1 /* Texas Instruments TMP108 SMBus temperature sensor driver 2 * 3 * Copyright (C) 2016 John Muir <john@jmuir.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/device.h> 18 #include <linux/err.h> 19 #include <linux/hwmon.h> 20 #include <linux/hwmon-sysfs.h> 21 #include <linux/module.h> 22 #include <linux/mutex.h> 23 #include <linux/of.h> 24 #include <linux/i2c.h> 25 #include <linux/init.h> 26 #include <linux/jiffies.h> 27 #include <linux/regmap.h> 28 #include <linux/slab.h> 29 30 #define DRIVER_NAME "tmp108" 31 32 #define TMP108_REG_TEMP 0x00 33 #define TMP108_REG_CONF 0x01 34 #define TMP108_REG_TLOW 0x02 35 #define TMP108_REG_THIGH 0x03 36 37 #define TMP108_TEMP_MIN_MC -50000 /* Minimum millicelcius. */ 38 #define TMP108_TEMP_MAX_MC 127937 /* Maximum millicelcius. */ 39 40 /* Configuration register bits. 41 * Note: these bit definitions are byte swapped. 42 */ 43 #define TMP108_CONF_M0 0x0100 /* Sensor mode. */ 44 #define TMP108_CONF_M1 0x0200 45 #define TMP108_CONF_TM 0x0400 /* Thermostat mode. */ 46 #define TMP108_CONF_FL 0x0800 /* Watchdog flag - TLOW */ 47 #define TMP108_CONF_FH 0x1000 /* Watchdog flag - THIGH */ 48 #define TMP108_CONF_CR0 0x2000 /* Conversion rate. */ 49 #define TMP108_CONF_CR1 0x4000 50 #define TMP108_CONF_ID 0x8000 51 #define TMP108_CONF_HYS0 0x0010 /* Hysteresis. */ 52 #define TMP108_CONF_HYS1 0x0020 53 #define TMP108_CONF_POL 0x0080 /* Polarity of alert. */ 54 55 /* Defaults set by the hardware upon reset. */ 56 #define TMP108_CONF_DEFAULTS (TMP108_CONF_CR0 | TMP108_CONF_TM |\ 57 TMP108_CONF_HYS0 | TMP108_CONF_M1) 58 /* These bits are read-only. */ 59 #define TMP108_CONF_READ_ONLY (TMP108_CONF_FL | TMP108_CONF_FH |\ 60 TMP108_CONF_ID) 61 62 #define TMP108_CONF_MODE_MASK (TMP108_CONF_M0|TMP108_CONF_M1) 63 #define TMP108_MODE_SHUTDOWN 0x0000 64 #define TMP108_MODE_ONE_SHOT TMP108_CONF_M0 65 #define TMP108_MODE_CONTINUOUS TMP108_CONF_M1 /* Default */ 66 /* When M1 is set, M0 is ignored. */ 67 68 #define TMP108_CONF_CONVRATE_MASK (TMP108_CONF_CR0|TMP108_CONF_CR1) 69 #define TMP108_CONVRATE_0P25HZ 0x0000 70 #define TMP108_CONVRATE_1HZ TMP108_CONF_CR0 /* Default */ 71 #define TMP108_CONVRATE_4HZ TMP108_CONF_CR1 72 #define TMP108_CONVRATE_16HZ (TMP108_CONF_CR0|TMP108_CONF_CR1) 73 74 #define TMP108_CONF_HYSTERESIS_MASK (TMP108_CONF_HYS0|TMP108_CONF_HYS1) 75 #define TMP108_HYSTERESIS_0C 0x0000 76 #define TMP108_HYSTERESIS_1C TMP108_CONF_HYS0 /* Default */ 77 #define TMP108_HYSTERESIS_2C TMP108_CONF_HYS1 78 #define TMP108_HYSTERESIS_4C (TMP108_CONF_HYS0|TMP108_CONF_HYS1) 79 80 #define TMP108_CONVERSION_TIME_MS 30 /* in milli-seconds */ 81 82 struct tmp108 { 83 struct regmap *regmap; 84 u16 orig_config; 85 unsigned long ready_time; 86 }; 87 88 /* convert 12-bit TMP108 register value to milliCelsius */ 89 static inline int tmp108_temp_reg_to_mC(s16 val) 90 { 91 return (val & ~0x0f) * 1000 / 256; 92 } 93 94 /* convert milliCelsius to left adjusted 12-bit TMP108 register value */ 95 static inline u16 tmp108_mC_to_temp_reg(int val) 96 { 97 return (val * 256) / 1000; 98 } 99 100 static int tmp108_read(struct device *dev, enum hwmon_sensor_types type, 101 u32 attr, int channel, long *temp) 102 { 103 struct tmp108 *tmp108 = dev_get_drvdata(dev); 104 unsigned int regval; 105 int err, hyst; 106 107 if (type == hwmon_chip) { 108 if (attr == hwmon_chip_update_interval) { 109 err = regmap_read(tmp108->regmap, TMP108_REG_CONF, 110 ®val); 111 if (err < 0) 112 return err; 113 switch (regval & TMP108_CONF_CONVRATE_MASK) { 114 case TMP108_CONVRATE_0P25HZ: 115 default: 116 *temp = 4000; 117 break; 118 case TMP108_CONVRATE_1HZ: 119 *temp = 1000; 120 break; 121 case TMP108_CONVRATE_4HZ: 122 *temp = 250; 123 break; 124 case TMP108_CONVRATE_16HZ: 125 *temp = 63; 126 break; 127 } 128 return 0; 129 } 130 return -EOPNOTSUPP; 131 } 132 133 switch (attr) { 134 case hwmon_temp_input: 135 /* Is it too early to return a conversion ? */ 136 if (time_before(jiffies, tmp108->ready_time)) { 137 dev_dbg(dev, "%s: Conversion not ready yet..\n", 138 __func__); 139 return -EAGAIN; 140 } 141 err = regmap_read(tmp108->regmap, TMP108_REG_TEMP, ®val); 142 if (err < 0) 143 return err; 144 *temp = tmp108_temp_reg_to_mC(regval); 145 break; 146 case hwmon_temp_min: 147 case hwmon_temp_max: 148 err = regmap_read(tmp108->regmap, attr == hwmon_temp_min ? 149 TMP108_REG_TLOW : TMP108_REG_THIGH, ®val); 150 if (err < 0) 151 return err; 152 *temp = tmp108_temp_reg_to_mC(regval); 153 break; 154 case hwmon_temp_min_alarm: 155 case hwmon_temp_max_alarm: 156 err = regmap_read(tmp108->regmap, TMP108_REG_CONF, ®val); 157 if (err < 0) 158 return err; 159 *temp = !!(regval & (attr == hwmon_temp_min_alarm ? 160 TMP108_CONF_FL : TMP108_CONF_FH)); 161 break; 162 case hwmon_temp_min_hyst: 163 case hwmon_temp_max_hyst: 164 err = regmap_read(tmp108->regmap, TMP108_REG_CONF, ®val); 165 if (err < 0) 166 return err; 167 switch (regval & TMP108_CONF_HYSTERESIS_MASK) { 168 case TMP108_HYSTERESIS_0C: 169 default: 170 hyst = 0; 171 break; 172 case TMP108_HYSTERESIS_1C: 173 hyst = 1000; 174 break; 175 case TMP108_HYSTERESIS_2C: 176 hyst = 2000; 177 break; 178 case TMP108_HYSTERESIS_4C: 179 hyst = 4000; 180 break; 181 } 182 err = regmap_read(tmp108->regmap, attr == hwmon_temp_min_hyst ? 183 TMP108_REG_TLOW : TMP108_REG_THIGH, ®val); 184 if (err < 0) 185 return err; 186 *temp = tmp108_temp_reg_to_mC(regval); 187 if (attr == hwmon_temp_min_hyst) 188 *temp += hyst; 189 else 190 *temp -= hyst; 191 break; 192 default: 193 return -EOPNOTSUPP; 194 } 195 196 return 0; 197 } 198 199 static int tmp108_write(struct device *dev, enum hwmon_sensor_types type, 200 u32 attr, int channel, long temp) 201 { 202 struct tmp108 *tmp108 = dev_get_drvdata(dev); 203 u32 regval, mask; 204 int err; 205 206 if (type == hwmon_chip) { 207 if (attr == hwmon_chip_update_interval) { 208 if (temp < 156) 209 mask = TMP108_CONVRATE_16HZ; 210 else if (temp < 625) 211 mask = TMP108_CONVRATE_4HZ; 212 else if (temp < 2500) 213 mask = TMP108_CONVRATE_1HZ; 214 else 215 mask = TMP108_CONVRATE_0P25HZ; 216 return regmap_update_bits(tmp108->regmap, 217 TMP108_REG_CONF, 218 TMP108_CONF_CONVRATE_MASK, 219 mask); 220 } 221 return -EOPNOTSUPP; 222 } 223 224 switch (attr) { 225 case hwmon_temp_min: 226 case hwmon_temp_max: 227 temp = clamp_val(temp, TMP108_TEMP_MIN_MC, TMP108_TEMP_MAX_MC); 228 return regmap_write(tmp108->regmap, 229 attr == hwmon_temp_min ? 230 TMP108_REG_TLOW : TMP108_REG_THIGH, 231 tmp108_mC_to_temp_reg(temp)); 232 case hwmon_temp_min_hyst: 233 case hwmon_temp_max_hyst: 234 temp = clamp_val(temp, TMP108_TEMP_MIN_MC, TMP108_TEMP_MAX_MC); 235 err = regmap_read(tmp108->regmap, 236 attr == hwmon_temp_min_hyst ? 237 TMP108_REG_TLOW : TMP108_REG_THIGH, 238 ®val); 239 if (err < 0) 240 return err; 241 if (attr == hwmon_temp_min_hyst) 242 temp -= tmp108_temp_reg_to_mC(regval); 243 else 244 temp = tmp108_temp_reg_to_mC(regval) - temp; 245 if (temp < 500) 246 mask = TMP108_HYSTERESIS_0C; 247 else if (temp < 1500) 248 mask = TMP108_HYSTERESIS_1C; 249 else if (temp < 3000) 250 mask = TMP108_HYSTERESIS_2C; 251 else 252 mask = TMP108_HYSTERESIS_4C; 253 return regmap_update_bits(tmp108->regmap, TMP108_REG_CONF, 254 TMP108_CONF_HYSTERESIS_MASK, mask); 255 default: 256 return -EOPNOTSUPP; 257 } 258 } 259 260 static umode_t tmp108_is_visible(const void *data, enum hwmon_sensor_types type, 261 u32 attr, int channel) 262 { 263 if (type == hwmon_chip && attr == hwmon_chip_update_interval) 264 return 0644; 265 266 if (type != hwmon_temp) 267 return 0; 268 269 switch (attr) { 270 case hwmon_temp_input: 271 case hwmon_temp_min_alarm: 272 case hwmon_temp_max_alarm: 273 return 0444; 274 case hwmon_temp_min: 275 case hwmon_temp_max: 276 case hwmon_temp_min_hyst: 277 case hwmon_temp_max_hyst: 278 return 0644; 279 default: 280 return 0; 281 } 282 } 283 284 static const struct hwmon_channel_info *tmp108_info[] = { 285 HWMON_CHANNEL_INFO(chip, 286 HWMON_C_REGISTER_TZ | HWMON_C_UPDATE_INTERVAL), 287 HWMON_CHANNEL_INFO(temp, 288 HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MIN | 289 HWMON_T_MIN_HYST | HWMON_T_MAX_HYST | 290 HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM), 291 NULL 292 }; 293 294 static const struct hwmon_ops tmp108_hwmon_ops = { 295 .is_visible = tmp108_is_visible, 296 .read = tmp108_read, 297 .write = tmp108_write, 298 }; 299 300 static const struct hwmon_chip_info tmp108_chip_info = { 301 .ops = &tmp108_hwmon_ops, 302 .info = tmp108_info, 303 }; 304 305 static void tmp108_restore_config(void *data) 306 { 307 struct tmp108 *tmp108 = data; 308 309 regmap_write(tmp108->regmap, TMP108_REG_CONF, tmp108->orig_config); 310 } 311 312 static bool tmp108_is_writeable_reg(struct device *dev, unsigned int reg) 313 { 314 return reg != TMP108_REG_TEMP; 315 } 316 317 static bool tmp108_is_volatile_reg(struct device *dev, unsigned int reg) 318 { 319 /* Configuration register must be volatile to enable FL and FH. */ 320 return reg == TMP108_REG_TEMP || reg == TMP108_REG_CONF; 321 } 322 323 static const struct regmap_config tmp108_regmap_config = { 324 .reg_bits = 8, 325 .val_bits = 16, 326 .max_register = TMP108_REG_THIGH, 327 .writeable_reg = tmp108_is_writeable_reg, 328 .volatile_reg = tmp108_is_volatile_reg, 329 .val_format_endian = REGMAP_ENDIAN_BIG, 330 .cache_type = REGCACHE_RBTREE, 331 .use_single_read = true, 332 .use_single_write = true, 333 }; 334 335 static int tmp108_probe(struct i2c_client *client, 336 const struct i2c_device_id *id) 337 { 338 struct device *dev = &client->dev; 339 struct device *hwmon_dev; 340 struct tmp108 *tmp108; 341 int err; 342 u32 config; 343 344 if (!i2c_check_functionality(client->adapter, 345 I2C_FUNC_SMBUS_WORD_DATA)) { 346 dev_err(dev, 347 "adapter doesn't support SMBus word transactions\n"); 348 return -ENODEV; 349 } 350 351 tmp108 = devm_kzalloc(dev, sizeof(*tmp108), GFP_KERNEL); 352 if (!tmp108) 353 return -ENOMEM; 354 355 dev_set_drvdata(dev, tmp108); 356 357 tmp108->regmap = devm_regmap_init_i2c(client, &tmp108_regmap_config); 358 if (IS_ERR(tmp108->regmap)) { 359 err = PTR_ERR(tmp108->regmap); 360 dev_err(dev, "regmap init failed: %d", err); 361 return err; 362 } 363 364 err = regmap_read(tmp108->regmap, TMP108_REG_CONF, &config); 365 if (err < 0) { 366 dev_err(dev, "error reading config register: %d", err); 367 return err; 368 } 369 tmp108->orig_config = config; 370 371 /* Only continuous mode is supported. */ 372 config &= ~TMP108_CONF_MODE_MASK; 373 config |= TMP108_MODE_CONTINUOUS; 374 375 /* Only comparator mode is supported. */ 376 config &= ~TMP108_CONF_TM; 377 378 err = regmap_write(tmp108->regmap, TMP108_REG_CONF, config); 379 if (err < 0) { 380 dev_err(dev, "error writing config register: %d", err); 381 return err; 382 } 383 384 tmp108->ready_time = jiffies; 385 if ((tmp108->orig_config & TMP108_CONF_MODE_MASK) == 386 TMP108_MODE_SHUTDOWN) 387 tmp108->ready_time += 388 msecs_to_jiffies(TMP108_CONVERSION_TIME_MS); 389 390 err = devm_add_action_or_reset(dev, tmp108_restore_config, tmp108); 391 if (err) { 392 dev_err(dev, "add action or reset failed: %d", err); 393 return err; 394 } 395 396 hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, 397 tmp108, 398 &tmp108_chip_info, 399 NULL); 400 return PTR_ERR_OR_ZERO(hwmon_dev); 401 } 402 403 static int __maybe_unused tmp108_suspend(struct device *dev) 404 { 405 struct tmp108 *tmp108 = dev_get_drvdata(dev); 406 407 return regmap_update_bits(tmp108->regmap, TMP108_REG_CONF, 408 TMP108_CONF_MODE_MASK, TMP108_MODE_SHUTDOWN); 409 } 410 411 static int __maybe_unused tmp108_resume(struct device *dev) 412 { 413 struct tmp108 *tmp108 = dev_get_drvdata(dev); 414 int err; 415 416 err = regmap_update_bits(tmp108->regmap, TMP108_REG_CONF, 417 TMP108_CONF_MODE_MASK, TMP108_MODE_CONTINUOUS); 418 tmp108->ready_time = jiffies + 419 msecs_to_jiffies(TMP108_CONVERSION_TIME_MS); 420 return err; 421 } 422 423 static SIMPLE_DEV_PM_OPS(tmp108_dev_pm_ops, tmp108_suspend, tmp108_resume); 424 425 static const struct i2c_device_id tmp108_i2c_ids[] = { 426 { "tmp108", 0 }, 427 { } 428 }; 429 MODULE_DEVICE_TABLE(i2c, tmp108_i2c_ids); 430 431 #ifdef CONFIG_OF 432 static const struct of_device_id tmp108_of_ids[] = { 433 { .compatible = "ti,tmp108", }, 434 {} 435 }; 436 MODULE_DEVICE_TABLE(of, tmp108_of_ids); 437 #endif 438 439 static struct i2c_driver tmp108_driver = { 440 .driver = { 441 .name = DRIVER_NAME, 442 .pm = &tmp108_dev_pm_ops, 443 .of_match_table = of_match_ptr(tmp108_of_ids), 444 }, 445 .probe = tmp108_probe, 446 .id_table = tmp108_i2c_ids, 447 }; 448 449 module_i2c_driver(tmp108_driver); 450 451 MODULE_AUTHOR("John Muir <john@jmuir.com>"); 452 MODULE_DESCRIPTION("Texas Instruments TMP108 temperature sensor driver"); 453 MODULE_LICENSE("GPL"); 454