1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Hardware monitoring driver for EMC2305 fan controller 4 * 5 * Copyright (C) 2022 Nvidia Technologies Ltd. 6 */ 7 8 #include <linux/err.h> 9 #include <linux/hwmon.h> 10 #include <linux/i2c.h> 11 #include <linux/module.h> 12 #include <linux/platform_data/emc2305.h> 13 #include <linux/thermal.h> 14 15 #define EMC2305_REG_DRIVE_FAIL_STATUS 0x27 16 #define EMC2305_REG_VENDOR 0xfe 17 #define EMC2305_FAN_MAX 0xff 18 #define EMC2305_FAN_MIN 0x00 19 #define EMC2305_FAN_MAX_STATE 10 20 #define EMC2305_DEVICE 0x34 21 #define EMC2305_VENDOR 0x5d 22 #define EMC2305_REG_PRODUCT_ID 0xfd 23 #define EMC2305_TACH_REGS_UNUSE_BITS 3 24 #define EMC2305_TACH_CNT_MULTIPLIER 0x02 25 #define EMC2305_TACH_RANGE_MIN 480 26 27 #define EMC2305_PWM_DUTY2STATE(duty, max_state, pwm_max) \ 28 DIV_ROUND_CLOSEST((duty) * (max_state), (pwm_max)) 29 #define EMC2305_PWM_STATE2DUTY(state, max_state, pwm_max) \ 30 DIV_ROUND_CLOSEST((state) * (pwm_max), (max_state)) 31 32 /* 33 * Factor by equations [2] and [3] from data sheet; valid for fans where the number of edges 34 * equal (poles * 2 + 1). 35 */ 36 #define EMC2305_RPM_FACTOR 3932160 37 38 #define EMC2305_REG_FAN_DRIVE(n) (0x30 + 0x10 * (n)) 39 #define EMC2305_REG_FAN_MIN_DRIVE(n) (0x38 + 0x10 * (n)) 40 #define EMC2305_REG_FAN_TACH(n) (0x3e + 0x10 * (n)) 41 42 enum emc230x_product_id { 43 EMC2305 = 0x34, 44 EMC2303 = 0x35, 45 EMC2302 = 0x36, 46 EMC2301 = 0x37, 47 }; 48 49 static const struct i2c_device_id emc2305_ids[] = { 50 { "emc2305" }, 51 { "emc2303" }, 52 { "emc2302" }, 53 { "emc2301" }, 54 { } 55 }; 56 MODULE_DEVICE_TABLE(i2c, emc2305_ids); 57 58 /** 59 * struct emc2305_cdev_data - device-specific cooling device state 60 * @cdev: cooling device 61 * @cur_state: cooling current state 62 * @last_hwmon_state: last cooling state updated by hwmon subsystem 63 * @last_thermal_state: last cooling state updated by thermal subsystem 64 * 65 * The 'last_hwmon_state' and 'last_thermal_state' fields are provided to support fan low limit 66 * speed feature. The purpose of this feature is to provides ability to limit fan speed 67 * according to some system wise considerations, like absence of some replaceable units (PSU or 68 * line cards), high system ambient temperature, unreliable transceivers temperature sensing or 69 * some other factors which indirectly impacts system's airflow 70 * Fan low limit feature is supported through 'hwmon' interface: 'hwmon' 'pwm' attribute is 71 * used for setting low limit for fan speed in case 'thermal' subsystem is configured in 72 * kernel. In this case setting fan speed through 'hwmon' will never let the 'thermal' 73 * subsystem to select a lower duty cycle than the duty cycle selected with the 'pwm' 74 * attribute. 75 * From other side, fan speed is to be updated in hardware through 'pwm' only in case the 76 * requested fan speed is above last speed set by 'thermal' subsystem, otherwise requested fan 77 * speed will be just stored with no PWM update. 78 */ 79 struct emc2305_cdev_data { 80 struct thermal_cooling_device *cdev; 81 unsigned int cur_state; 82 unsigned long last_hwmon_state; 83 unsigned long last_thermal_state; 84 }; 85 86 /** 87 * struct emc2305_data - device-specific data 88 * @client: i2c client 89 * @hwmon_dev: hwmon device 90 * @max_state: maximum cooling state of the cooling device 91 * @pwm_num: number of PWM channels 92 * @pwm_separate: separate PWM settings for every channel 93 * @pwm_min: array of minimum PWM per channel 94 * @cdev_data: array of cooling devices data 95 */ 96 struct emc2305_data { 97 struct i2c_client *client; 98 struct device *hwmon_dev; 99 u8 max_state; 100 u8 pwm_num; 101 bool pwm_separate; 102 u8 pwm_min[EMC2305_PWM_MAX]; 103 struct emc2305_cdev_data cdev_data[EMC2305_PWM_MAX]; 104 }; 105 106 static char *emc2305_fan_name[] = { 107 "emc2305_fan", 108 "emc2305_fan1", 109 "emc2305_fan2", 110 "emc2305_fan3", 111 "emc2305_fan4", 112 "emc2305_fan5", 113 }; 114 115 static int emc2305_get_max_channel(const struct emc2305_data *data) 116 { 117 return data->pwm_num; 118 } 119 120 static int emc2305_get_cdev_idx(struct thermal_cooling_device *cdev) 121 { 122 struct emc2305_data *data = cdev->devdata; 123 size_t len = strlen(cdev->type); 124 int ret; 125 126 if (len <= 0) 127 return -EINVAL; 128 129 /* 130 * Returns index of cooling device 0..4 in case of separate PWM setting. 131 * Zero index is used in case of one common PWM setting. 132 * If the mode is not set as pwm_separate, all PWMs are to be bound 133 * to the common thermal zone and should work at the same speed 134 * to perform cooling for the same thermal junction. 135 * Otherwise, return specific channel that will be used in bound 136 * related PWM to the thermal zone. 137 */ 138 if (!data->pwm_separate) 139 return 0; 140 141 ret = cdev->type[len - 1]; 142 switch (ret) { 143 case '1' ... '5': 144 return ret - '1'; 145 default: 146 break; 147 } 148 return -EINVAL; 149 } 150 151 static int emc2305_get_cur_state(struct thermal_cooling_device *cdev, unsigned long *state) 152 { 153 int cdev_idx; 154 struct emc2305_data *data = cdev->devdata; 155 156 cdev_idx = emc2305_get_cdev_idx(cdev); 157 if (cdev_idx < 0) 158 return cdev_idx; 159 160 *state = data->cdev_data[cdev_idx].cur_state; 161 return 0; 162 } 163 164 static int emc2305_get_max_state(struct thermal_cooling_device *cdev, unsigned long *state) 165 { 166 struct emc2305_data *data = cdev->devdata; 167 *state = data->max_state; 168 return 0; 169 } 170 171 static int __emc2305_set_cur_state(struct emc2305_data *data, int cdev_idx, unsigned long state) 172 { 173 int ret; 174 struct i2c_client *client = data->client; 175 u8 val, i; 176 177 state = max_t(unsigned long, state, data->cdev_data[cdev_idx].last_hwmon_state); 178 179 val = EMC2305_PWM_STATE2DUTY(state, data->max_state, EMC2305_FAN_MAX); 180 181 data->cdev_data[cdev_idx].cur_state = state; 182 if (data->pwm_separate) { 183 ret = i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_DRIVE(cdev_idx), val); 184 if (ret < 0) 185 return ret; 186 } else { 187 /* 188 * Set the same PWM value in all channels 189 * if common PWM channel is used. 190 */ 191 for (i = 0; i < data->pwm_num; i++) { 192 ret = i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_DRIVE(i), val); 193 if (ret < 0) 194 return ret; 195 } 196 } 197 198 return 0; 199 } 200 201 static int emc2305_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state) 202 { 203 int cdev_idx, ret; 204 struct emc2305_data *data = cdev->devdata; 205 206 if (state > data->max_state) 207 return -EINVAL; 208 209 cdev_idx = emc2305_get_cdev_idx(cdev); 210 if (cdev_idx < 0) 211 return cdev_idx; 212 213 /* Save thermal state. */ 214 data->cdev_data[cdev_idx].last_thermal_state = state; 215 ret = __emc2305_set_cur_state(data, cdev_idx, state); 216 if (ret < 0) 217 return ret; 218 219 return 0; 220 } 221 222 static const struct thermal_cooling_device_ops emc2305_cooling_ops = { 223 .get_max_state = emc2305_get_max_state, 224 .get_cur_state = emc2305_get_cur_state, 225 .set_cur_state = emc2305_set_cur_state, 226 }; 227 228 static int emc2305_show_fault(struct device *dev, int channel) 229 { 230 struct emc2305_data *data = dev_get_drvdata(dev); 231 struct i2c_client *client = data->client; 232 int status_reg; 233 234 status_reg = i2c_smbus_read_byte_data(client, EMC2305_REG_DRIVE_FAIL_STATUS); 235 if (status_reg < 0) 236 return status_reg; 237 238 return status_reg & (1 << channel) ? 1 : 0; 239 } 240 241 static int emc2305_show_fan(struct device *dev, int channel) 242 { 243 struct emc2305_data *data = dev_get_drvdata(dev); 244 struct i2c_client *client = data->client; 245 int ret; 246 247 ret = i2c_smbus_read_word_swapped(client, EMC2305_REG_FAN_TACH(channel)); 248 if (ret <= 0) 249 return ret; 250 251 ret = ret >> EMC2305_TACH_REGS_UNUSE_BITS; 252 ret = EMC2305_RPM_FACTOR / ret; 253 if (ret <= EMC2305_TACH_RANGE_MIN) 254 return 0; 255 256 return ret * EMC2305_TACH_CNT_MULTIPLIER; 257 } 258 259 static int emc2305_show_pwm(struct device *dev, int channel) 260 { 261 struct emc2305_data *data = dev_get_drvdata(dev); 262 struct i2c_client *client = data->client; 263 264 return i2c_smbus_read_byte_data(client, EMC2305_REG_FAN_DRIVE(channel)); 265 } 266 267 static int emc2305_set_pwm(struct device *dev, long val, int channel) 268 { 269 struct emc2305_data *data = dev_get_drvdata(dev); 270 struct i2c_client *client = data->client; 271 int ret; 272 273 if (val < data->pwm_min[channel] || val > EMC2305_FAN_MAX) 274 return -EINVAL; 275 276 ret = i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_DRIVE(channel), val); 277 if (ret < 0) 278 return ret; 279 data->cdev_data[channel].cur_state = EMC2305_PWM_DUTY2STATE(val, data->max_state, 280 EMC2305_FAN_MAX); 281 return 0; 282 } 283 284 static int emc2305_set_single_tz(struct device *dev, int idx) 285 { 286 struct emc2305_data *data = dev_get_drvdata(dev); 287 long pwm; 288 int i, cdev_idx, ret; 289 290 cdev_idx = (idx) ? idx - 1 : 0; 291 pwm = data->pwm_min[cdev_idx]; 292 293 data->cdev_data[cdev_idx].cdev = 294 devm_thermal_of_cooling_device_register(dev, dev->of_node, 295 emc2305_fan_name[idx], data, 296 &emc2305_cooling_ops); 297 298 if (IS_ERR(data->cdev_data[cdev_idx].cdev)) { 299 dev_err(dev, "Failed to register cooling device %s\n", emc2305_fan_name[idx]); 300 return PTR_ERR(data->cdev_data[cdev_idx].cdev); 301 } 302 /* Set minimal PWM speed. */ 303 if (data->pwm_separate) { 304 ret = emc2305_set_pwm(dev, pwm, cdev_idx); 305 if (ret < 0) 306 return ret; 307 } else { 308 for (i = 0; i < data->pwm_num; i++) { 309 ret = emc2305_set_pwm(dev, pwm, i); 310 if (ret < 0) 311 return ret; 312 } 313 } 314 data->cdev_data[cdev_idx].cur_state = 315 EMC2305_PWM_DUTY2STATE(data->pwm_min[cdev_idx], data->max_state, 316 EMC2305_FAN_MAX); 317 data->cdev_data[cdev_idx].last_hwmon_state = 318 EMC2305_PWM_DUTY2STATE(data->pwm_min[cdev_idx], data->max_state, 319 EMC2305_FAN_MAX); 320 return 0; 321 } 322 323 static int emc2305_set_tz(struct device *dev) 324 { 325 struct emc2305_data *data = dev_get_drvdata(dev); 326 int i, ret; 327 328 if (!data->pwm_separate) 329 return emc2305_set_single_tz(dev, 0); 330 331 for (i = 0; i < data->pwm_num; i++) { 332 ret = emc2305_set_single_tz(dev, i + 1); 333 if (ret) 334 return ret; 335 } 336 return 0; 337 } 338 339 static umode_t 340 emc2305_is_visible(const void *data, enum hwmon_sensor_types type, u32 attr, int channel) 341 { 342 int max_channel = emc2305_get_max_channel(data); 343 344 /* Don't show channels which are not physically connected. */ 345 if (channel >= max_channel) 346 return 0; 347 switch (type) { 348 case hwmon_fan: 349 switch (attr) { 350 case hwmon_fan_input: 351 return 0444; 352 case hwmon_fan_fault: 353 return 0444; 354 default: 355 break; 356 } 357 break; 358 case hwmon_pwm: 359 switch (attr) { 360 case hwmon_pwm_input: 361 return 0644; 362 default: 363 break; 364 } 365 break; 366 default: 367 break; 368 } 369 370 return 0; 371 }; 372 373 static int 374 emc2305_write(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel, long val) 375 { 376 struct emc2305_data *data = dev_get_drvdata(dev); 377 int cdev_idx; 378 379 switch (type) { 380 case hwmon_pwm: 381 switch (attr) { 382 case hwmon_pwm_input: 383 /* If thermal is configured - handle PWM limit setting. */ 384 if (IS_REACHABLE(CONFIG_THERMAL)) { 385 if (data->pwm_separate) 386 cdev_idx = channel; 387 else 388 cdev_idx = 0; 389 data->cdev_data[cdev_idx].last_hwmon_state = 390 EMC2305_PWM_DUTY2STATE(val, data->max_state, 391 EMC2305_FAN_MAX); 392 /* 393 * Update PWM only in case requested state is not less than the 394 * last thermal state. 395 */ 396 if (data->cdev_data[cdev_idx].last_hwmon_state >= 397 data->cdev_data[cdev_idx].last_thermal_state) 398 return __emc2305_set_cur_state(data, cdev_idx, 399 data->cdev_data[cdev_idx].last_hwmon_state); 400 return 0; 401 } 402 return emc2305_set_pwm(dev, val, channel); 403 default: 404 break; 405 } 406 break; 407 default: 408 break; 409 } 410 411 return -EOPNOTSUPP; 412 }; 413 414 static int 415 emc2305_read(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel, long *val) 416 { 417 int ret; 418 419 switch (type) { 420 case hwmon_fan: 421 switch (attr) { 422 case hwmon_fan_input: 423 ret = emc2305_show_fan(dev, channel); 424 if (ret < 0) 425 return ret; 426 *val = ret; 427 return 0; 428 case hwmon_fan_fault: 429 ret = emc2305_show_fault(dev, channel); 430 if (ret < 0) 431 return ret; 432 *val = ret; 433 return 0; 434 default: 435 break; 436 } 437 break; 438 case hwmon_pwm: 439 switch (attr) { 440 case hwmon_pwm_input: 441 ret = emc2305_show_pwm(dev, channel); 442 if (ret < 0) 443 return ret; 444 *val = ret; 445 return 0; 446 default: 447 break; 448 } 449 break; 450 default: 451 break; 452 } 453 454 return -EOPNOTSUPP; 455 }; 456 457 static const struct hwmon_ops emc2305_ops = { 458 .is_visible = emc2305_is_visible, 459 .read = emc2305_read, 460 .write = emc2305_write, 461 }; 462 463 static const struct hwmon_channel_info * const emc2305_info[] = { 464 HWMON_CHANNEL_INFO(fan, 465 HWMON_F_INPUT | HWMON_F_FAULT, 466 HWMON_F_INPUT | HWMON_F_FAULT, 467 HWMON_F_INPUT | HWMON_F_FAULT, 468 HWMON_F_INPUT | HWMON_F_FAULT, 469 HWMON_F_INPUT | HWMON_F_FAULT), 470 HWMON_CHANNEL_INFO(pwm, 471 HWMON_PWM_INPUT, 472 HWMON_PWM_INPUT, 473 HWMON_PWM_INPUT, 474 HWMON_PWM_INPUT, 475 HWMON_PWM_INPUT), 476 NULL 477 }; 478 479 static const struct hwmon_chip_info emc2305_chip_info = { 480 .ops = &emc2305_ops, 481 .info = emc2305_info, 482 }; 483 484 static int emc2305_identify(struct device *dev) 485 { 486 struct i2c_client *client = to_i2c_client(dev); 487 struct emc2305_data *data = i2c_get_clientdata(client); 488 int ret; 489 490 ret = i2c_smbus_read_byte_data(client, EMC2305_REG_PRODUCT_ID); 491 if (ret < 0) 492 return ret; 493 494 switch (ret) { 495 case EMC2305: 496 data->pwm_num = 5; 497 break; 498 case EMC2303: 499 data->pwm_num = 3; 500 break; 501 case EMC2302: 502 data->pwm_num = 2; 503 break; 504 case EMC2301: 505 data->pwm_num = 1; 506 break; 507 default: 508 return -ENODEV; 509 } 510 511 return 0; 512 } 513 514 static int emc2305_probe(struct i2c_client *client) 515 { 516 struct i2c_adapter *adapter = client->adapter; 517 struct device *dev = &client->dev; 518 struct emc2305_data *data; 519 struct emc2305_platform_data *pdata; 520 int vendor; 521 int ret; 522 int i; 523 524 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA)) 525 return -ENODEV; 526 527 vendor = i2c_smbus_read_byte_data(client, EMC2305_REG_VENDOR); 528 if (vendor != EMC2305_VENDOR) 529 return -ENODEV; 530 531 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); 532 if (!data) 533 return -ENOMEM; 534 535 i2c_set_clientdata(client, data); 536 data->client = client; 537 538 ret = emc2305_identify(dev); 539 if (ret) 540 return ret; 541 542 pdata = dev_get_platdata(&client->dev); 543 if (pdata) { 544 if (!pdata->max_state || pdata->max_state > EMC2305_FAN_MAX_STATE) 545 return -EINVAL; 546 data->max_state = pdata->max_state; 547 /* 548 * Validate a number of active PWM channels. Note that 549 * configured number can be less than the actual maximum 550 * supported by the device. 551 */ 552 if (!pdata->pwm_num || pdata->pwm_num > EMC2305_PWM_MAX) 553 return -EINVAL; 554 data->pwm_num = pdata->pwm_num; 555 data->pwm_separate = pdata->pwm_separate; 556 for (i = 0; i < EMC2305_PWM_MAX; i++) 557 data->pwm_min[i] = pdata->pwm_min[i]; 558 } else { 559 data->max_state = EMC2305_FAN_MAX_STATE; 560 data->pwm_separate = false; 561 for (i = 0; i < EMC2305_PWM_MAX; i++) 562 data->pwm_min[i] = EMC2305_FAN_MIN; 563 } 564 565 data->hwmon_dev = devm_hwmon_device_register_with_info(dev, "emc2305", data, 566 &emc2305_chip_info, NULL); 567 if (IS_ERR(data->hwmon_dev)) 568 return PTR_ERR(data->hwmon_dev); 569 570 if (IS_REACHABLE(CONFIG_THERMAL)) { 571 ret = emc2305_set_tz(dev); 572 if (ret != 0) 573 return ret; 574 } 575 576 for (i = 0; i < data->pwm_num; i++) { 577 ret = i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_MIN_DRIVE(i), 578 data->pwm_min[i]); 579 if (ret < 0) 580 return ret; 581 } 582 583 return 0; 584 } 585 586 static const struct of_device_id of_emc2305_match_table[] = { 587 { .compatible = "microchip,emc2305", }, 588 {}, 589 }; 590 MODULE_DEVICE_TABLE(of, of_emc2305_match_table); 591 592 static struct i2c_driver emc2305_driver = { 593 .driver = { 594 .name = "emc2305", 595 .of_match_table = of_emc2305_match_table, 596 }, 597 .probe = emc2305_probe, 598 .id_table = emc2305_ids, 599 }; 600 601 module_i2c_driver(emc2305_driver); 602 603 MODULE_AUTHOR("Nvidia"); 604 MODULE_DESCRIPTION("Microchip EMC2305 fan controller driver"); 605 MODULE_LICENSE("GPL"); 606