1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Driver for Linear Technology LTC2945 I2C Power Monitor 4 * 5 * Copyright (c) 2014 Guenter Roeck 6 */ 7 8 #include <linux/kernel.h> 9 #include <linux/module.h> 10 #include <linux/err.h> 11 #include <linux/slab.h> 12 #include <linux/i2c.h> 13 #include <linux/hwmon.h> 14 #include <linux/hwmon-sysfs.h> 15 #include <linux/jiffies.h> 16 #include <linux/regmap.h> 17 18 /* chip registers */ 19 #define LTC2945_CONTROL 0x00 20 #define LTC2945_ALERT 0x01 21 #define LTC2945_STATUS 0x02 22 #define LTC2945_FAULT 0x03 23 #define LTC2945_POWER_H 0x05 24 #define LTC2945_MAX_POWER_H 0x08 25 #define LTC2945_MIN_POWER_H 0x0b 26 #define LTC2945_MAX_POWER_THRES_H 0x0e 27 #define LTC2945_MIN_POWER_THRES_H 0x11 28 #define LTC2945_SENSE_H 0x14 29 #define LTC2945_MAX_SENSE_H 0x16 30 #define LTC2945_MIN_SENSE_H 0x18 31 #define LTC2945_MAX_SENSE_THRES_H 0x1a 32 #define LTC2945_MIN_SENSE_THRES_H 0x1c 33 #define LTC2945_VIN_H 0x1e 34 #define LTC2945_MAX_VIN_H 0x20 35 #define LTC2945_MIN_VIN_H 0x22 36 #define LTC2945_MAX_VIN_THRES_H 0x24 37 #define LTC2945_MIN_VIN_THRES_H 0x26 38 #define LTC2945_ADIN_H 0x28 39 #define LTC2945_MAX_ADIN_H 0x2a 40 #define LTC2945_MIN_ADIN_H 0x2c 41 #define LTC2945_MAX_ADIN_THRES_H 0x2e 42 #define LTC2945_MIN_ADIN_THRES_H 0x30 43 #define LTC2945_MIN_ADIN_THRES_L 0x31 44 45 /* Fault register bits */ 46 47 #define FAULT_ADIN_UV (1 << 0) 48 #define FAULT_ADIN_OV (1 << 1) 49 #define FAULT_VIN_UV (1 << 2) 50 #define FAULT_VIN_OV (1 << 3) 51 #define FAULT_SENSE_UV (1 << 4) 52 #define FAULT_SENSE_OV (1 << 5) 53 #define FAULT_POWER_UV (1 << 6) 54 #define FAULT_POWER_OV (1 << 7) 55 56 /* Control register bits */ 57 58 #define CONTROL_MULT_SELECT (1 << 0) 59 #define CONTROL_TEST_MODE (1 << 4) 60 61 static const struct of_device_id __maybe_unused ltc2945_of_match[] = { 62 { .compatible = "adi,ltc2945" }, 63 { } 64 }; 65 MODULE_DEVICE_TABLE(of, ltc2945_of_match); 66 67 /** 68 * struct ltc2945_data - LTC2945 device data 69 * @regmap: regmap device 70 * @shunt_resistor: shunt resistor value in micro ohms (1000 by default) 71 */ 72 struct ltc2945_data { 73 struct regmap *regmap; 74 u32 shunt_resistor; 75 }; 76 77 static inline bool is_power_reg(u8 reg) 78 { 79 return reg < LTC2945_SENSE_H; 80 } 81 82 /* Return the value from the given register in uW, mV, or mA */ 83 static long long ltc2945_reg_to_val(struct device *dev, u8 reg) 84 { 85 struct ltc2945_data *data = dev_get_drvdata(dev); 86 struct regmap *regmap = data->regmap; 87 u32 shunt_resistor = data->shunt_resistor; 88 unsigned int control; 89 u8 buf[3]; 90 long long val; 91 int ret; 92 93 ret = regmap_bulk_read(regmap, reg, buf, 94 is_power_reg(reg) ? 3 : 2); 95 if (ret < 0) 96 return ret; 97 98 if (is_power_reg(reg)) { 99 /* 24-bit power */ 100 val = (buf[0] << 16) + (buf[1] << 8) + buf[2]; 101 } else { 102 /* 12-bit current, voltage */ 103 val = (buf[0] << 4) + (buf[1] >> 4); 104 } 105 106 switch (reg) { 107 case LTC2945_POWER_H: 108 case LTC2945_MAX_POWER_H: 109 case LTC2945_MIN_POWER_H: 110 case LTC2945_MAX_POWER_THRES_H: 111 case LTC2945_MIN_POWER_THRES_H: 112 /* 113 * Convert to uW 114 * Control register bit 0 selects if voltage at SENSE+/VDD 115 * or voltage at ADIN is used to measure power. 116 */ 117 ret = regmap_read(regmap, LTC2945_CONTROL, &control); 118 if (ret < 0) 119 return ret; 120 if (control & CONTROL_MULT_SELECT) { 121 /* 25 mV * 25 uV = 0.625 uV resolution. */ 122 val *= 625LL; 123 } else { 124 /* 0.5 mV * 25 uV = 0.0125 uV resolution. */ 125 val = (val * 25LL) >> 1; 126 } 127 val *= 1000; 128 /* Overflow check: Assuming max 24-bit power, val is at most 53 bits right now. */ 129 val = DIV_ROUND_CLOSEST_ULL(val, shunt_resistor); 130 /* 131 * Overflow check: After division, depending on shunt resistor, 132 * val can still be > 32 bits so returning long long makes sense 133 */ 134 135 break; 136 case LTC2945_VIN_H: 137 case LTC2945_MAX_VIN_H: 138 case LTC2945_MIN_VIN_H: 139 case LTC2945_MAX_VIN_THRES_H: 140 case LTC2945_MIN_VIN_THRES_H: 141 /* 25 mV resolution. Convert to mV. */ 142 val *= 25; 143 break; 144 case LTC2945_ADIN_H: 145 case LTC2945_MAX_ADIN_H: 146 case LTC2945_MIN_ADIN_THRES_H: 147 case LTC2945_MAX_ADIN_THRES_H: 148 case LTC2945_MIN_ADIN_H: 149 /* 0.5mV resolution. Convert to mV. */ 150 val = val >> 1; 151 break; 152 case LTC2945_SENSE_H: 153 case LTC2945_MAX_SENSE_H: 154 case LTC2945_MIN_SENSE_H: 155 case LTC2945_MAX_SENSE_THRES_H: 156 case LTC2945_MIN_SENSE_THRES_H: 157 /* 25 uV resolution. Convert to mA. */ 158 val *= 25 * 1000; 159 /* Overflow check: Assuming max 12-bit sense, val is at most 27 bits right now */ 160 val = DIV_ROUND_CLOSEST_ULL(val, shunt_resistor); 161 /* Overflow check: After division, <= 27 bits */ 162 break; 163 default: 164 return -EINVAL; 165 } 166 return val; 167 } 168 169 static long long ltc2945_val_to_reg(struct device *dev, u8 reg, 170 unsigned long long val) 171 { 172 struct ltc2945_data *data = dev_get_drvdata(dev); 173 struct regmap *regmap = data->regmap; 174 u32 shunt_resistor = data->shunt_resistor; 175 unsigned int control; 176 int ret; 177 178 /* Ensure we don't overflow */ 179 val = clamp_val(val, 0, U32_MAX); 180 181 switch (reg) { 182 case LTC2945_POWER_H: 183 case LTC2945_MAX_POWER_H: 184 case LTC2945_MIN_POWER_H: 185 case LTC2945_MAX_POWER_THRES_H: 186 case LTC2945_MIN_POWER_THRES_H: 187 /* 188 * Control register bit 0 selects if voltage at SENSE+/VDD 189 * or voltage at ADIN is used to measure power, which in turn 190 * determines register calculations. 191 */ 192 ret = regmap_read(regmap, LTC2945_CONTROL, &control); 193 if (ret < 0) 194 return ret; 195 if (control & CONTROL_MULT_SELECT) { 196 /* 25 mV * 25 uV = 0.625 uV resolution. */ 197 val *= shunt_resistor; 198 /* Overflow check: Assuming 32-bit val and shunt resistor, val <= 64bits */ 199 val = DIV_ROUND_CLOSEST_ULL(val, 625 * 1000); 200 /* Overflow check: val is now <= 44 bits */ 201 } else { 202 /* 0.5 mV * 25 uV = 0.0125 uV resolution. */ 203 val *= shunt_resistor; 204 /* Overflow check: Assuming 32-bit val and shunt resistor, val <= 64bits */ 205 val = DIV_ROUND_CLOSEST_ULL(val, 25 * 1000) * 2; 206 /* Overflow check: val is now <= 51 bits */ 207 } 208 break; 209 case LTC2945_VIN_H: 210 case LTC2945_MAX_VIN_H: 211 case LTC2945_MIN_VIN_H: 212 case LTC2945_MAX_VIN_THRES_H: 213 case LTC2945_MIN_VIN_THRES_H: 214 /* 25 mV resolution. */ 215 val = DIV_ROUND_CLOSEST_ULL(val, 25); 216 break; 217 case LTC2945_ADIN_H: 218 case LTC2945_MAX_ADIN_H: 219 case LTC2945_MIN_ADIN_THRES_H: 220 case LTC2945_MAX_ADIN_THRES_H: 221 case LTC2945_MIN_ADIN_H: 222 /* 0.5mV resolution. */ 223 val *= 2; 224 break; 225 case LTC2945_SENSE_H: 226 case LTC2945_MAX_SENSE_H: 227 case LTC2945_MIN_SENSE_H: 228 case LTC2945_MAX_SENSE_THRES_H: 229 case LTC2945_MIN_SENSE_THRES_H: 230 /* 25 uV resolution. Convert to mA. */ 231 val *= shunt_resistor; 232 /* Overflow check: Assuming 32-bit val and 32-bit shunt resistor, val is 64bits */ 233 val = DIV_ROUND_CLOSEST_ULL(val, 25 * 1000); 234 /* Overflow check: val is now <= 50 bits */ 235 break; 236 default: 237 return -EINVAL; 238 } 239 return val; 240 } 241 242 static ssize_t ltc2945_value_show(struct device *dev, 243 struct device_attribute *da, char *buf) 244 { 245 struct sensor_device_attribute *attr = to_sensor_dev_attr(da); 246 long long value; 247 248 value = ltc2945_reg_to_val(dev, attr->index); 249 if (value < 0) 250 return value; 251 return sysfs_emit(buf, "%lld\n", value); 252 } 253 254 static ssize_t ltc2945_value_store(struct device *dev, 255 struct device_attribute *da, 256 const char *buf, size_t count) 257 { 258 struct sensor_device_attribute *attr = to_sensor_dev_attr(da); 259 struct ltc2945_data *data = dev_get_drvdata(dev); 260 struct regmap *regmap = data->regmap; 261 u8 reg = attr->index; 262 unsigned int val; 263 u8 regbuf[3]; 264 int num_regs; 265 long long regval; 266 int ret; 267 268 ret = kstrtouint(buf, 10, &val); 269 if (ret) 270 return ret; 271 272 /* convert to register value, then clamp and write result */ 273 regval = ltc2945_val_to_reg(dev, reg, val); 274 if (regval < 0) 275 return regval; 276 if (is_power_reg(reg)) { 277 regval = clamp_val(regval, 0, 0xffffff); 278 regbuf[0] = regval >> 16; 279 regbuf[1] = (regval >> 8) & 0xff; 280 regbuf[2] = regval; 281 num_regs = 3; 282 } else { 283 regval = clamp_val(regval, 0, 0xfff) << 4; 284 regbuf[0] = regval >> 8; 285 regbuf[1] = regval & 0xff; 286 num_regs = 2; 287 } 288 ret = regmap_bulk_write(regmap, reg, regbuf, num_regs); 289 return ret < 0 ? ret : count; 290 } 291 292 static ssize_t ltc2945_history_store(struct device *dev, 293 struct device_attribute *da, 294 const char *buf, size_t count) 295 { 296 struct sensor_device_attribute *attr = to_sensor_dev_attr(da); 297 struct ltc2945_data *data = dev_get_drvdata(dev); 298 struct regmap *regmap = data->regmap; 299 u8 reg = attr->index; 300 int num_regs = is_power_reg(reg) ? 3 : 2; 301 u8 buf_min[3] = { 0xff, 0xff, 0xff }; 302 u8 buf_max[3] = { 0, 0, 0 }; 303 unsigned long val; 304 int ret; 305 306 ret = kstrtoul(buf, 10, &val); 307 if (ret) 308 return ret; 309 if (val != 1) 310 return -EINVAL; 311 312 ret = regmap_update_bits(regmap, LTC2945_CONTROL, CONTROL_TEST_MODE, 313 CONTROL_TEST_MODE); 314 315 /* Reset minimum */ 316 ret = regmap_bulk_write(regmap, reg, buf_min, num_regs); 317 if (ret) 318 return ret; 319 320 switch (reg) { 321 case LTC2945_MIN_POWER_H: 322 reg = LTC2945_MAX_POWER_H; 323 break; 324 case LTC2945_MIN_SENSE_H: 325 reg = LTC2945_MAX_SENSE_H; 326 break; 327 case LTC2945_MIN_VIN_H: 328 reg = LTC2945_MAX_VIN_H; 329 break; 330 case LTC2945_MIN_ADIN_H: 331 reg = LTC2945_MAX_ADIN_H; 332 break; 333 default: 334 WARN_ONCE(1, "Bad register: 0x%x\n", reg); 335 return -EINVAL; 336 } 337 /* Reset maximum */ 338 ret = regmap_bulk_write(regmap, reg, buf_max, num_regs); 339 340 /* Try resetting test mode even if there was an error */ 341 regmap_update_bits(regmap, LTC2945_CONTROL, CONTROL_TEST_MODE, 0); 342 343 return ret ? : count; 344 } 345 346 static ssize_t ltc2945_bool_show(struct device *dev, 347 struct device_attribute *da, char *buf) 348 { 349 struct sensor_device_attribute *attr = to_sensor_dev_attr(da); 350 struct ltc2945_data *data = dev_get_drvdata(dev); 351 struct regmap *regmap = data->regmap; 352 unsigned int fault; 353 int ret; 354 355 ret = regmap_read(regmap, LTC2945_FAULT, &fault); 356 if (ret < 0) 357 return ret; 358 359 fault &= attr->index; 360 if (fault) /* Clear reported faults in chip register */ 361 regmap_update_bits(regmap, LTC2945_FAULT, attr->index, 0); 362 363 return sysfs_emit(buf, "%d\n", !!fault); 364 } 365 366 /* Input voltages */ 367 368 static SENSOR_DEVICE_ATTR_RO(in1_input, ltc2945_value, LTC2945_VIN_H); 369 static SENSOR_DEVICE_ATTR_RW(in1_min, ltc2945_value, LTC2945_MIN_VIN_THRES_H); 370 static SENSOR_DEVICE_ATTR_RW(in1_max, ltc2945_value, LTC2945_MAX_VIN_THRES_H); 371 static SENSOR_DEVICE_ATTR_RO(in1_lowest, ltc2945_value, LTC2945_MIN_VIN_H); 372 static SENSOR_DEVICE_ATTR_RO(in1_highest, ltc2945_value, LTC2945_MAX_VIN_H); 373 static SENSOR_DEVICE_ATTR_WO(in1_reset_history, ltc2945_history, 374 LTC2945_MIN_VIN_H); 375 376 static SENSOR_DEVICE_ATTR_RO(in2_input, ltc2945_value, LTC2945_ADIN_H); 377 static SENSOR_DEVICE_ATTR_RW(in2_min, ltc2945_value, LTC2945_MIN_ADIN_THRES_H); 378 static SENSOR_DEVICE_ATTR_RW(in2_max, ltc2945_value, LTC2945_MAX_ADIN_THRES_H); 379 static SENSOR_DEVICE_ATTR_RO(in2_lowest, ltc2945_value, LTC2945_MIN_ADIN_H); 380 static SENSOR_DEVICE_ATTR_RO(in2_highest, ltc2945_value, LTC2945_MAX_ADIN_H); 381 static SENSOR_DEVICE_ATTR_WO(in2_reset_history, ltc2945_history, 382 LTC2945_MIN_ADIN_H); 383 384 /* Voltage alarms */ 385 386 static SENSOR_DEVICE_ATTR_RO(in1_min_alarm, ltc2945_bool, FAULT_VIN_UV); 387 static SENSOR_DEVICE_ATTR_RO(in1_max_alarm, ltc2945_bool, FAULT_VIN_OV); 388 static SENSOR_DEVICE_ATTR_RO(in2_min_alarm, ltc2945_bool, FAULT_ADIN_UV); 389 static SENSOR_DEVICE_ATTR_RO(in2_max_alarm, ltc2945_bool, FAULT_ADIN_OV); 390 391 /* Currents (via sense resistor) */ 392 393 static SENSOR_DEVICE_ATTR_RO(curr1_input, ltc2945_value, LTC2945_SENSE_H); 394 static SENSOR_DEVICE_ATTR_RW(curr1_min, ltc2945_value, 395 LTC2945_MIN_SENSE_THRES_H); 396 static SENSOR_DEVICE_ATTR_RW(curr1_max, ltc2945_value, 397 LTC2945_MAX_SENSE_THRES_H); 398 static SENSOR_DEVICE_ATTR_RO(curr1_lowest, ltc2945_value, LTC2945_MIN_SENSE_H); 399 static SENSOR_DEVICE_ATTR_RO(curr1_highest, ltc2945_value, 400 LTC2945_MAX_SENSE_H); 401 static SENSOR_DEVICE_ATTR_WO(curr1_reset_history, ltc2945_history, 402 LTC2945_MIN_SENSE_H); 403 404 /* Current alarms */ 405 406 static SENSOR_DEVICE_ATTR_RO(curr1_min_alarm, ltc2945_bool, FAULT_SENSE_UV); 407 static SENSOR_DEVICE_ATTR_RO(curr1_max_alarm, ltc2945_bool, FAULT_SENSE_OV); 408 409 /* Power */ 410 411 static SENSOR_DEVICE_ATTR_RO(power1_input, ltc2945_value, LTC2945_POWER_H); 412 static SENSOR_DEVICE_ATTR_RW(power1_min, ltc2945_value, 413 LTC2945_MIN_POWER_THRES_H); 414 static SENSOR_DEVICE_ATTR_RW(power1_max, ltc2945_value, 415 LTC2945_MAX_POWER_THRES_H); 416 static SENSOR_DEVICE_ATTR_RO(power1_input_lowest, ltc2945_value, 417 LTC2945_MIN_POWER_H); 418 static SENSOR_DEVICE_ATTR_RO(power1_input_highest, ltc2945_value, 419 LTC2945_MAX_POWER_H); 420 static SENSOR_DEVICE_ATTR_WO(power1_reset_history, ltc2945_history, 421 LTC2945_MIN_POWER_H); 422 423 /* Power alarms */ 424 425 static SENSOR_DEVICE_ATTR_RO(power1_min_alarm, ltc2945_bool, FAULT_POWER_UV); 426 static SENSOR_DEVICE_ATTR_RO(power1_max_alarm, ltc2945_bool, FAULT_POWER_OV); 427 428 static struct attribute *ltc2945_attrs[] = { 429 &sensor_dev_attr_in1_input.dev_attr.attr, 430 &sensor_dev_attr_in1_min.dev_attr.attr, 431 &sensor_dev_attr_in1_max.dev_attr.attr, 432 &sensor_dev_attr_in1_lowest.dev_attr.attr, 433 &sensor_dev_attr_in1_highest.dev_attr.attr, 434 &sensor_dev_attr_in1_reset_history.dev_attr.attr, 435 &sensor_dev_attr_in1_min_alarm.dev_attr.attr, 436 &sensor_dev_attr_in1_max_alarm.dev_attr.attr, 437 438 &sensor_dev_attr_in2_input.dev_attr.attr, 439 &sensor_dev_attr_in2_min.dev_attr.attr, 440 &sensor_dev_attr_in2_max.dev_attr.attr, 441 &sensor_dev_attr_in2_lowest.dev_attr.attr, 442 &sensor_dev_attr_in2_highest.dev_attr.attr, 443 &sensor_dev_attr_in2_reset_history.dev_attr.attr, 444 &sensor_dev_attr_in2_min_alarm.dev_attr.attr, 445 &sensor_dev_attr_in2_max_alarm.dev_attr.attr, 446 447 &sensor_dev_attr_curr1_input.dev_attr.attr, 448 &sensor_dev_attr_curr1_min.dev_attr.attr, 449 &sensor_dev_attr_curr1_max.dev_attr.attr, 450 &sensor_dev_attr_curr1_lowest.dev_attr.attr, 451 &sensor_dev_attr_curr1_highest.dev_attr.attr, 452 &sensor_dev_attr_curr1_reset_history.dev_attr.attr, 453 &sensor_dev_attr_curr1_min_alarm.dev_attr.attr, 454 &sensor_dev_attr_curr1_max_alarm.dev_attr.attr, 455 456 &sensor_dev_attr_power1_input.dev_attr.attr, 457 &sensor_dev_attr_power1_min.dev_attr.attr, 458 &sensor_dev_attr_power1_max.dev_attr.attr, 459 &sensor_dev_attr_power1_input_lowest.dev_attr.attr, 460 &sensor_dev_attr_power1_input_highest.dev_attr.attr, 461 &sensor_dev_attr_power1_reset_history.dev_attr.attr, 462 &sensor_dev_attr_power1_min_alarm.dev_attr.attr, 463 &sensor_dev_attr_power1_max_alarm.dev_attr.attr, 464 465 NULL, 466 }; 467 ATTRIBUTE_GROUPS(ltc2945); 468 469 static const struct regmap_config ltc2945_regmap_config = { 470 .reg_bits = 8, 471 .val_bits = 8, 472 .max_register = LTC2945_MIN_ADIN_THRES_L, 473 }; 474 475 static int ltc2945_probe(struct i2c_client *client) 476 { 477 struct device *dev = &client->dev; 478 struct device *hwmon_dev; 479 struct regmap *regmap; 480 struct ltc2945_data *data; 481 482 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); 483 if (!data) 484 return -ENOMEM; 485 dev_set_drvdata(dev, data); 486 487 regmap = devm_regmap_init_i2c(client, <c2945_regmap_config); 488 if (IS_ERR(regmap)) { 489 dev_err(dev, "failed to allocate register map\n"); 490 return PTR_ERR(regmap); 491 } 492 493 data->regmap = regmap; 494 if (device_property_read_u32(dev, "shunt-resistor-micro-ohms", 495 &data->shunt_resistor)) 496 data->shunt_resistor = 1000; 497 498 if (data->shunt_resistor == 0) 499 return -EINVAL; 500 501 /* Clear faults */ 502 regmap_write(regmap, LTC2945_FAULT, 0x00); 503 504 hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name, 505 data, 506 ltc2945_groups); 507 return PTR_ERR_OR_ZERO(hwmon_dev); 508 } 509 510 static const struct i2c_device_id ltc2945_id[] = { 511 {"ltc2945", 0}, 512 { } 513 }; 514 515 MODULE_DEVICE_TABLE(i2c, ltc2945_id); 516 517 static struct i2c_driver ltc2945_driver = { 518 .driver = { 519 .name = "ltc2945", 520 .of_match_table = of_match_ptr(ltc2945_of_match), 521 }, 522 .probe_new = ltc2945_probe, 523 .id_table = ltc2945_id, 524 }; 525 526 module_i2c_driver(ltc2945_driver); 527 528 MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>"); 529 MODULE_DESCRIPTION("LTC2945 driver"); 530 MODULE_LICENSE("GPL"); 531