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", 0 }, 51 { "emc2303", 0 }, 52 { "emc2302", 0 }, 53 { "emc2301", 0 }, 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 void emc2305_unset_tz(struct device *dev); 116 117 static int emc2305_get_max_channel(const struct emc2305_data *data) 118 { 119 return data->pwm_num; 120 } 121 122 static int emc2305_get_cdev_idx(struct thermal_cooling_device *cdev) 123 { 124 struct emc2305_data *data = cdev->devdata; 125 size_t len = strlen(cdev->type); 126 int ret; 127 128 if (len <= 0) 129 return -EINVAL; 130 131 /* 132 * Returns index of cooling device 0..4 in case of separate PWM setting. 133 * Zero index is used in case of one common PWM setting. 134 * If the mode is not set as pwm_separate, all PWMs are to be bound 135 * to the common thermal zone and should work at the same speed 136 * to perform cooling for the same thermal junction. 137 * Otherwise, return specific channel that will be used in bound 138 * related PWM to the thermal zone. 139 */ 140 if (!data->pwm_separate) 141 return 0; 142 143 ret = cdev->type[len - 1]; 144 switch (ret) { 145 case '1' ... '5': 146 return ret - '1'; 147 default: 148 break; 149 } 150 return -EINVAL; 151 } 152 153 static int emc2305_get_cur_state(struct thermal_cooling_device *cdev, unsigned long *state) 154 { 155 int cdev_idx; 156 struct emc2305_data *data = cdev->devdata; 157 158 cdev_idx = emc2305_get_cdev_idx(cdev); 159 if (cdev_idx < 0) 160 return cdev_idx; 161 162 *state = data->cdev_data[cdev_idx].cur_state; 163 return 0; 164 } 165 166 static int emc2305_get_max_state(struct thermal_cooling_device *cdev, unsigned long *state) 167 { 168 struct emc2305_data *data = cdev->devdata; 169 *state = data->max_state; 170 return 0; 171 } 172 173 static int __emc2305_set_cur_state(struct emc2305_data *data, int cdev_idx, unsigned long state) 174 { 175 int ret; 176 struct i2c_client *client = data->client; 177 u8 val, i; 178 179 state = max_t(unsigned long, state, data->cdev_data[cdev_idx].last_hwmon_state); 180 181 val = EMC2305_PWM_STATE2DUTY(state, data->max_state, EMC2305_FAN_MAX); 182 183 data->cdev_data[cdev_idx].cur_state = state; 184 if (data->pwm_separate) { 185 ret = i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_DRIVE(cdev_idx), val); 186 if (ret < 0) 187 return ret; 188 } else { 189 /* 190 * Set the same PWM value in all channels 191 * if common PWM channel is used. 192 */ 193 for (i = 0; i < data->pwm_num; i++) { 194 ret = i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_DRIVE(i), val); 195 if (ret < 0) 196 return ret; 197 } 198 } 199 200 return 0; 201 } 202 203 static int emc2305_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state) 204 { 205 int cdev_idx, ret; 206 struct emc2305_data *data = cdev->devdata; 207 208 if (state > data->max_state) 209 return -EINVAL; 210 211 cdev_idx = emc2305_get_cdev_idx(cdev); 212 if (cdev_idx < 0) 213 return cdev_idx; 214 215 /* Save thermal state. */ 216 data->cdev_data[cdev_idx].last_thermal_state = state; 217 ret = __emc2305_set_cur_state(data, cdev_idx, state); 218 if (ret < 0) 219 return ret; 220 221 return 0; 222 } 223 224 static const struct thermal_cooling_device_ops emc2305_cooling_ops = { 225 .get_max_state = emc2305_get_max_state, 226 .get_cur_state = emc2305_get_cur_state, 227 .set_cur_state = emc2305_set_cur_state, 228 }; 229 230 static int emc2305_show_fault(struct device *dev, int channel) 231 { 232 struct emc2305_data *data = dev_get_drvdata(dev); 233 struct i2c_client *client = data->client; 234 int status_reg; 235 236 status_reg = i2c_smbus_read_byte_data(client, EMC2305_REG_DRIVE_FAIL_STATUS); 237 if (status_reg < 0) 238 return status_reg; 239 240 return status_reg & (1 << channel) ? 1 : 0; 241 } 242 243 static int emc2305_show_fan(struct device *dev, int channel) 244 { 245 struct emc2305_data *data = dev_get_drvdata(dev); 246 struct i2c_client *client = data->client; 247 int ret; 248 249 ret = i2c_smbus_read_word_swapped(client, EMC2305_REG_FAN_TACH(channel)); 250 if (ret <= 0) 251 return ret; 252 253 ret = ret >> EMC2305_TACH_REGS_UNUSE_BITS; 254 ret = EMC2305_RPM_FACTOR / ret; 255 if (ret <= EMC2305_TACH_RANGE_MIN) 256 return 0; 257 258 return ret * EMC2305_TACH_CNT_MULTIPLIER; 259 } 260 261 static int emc2305_show_pwm(struct device *dev, int channel) 262 { 263 struct emc2305_data *data = dev_get_drvdata(dev); 264 struct i2c_client *client = data->client; 265 266 return i2c_smbus_read_byte_data(client, EMC2305_REG_FAN_DRIVE(channel)); 267 } 268 269 static int emc2305_set_pwm(struct device *dev, long val, int channel) 270 { 271 struct emc2305_data *data = dev_get_drvdata(dev); 272 struct i2c_client *client = data->client; 273 int ret; 274 275 if (val < data->pwm_min[channel] || val > EMC2305_FAN_MAX) 276 return -EINVAL; 277 278 ret = i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_DRIVE(channel), val); 279 if (ret < 0) 280 return ret; 281 data->cdev_data[channel].cur_state = EMC2305_PWM_DUTY2STATE(val, data->max_state, 282 EMC2305_FAN_MAX); 283 return 0; 284 } 285 286 static int emc2305_set_single_tz(struct device *dev, int idx) 287 { 288 struct emc2305_data *data = dev_get_drvdata(dev); 289 long pwm; 290 int i, cdev_idx, ret; 291 292 cdev_idx = (idx) ? idx - 1 : 0; 293 pwm = data->pwm_min[cdev_idx]; 294 295 data->cdev_data[cdev_idx].cdev = 296 thermal_cooling_device_register(emc2305_fan_name[idx], data, 297 &emc2305_cooling_ops); 298 299 if (IS_ERR(data->cdev_data[cdev_idx].cdev)) { 300 dev_err(dev, "Failed to register cooling device %s\n", emc2305_fan_name[idx]); 301 return PTR_ERR(data->cdev_data[cdev_idx].cdev); 302 } 303 /* Set minimal PWM speed. */ 304 if (data->pwm_separate) { 305 ret = emc2305_set_pwm(dev, pwm, cdev_idx); 306 if (ret < 0) 307 return ret; 308 } else { 309 for (i = 0; i < data->pwm_num; i++) { 310 ret = emc2305_set_pwm(dev, pwm, i); 311 if (ret < 0) 312 return ret; 313 } 314 } 315 data->cdev_data[cdev_idx].cur_state = 316 EMC2305_PWM_DUTY2STATE(data->pwm_min[cdev_idx], data->max_state, 317 EMC2305_FAN_MAX); 318 data->cdev_data[cdev_idx].last_hwmon_state = 319 EMC2305_PWM_DUTY2STATE(data->pwm_min[cdev_idx], data->max_state, 320 EMC2305_FAN_MAX); 321 return 0; 322 } 323 324 static int emc2305_set_tz(struct device *dev) 325 { 326 struct emc2305_data *data = dev_get_drvdata(dev); 327 int i, ret; 328 329 if (!data->pwm_separate) 330 return emc2305_set_single_tz(dev, 0); 331 332 for (i = 0; i < data->pwm_num; i++) { 333 ret = emc2305_set_single_tz(dev, i + 1); 334 if (ret) 335 goto thermal_cooling_device_register_fail; 336 } 337 return 0; 338 339 thermal_cooling_device_register_fail: 340 emc2305_unset_tz(dev); 341 return ret; 342 } 343 344 static void emc2305_unset_tz(struct device *dev) 345 { 346 struct emc2305_data *data = dev_get_drvdata(dev); 347 int i; 348 349 /* Unregister cooling device. */ 350 for (i = 0; i < EMC2305_PWM_MAX; i++) 351 if (data->cdev_data[i].cdev) 352 thermal_cooling_device_unregister(data->cdev_data[i].cdev); 353 } 354 355 static umode_t 356 emc2305_is_visible(const void *data, enum hwmon_sensor_types type, u32 attr, int channel) 357 { 358 int max_channel = emc2305_get_max_channel(data); 359 360 /* Don't show channels which are not physically connected. */ 361 if (channel >= max_channel) 362 return 0; 363 switch (type) { 364 case hwmon_fan: 365 switch (attr) { 366 case hwmon_fan_input: 367 return 0444; 368 case hwmon_fan_fault: 369 return 0444; 370 default: 371 break; 372 } 373 break; 374 case hwmon_pwm: 375 switch (attr) { 376 case hwmon_pwm_input: 377 return 0644; 378 default: 379 break; 380 } 381 break; 382 default: 383 break; 384 } 385 386 return 0; 387 }; 388 389 static int 390 emc2305_write(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel, long val) 391 { 392 struct emc2305_data *data = dev_get_drvdata(dev); 393 int cdev_idx; 394 395 switch (type) { 396 case hwmon_pwm: 397 switch (attr) { 398 case hwmon_pwm_input: 399 /* If thermal is configured - handle PWM limit setting. */ 400 if (IS_REACHABLE(CONFIG_THERMAL)) { 401 if (data->pwm_separate) 402 cdev_idx = channel; 403 else 404 cdev_idx = 0; 405 data->cdev_data[cdev_idx].last_hwmon_state = 406 EMC2305_PWM_DUTY2STATE(val, data->max_state, 407 EMC2305_FAN_MAX); 408 /* 409 * Update PWM only in case requested state is not less than the 410 * last thermal state. 411 */ 412 if (data->cdev_data[cdev_idx].last_hwmon_state >= 413 data->cdev_data[cdev_idx].last_thermal_state) 414 return __emc2305_set_cur_state(data, cdev_idx, 415 data->cdev_data[cdev_idx].last_hwmon_state); 416 return 0; 417 } 418 return emc2305_set_pwm(dev, val, channel); 419 default: 420 break; 421 } 422 break; 423 default: 424 break; 425 } 426 427 return -EOPNOTSUPP; 428 }; 429 430 static int 431 emc2305_read(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel, long *val) 432 { 433 int ret; 434 435 switch (type) { 436 case hwmon_fan: 437 switch (attr) { 438 case hwmon_fan_input: 439 ret = emc2305_show_fan(dev, channel); 440 if (ret < 0) 441 return ret; 442 *val = ret; 443 return 0; 444 case hwmon_fan_fault: 445 ret = emc2305_show_fault(dev, channel); 446 if (ret < 0) 447 return ret; 448 *val = ret; 449 return 0; 450 default: 451 break; 452 } 453 break; 454 case hwmon_pwm: 455 switch (attr) { 456 case hwmon_pwm_input: 457 ret = emc2305_show_pwm(dev, channel); 458 if (ret < 0) 459 return ret; 460 *val = ret; 461 return 0; 462 default: 463 break; 464 } 465 break; 466 default: 467 break; 468 } 469 470 return -EOPNOTSUPP; 471 }; 472 473 static const struct hwmon_ops emc2305_ops = { 474 .is_visible = emc2305_is_visible, 475 .read = emc2305_read, 476 .write = emc2305_write, 477 }; 478 479 static const struct hwmon_channel_info * const emc2305_info[] = { 480 HWMON_CHANNEL_INFO(fan, 481 HWMON_F_INPUT | HWMON_F_FAULT, 482 HWMON_F_INPUT | HWMON_F_FAULT, 483 HWMON_F_INPUT | HWMON_F_FAULT, 484 HWMON_F_INPUT | HWMON_F_FAULT, 485 HWMON_F_INPUT | HWMON_F_FAULT), 486 HWMON_CHANNEL_INFO(pwm, 487 HWMON_PWM_INPUT, 488 HWMON_PWM_INPUT, 489 HWMON_PWM_INPUT, 490 HWMON_PWM_INPUT, 491 HWMON_PWM_INPUT), 492 NULL 493 }; 494 495 static const struct hwmon_chip_info emc2305_chip_info = { 496 .ops = &emc2305_ops, 497 .info = emc2305_info, 498 }; 499 500 static int emc2305_identify(struct device *dev) 501 { 502 struct i2c_client *client = to_i2c_client(dev); 503 struct emc2305_data *data = i2c_get_clientdata(client); 504 int ret; 505 506 ret = i2c_smbus_read_byte_data(client, EMC2305_REG_PRODUCT_ID); 507 if (ret < 0) 508 return ret; 509 510 switch (ret) { 511 case EMC2305: 512 data->pwm_num = 5; 513 break; 514 case EMC2303: 515 data->pwm_num = 3; 516 break; 517 case EMC2302: 518 data->pwm_num = 2; 519 break; 520 case EMC2301: 521 data->pwm_num = 1; 522 break; 523 default: 524 return -ENODEV; 525 } 526 527 return 0; 528 } 529 530 static int emc2305_probe(struct i2c_client *client) 531 { 532 struct i2c_adapter *adapter = client->adapter; 533 struct device *dev = &client->dev; 534 struct emc2305_data *data; 535 struct emc2305_platform_data *pdata; 536 int vendor; 537 int ret; 538 int i; 539 540 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA)) 541 return -ENODEV; 542 543 vendor = i2c_smbus_read_byte_data(client, EMC2305_REG_VENDOR); 544 if (vendor != EMC2305_VENDOR) 545 return -ENODEV; 546 547 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); 548 if (!data) 549 return -ENOMEM; 550 551 i2c_set_clientdata(client, data); 552 data->client = client; 553 554 ret = emc2305_identify(dev); 555 if (ret) 556 return ret; 557 558 pdata = dev_get_platdata(&client->dev); 559 if (pdata) { 560 if (!pdata->max_state || pdata->max_state > EMC2305_FAN_MAX_STATE) 561 return -EINVAL; 562 data->max_state = pdata->max_state; 563 /* 564 * Validate a number of active PWM channels. Note that 565 * configured number can be less than the actual maximum 566 * supported by the device. 567 */ 568 if (!pdata->pwm_num || pdata->pwm_num > EMC2305_PWM_MAX) 569 return -EINVAL; 570 data->pwm_num = pdata->pwm_num; 571 data->pwm_separate = pdata->pwm_separate; 572 for (i = 0; i < EMC2305_PWM_MAX; i++) 573 data->pwm_min[i] = pdata->pwm_min[i]; 574 } else { 575 data->max_state = EMC2305_FAN_MAX_STATE; 576 data->pwm_separate = false; 577 for (i = 0; i < EMC2305_PWM_MAX; i++) 578 data->pwm_min[i] = EMC2305_FAN_MIN; 579 } 580 581 data->hwmon_dev = devm_hwmon_device_register_with_info(dev, "emc2305", data, 582 &emc2305_chip_info, NULL); 583 if (IS_ERR(data->hwmon_dev)) 584 return PTR_ERR(data->hwmon_dev); 585 586 if (IS_REACHABLE(CONFIG_THERMAL)) { 587 ret = emc2305_set_tz(dev); 588 if (ret != 0) 589 return ret; 590 } 591 592 for (i = 0; i < data->pwm_num; i++) { 593 ret = i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_MIN_DRIVE(i), 594 data->pwm_min[i]); 595 if (ret < 0) 596 return ret; 597 } 598 599 return 0; 600 } 601 602 static void emc2305_remove(struct i2c_client *client) 603 { 604 struct device *dev = &client->dev; 605 606 if (IS_REACHABLE(CONFIG_THERMAL)) 607 emc2305_unset_tz(dev); 608 } 609 610 static struct i2c_driver emc2305_driver = { 611 .driver = { 612 .name = "emc2305", 613 }, 614 .probe = emc2305_probe, 615 .remove = emc2305_remove, 616 .id_table = emc2305_ids, 617 }; 618 619 module_i2c_driver(emc2305_driver); 620 621 MODULE_AUTHOR("Nvidia"); 622 MODULE_DESCRIPTION("Microchip EMC2305 fan controller driver"); 623 MODULE_LICENSE("GPL"); 624