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
  16 #include <linux/delay.h>
  17 #include <linux/module.h>
  18 #include <linux/init.h>
  19 #include <linux/slab.h>
  20 #include <linux/i2c.h>
  21 #include <linux/hwmon.h>
  22 #include <linux/hwmon-sysfs.h>
  23 #include <linux/err.h>
  24 #include <linux/mutex.h>
  25 #include <linux/device.h>
  26 #include <linux/jiffies.h>
  27 #include <linux/regmap.h>
  28 #include <linux/of.h>
  29
  30 #define DRIVER_NAME "tmp102"
  31
  32 #define TMP102_TEMP_REG                 0x00
  33 #define TMP102_CONF_REG                 0x01
  34 /* note: these bit definitions are byte swapped */
  35 #define         TMP102_CONF_SD          0x0100
  36 #define         TMP102_CONF_TM          0x0200
  37 #define         TMP102_CONF_POL         0x0400
  38 #define         TMP102_CONF_F0          0x0800
  39 #define         TMP102_CONF_F1          0x1000
  40 #define         TMP102_CONF_R0          0x2000
  41 #define         TMP102_CONF_R1          0x4000
  42 #define         TMP102_CONF_OS          0x8000
  43 #define         TMP102_CONF_EM          0x0010
  44 #define         TMP102_CONF_AL          0x0020
  45 #define         TMP102_CONF_CR0         0x0040
  46 #define         TMP102_CONF_CR1         0x0080
  47 #define TMP102_TLOW_REG                 0x02
  48 #define TMP102_THIGH_REG                0x03
  49
  50 #define TMP102_CONFREG_MASK     (TMP102_CONF_SD | TMP102_CONF_TM | \
  51                                  TMP102_CONF_POL | TMP102_CONF_F0 | \
  52                                  TMP102_CONF_F1 | TMP102_CONF_OS | \
  53                                  TMP102_CONF_EM | TMP102_CONF_AL | \
  54                                  TMP102_CONF_CR0 | TMP102_CONF_CR1)
  55
  56 #define TMP102_CONFIG_CLEAR     (TMP102_CONF_SD | TMP102_CONF_OS | \
  57                                  TMP102_CONF_CR0)
  58 #define TMP102_CONFIG_SET       (TMP102_CONF_TM | TMP102_CONF_EM | \
  59                                  TMP102_CONF_CR1)
  60
  61 #define CONVERSION_TIME_MS              35      /* in milli-seconds */
  62
  63 struct tmp102 {
  64         struct regmap *regmap;
  65         u16 config_orig;
  66         unsigned long ready_time;
  67 };
  68
  69 /* convert left adjusted 13-bit TMP102 register value to milliCelsius */
  70 static inline int tmp102_reg_to_mC(s16 val)
  71 {
  72         return ((val & ~0x01) * 1000) / 128;
  73 }
  74
  75 /* convert milliCelsius to left adjusted 13-bit TMP102 register value */
  76 static inline u16 tmp102_mC_to_reg(int val)
  77 {
  78         return (val * 128) / 1000;
  79 }
  80
  81 static int tmp102_read(struct device *dev, enum hwmon_sensor_types type,
  82                        u32 attr, int channel, long *temp)
  83 {
  84         struct tmp102 *tmp102 = dev_get_drvdata(dev);
  85         unsigned int regval;
  86         int err, reg;
  87
  88         switch (attr) {
  89         case hwmon_temp_input:
  90                 /* Is it too early to return a conversion ? */
  91                 if (time_before(jiffies, tmp102->ready_time)) {
  92                         dev_dbg(dev, "%s: Conversion not ready yet..\n", __func__);
  93                         return -EAGAIN;
  94                 }
  95                 reg = TMP102_TEMP_REG;
  96                 break;
  97         case hwmon_temp_max_hyst:
  98                 reg = TMP102_TLOW_REG;
  99                 break;
 100         case hwmon_temp_max:
 101                 reg = TMP102_THIGH_REG;
 102                 break;
 103         default:
 104                 return -EOPNOTSUPP;
 105         }
 106
 107         err = regmap_read(tmp102->regmap, reg, &regval);
 108         if (err < 0)
 109                 return err;
 110         *temp = tmp102_reg_to_mC(regval);
 111
 112         return 0;
 113 }
 114
 115 static int tmp102_write(struct device *dev, enum hwmon_sensor_types type,
 116                         u32 attr, int channel, long temp)
 117 {
 118         struct tmp102 *tmp102 = dev_get_drvdata(dev);
 119         int reg;
 120
 121         switch (attr) {
 122         case hwmon_temp_max_hyst:
 123                 reg = TMP102_TLOW_REG;
 124                 break;
 125         case hwmon_temp_max:
 126                 reg = TMP102_THIGH_REG;
 127                 break;
 128         default:
 129                 return -EOPNOTSUPP;
 130         }
 131
 132         temp = clamp_val(temp, -256000, 255000);
 133         return regmap_write(tmp102->regmap, reg, tmp102_mC_to_reg(temp));
 134 }
 135
 136 static umode_t tmp102_is_visible(const void *data, enum hwmon_sensor_types type,
 137                                  u32 attr, int channel)
 138 {
 139         if (type != hwmon_temp)
 140                 return 0;
 141
 142         switch (attr) {
 143         case hwmon_temp_input:
 144                 return S_IRUGO;
 145         case hwmon_temp_max_hyst:
 146         case hwmon_temp_max:
 147                 return S_IRUGO | S_IWUSR;
 148         default:
 149                 return 0;
 150         }
 151 }
 152
 153 static u32 tmp102_chip_config[] = {
 154         HWMON_C_REGISTER_TZ,
 155         0
 156 };
 157
 158 static const struct hwmon_channel_info tmp102_chip = {
 159         .type = hwmon_chip,
 160         .config = tmp102_chip_config,
 161 };
 162
 163 static u32 tmp102_temp_config[] = {
 164         HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MAX_HYST,
 165         0
 166 };
 167
 168 static const struct hwmon_channel_info tmp102_temp = {
 169         .type = hwmon_temp,
 170         .config = tmp102_temp_config,
 171 };
 172
 173 static const struct hwmon_channel_info *tmp102_info[] = {
 174         &tmp102_chip,
 175         &tmp102_temp,
 176         NULL
 177 };
 178
 179 static const struct hwmon_ops tmp102_hwmon_ops = {
 180         .is_visible = tmp102_is_visible,
 181         .read = tmp102_read,
 182         .write = tmp102_write,
 183 };
 184
 185 static const struct hwmon_chip_info tmp102_chip_info = {
 186         .ops = &tmp102_hwmon_ops,
 187         .info = tmp102_info,
 188 };
 189
 190 static void tmp102_restore_config(void *data)
 191 {
 192         struct tmp102 *tmp102 = data;
 193
 194         regmap_write(tmp102->regmap, TMP102_CONF_REG, tmp102->config_orig);
 195 }
 196
 197 static bool tmp102_is_writeable_reg(struct device *dev, unsigned int reg)
 198 {
 199         return reg != TMP102_TEMP_REG;
 200 }
 201
 202 static bool tmp102_is_volatile_reg(struct device *dev, unsigned int reg)
 203 {
 204         return reg == TMP102_TEMP_REG;
 205 }
 206
 207 static const struct regmap_config tmp102_regmap_config = {
 208         .reg_bits = 8,
 209         .val_bits = 16,
 210         .max_register = TMP102_THIGH_REG,
 211         .writeable_reg = tmp102_is_writeable_reg,
 212         .volatile_reg = tmp102_is_volatile_reg,
 213         .val_format_endian = REGMAP_ENDIAN_BIG,
 214         .cache_type = REGCACHE_RBTREE,
 215         .use_single_rw = true,
 216 };
 217
 218 static int tmp102_probe(struct i2c_client *client,
 219                         const struct i2c_device_id *id)
 220 {
 221         struct device *dev = &client->dev;
 222         struct device *hwmon_dev;
 223         struct tmp102 *tmp102;
 224         unsigned int regval;
 225         int err;
 226
 227         if (!i2c_check_functionality(client->adapter,
 228                                      I2C_FUNC_SMBUS_WORD_DATA)) {
 229                 dev_err(dev,
 230                         "adapter doesn't support SMBus word transactions\n");
 231                 return -ENODEV;
 232         }
 233
 234         tmp102 = devm_kzalloc(dev, sizeof(*tmp102), GFP_KERNEL);
 235         if (!tmp102)
 236                 return -ENOMEM;
 237
 238         i2c_set_clientdata(client, tmp102);
 239
 240         tmp102->regmap = devm_regmap_init_i2c(client, &tmp102_regmap_config);
 241         if (IS_ERR(tmp102->regmap))
 242                 return PTR_ERR(tmp102->regmap);
 243
 244         err = regmap_read(tmp102->regmap, TMP102_CONF_REG, &regval);
 245         if (err < 0) {
 246                 dev_err(dev, "error reading config register\n");
 247                 return err;
 248         }
 249
 250         if ((regval & ~TMP102_CONFREG_MASK) !=
 251             (TMP102_CONF_R0 | TMP102_CONF_R1)) {
 252                 dev_err(dev, "unexpected config register value\n");
 253                 return -ENODEV;
 254         }
 255
 256         tmp102->config_orig = regval;
 257
 258         err = devm_add_action_or_reset(dev, tmp102_restore_config, tmp102);
 259         if (err)
 260                 return err;
 261
 262         regval &= ~TMP102_CONFIG_CLEAR;
 263         regval |= TMP102_CONFIG_SET;
 264
 265         err = regmap_write(tmp102->regmap, TMP102_CONF_REG, regval);
 266         if (err < 0) {
 267                 dev_err(dev, "error writing config register\n");
 268                 return err;
 269         }
 270
 271         /*
 272          * Mark that we are not ready with data until the first
 273          * conversion is complete
 274          */
 275         tmp102->ready_time = jiffies + msecs_to_jiffies(CONVERSION_TIME_MS);
 276
 277         hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
 278                                                          tmp102,
 279                                                          &tmp102_chip_info,
 280                                                          NULL);
 281         if (IS_ERR(hwmon_dev)) {
 282                 dev_dbg(dev, "unable to register hwmon device\n");
 283                 return PTR_ERR(hwmon_dev);
 284         }
 285         dev_info(dev, "initialized\n");
 286
 287         return 0;
 288 }
 289
 290 #ifdef CONFIG_PM_SLEEP
 291 static int tmp102_suspend(struct device *dev)
 292 {
 293         struct i2c_client *client = to_i2c_client(dev);
 294         struct tmp102 *tmp102 = i2c_get_clientdata(client);
 295
 296         return regmap_update_bits(tmp102->regmap, TMP102_CONF_REG,
 297                                   TMP102_CONF_SD, TMP102_CONF_SD);
 298 }
 299
 300 static int tmp102_resume(struct device *dev)
 301 {
 302         struct i2c_client *client = to_i2c_client(dev);
 303         struct tmp102 *tmp102 = i2c_get_clientdata(client);
 304         int err;
 305
 306         err = regmap_update_bits(tmp102->regmap, TMP102_CONF_REG,
 307                                  TMP102_CONF_SD, 0);
 308
 309         tmp102->ready_time = jiffies + msecs_to_jiffies(CONVERSION_TIME_MS);
 310
 311         return err;
 312 }
 313 #endif /* CONFIG_PM */
 314
 315 static SIMPLE_DEV_PM_OPS(tmp102_dev_pm_ops, tmp102_suspend, tmp102_resume);
 316
 317 static const struct i2c_device_id tmp102_id[] = {
 318         { "tmp102", 0 },
 319         { }
 320 };
 321 MODULE_DEVICE_TABLE(i2c, tmp102_id);
 322
 323 static const struct of_device_id tmp102_of_match[] = {
 324         { .compatible = "ti,tmp102" },
 325         { },
 326 };
 327 MODULE_DEVICE_TABLE(of, tmp102_of_match);
 328
 329 static struct i2c_driver tmp102_driver = {
 330         .driver.name    = DRIVER_NAME,
 331         .driver.of_match_table = of_match_ptr(tmp102_of_match),
 332         .driver.pm      = &tmp102_dev_pm_ops,
 333         .probe          = tmp102_probe,
 334         .id_table       = tmp102_id,
 335 };
 336
 337 module_i2c_driver(tmp102_driver);
 338
 339 MODULE_AUTHOR("Steven King <sfking@fdwdc.com>");
 340 MODULE_DESCRIPTION("Texas Instruments TMP102 temperature sensor driver");
 341 MODULE_LICENSE("GPL");