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_DEVICE 0xfd 20 #define EMC2305_REG_VENDOR 0xfe 21 #define EMC2305_FAN_MAX 0xff 22 #define EMC2305_FAN_MIN 0x00 23 #define EMC2305_FAN_MAX_STATE 10 24 #define EMC2305_DEVICE 0x34 25 #define EMC2305_VENDOR 0x5d 26 #define EMC2305_REG_PRODUCT_ID 0xfd 27 #define EMC2305_TACH_REGS_UNUSE_BITS 3 28 #define EMC2305_TACH_CNT_MULTIPLIER 0x02 29 #define EMC2305_TACH_RANGE_MIN 480 30 31 #define EMC2305_PWM_DUTY2STATE(duty, max_state, pwm_max) \ 32 DIV_ROUND_CLOSEST((duty) * (max_state), (pwm_max)) 33 #define EMC2305_PWM_STATE2DUTY(state, max_state, pwm_max) \ 34 DIV_ROUND_CLOSEST((state) * (pwm_max), (max_state)) 35 36 /* 37 * Factor by equations [2] and [3] from data sheet; valid for fans where the number of edges 38 * equal (poles * 2 + 1). 39 */ 40 #define EMC2305_RPM_FACTOR 3932160 41 42 #define EMC2305_REG_FAN_DRIVE(n) (0x30 + 0x10 * (n)) 43 #define EMC2305_REG_FAN_MIN_DRIVE(n) (0x38 + 0x10 * (n)) 44 #define EMC2305_REG_FAN_TACH(n) (0x3e + 0x10 * (n)) 45 46 enum emc230x_product_id { 47 EMC2305 = 0x34, 48 EMC2303 = 0x35, 49 EMC2302 = 0x36, 50 EMC2301 = 0x37, 51 }; 52 53 static const struct i2c_device_id emc2305_ids[] = { 54 { "emc2305", 0 }, 55 { "emc2303", 0 }, 56 { "emc2302", 0 }, 57 { "emc2301", 0 }, 58 { } 59 }; 60 MODULE_DEVICE_TABLE(i2c, emc2305_ids); 61 62 /** 63 * @cdev: cooling device; 64 * @curr_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 * @client: i2c client; 91 * @hwmon_dev: hwmon device; 92 * @max_state: maximum cooling state of the cooling device; 93 * @pwm_num: number of PWM channels; 94 * @pwm_separate: separate PWM settings for every channel; 95 * @pwm_min: array of minimum PWM per channel; 96 * @cdev_data: array of cooling devices data; 97 */ 98 struct emc2305_data { 99 struct i2c_client *client; 100 struct device *hwmon_dev; 101 u8 max_state; 102 u8 pwm_num; 103 bool pwm_separate; 104 u8 pwm_min[EMC2305_PWM_MAX]; 105 struct emc2305_cdev_data cdev_data[EMC2305_PWM_MAX]; 106 }; 107 108 static char *emc2305_fan_name[] = { 109 "emc2305_fan", 110 "emc2305_fan1", 111 "emc2305_fan2", 112 "emc2305_fan3", 113 "emc2305_fan4", 114 "emc2305_fan5", 115 }; 116 117 static void emc2305_unset_tz(struct device *dev); 118 119 static int emc2305_get_max_channel(const struct emc2305_data *data) 120 { 121 return data->pwm_num; 122 } 123 124 static int emc2305_get_cdev_idx(struct thermal_cooling_device *cdev) 125 { 126 struct emc2305_data *data = cdev->devdata; 127 size_t len = strlen(cdev->type); 128 int ret; 129 130 if (len <= 0) 131 return -EINVAL; 132 133 /* 134 * Returns index of cooling device 0..4 in case of separate PWM setting. 135 * Zero index is used in case of one common PWM setting. 136 * If the mode is not set as pwm_separate, all PWMs are to be bound 137 * to the common thermal zone and should work at the same speed 138 * to perform cooling for the same thermal junction. 139 * Otherwise, return specific channel that will be used in bound 140 * related PWM to the thermal zone. 141 */ 142 if (!data->pwm_separate) 143 return 0; 144 145 ret = cdev->type[len - 1]; 146 switch (ret) { 147 case '1' ... '5': 148 return ret - '1'; 149 default: 150 break; 151 } 152 return -EINVAL; 153 } 154 155 static int emc2305_get_cur_state(struct thermal_cooling_device *cdev, unsigned long *state) 156 { 157 int cdev_idx; 158 struct emc2305_data *data = cdev->devdata; 159 160 cdev_idx = emc2305_get_cdev_idx(cdev); 161 if (cdev_idx < 0) 162 return cdev_idx; 163 164 *state = data->cdev_data[cdev_idx].cur_state; 165 return 0; 166 } 167 168 static int emc2305_get_max_state(struct thermal_cooling_device *cdev, unsigned long *state) 169 { 170 struct emc2305_data *data = cdev->devdata; 171 *state = data->max_state; 172 return 0; 173 } 174 175 static int emc2305_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state) 176 { 177 int cdev_idx, ret; 178 struct emc2305_data *data = cdev->devdata; 179 struct i2c_client *client = data->client; 180 u8 val, i; 181 182 if (state > data->max_state) 183 return -EINVAL; 184 185 cdev_idx = emc2305_get_cdev_idx(cdev); 186 if (cdev_idx < 0) 187 return cdev_idx; 188 189 /* Save thermal state. */ 190 data->cdev_data[cdev_idx].last_thermal_state = state; 191 state = max_t(unsigned long, state, data->cdev_data[cdev_idx].last_hwmon_state); 192 193 val = EMC2305_PWM_STATE2DUTY(state, data->max_state, EMC2305_FAN_MAX); 194 195 data->cdev_data[cdev_idx].cur_state = state; 196 if (data->pwm_separate) { 197 ret = i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_DRIVE(cdev_idx), val); 198 if (ret < 0) 199 return ret; 200 } else { 201 /* 202 * Set the same PWM value in all channels 203 * if common PWM channel is used. 204 */ 205 for (i = 0; i < data->pwm_num; i++) { 206 ret = i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_DRIVE(i), val); 207 if (ret < 0) 208 return ret; 209 } 210 } 211 212 return 0; 213 } 214 215 static const struct thermal_cooling_device_ops emc2305_cooling_ops = { 216 .get_max_state = emc2305_get_max_state, 217 .get_cur_state = emc2305_get_cur_state, 218 .set_cur_state = emc2305_set_cur_state, 219 }; 220 221 static int emc2305_show_fault(struct device *dev, int channel) 222 { 223 struct emc2305_data *data = dev_get_drvdata(dev); 224 struct i2c_client *client = data->client; 225 int status_reg; 226 227 status_reg = i2c_smbus_read_byte_data(client, EMC2305_REG_DRIVE_FAIL_STATUS); 228 if (status_reg < 0) 229 return status_reg; 230 231 return status_reg & (1 << channel) ? 1 : 0; 232 } 233 234 static int emc2305_show_fan(struct device *dev, int channel) 235 { 236 struct emc2305_data *data = dev_get_drvdata(dev); 237 struct i2c_client *client = data->client; 238 int ret; 239 240 ret = i2c_smbus_read_word_swapped(client, EMC2305_REG_FAN_TACH(channel)); 241 if (ret <= 0) 242 return ret; 243 244 ret = ret >> EMC2305_TACH_REGS_UNUSE_BITS; 245 ret = EMC2305_RPM_FACTOR / ret; 246 if (ret <= EMC2305_TACH_RANGE_MIN) 247 return 0; 248 249 return ret * EMC2305_TACH_CNT_MULTIPLIER; 250 } 251 252 static int emc2305_show_pwm(struct device *dev, int channel) 253 { 254 struct emc2305_data *data = dev_get_drvdata(dev); 255 struct i2c_client *client = data->client; 256 257 return i2c_smbus_read_byte_data(client, EMC2305_REG_FAN_DRIVE(channel)); 258 } 259 260 static int emc2305_set_pwm(struct device *dev, long val, int channel) 261 { 262 struct emc2305_data *data = dev_get_drvdata(dev); 263 struct i2c_client *client = data->client; 264 int ret; 265 266 if (val < data->pwm_min[channel] || val > EMC2305_FAN_MAX) 267 return -EINVAL; 268 269 ret = i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_DRIVE(channel), val); 270 if (ret < 0) 271 return ret; 272 data->cdev_data[channel].cur_state = EMC2305_PWM_DUTY2STATE(val, data->max_state, 273 EMC2305_FAN_MAX); 274 return 0; 275 } 276 277 static int emc2305_set_single_tz(struct device *dev, int idx) 278 { 279 struct emc2305_data *data = dev_get_drvdata(dev); 280 long pwm; 281 int i, cdev_idx, ret; 282 283 cdev_idx = (idx) ? idx - 1 : 0; 284 pwm = data->pwm_min[cdev_idx]; 285 286 data->cdev_data[cdev_idx].cdev = 287 thermal_cooling_device_register(emc2305_fan_name[idx], data, 288 &emc2305_cooling_ops); 289 290 if (IS_ERR(data->cdev_data[cdev_idx].cdev)) { 291 dev_err(dev, "Failed to register cooling device %s\n", emc2305_fan_name[idx]); 292 return PTR_ERR(data->cdev_data[cdev_idx].cdev); 293 } 294 /* Set minimal PWM speed. */ 295 if (data->pwm_separate) { 296 ret = emc2305_set_pwm(dev, pwm, cdev_idx); 297 if (ret < 0) 298 return ret; 299 } else { 300 for (i = 0; i < data->pwm_num; i++) { 301 ret = emc2305_set_pwm(dev, pwm, i); 302 if (ret < 0) 303 return ret; 304 } 305 } 306 data->cdev_data[cdev_idx].cur_state = 307 EMC2305_PWM_DUTY2STATE(data->pwm_min[cdev_idx], data->max_state, 308 EMC2305_FAN_MAX); 309 data->cdev_data[cdev_idx].last_hwmon_state = 310 EMC2305_PWM_DUTY2STATE(data->pwm_min[cdev_idx], data->max_state, 311 EMC2305_FAN_MAX); 312 return 0; 313 } 314 315 static int emc2305_set_tz(struct device *dev) 316 { 317 struct emc2305_data *data = dev_get_drvdata(dev); 318 int i, ret; 319 320 if (!data->pwm_separate) 321 return emc2305_set_single_tz(dev, 0); 322 323 for (i = 0; i < data->pwm_num; i++) { 324 ret = emc2305_set_single_tz(dev, i + 1); 325 if (ret) 326 goto thermal_cooling_device_register_fail; 327 } 328 return 0; 329 330 thermal_cooling_device_register_fail: 331 emc2305_unset_tz(dev); 332 return ret; 333 } 334 335 static void emc2305_unset_tz(struct device *dev) 336 { 337 struct emc2305_data *data = dev_get_drvdata(dev); 338 int i; 339 340 /* Unregister cooling device. */ 341 for (i = 0; i < EMC2305_PWM_MAX; i++) 342 if (data->cdev_data[i].cdev) 343 thermal_cooling_device_unregister(data->cdev_data[i].cdev); 344 } 345 346 static umode_t 347 emc2305_is_visible(const void *data, enum hwmon_sensor_types type, u32 attr, int channel) 348 { 349 int max_channel = emc2305_get_max_channel(data); 350 351 /* Don't show channels which are not physically connected. */ 352 if (channel >= max_channel) 353 return 0; 354 switch (type) { 355 case hwmon_fan: 356 switch (attr) { 357 case hwmon_fan_input: 358 return 0444; 359 case hwmon_fan_fault: 360 return 0444; 361 default: 362 break; 363 } 364 break; 365 case hwmon_pwm: 366 switch (attr) { 367 case hwmon_pwm_input: 368 return 0644; 369 default: 370 break; 371 } 372 break; 373 default: 374 break; 375 } 376 377 return 0; 378 }; 379 380 static int 381 emc2305_write(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel, long val) 382 { 383 struct emc2305_data *data = dev_get_drvdata(dev); 384 int cdev_idx; 385 386 switch (type) { 387 case hwmon_pwm: 388 switch (attr) { 389 case hwmon_pwm_input: 390 /* If thermal is configured - handle PWM limit setting. */ 391 if (IS_REACHABLE(CONFIG_THERMAL)) { 392 if (data->pwm_separate) 393 cdev_idx = channel; 394 else 395 cdev_idx = 0; 396 data->cdev_data[cdev_idx].last_hwmon_state = 397 EMC2305_PWM_DUTY2STATE(val, data->max_state, 398 EMC2305_FAN_MAX); 399 /* 400 * Update PWM only in case requested state is not less than the 401 * last thermal state. 402 */ 403 if (data->cdev_data[cdev_idx].last_hwmon_state >= 404 data->cdev_data[cdev_idx].last_thermal_state) 405 return emc2305_set_cur_state(data->cdev_data[cdev_idx].cdev, 406 data->cdev_data[cdev_idx].last_hwmon_state); 407 return 0; 408 } 409 return emc2305_set_pwm(dev, val, channel); 410 default: 411 break; 412 } 413 break; 414 default: 415 break; 416 } 417 418 return -EOPNOTSUPP; 419 }; 420 421 static int 422 emc2305_read(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel, long *val) 423 { 424 int ret; 425 426 switch (type) { 427 case hwmon_fan: 428 switch (attr) { 429 case hwmon_fan_input: 430 ret = emc2305_show_fan(dev, channel); 431 if (ret < 0) 432 return ret; 433 *val = ret; 434 return 0; 435 case hwmon_fan_fault: 436 ret = emc2305_show_fault(dev, channel); 437 if (ret < 0) 438 return ret; 439 *val = ret; 440 return 0; 441 default: 442 break; 443 } 444 break; 445 case hwmon_pwm: 446 switch (attr) { 447 case hwmon_pwm_input: 448 ret = emc2305_show_pwm(dev, channel); 449 if (ret < 0) 450 return ret; 451 *val = ret; 452 return 0; 453 default: 454 break; 455 } 456 break; 457 default: 458 break; 459 } 460 461 return -EOPNOTSUPP; 462 }; 463 464 static const struct hwmon_ops emc2305_ops = { 465 .is_visible = emc2305_is_visible, 466 .read = emc2305_read, 467 .write = emc2305_write, 468 }; 469 470 static const struct hwmon_channel_info *emc2305_info[] = { 471 HWMON_CHANNEL_INFO(fan, 472 HWMON_F_INPUT | HWMON_F_FAULT, 473 HWMON_F_INPUT | HWMON_F_FAULT, 474 HWMON_F_INPUT | HWMON_F_FAULT, 475 HWMON_F_INPUT | HWMON_F_FAULT, 476 HWMON_F_INPUT | HWMON_F_FAULT), 477 HWMON_CHANNEL_INFO(pwm, 478 HWMON_PWM_INPUT, 479 HWMON_PWM_INPUT, 480 HWMON_PWM_INPUT, 481 HWMON_PWM_INPUT, 482 HWMON_PWM_INPUT), 483 NULL 484 }; 485 486 static const struct hwmon_chip_info emc2305_chip_info = { 487 .ops = &emc2305_ops, 488 .info = emc2305_info, 489 }; 490 491 static int emc2305_identify(struct device *dev) 492 { 493 struct i2c_client *client = to_i2c_client(dev); 494 struct emc2305_data *data = i2c_get_clientdata(client); 495 int ret; 496 497 ret = i2c_smbus_read_byte_data(client, EMC2305_REG_PRODUCT_ID); 498 if (ret < 0) 499 return ret; 500 501 switch (ret) { 502 case EMC2305: 503 data->pwm_num = 5; 504 break; 505 case EMC2303: 506 data->pwm_num = 3; 507 break; 508 case EMC2302: 509 data->pwm_num = 2; 510 break; 511 case EMC2301: 512 data->pwm_num = 1; 513 break; 514 default: 515 return -ENODEV; 516 } 517 518 return 0; 519 } 520 521 static int emc2305_probe(struct i2c_client *client, const struct i2c_device_id *id) 522 { 523 struct i2c_adapter *adapter = client->adapter; 524 struct device *dev = &client->dev; 525 struct emc2305_data *data; 526 struct emc2305_platform_data *pdata; 527 int vendor, device; 528 int ret; 529 int i; 530 531 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA)) 532 return -ENODEV; 533 534 vendor = i2c_smbus_read_byte_data(client, EMC2305_REG_VENDOR); 535 if (vendor != EMC2305_VENDOR) 536 return -ENODEV; 537 538 device = i2c_smbus_read_byte_data(client, EMC2305_REG_DEVICE); 539 if (device != EMC2305_DEVICE) 540 return -ENODEV; 541 542 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); 543 if (!data) 544 return -ENOMEM; 545 546 i2c_set_clientdata(client, data); 547 data->client = client; 548 549 ret = emc2305_identify(dev); 550 if (ret) 551 return ret; 552 553 pdata = dev_get_platdata(&client->dev); 554 if (pdata) { 555 if (!pdata->max_state || pdata->max_state > EMC2305_FAN_MAX_STATE) 556 return -EINVAL; 557 data->max_state = pdata->max_state; 558 /* 559 * Validate a number of active PWM channels. Note that 560 * configured number can be less than the actual maximum 561 * supported by the device. 562 */ 563 if (!pdata->pwm_num || pdata->pwm_num > EMC2305_PWM_MAX) 564 return -EINVAL; 565 data->pwm_num = pdata->pwm_num; 566 data->pwm_separate = pdata->pwm_separate; 567 for (i = 0; i < EMC2305_PWM_MAX; i++) 568 data->pwm_min[i] = pdata->pwm_min[i]; 569 } else { 570 data->max_state = EMC2305_FAN_MAX_STATE; 571 data->pwm_separate = false; 572 for (i = 0; i < EMC2305_PWM_MAX; i++) 573 data->pwm_min[i] = EMC2305_FAN_MIN; 574 } 575 576 data->hwmon_dev = devm_hwmon_device_register_with_info(dev, "emc2305", data, 577 &emc2305_chip_info, NULL); 578 if (IS_ERR(data->hwmon_dev)) 579 return PTR_ERR(data->hwmon_dev); 580 581 if (IS_REACHABLE(CONFIG_THERMAL)) { 582 ret = emc2305_set_tz(dev); 583 if (ret != 0) 584 return ret; 585 } 586 587 for (i = 0; i < data->pwm_num; i++) { 588 ret = i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_MIN_DRIVE(i), 589 data->pwm_min[i]); 590 if (ret < 0) 591 return ret; 592 } 593 594 return 0; 595 } 596 597 static int emc2305_remove(struct i2c_client *client) 598 { 599 struct device *dev = &client->dev; 600 601 if (IS_REACHABLE(CONFIG_THERMAL)) 602 emc2305_unset_tz(dev); 603 return 0; 604 } 605 606 static struct i2c_driver emc2305_driver = { 607 .class = I2C_CLASS_HWMON, 608 .driver = { 609 .name = "emc2305", 610 }, 611 .probe = emc2305_probe, 612 .remove = emc2305_remove, 613 .id_table = emc2305_ids, 614 .address_list = emc2305_normal_i2c, 615 }; 616 617 module_i2c_driver(emc2305_driver); 618 619 MODULE_AUTHOR("Nvidia"); 620 MODULE_DESCRIPTION("Microchip EMC2305 fan controller driver"); 621 MODULE_LICENSE("GPL"); 622