1 /* 2 * Driver for Linear Technology LTC2945 I2C Power Monitor 3 * 4 * Copyright (c) 2014 Guenter Roeck 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation; either version 2 of the License, or 9 * (at your option) any later version. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 */ 16 17 #include <linux/kernel.h> 18 #include <linux/module.h> 19 #include <linux/err.h> 20 #include <linux/slab.h> 21 #include <linux/i2c.h> 22 #include <linux/hwmon.h> 23 #include <linux/hwmon-sysfs.h> 24 #include <linux/jiffies.h> 25 #include <linux/regmap.h> 26 27 /* chip registers */ 28 #define LTC2945_CONTROL 0x00 29 #define LTC2945_ALERT 0x01 30 #define LTC2945_STATUS 0x02 31 #define LTC2945_FAULT 0x03 32 #define LTC2945_POWER_H 0x05 33 #define LTC2945_MAX_POWER_H 0x08 34 #define LTC2945_MIN_POWER_H 0x0b 35 #define LTC2945_MAX_POWER_THRES_H 0x0e 36 #define LTC2945_MIN_POWER_THRES_H 0x11 37 #define LTC2945_SENSE_H 0x14 38 #define LTC2945_MAX_SENSE_H 0x16 39 #define LTC2945_MIN_SENSE_H 0x18 40 #define LTC2945_MAX_SENSE_THRES_H 0x1a 41 #define LTC2945_MIN_SENSE_THRES_H 0x1c 42 #define LTC2945_VIN_H 0x1e 43 #define LTC2945_MAX_VIN_H 0x20 44 #define LTC2945_MIN_VIN_H 0x22 45 #define LTC2945_MAX_VIN_THRES_H 0x24 46 #define LTC2945_MIN_VIN_THRES_H 0x26 47 #define LTC2945_ADIN_H 0x28 48 #define LTC2945_MAX_ADIN_H 0x2a 49 #define LTC2945_MIN_ADIN_H 0x2c 50 #define LTC2945_MAX_ADIN_THRES_H 0x2e 51 #define LTC2945_MIN_ADIN_THRES_H 0x30 52 #define LTC2945_MIN_ADIN_THRES_L 0x31 53 54 /* Fault register bits */ 55 56 #define FAULT_ADIN_UV (1 << 0) 57 #define FAULT_ADIN_OV (1 << 1) 58 #define FAULT_VIN_UV (1 << 2) 59 #define FAULT_VIN_OV (1 << 3) 60 #define FAULT_SENSE_UV (1 << 4) 61 #define FAULT_SENSE_OV (1 << 5) 62 #define FAULT_POWER_UV (1 << 6) 63 #define FAULT_POWER_OV (1 << 7) 64 65 /* Control register bits */ 66 67 #define CONTROL_MULT_SELECT (1 << 0) 68 #define CONTROL_TEST_MODE (1 << 4) 69 70 static inline bool is_power_reg(u8 reg) 71 { 72 return reg < LTC2945_SENSE_H; 73 } 74 75 /* Return the value from the given register in uW, mV, or mA */ 76 static long long ltc2945_reg_to_val(struct device *dev, u8 reg) 77 { 78 struct regmap *regmap = dev_get_drvdata(dev); 79 unsigned int control; 80 u8 buf[3]; 81 long long val; 82 int ret; 83 84 ret = regmap_bulk_read(regmap, reg, buf, 85 is_power_reg(reg) ? 3 : 2); 86 if (ret < 0) 87 return ret; 88 89 if (is_power_reg(reg)) { 90 /* power */ 91 val = (buf[0] << 16) + (buf[1] << 8) + buf[2]; 92 } else { 93 /* current, voltage */ 94 val = (buf[0] << 4) + (buf[1] >> 4); 95 } 96 97 switch (reg) { 98 case LTC2945_POWER_H: 99 case LTC2945_MAX_POWER_H: 100 case LTC2945_MIN_POWER_H: 101 case LTC2945_MAX_POWER_THRES_H: 102 case LTC2945_MIN_POWER_THRES_H: 103 /* 104 * Convert to uW by assuming current is measured with 105 * an 1mOhm sense resistor, similar to current 106 * measurements. 107 * Control register bit 0 selects if voltage at SENSE+/VDD 108 * or voltage at ADIN is used to measure power. 109 */ 110 ret = regmap_read(regmap, LTC2945_CONTROL, &control); 111 if (ret < 0) 112 return ret; 113 if (control & CONTROL_MULT_SELECT) { 114 /* 25 mV * 25 uV = 0.625 uV resolution. */ 115 val *= 625LL; 116 } else { 117 /* 0.5 mV * 25 uV = 0.0125 uV resolution. */ 118 val = (val * 25LL) >> 1; 119 } 120 break; 121 case LTC2945_VIN_H: 122 case LTC2945_MAX_VIN_H: 123 case LTC2945_MIN_VIN_H: 124 case LTC2945_MAX_VIN_THRES_H: 125 case LTC2945_MIN_VIN_THRES_H: 126 /* 25 mV resolution. Convert to mV. */ 127 val *= 25; 128 break; 129 case LTC2945_ADIN_H: 130 case LTC2945_MAX_ADIN_H: 131 case LTC2945_MIN_ADIN_THRES_H: 132 case LTC2945_MAX_ADIN_THRES_H: 133 case LTC2945_MIN_ADIN_H: 134 /* 0.5mV resolution. Convert to mV. */ 135 val = val >> 1; 136 break; 137 case LTC2945_SENSE_H: 138 case LTC2945_MAX_SENSE_H: 139 case LTC2945_MIN_SENSE_H: 140 case LTC2945_MAX_SENSE_THRES_H: 141 case LTC2945_MIN_SENSE_THRES_H: 142 /* 143 * 25 uV resolution. Convert to current as measured with 144 * an 1 mOhm sense resistor, in mA. If a different sense 145 * resistor is installed, calculate the actual current by 146 * dividing the reported current by the sense resistor value 147 * in mOhm. 148 */ 149 val *= 25; 150 break; 151 default: 152 return -EINVAL; 153 } 154 return val; 155 } 156 157 static int ltc2945_val_to_reg(struct device *dev, u8 reg, 158 unsigned long val) 159 { 160 struct regmap *regmap = dev_get_drvdata(dev); 161 unsigned int control; 162 int ret; 163 164 switch (reg) { 165 case LTC2945_POWER_H: 166 case LTC2945_MAX_POWER_H: 167 case LTC2945_MIN_POWER_H: 168 case LTC2945_MAX_POWER_THRES_H: 169 case LTC2945_MIN_POWER_THRES_H: 170 /* 171 * Convert to register value by assuming current is measured 172 * with an 1mOhm sense resistor, similar to current 173 * measurements. 174 * Control register bit 0 selects if voltage at SENSE+/VDD 175 * or voltage at ADIN is used to measure power, which in turn 176 * determines register calculations. 177 */ 178 ret = regmap_read(regmap, LTC2945_CONTROL, &control); 179 if (ret < 0) 180 return ret; 181 if (control & CONTROL_MULT_SELECT) { 182 /* 25 mV * 25 uV = 0.625 uV resolution. */ 183 val = DIV_ROUND_CLOSEST(val, 625); 184 } else { 185 /* 186 * 0.5 mV * 25 uV = 0.0125 uV resolution. 187 * Divide first to avoid overflow; 188 * accept loss of accuracy. 189 */ 190 val = DIV_ROUND_CLOSEST(val, 25) * 2; 191 } 192 break; 193 case LTC2945_VIN_H: 194 case LTC2945_MAX_VIN_H: 195 case LTC2945_MIN_VIN_H: 196 case LTC2945_MAX_VIN_THRES_H: 197 case LTC2945_MIN_VIN_THRES_H: 198 /* 25 mV resolution. */ 199 val /= 25; 200 break; 201 case LTC2945_ADIN_H: 202 case LTC2945_MAX_ADIN_H: 203 case LTC2945_MIN_ADIN_THRES_H: 204 case LTC2945_MAX_ADIN_THRES_H: 205 case LTC2945_MIN_ADIN_H: 206 /* 0.5mV resolution. */ 207 val *= 2; 208 break; 209 case LTC2945_SENSE_H: 210 case LTC2945_MAX_SENSE_H: 211 case LTC2945_MIN_SENSE_H: 212 case LTC2945_MAX_SENSE_THRES_H: 213 case LTC2945_MIN_SENSE_THRES_H: 214 /* 215 * 25 uV resolution. Convert to current as measured with 216 * an 1 mOhm sense resistor, in mA. If a different sense 217 * resistor is installed, calculate the actual current by 218 * dividing the reported current by the sense resistor value 219 * in mOhm. 220 */ 221 val = DIV_ROUND_CLOSEST(val, 25); 222 break; 223 default: 224 return -EINVAL; 225 } 226 return val; 227 } 228 229 static ssize_t ltc2945_show_value(struct device *dev, 230 struct device_attribute *da, char *buf) 231 { 232 struct sensor_device_attribute *attr = to_sensor_dev_attr(da); 233 long long value; 234 235 value = ltc2945_reg_to_val(dev, attr->index); 236 if (value < 0) 237 return value; 238 return snprintf(buf, PAGE_SIZE, "%lld\n", value); 239 } 240 241 static ssize_t ltc2945_set_value(struct device *dev, 242 struct device_attribute *da, 243 const char *buf, size_t count) 244 { 245 struct sensor_device_attribute *attr = to_sensor_dev_attr(da); 246 struct regmap *regmap = dev_get_drvdata(dev); 247 u8 reg = attr->index; 248 unsigned long val; 249 u8 regbuf[3]; 250 int num_regs; 251 int regval; 252 int ret; 253 254 ret = kstrtoul(buf, 10, &val); 255 if (ret) 256 return ret; 257 258 /* convert to register value, then clamp and write result */ 259 regval = ltc2945_val_to_reg(dev, reg, val); 260 if (is_power_reg(reg)) { 261 regval = clamp_val(regval, 0, 0xffffff); 262 regbuf[0] = regval >> 16; 263 regbuf[1] = (regval >> 8) & 0xff; 264 regbuf[2] = regval; 265 num_regs = 3; 266 } else { 267 regval = clamp_val(regval, 0, 0xfff) << 4; 268 regbuf[0] = regval >> 8; 269 regbuf[1] = regval & 0xff; 270 num_regs = 2; 271 } 272 ret = regmap_bulk_write(regmap, reg, regbuf, num_regs); 273 return ret < 0 ? ret : count; 274 } 275 276 static ssize_t ltc2945_reset_history(struct device *dev, 277 struct device_attribute *da, 278 const char *buf, size_t count) 279 { 280 struct sensor_device_attribute *attr = to_sensor_dev_attr(da); 281 struct regmap *regmap = dev_get_drvdata(dev); 282 u8 reg = attr->index; 283 int num_regs = is_power_reg(reg) ? 3 : 2; 284 u8 buf_min[3] = { 0xff, 0xff, 0xff }; 285 u8 buf_max[3] = { 0, 0, 0 }; 286 unsigned long val; 287 int ret; 288 289 ret = kstrtoul(buf, 10, &val); 290 if (ret) 291 return ret; 292 if (val != 1) 293 return -EINVAL; 294 295 ret = regmap_update_bits(regmap, LTC2945_CONTROL, CONTROL_TEST_MODE, 296 CONTROL_TEST_MODE); 297 298 /* Reset minimum */ 299 ret = regmap_bulk_write(regmap, reg, buf_min, num_regs); 300 if (ret) 301 return ret; 302 303 switch (reg) { 304 case LTC2945_MIN_POWER_H: 305 reg = LTC2945_MAX_POWER_H; 306 break; 307 case LTC2945_MIN_SENSE_H: 308 reg = LTC2945_MAX_SENSE_H; 309 break; 310 case LTC2945_MIN_VIN_H: 311 reg = LTC2945_MAX_VIN_H; 312 break; 313 case LTC2945_MIN_ADIN_H: 314 reg = LTC2945_MAX_ADIN_H; 315 break; 316 default: 317 WARN_ONCE(1, "Bad register: 0x%x\n", reg); 318 return -EINVAL; 319 } 320 /* Reset maximum */ 321 ret = regmap_bulk_write(regmap, reg, buf_max, num_regs); 322 323 /* Try resetting test mode even if there was an error */ 324 regmap_update_bits(regmap, LTC2945_CONTROL, CONTROL_TEST_MODE, 0); 325 326 return ret ? : count; 327 } 328 329 static ssize_t ltc2945_show_bool(struct device *dev, 330 struct device_attribute *da, char *buf) 331 { 332 struct sensor_device_attribute *attr = to_sensor_dev_attr(da); 333 struct regmap *regmap = dev_get_drvdata(dev); 334 unsigned int fault; 335 int ret; 336 337 ret = regmap_read(regmap, LTC2945_FAULT, &fault); 338 if (ret < 0) 339 return ret; 340 341 fault &= attr->index; 342 if (fault) /* Clear reported faults in chip register */ 343 regmap_update_bits(regmap, LTC2945_FAULT, attr->index, 0); 344 345 return snprintf(buf, PAGE_SIZE, "%d\n", !!fault); 346 } 347 348 /* Input voltages */ 349 350 static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ltc2945_show_value, NULL, 351 LTC2945_VIN_H); 352 static SENSOR_DEVICE_ATTR(in1_min, S_IRUGO | S_IWUSR, ltc2945_show_value, 353 ltc2945_set_value, LTC2945_MIN_VIN_THRES_H); 354 static SENSOR_DEVICE_ATTR(in1_max, S_IRUGO | S_IWUSR, ltc2945_show_value, 355 ltc2945_set_value, LTC2945_MAX_VIN_THRES_H); 356 static SENSOR_DEVICE_ATTR(in1_lowest, S_IRUGO, ltc2945_show_value, NULL, 357 LTC2945_MIN_VIN_H); 358 static SENSOR_DEVICE_ATTR(in1_highest, S_IRUGO, ltc2945_show_value, NULL, 359 LTC2945_MAX_VIN_H); 360 static SENSOR_DEVICE_ATTR(in1_reset_history, S_IWUSR, NULL, 361 ltc2945_reset_history, LTC2945_MIN_VIN_H); 362 363 static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, ltc2945_show_value, NULL, 364 LTC2945_ADIN_H); 365 static SENSOR_DEVICE_ATTR(in2_min, S_IRUGO | S_IWUSR, ltc2945_show_value, 366 ltc2945_set_value, LTC2945_MIN_ADIN_THRES_H); 367 static SENSOR_DEVICE_ATTR(in2_max, S_IRUGO | S_IWUSR, ltc2945_show_value, 368 ltc2945_set_value, LTC2945_MAX_ADIN_THRES_H); 369 static SENSOR_DEVICE_ATTR(in2_lowest, S_IRUGO, ltc2945_show_value, NULL, 370 LTC2945_MIN_ADIN_H); 371 static SENSOR_DEVICE_ATTR(in2_highest, S_IRUGO, ltc2945_show_value, NULL, 372 LTC2945_MAX_ADIN_H); 373 static SENSOR_DEVICE_ATTR(in2_reset_history, S_IWUSR, NULL, 374 ltc2945_reset_history, LTC2945_MIN_ADIN_H); 375 376 /* Voltage alarms */ 377 378 static SENSOR_DEVICE_ATTR(in1_min_alarm, S_IRUGO, ltc2945_show_bool, NULL, 379 FAULT_VIN_UV); 380 static SENSOR_DEVICE_ATTR(in1_max_alarm, S_IRUGO, ltc2945_show_bool, NULL, 381 FAULT_VIN_OV); 382 static SENSOR_DEVICE_ATTR(in2_min_alarm, S_IRUGO, ltc2945_show_bool, NULL, 383 FAULT_ADIN_UV); 384 static SENSOR_DEVICE_ATTR(in2_max_alarm, S_IRUGO, ltc2945_show_bool, NULL, 385 FAULT_ADIN_OV); 386 387 /* Currents (via sense resistor) */ 388 389 static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ltc2945_show_value, NULL, 390 LTC2945_SENSE_H); 391 static SENSOR_DEVICE_ATTR(curr1_min, S_IRUGO | S_IWUSR, ltc2945_show_value, 392 ltc2945_set_value, LTC2945_MIN_SENSE_THRES_H); 393 static SENSOR_DEVICE_ATTR(curr1_max, S_IRUGO | S_IWUSR, ltc2945_show_value, 394 ltc2945_set_value, LTC2945_MAX_SENSE_THRES_H); 395 static SENSOR_DEVICE_ATTR(curr1_lowest, S_IRUGO, ltc2945_show_value, NULL, 396 LTC2945_MIN_SENSE_H); 397 static SENSOR_DEVICE_ATTR(curr1_highest, S_IRUGO, ltc2945_show_value, NULL, 398 LTC2945_MAX_SENSE_H); 399 static SENSOR_DEVICE_ATTR(curr1_reset_history, S_IWUSR, NULL, 400 ltc2945_reset_history, LTC2945_MIN_SENSE_H); 401 402 /* Current alarms */ 403 404 static SENSOR_DEVICE_ATTR(curr1_min_alarm, S_IRUGO, ltc2945_show_bool, NULL, 405 FAULT_SENSE_UV); 406 static SENSOR_DEVICE_ATTR(curr1_max_alarm, S_IRUGO, ltc2945_show_bool, NULL, 407 FAULT_SENSE_OV); 408 409 /* Power */ 410 411 static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, ltc2945_show_value, NULL, 412 LTC2945_POWER_H); 413 static SENSOR_DEVICE_ATTR(power1_min, S_IRUGO | S_IWUSR, ltc2945_show_value, 414 ltc2945_set_value, LTC2945_MIN_POWER_THRES_H); 415 static SENSOR_DEVICE_ATTR(power1_max, S_IRUGO | S_IWUSR, ltc2945_show_value, 416 ltc2945_set_value, LTC2945_MAX_POWER_THRES_H); 417 static SENSOR_DEVICE_ATTR(power1_input_lowest, S_IRUGO, ltc2945_show_value, 418 NULL, LTC2945_MIN_POWER_H); 419 static SENSOR_DEVICE_ATTR(power1_input_highest, S_IRUGO, ltc2945_show_value, 420 NULL, LTC2945_MAX_POWER_H); 421 static SENSOR_DEVICE_ATTR(power1_reset_history, S_IWUSR, NULL, 422 ltc2945_reset_history, LTC2945_MIN_POWER_H); 423 424 /* Power alarms */ 425 426 static SENSOR_DEVICE_ATTR(power1_min_alarm, S_IRUGO, ltc2945_show_bool, NULL, 427 FAULT_POWER_UV); 428 static SENSOR_DEVICE_ATTR(power1_max_alarm, S_IRUGO, ltc2945_show_bool, NULL, 429 FAULT_POWER_OV); 430 431 static struct attribute *ltc2945_attrs[] = { 432 &sensor_dev_attr_in1_input.dev_attr.attr, 433 &sensor_dev_attr_in1_min.dev_attr.attr, 434 &sensor_dev_attr_in1_max.dev_attr.attr, 435 &sensor_dev_attr_in1_lowest.dev_attr.attr, 436 &sensor_dev_attr_in1_highest.dev_attr.attr, 437 &sensor_dev_attr_in1_reset_history.dev_attr.attr, 438 &sensor_dev_attr_in1_min_alarm.dev_attr.attr, 439 &sensor_dev_attr_in1_max_alarm.dev_attr.attr, 440 441 &sensor_dev_attr_in2_input.dev_attr.attr, 442 &sensor_dev_attr_in2_min.dev_attr.attr, 443 &sensor_dev_attr_in2_max.dev_attr.attr, 444 &sensor_dev_attr_in2_lowest.dev_attr.attr, 445 &sensor_dev_attr_in2_highest.dev_attr.attr, 446 &sensor_dev_attr_in2_reset_history.dev_attr.attr, 447 &sensor_dev_attr_in2_min_alarm.dev_attr.attr, 448 &sensor_dev_attr_in2_max_alarm.dev_attr.attr, 449 450 &sensor_dev_attr_curr1_input.dev_attr.attr, 451 &sensor_dev_attr_curr1_min.dev_attr.attr, 452 &sensor_dev_attr_curr1_max.dev_attr.attr, 453 &sensor_dev_attr_curr1_lowest.dev_attr.attr, 454 &sensor_dev_attr_curr1_highest.dev_attr.attr, 455 &sensor_dev_attr_curr1_reset_history.dev_attr.attr, 456 &sensor_dev_attr_curr1_min_alarm.dev_attr.attr, 457 &sensor_dev_attr_curr1_max_alarm.dev_attr.attr, 458 459 &sensor_dev_attr_power1_input.dev_attr.attr, 460 &sensor_dev_attr_power1_min.dev_attr.attr, 461 &sensor_dev_attr_power1_max.dev_attr.attr, 462 &sensor_dev_attr_power1_input_lowest.dev_attr.attr, 463 &sensor_dev_attr_power1_input_highest.dev_attr.attr, 464 &sensor_dev_attr_power1_reset_history.dev_attr.attr, 465 &sensor_dev_attr_power1_min_alarm.dev_attr.attr, 466 &sensor_dev_attr_power1_max_alarm.dev_attr.attr, 467 468 NULL, 469 }; 470 ATTRIBUTE_GROUPS(ltc2945); 471 472 static const struct regmap_config ltc2945_regmap_config = { 473 .reg_bits = 8, 474 .val_bits = 8, 475 .max_register = LTC2945_MIN_ADIN_THRES_L, 476 }; 477 478 static int ltc2945_probe(struct i2c_client *client, 479 const struct i2c_device_id *id) 480 { 481 struct device *dev = &client->dev; 482 struct device *hwmon_dev; 483 struct regmap *regmap; 484 485 regmap = devm_regmap_init_i2c(client, <c2945_regmap_config); 486 if (IS_ERR(regmap)) { 487 dev_err(dev, "failed to allocate register map\n"); 488 return PTR_ERR(regmap); 489 } 490 491 /* Clear faults */ 492 regmap_write(regmap, LTC2945_FAULT, 0x00); 493 494 hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name, 495 regmap, 496 ltc2945_groups); 497 return PTR_ERR_OR_ZERO(hwmon_dev); 498 } 499 500 static const struct i2c_device_id ltc2945_id[] = { 501 {"ltc2945", 0}, 502 { } 503 }; 504 505 MODULE_DEVICE_TABLE(i2c, ltc2945_id); 506 507 static struct i2c_driver ltc2945_driver = { 508 .driver = { 509 .name = "ltc2945", 510 }, 511 .probe = ltc2945_probe, 512 .id_table = ltc2945_id, 513 }; 514 515 module_i2c_driver(ltc2945_driver); 516 517 MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>"); 518 MODULE_DESCRIPTION("LTC2945 driver"); 519 MODULE_LICENSE("GPL"); 520