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 static const unsigned short 16 emc2305_normal_i2c[] = { 0x27, 0x2c, 0x2d, 0x2e, 0x2f, 0x4c, 0x4d, I2C_CLIENT_END }; 17 18 #define EMC2305_REG_DRIVE_FAIL_STATUS 0x27 19 #define EMC2305_REG_VENDOR 0xfe 20 #define EMC2305_FAN_MAX 0xff 21 #define EMC2305_FAN_MIN 0x00 22 #define EMC2305_FAN_MAX_STATE 10 23 #define EMC2305_DEVICE 0x34 24 #define EMC2305_VENDOR 0x5d 25 #define EMC2305_REG_PRODUCT_ID 0xfd 26 #define EMC2305_TACH_REGS_UNUSE_BITS 3 27 #define EMC2305_TACH_CNT_MULTIPLIER 0x02 28 #define EMC2305_TACH_RANGE_MIN 480 29 30 #define EMC2305_PWM_DUTY2STATE(duty, max_state, pwm_max) \ 31 DIV_ROUND_CLOSEST((duty) * (max_state), (pwm_max)) 32 #define EMC2305_PWM_STATE2DUTY(state, max_state, pwm_max) \ 33 DIV_ROUND_CLOSEST((state) * (pwm_max), (max_state)) 34 35 /* 36 * Factor by equations [2] and [3] from data sheet; valid for fans where the number of edges 37 * equal (poles * 2 + 1). 38 */ 39 #define EMC2305_RPM_FACTOR 3932160 40 41 #define EMC2305_REG_FAN_DRIVE(n) (0x30 + 0x10 * (n)) 42 #define EMC2305_REG_FAN_MIN_DRIVE(n) (0x38 + 0x10 * (n)) 43 #define EMC2305_REG_FAN_TACH(n) (0x3e + 0x10 * (n)) 44 45 enum emc230x_product_id { 46 EMC2305 = 0x34, 47 EMC2303 = 0x35, 48 EMC2302 = 0x36, 49 EMC2301 = 0x37, 50 }; 51 52 static const struct i2c_device_id emc2305_ids[] = { 53 { "emc2305", 0 }, 54 { "emc2303", 0 }, 55 { "emc2302", 0 }, 56 { "emc2301", 0 }, 57 { } 58 }; 59 MODULE_DEVICE_TABLE(i2c, emc2305_ids); 60 61 /** 62 * struct emc2305_cdev_data - device-specific cooling device state 63 * @cdev: cooling device 64 * @cur_state: cooling current state 65 * @last_hwmon_state: last cooling state updated by hwmon subsystem 66 * @last_thermal_state: last cooling state updated by thermal subsystem 67 * 68 * The 'last_hwmon_state' and 'last_thermal_state' fields are provided to support fan low limit 69 * speed feature. The purpose of this feature is to provides ability to limit fan speed 70 * according to some system wise considerations, like absence of some replaceable units (PSU or 71 * line cards), high system ambient temperature, unreliable transceivers temperature sensing or 72 * some other factors which indirectly impacts system's airflow 73 * Fan low limit feature is supported through 'hwmon' interface: 'hwmon' 'pwm' attribute is 74 * used for setting low limit for fan speed in case 'thermal' subsystem is configured in 75 * kernel. In this case setting fan speed through 'hwmon' will never let the 'thermal' 76 * subsystem to select a lower duty cycle than the duty cycle selected with the 'pwm' 77 * attribute. 78 * From other side, fan speed is to be updated in hardware through 'pwm' only in case the 79 * requested fan speed is above last speed set by 'thermal' subsystem, otherwise requested fan 80 * speed will be just stored with no PWM update. 81 */ 82 struct emc2305_cdev_data { 83 struct thermal_cooling_device *cdev; 84 unsigned int cur_state; 85 unsigned long last_hwmon_state; 86 unsigned long last_thermal_state; 87 }; 88 89 /** 90 * struct emc2305_data - device-specific data 91 * @client: i2c client 92 * @hwmon_dev: hwmon device 93 * @max_state: maximum cooling state of the cooling device 94 * @pwm_num: number of PWM channels 95 * @pwm_separate: separate PWM settings for every channel 96 * @pwm_min: array of minimum PWM per channel 97 * @cdev_data: array of cooling devices data 98 */ 99 struct emc2305_data { 100 struct i2c_client *client; 101 struct device *hwmon_dev; 102 u8 max_state; 103 u8 pwm_num; 104 bool pwm_separate; 105 u8 pwm_min[EMC2305_PWM_MAX]; 106 struct emc2305_cdev_data cdev_data[EMC2305_PWM_MAX]; 107 }; 108 109 static char *emc2305_fan_name[] = { 110 "emc2305_fan", 111 "emc2305_fan1", 112 "emc2305_fan2", 113 "emc2305_fan3", 114 "emc2305_fan4", 115 "emc2305_fan5", 116 }; 117 118 static void emc2305_unset_tz(struct device *dev); 119 120 static int emc2305_get_max_channel(const struct emc2305_data *data) 121 { 122 return data->pwm_num; 123 } 124 125 static int emc2305_get_cdev_idx(struct thermal_cooling_device *cdev) 126 { 127 struct emc2305_data *data = cdev->devdata; 128 size_t len = strlen(cdev->type); 129 int ret; 130 131 if (len <= 0) 132 return -EINVAL; 133 134 /* 135 * Returns index of cooling device 0..4 in case of separate PWM setting. 136 * Zero index is used in case of one common PWM setting. 137 * If the mode is not set as pwm_separate, all PWMs are to be bound 138 * to the common thermal zone and should work at the same speed 139 * to perform cooling for the same thermal junction. 140 * Otherwise, return specific channel that will be used in bound 141 * related PWM to the thermal zone. 142 */ 143 if (!data->pwm_separate) 144 return 0; 145 146 ret = cdev->type[len - 1]; 147 switch (ret) { 148 case '1' ... '5': 149 return ret - '1'; 150 default: 151 break; 152 } 153 return -EINVAL; 154 } 155 156 static int emc2305_get_cur_state(struct thermal_cooling_device *cdev, unsigned long *state) 157 { 158 int cdev_idx; 159 struct emc2305_data *data = cdev->devdata; 160 161 cdev_idx = emc2305_get_cdev_idx(cdev); 162 if (cdev_idx < 0) 163 return cdev_idx; 164 165 *state = data->cdev_data[cdev_idx].cur_state; 166 return 0; 167 } 168 169 static int emc2305_get_max_state(struct thermal_cooling_device *cdev, unsigned long *state) 170 { 171 struct emc2305_data *data = cdev->devdata; 172 *state = data->max_state; 173 return 0; 174 } 175 176 static int __emc2305_set_cur_state(struct emc2305_data *data, int cdev_idx, unsigned long state) 177 { 178 int ret; 179 struct i2c_client *client = data->client; 180 u8 val, i; 181 182 state = max_t(unsigned long, state, data->cdev_data[cdev_idx].last_hwmon_state); 183 184 val = EMC2305_PWM_STATE2DUTY(state, data->max_state, EMC2305_FAN_MAX); 185 186 data->cdev_data[cdev_idx].cur_state = state; 187 if (data->pwm_separate) { 188 ret = i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_DRIVE(cdev_idx), val); 189 if (ret < 0) 190 return ret; 191 } else { 192 /* 193 * Set the same PWM value in all channels 194 * if common PWM channel is used. 195 */ 196 for (i = 0; i < data->pwm_num; i++) { 197 ret = i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_DRIVE(i), val); 198 if (ret < 0) 199 return ret; 200 } 201 } 202 203 return 0; 204 } 205 206 static int emc2305_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state) 207 { 208 int cdev_idx, ret; 209 struct emc2305_data *data = cdev->devdata; 210 211 if (state > data->max_state) 212 return -EINVAL; 213 214 cdev_idx = emc2305_get_cdev_idx(cdev); 215 if (cdev_idx < 0) 216 return cdev_idx; 217 218 /* Save thermal state. */ 219 data->cdev_data[cdev_idx].last_thermal_state = state; 220 ret = __emc2305_set_cur_state(data, cdev_idx, state); 221 if (ret < 0) 222 return ret; 223 224 return 0; 225 } 226 227 static const struct thermal_cooling_device_ops emc2305_cooling_ops = { 228 .get_max_state = emc2305_get_max_state, 229 .get_cur_state = emc2305_get_cur_state, 230 .set_cur_state = emc2305_set_cur_state, 231 }; 232 233 static int emc2305_show_fault(struct device *dev, int channel) 234 { 235 struct emc2305_data *data = dev_get_drvdata(dev); 236 struct i2c_client *client = data->client; 237 int status_reg; 238 239 status_reg = i2c_smbus_read_byte_data(client, EMC2305_REG_DRIVE_FAIL_STATUS); 240 if (status_reg < 0) 241 return status_reg; 242 243 return status_reg & (1 << channel) ? 1 : 0; 244 } 245 246 static int emc2305_show_fan(struct device *dev, int channel) 247 { 248 struct emc2305_data *data = dev_get_drvdata(dev); 249 struct i2c_client *client = data->client; 250 int ret; 251 252 ret = i2c_smbus_read_word_swapped(client, EMC2305_REG_FAN_TACH(channel)); 253 if (ret <= 0) 254 return ret; 255 256 ret = ret >> EMC2305_TACH_REGS_UNUSE_BITS; 257 ret = EMC2305_RPM_FACTOR / ret; 258 if (ret <= EMC2305_TACH_RANGE_MIN) 259 return 0; 260 261 return ret * EMC2305_TACH_CNT_MULTIPLIER; 262 } 263 264 static int emc2305_show_pwm(struct device *dev, int channel) 265 { 266 struct emc2305_data *data = dev_get_drvdata(dev); 267 struct i2c_client *client = data->client; 268 269 return i2c_smbus_read_byte_data(client, EMC2305_REG_FAN_DRIVE(channel)); 270 } 271 272 static int emc2305_set_pwm(struct device *dev, long val, int channel) 273 { 274 struct emc2305_data *data = dev_get_drvdata(dev); 275 struct i2c_client *client = data->client; 276 int ret; 277 278 if (val < data->pwm_min[channel] || val > EMC2305_FAN_MAX) 279 return -EINVAL; 280 281 ret = i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_DRIVE(channel), val); 282 if (ret < 0) 283 return ret; 284 data->cdev_data[channel].cur_state = EMC2305_PWM_DUTY2STATE(val, data->max_state, 285 EMC2305_FAN_MAX); 286 return 0; 287 } 288 289 static int emc2305_set_single_tz(struct device *dev, int idx) 290 { 291 struct emc2305_data *data = dev_get_drvdata(dev); 292 long pwm; 293 int i, cdev_idx, ret; 294 295 cdev_idx = (idx) ? idx - 1 : 0; 296 pwm = data->pwm_min[cdev_idx]; 297 298 data->cdev_data[cdev_idx].cdev = 299 thermal_cooling_device_register(emc2305_fan_name[idx], data, 300 &emc2305_cooling_ops); 301 302 if (IS_ERR(data->cdev_data[cdev_idx].cdev)) { 303 dev_err(dev, "Failed to register cooling device %s\n", emc2305_fan_name[idx]); 304 return PTR_ERR(data->cdev_data[cdev_idx].cdev); 305 } 306 /* Set minimal PWM speed. */ 307 if (data->pwm_separate) { 308 ret = emc2305_set_pwm(dev, pwm, cdev_idx); 309 if (ret < 0) 310 return ret; 311 } else { 312 for (i = 0; i < data->pwm_num; i++) { 313 ret = emc2305_set_pwm(dev, pwm, i); 314 if (ret < 0) 315 return ret; 316 } 317 } 318 data->cdev_data[cdev_idx].cur_state = 319 EMC2305_PWM_DUTY2STATE(data->pwm_min[cdev_idx], data->max_state, 320 EMC2305_FAN_MAX); 321 data->cdev_data[cdev_idx].last_hwmon_state = 322 EMC2305_PWM_DUTY2STATE(data->pwm_min[cdev_idx], data->max_state, 323 EMC2305_FAN_MAX); 324 return 0; 325 } 326 327 static int emc2305_set_tz(struct device *dev) 328 { 329 struct emc2305_data *data = dev_get_drvdata(dev); 330 int i, ret; 331 332 if (!data->pwm_separate) 333 return emc2305_set_single_tz(dev, 0); 334 335 for (i = 0; i < data->pwm_num; i++) { 336 ret = emc2305_set_single_tz(dev, i + 1); 337 if (ret) 338 goto thermal_cooling_device_register_fail; 339 } 340 return 0; 341 342 thermal_cooling_device_register_fail: 343 emc2305_unset_tz(dev); 344 return ret; 345 } 346 347 static void emc2305_unset_tz(struct device *dev) 348 { 349 struct emc2305_data *data = dev_get_drvdata(dev); 350 int i; 351 352 /* Unregister cooling device. */ 353 for (i = 0; i < EMC2305_PWM_MAX; i++) 354 if (data->cdev_data[i].cdev) 355 thermal_cooling_device_unregister(data->cdev_data[i].cdev); 356 } 357 358 static umode_t 359 emc2305_is_visible(const void *data, enum hwmon_sensor_types type, u32 attr, int channel) 360 { 361 int max_channel = emc2305_get_max_channel(data); 362 363 /* Don't show channels which are not physically connected. */ 364 if (channel >= max_channel) 365 return 0; 366 switch (type) { 367 case hwmon_fan: 368 switch (attr) { 369 case hwmon_fan_input: 370 return 0444; 371 case hwmon_fan_fault: 372 return 0444; 373 default: 374 break; 375 } 376 break; 377 case hwmon_pwm: 378 switch (attr) { 379 case hwmon_pwm_input: 380 return 0644; 381 default: 382 break; 383 } 384 break; 385 default: 386 break; 387 } 388 389 return 0; 390 }; 391 392 static int 393 emc2305_write(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel, long val) 394 { 395 struct emc2305_data *data = dev_get_drvdata(dev); 396 int cdev_idx; 397 398 switch (type) { 399 case hwmon_pwm: 400 switch (attr) { 401 case hwmon_pwm_input: 402 /* If thermal is configured - handle PWM limit setting. */ 403 if (IS_REACHABLE(CONFIG_THERMAL)) { 404 if (data->pwm_separate) 405 cdev_idx = channel; 406 else 407 cdev_idx = 0; 408 data->cdev_data[cdev_idx].last_hwmon_state = 409 EMC2305_PWM_DUTY2STATE(val, data->max_state, 410 EMC2305_FAN_MAX); 411 /* 412 * Update PWM only in case requested state is not less than the 413 * last thermal state. 414 */ 415 if (data->cdev_data[cdev_idx].last_hwmon_state >= 416 data->cdev_data[cdev_idx].last_thermal_state) 417 return __emc2305_set_cur_state(data, cdev_idx, 418 data->cdev_data[cdev_idx].last_hwmon_state); 419 return 0; 420 } 421 return emc2305_set_pwm(dev, val, channel); 422 default: 423 break; 424 } 425 break; 426 default: 427 break; 428 } 429 430 return -EOPNOTSUPP; 431 }; 432 433 static int 434 emc2305_read(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel, long *val) 435 { 436 int ret; 437 438 switch (type) { 439 case hwmon_fan: 440 switch (attr) { 441 case hwmon_fan_input: 442 ret = emc2305_show_fan(dev, channel); 443 if (ret < 0) 444 return ret; 445 *val = ret; 446 return 0; 447 case hwmon_fan_fault: 448 ret = emc2305_show_fault(dev, channel); 449 if (ret < 0) 450 return ret; 451 *val = ret; 452 return 0; 453 default: 454 break; 455 } 456 break; 457 case hwmon_pwm: 458 switch (attr) { 459 case hwmon_pwm_input: 460 ret = emc2305_show_pwm(dev, channel); 461 if (ret < 0) 462 return ret; 463 *val = ret; 464 return 0; 465 default: 466 break; 467 } 468 break; 469 default: 470 break; 471 } 472 473 return -EOPNOTSUPP; 474 }; 475 476 static const struct hwmon_ops emc2305_ops = { 477 .is_visible = emc2305_is_visible, 478 .read = emc2305_read, 479 .write = emc2305_write, 480 }; 481 482 static const struct hwmon_channel_info * const emc2305_info[] = { 483 HWMON_CHANNEL_INFO(fan, 484 HWMON_F_INPUT | HWMON_F_FAULT, 485 HWMON_F_INPUT | HWMON_F_FAULT, 486 HWMON_F_INPUT | HWMON_F_FAULT, 487 HWMON_F_INPUT | HWMON_F_FAULT, 488 HWMON_F_INPUT | HWMON_F_FAULT), 489 HWMON_CHANNEL_INFO(pwm, 490 HWMON_PWM_INPUT, 491 HWMON_PWM_INPUT, 492 HWMON_PWM_INPUT, 493 HWMON_PWM_INPUT, 494 HWMON_PWM_INPUT), 495 NULL 496 }; 497 498 static const struct hwmon_chip_info emc2305_chip_info = { 499 .ops = &emc2305_ops, 500 .info = emc2305_info, 501 }; 502 503 static int emc2305_identify(struct device *dev) 504 { 505 struct i2c_client *client = to_i2c_client(dev); 506 struct emc2305_data *data = i2c_get_clientdata(client); 507 int ret; 508 509 ret = i2c_smbus_read_byte_data(client, EMC2305_REG_PRODUCT_ID); 510 if (ret < 0) 511 return ret; 512 513 switch (ret) { 514 case EMC2305: 515 data->pwm_num = 5; 516 break; 517 case EMC2303: 518 data->pwm_num = 3; 519 break; 520 case EMC2302: 521 data->pwm_num = 2; 522 break; 523 case EMC2301: 524 data->pwm_num = 1; 525 break; 526 default: 527 return -ENODEV; 528 } 529 530 return 0; 531 } 532 533 static int emc2305_probe(struct i2c_client *client) 534 { 535 struct i2c_adapter *adapter = client->adapter; 536 struct device *dev = &client->dev; 537 struct emc2305_data *data; 538 struct emc2305_platform_data *pdata; 539 int vendor; 540 int ret; 541 int i; 542 543 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA)) 544 return -ENODEV; 545 546 vendor = i2c_smbus_read_byte_data(client, EMC2305_REG_VENDOR); 547 if (vendor != EMC2305_VENDOR) 548 return -ENODEV; 549 550 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); 551 if (!data) 552 return -ENOMEM; 553 554 i2c_set_clientdata(client, data); 555 data->client = client; 556 557 ret = emc2305_identify(dev); 558 if (ret) 559 return ret; 560 561 pdata = dev_get_platdata(&client->dev); 562 if (pdata) { 563 if (!pdata->max_state || pdata->max_state > EMC2305_FAN_MAX_STATE) 564 return -EINVAL; 565 data->max_state = pdata->max_state; 566 /* 567 * Validate a number of active PWM channels. Note that 568 * configured number can be less than the actual maximum 569 * supported by the device. 570 */ 571 if (!pdata->pwm_num || pdata->pwm_num > EMC2305_PWM_MAX) 572 return -EINVAL; 573 data->pwm_num = pdata->pwm_num; 574 data->pwm_separate = pdata->pwm_separate; 575 for (i = 0; i < EMC2305_PWM_MAX; i++) 576 data->pwm_min[i] = pdata->pwm_min[i]; 577 } else { 578 data->max_state = EMC2305_FAN_MAX_STATE; 579 data->pwm_separate = false; 580 for (i = 0; i < EMC2305_PWM_MAX; i++) 581 data->pwm_min[i] = EMC2305_FAN_MIN; 582 } 583 584 data->hwmon_dev = devm_hwmon_device_register_with_info(dev, "emc2305", data, 585 &emc2305_chip_info, NULL); 586 if (IS_ERR(data->hwmon_dev)) 587 return PTR_ERR(data->hwmon_dev); 588 589 if (IS_REACHABLE(CONFIG_THERMAL)) { 590 ret = emc2305_set_tz(dev); 591 if (ret != 0) 592 return ret; 593 } 594 595 for (i = 0; i < data->pwm_num; i++) { 596 ret = i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_MIN_DRIVE(i), 597 data->pwm_min[i]); 598 if (ret < 0) 599 return ret; 600 } 601 602 return 0; 603 } 604 605 static void emc2305_remove(struct i2c_client *client) 606 { 607 struct device *dev = &client->dev; 608 609 if (IS_REACHABLE(CONFIG_THERMAL)) 610 emc2305_unset_tz(dev); 611 } 612 613 static struct i2c_driver emc2305_driver = { 614 .class = I2C_CLASS_HWMON, 615 .driver = { 616 .name = "emc2305", 617 }, 618 .probe = emc2305_probe, 619 .remove = emc2305_remove, 620 .id_table = emc2305_ids, 621 .address_list = emc2305_normal_i2c, 622 }; 623 624 module_i2c_driver(emc2305_driver); 625 626 MODULE_AUTHOR("Nvidia"); 627 MODULE_DESCRIPTION("Microchip EMC2305 fan controller driver"); 628 MODULE_LICENSE("GPL"); 629