg(client, TMP102_CONF_REG);
 182         if (status < 0) {
 183                 dev_dbg(&client->dev, "error reading config register\n");
 184                 goto fail0;
 185         }
 186         status &= ~TMP102_CONFIG_RD_ONLY;
 187         if (status != TMP102_CONFIG) {
 188                 dev_dbg(&client->dev, "could not verify config settings\n");
 189                 status = -EIO;
 190                 goto fail0;
 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 fail0;
 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 fail1;
 205         }
 206
 207         dev_info(&client->dev, "initialized\n");
 208
 209         return 0;
 210 fail1:
 211         sysfs_remove_group(&client->dev.kobj, &tmp102_attr_group);
 212 fail0:
 213         i2c_set_clientdata(client, NULL);
 214         kfree(tmp102);
 215
 216         return 0;
 217 }
 218
 219 static int __devexit tmp102_remove(struct i2c_client *client)
 220 {
 221         struct tmp102 *tmp102 = i2c_get_clientdata(client);
 222
 223         /* shutdown the chip */
 224         tmp102_write_reg(client, TMP102_CONF_REG, TMP102_CONF_SD);
 225
 226         hwmon_device_unregister(tmp102->hwmon_dev);
 227         sysfs_remove_group(&client->dev.kobj, &tmp102_attr_group);
 228         i2c_set_clientdata(client, NULL);
 229         kfree(tmp102);
 230
 231         return 0;
 232 }
 233
 234 #ifdef CONFIG_PM
 235 static int tmp102_suspend(struct device *dev)
 236 {
 237         struct i2c_client *client = to_i2c_client(dev);
 238
 239         tmp102_write_reg(client, TMP102_CONF_REG, TMP102_CONF_SD);
 240
 241         return 0;
 242 }
 243
 244 static int tmp102_resume(struct device *dev)
 245 {
 246         struct i2c_client *client = to_i2c_client(dev);
 247
 248         tmp102_write_reg(client, TMP102_CONF_REG, TMP102_CONFIG);
 249
 250         return 0;
 251 }
 252
 253 static const struct dev_pm_ops tmp102_dev_pm_ops = {
 254         .suspend        = tmp102_suspend,
 255         .resume         = tmp102_resume,
 256 };
 257
 258 #define TMP102_DEV_PM_OPS (&tmp102_dev_pm_ops)
 259 #else
 260 #define TMP102_DEV_PM_OPS NULL
 261 #endif /* CONFIG_PM */
 262
 263 static const unsigned short normal_i2c[] = {
 264         0x48, 0x49, 0x4a, 0x4b, I2C_CLIENT_END
 265 };
 266
 267 static const struct i2c_device_id tmp102_id[] = {
 268         { DRIVER_NAME, 0 },
 269         { }
 270 };
 271
 272 static struct i2c_driver tmp102_driver = {
 273         .driver.name    = DRIVER_NAME,
 274         .driver.pm      = TMP102_DEV_PM_OPS,
 275         .class          = I2C_CLASS_HWMON,
 276         .probe          = tmp102_probe,
 277         .remove         = __devexit_p(tmp102_remove),
 278         .id_table       = tmp102_id,
 279         .address_list   = normal_i2c,
 280 };
 281
 282 static int __init tmp102_init(void)
 283 {
 284         return i2c_add_driver(&tmp102_driver);
 285 }
 286 module_init(tmp102_init);
 287
 288 static void __exit tmp102_exit(void)
 289 {
 290         i2c_del_driver(&tmp102_driver);
 291 }
 292 module_exit(tmp102_exit);
 293
 294
 295 MODULE_AUTHOR("Steven King <sfking@fdwdc.com>");
 296 MODULE_DESCRIPTION("Texas Instruments TMP102 temperature sensor driver");
 297 MODULE_LICENSE("GPL");