1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* Texas Instruments TMP108 SMBus temperature sensor driver 3 * 4 * Copyright (C) 2016 John Muir <john@jmuir.com> 5 */ 6 7 #include <linux/delay.h> 8 #include <linux/device.h> 9 #include <linux/err.h> 10 #include <linux/hwmon.h> 11 #include <linux/hwmon-sysfs.h> 12 #include <linux/module.h> 13 #include <linux/mutex.h> 14 #include <linux/of.h> 15 #include <linux/i2c.h> 16 #include <linux/init.h> 17 #include <linux/jiffies.h> 18 #include <linux/regmap.h> 19 #include <linux/slab.h> 20 21 #define DRIVER_NAME "tmp108" 22 23 #define TMP108_REG_TEMP 0x00 24 #define TMP108_REG_CONF 0x01 25 #define TMP108_REG_TLOW 0x02 26 #define TMP108_REG_THIGH 0x03 27 28 #define TMP108_TEMP_MIN_MC -50000 /* Minimum millicelcius. */ 29 #define TMP108_TEMP_MAX_MC 127937 /* Maximum millicelcius. */ 30 31 /* Configuration register bits. 32 * Note: these bit definitions are byte swapped. 33 */ 34 #define TMP108_CONF_M0 0x0100 /* Sensor mode. */ 35 #define TMP108_CONF_M1 0x0200 36 #define TMP108_CONF_TM 0x0400 /* Thermostat mode. */ 37 #define TMP108_CONF_FL 0x0800 /* Watchdog flag - TLOW */ 38 #define TMP108_CONF_FH 0x1000 /* Watchdog flag - THIGH */ 39 #define TMP108_CONF_CR0 0x2000 /* Conversion rate. */ 40 #define TMP108_CONF_CR1 0x4000 41 #define TMP108_CONF_ID 0x8000 42 #define TMP108_CONF_HYS0 0x0010 /* Hysteresis. */ 43 #define TMP108_CONF_HYS1 0x0020 44 #define TMP108_CONF_POL 0x0080 /* Polarity of alert. */ 45 46 /* Defaults set by the hardware upon reset. */ 47 #define TMP108_CONF_DEFAULTS (TMP108_CONF_CR0 | TMP108_CONF_TM |\ 48 TMP108_CONF_HYS0 | TMP108_CONF_M1) 49 /* These bits are read-only. */ 50 #define TMP108_CONF_READ_ONLY (TMP108_CONF_FL | TMP108_CONF_FH |\ 51 TMP108_CONF_ID) 52 53 #define TMP108_CONF_MODE_MASK (TMP108_CONF_M0|TMP108_CONF_M1) 54 #define TMP108_MODE_SHUTDOWN 0x0000 55 #define TMP108_MODE_ONE_SHOT TMP108_CONF_M0 56 #define TMP108_MODE_CONTINUOUS TMP108_CONF_M1 /* Default */ 57 /* When M1 is set, M0 is ignored. */ 58 59 #define TMP108_CONF_CONVRATE_MASK (TMP108_CONF_CR0|TMP108_CONF_CR1) 60 #define TMP108_CONVRATE_0P25HZ 0x0000 61 #define TMP108_CONVRATE_1HZ TMP108_CONF_CR0 /* Default */ 62 #define TMP108_CONVRATE_4HZ TMP108_CONF_CR1 63 #define TMP108_CONVRATE_16HZ (TMP108_CONF_CR0|TMP108_CONF_CR1) 64 65 #define TMP108_CONF_HYSTERESIS_MASK (TMP108_CONF_HYS0|TMP108_CONF_HYS1) 66 #define TMP108_HYSTERESIS_0C 0x0000 67 #define TMP108_HYSTERESIS_1C TMP108_CONF_HYS0 /* Default */ 68 #define TMP108_HYSTERESIS_2C TMP108_CONF_HYS1 69 #define TMP108_HYSTERESIS_4C (TMP108_CONF_HYS0|TMP108_CONF_HYS1) 70 71 #define TMP108_CONVERSION_TIME_MS 30 /* in milli-seconds */ 72 73 struct tmp108 { 74 struct regmap *regmap; 75 u16 orig_config; 76 unsigned long ready_time; 77 }; 78 79 /* convert 12-bit TMP108 register value to milliCelsius */ 80 static inline int tmp108_temp_reg_to_mC(s16 val) 81 { 82 return (val & ~0x0f) * 1000 / 256; 83 } 84 85 /* convert milliCelsius to left adjusted 12-bit TMP108 register value */ 86 static inline u16 tmp108_mC_to_temp_reg(int val) 87 { 88 return (val * 256) / 1000; 89 } 90 91 static int tmp108_read(struct device *dev, enum hwmon_sensor_types type, 92 u32 attr, int channel, long *temp) 93 { 94 struct tmp108 *tmp108 = dev_get_drvdata(dev); 95 unsigned int regval; 96 int err, hyst; 97 98 if (type == hwmon_chip) { 99 if (attr == hwmon_chip_update_interval) { 100 err = regmap_read(tmp108->regmap, TMP108_REG_CONF, 101 ®val); 102 if (err < 0) 103 return err; 104 switch (regval & TMP108_CONF_CONVRATE_MASK) { 105 case TMP108_CONVRATE_0P25HZ: 106 default: 107 *temp = 4000; 108 break; 109 case TMP108_CONVRATE_1HZ: 110 *temp = 1000; 111 break; 112 case TMP108_CONVRATE_4HZ: 113 *temp = 250; 114 break; 115 case TMP108_CONVRATE_16HZ: 116 *temp = 63; 117 break; 118 } 119 return 0; 120 } 121 return -EOPNOTSUPP; 122 } 123 124 switch (attr) { 125 case hwmon_temp_input: 126 /* Is it too early to return a conversion ? */ 127 if (time_before(jiffies, tmp108->ready_time)) { 128 dev_dbg(dev, "%s: Conversion not ready yet..\n", 129 __func__); 130 return -EAGAIN; 131 } 132 err = regmap_read(tmp108->regmap, TMP108_REG_TEMP, ®val); 133 if (err < 0) 134 return err; 135 *temp = tmp108_temp_reg_to_mC(regval); 136 break; 137 case hwmon_temp_min: 138 case hwmon_temp_max: 139 err = regmap_read(tmp108->regmap, attr == hwmon_temp_min ? 140 TMP108_REG_TLOW : TMP108_REG_THIGH, ®val); 141 if (err < 0) 142 return err; 143 *temp = tmp108_temp_reg_to_mC(regval); 144 break; 145 case hwmon_temp_min_alarm: 146 case hwmon_temp_max_alarm: 147 err = regmap_read(tmp108->regmap, TMP108_REG_CONF, ®val); 148 if (err < 0) 149 return err; 150 *temp = !!(regval & (attr == hwmon_temp_min_alarm ? 151 TMP108_CONF_FL : TMP108_CONF_FH)); 152 break; 153 case hwmon_temp_min_hyst: 154 case hwmon_temp_max_hyst: 155 err = regmap_read(tmp108->regmap, TMP108_REG_CONF, ®val); 156 if (err < 0) 157 return err; 158 switch (regval & TMP108_CONF_HYSTERESIS_MASK) { 159 case TMP108_HYSTERESIS_0C: 160 default: 161 hyst = 0; 162 break; 163 case TMP108_HYSTERESIS_1C: 164 hyst = 1000; 165 break; 166 case TMP108_HYSTERESIS_2C: 167 hyst = 2000; 168 break; 169 case TMP108_HYSTERESIS_4C: 170 hyst = 4000; 171 break; 172 } 173 err = regmap_read(tmp108->regmap, attr == hwmon_temp_min_hyst ? 174 TMP108_REG_TLOW : TMP108_REG_THIGH, ®val); 175 if (err < 0) 176 return err; 177 *temp = tmp108_temp_reg_to_mC(regval); 178 if (attr == hwmon_temp_min_hyst) 179 *temp += hyst; 180 else 181 *temp -= hyst; 182 break; 183 default: 184 return -EOPNOTSUPP; 185 } 186 187 return 0; 188 } 189 190 static int tmp108_write(struct device *dev, enum hwmon_sensor_types type, 191 u32 attr, int channel, long temp) 192 { 193 struct tmp108 *tmp108 = dev_get_drvdata(dev); 194 u32 regval, mask; 195 int err; 196 197 if (type == hwmon_chip) { 198 if (attr == hwmon_chip_update_interval) { 199 if (temp < 156) 200 mask = TMP108_CONVRATE_16HZ; 201 else if (temp < 625) 202 mask = TMP108_CONVRATE_4HZ; 203 else if (temp < 2500) 204 mask = TMP108_CONVRATE_1HZ; 205 else 206 mask = TMP108_CONVRATE_0P25HZ; 207 return regmap_update_bits(tmp108->regmap, 208 TMP108_REG_CONF, 209 TMP108_CONF_CONVRATE_MASK, 210 mask); 211 } 212 return -EOPNOTSUPP; 213 } 214 215 switch (attr) { 216 case hwmon_temp_min: 217 case hwmon_temp_max: 218 temp = clamp_val(temp, TMP108_TEMP_MIN_MC, TMP108_TEMP_MAX_MC); 219 return regmap_write(tmp108->regmap, 220 attr == hwmon_temp_min ? 221 TMP108_REG_TLOW : TMP108_REG_THIGH, 222 tmp108_mC_to_temp_reg(temp)); 223 case hwmon_temp_min_hyst: 224 case hwmon_temp_max_hyst: 225 temp = clamp_val(temp, TMP108_TEMP_MIN_MC, TMP108_TEMP_MAX_MC); 226 err = regmap_read(tmp108->regmap, 227 attr == hwmon_temp_min_hyst ? 228 TMP108_REG_TLOW : TMP108_REG_THIGH, 229 ®val); 230 if (err < 0) 231 return err; 232 if (attr == hwmon_temp_min_hyst) 233 temp -= tmp108_temp_reg_to_mC(regval); 234 else 235 temp = tmp108_temp_reg_to_mC(regval) - temp; 236 if (temp < 500) 237 mask = TMP108_HYSTERESIS_0C; 238 else if (temp < 1500) 239 mask = TMP108_HYSTERESIS_1C; 240 else if (temp < 3000) 241 mask = TMP108_HYSTERESIS_2C; 242 else 243 mask = TMP108_HYSTERESIS_4C; 244 return regmap_update_bits(tmp108->regmap, TMP108_REG_CONF, 245 TMP108_CONF_HYSTERESIS_MASK, mask); 246 default: 247 return -EOPNOTSUPP; 248 } 249 } 250 251 static umode_t tmp108_is_visible(const void *data, enum hwmon_sensor_types type, 252 u32 attr, int channel) 253 { 254 if (type == hwmon_chip && attr == hwmon_chip_update_interval) 255 return 0644; 256 257 if (type != hwmon_temp) 258 return 0; 259 260 switch (attr) { 261 case hwmon_temp_input: 262 case hwmon_temp_min_alarm: 263 case hwmon_temp_max_alarm: 264 return 0444; 265 case hwmon_temp_min: 266 case hwmon_temp_max: 267 case hwmon_temp_min_hyst: 268 case hwmon_temp_max_hyst: 269 return 0644; 270 default: 271 return 0; 272 } 273 } 274 275 static const struct hwmon_channel_info *tmp108_info[] = { 276 HWMON_CHANNEL_INFO(chip, 277 HWMON_C_REGISTER_TZ | HWMON_C_UPDATE_INTERVAL), 278 HWMON_CHANNEL_INFO(temp, 279 HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MIN | 280 HWMON_T_MIN_HYST | HWMON_T_MAX_HYST | 281 HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM), 282 NULL 283 }; 284 285 static const struct hwmon_ops tmp108_hwmon_ops = { 286 .is_visible = tmp108_is_visible, 287 .read = tmp108_read, 288 .write = tmp108_write, 289 }; 290 291 static const struct hwmon_chip_info tmp108_chip_info = { 292 .ops = &tmp108_hwmon_ops, 293 .info = tmp108_info, 294 }; 295 296 static void tmp108_restore_config(void *data) 297 { 298 struct tmp108 *tmp108 = data; 299 300 regmap_write(tmp108->regmap, TMP108_REG_CONF, tmp108->orig_config); 301 } 302 303 static bool tmp108_is_writeable_reg(struct device *dev, unsigned int reg) 304 { 305 return reg != TMP108_REG_TEMP; 306 } 307 308 static bool tmp108_is_volatile_reg(struct device *dev, unsigned int reg) 309 { 310 /* Configuration register must be volatile to enable FL and FH. */ 311 return reg == TMP108_REG_TEMP || reg == TMP108_REG_CONF; 312 } 313 314 static const struct regmap_config tmp108_regmap_config = { 315 .reg_bits = 8, 316 .val_bits = 16, 317 .max_register = TMP108_REG_THIGH, 318 .writeable_reg = tmp108_is_writeable_reg, 319 .volatile_reg = tmp108_is_volatile_reg, 320 .val_format_endian = REGMAP_ENDIAN_BIG, 321 .cache_type = REGCACHE_RBTREE, 322 .use_single_read = true, 323 .use_single_write = true, 324 }; 325 326 static int tmp108_probe(struct i2c_client *client) 327 { 328 struct device *dev = &client->dev; 329 struct device *hwmon_dev; 330 struct tmp108 *tmp108; 331 int err; 332 u32 config; 333 334 if (!i2c_check_functionality(client->adapter, 335 I2C_FUNC_SMBUS_WORD_DATA)) { 336 dev_err(dev, 337 "adapter doesn't support SMBus word transactions\n"); 338 return -ENODEV; 339 } 340 341 tmp108 = devm_kzalloc(dev, sizeof(*tmp108), GFP_KERNEL); 342 if (!tmp108) 343 return -ENOMEM; 344 345 dev_set_drvdata(dev, tmp108); 346 347 tmp108->regmap = devm_regmap_init_i2c(client, &tmp108_regmap_config); 348 if (IS_ERR(tmp108->regmap)) { 349 err = PTR_ERR(tmp108->regmap); 350 dev_err(dev, "regmap init failed: %d", err); 351 return err; 352 } 353 354 err = regmap_read(tmp108->regmap, TMP108_REG_CONF, &config); 355 if (err < 0) { 356 dev_err(dev, "error reading config register: %d", err); 357 return err; 358 } 359 tmp108->orig_config = config; 360 361 /* Only continuous mode is supported. */ 362 config &= ~TMP108_CONF_MODE_MASK; 363 config |= TMP108_MODE_CONTINUOUS; 364 365 /* Only comparator mode is supported. */ 366 config &= ~TMP108_CONF_TM; 367 368 err = regmap_write(tmp108->regmap, TMP108_REG_CONF, config); 369 if (err < 0) { 370 dev_err(dev, "error writing config register: %d", err); 371 return err; 372 } 373 374 tmp108->ready_time = jiffies; 375 if ((tmp108->orig_config & TMP108_CONF_MODE_MASK) == 376 TMP108_MODE_SHUTDOWN) 377 tmp108->ready_time += 378 msecs_to_jiffies(TMP108_CONVERSION_TIME_MS); 379 380 err = devm_add_action_or_reset(dev, tmp108_restore_config, tmp108); 381 if (err) { 382 dev_err(dev, "add action or reset failed: %d", err); 383 return err; 384 } 385 386 hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, 387 tmp108, 388 &tmp108_chip_info, 389 NULL); 390 return PTR_ERR_OR_ZERO(hwmon_dev); 391 } 392 393 static int tmp108_suspend(struct device *dev) 394 { 395 struct tmp108 *tmp108 = dev_get_drvdata(dev); 396 397 return regmap_update_bits(tmp108->regmap, TMP108_REG_CONF, 398 TMP108_CONF_MODE_MASK, TMP108_MODE_SHUTDOWN); 399 } 400 401 static int tmp108_resume(struct device *dev) 402 { 403 struct tmp108 *tmp108 = dev_get_drvdata(dev); 404 int err; 405 406 err = regmap_update_bits(tmp108->regmap, TMP108_REG_CONF, 407 TMP108_CONF_MODE_MASK, TMP108_MODE_CONTINUOUS); 408 tmp108->ready_time = jiffies + 409 msecs_to_jiffies(TMP108_CONVERSION_TIME_MS); 410 return err; 411 } 412 413 static DEFINE_SIMPLE_DEV_PM_OPS(tmp108_dev_pm_ops, tmp108_suspend, tmp108_resume); 414 415 static const struct i2c_device_id tmp108_i2c_ids[] = { 416 { "tmp108", 0 }, 417 { } 418 }; 419 MODULE_DEVICE_TABLE(i2c, tmp108_i2c_ids); 420 421 #ifdef CONFIG_OF 422 static const struct of_device_id tmp108_of_ids[] = { 423 { .compatible = "ti,tmp108", }, 424 {} 425 }; 426 MODULE_DEVICE_TABLE(of, tmp108_of_ids); 427 #endif 428 429 static struct i2c_driver tmp108_driver = { 430 .driver = { 431 .name = DRIVER_NAME, 432 .pm = pm_sleep_ptr(&tmp108_dev_pm_ops), 433 .of_match_table = of_match_ptr(tmp108_of_ids), 434 }, 435 .probe_new = tmp108_probe, 436 .id_table = tmp108_i2c_ids, 437 }; 438 439 module_i2c_driver(tmp108_driver); 440 441 MODULE_AUTHOR("John Muir <john@jmuir.com>"); 442 MODULE_DESCRIPTION("Texas Instruments TMP108 temperature sensor driver"); 443 MODULE_LICENSE("GPL"); 444