1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Hardware monitoring driver for MPS Multi-phase Digital VR Controllers(MP2891) 4 */ 5 6 #include <linux/bitfield.h> 7 #include <linux/i2c.h> 8 #include <linux/module.h> 9 #include <linux/of_device.h> 10 #include "pmbus.h" 11 12 /* 13 * Vender specific registers, the register MFR_SVI3_IOUT_PRT(0x65), 14 * MFR_VOUT_LOOP_CTRL(0xBD), READ_PIN_EST(0x94)and READ_IIN_EST(0x95) 15 * redefine the standard PMBUS register. The MFR_SVI3_IOUT_PRT(0x65) 16 * is used to identify the iout scale and the MFR_VOUT_LOOP_CTRL(0xBD) 17 * is used to identify the vout scale. The READ_PIN_EST(0x94) is used 18 * to read input power per rail. The MP2891 does not have standard 19 * READ_IIN register(0x89), the iin telemetry can be obtained through 20 * the vendor redefined register READ_IIN_EST(0x95). 21 */ 22 #define MFR_VOUT_LOOP_CTRL 0xBD 23 #define READ_PIN_EST 0x94 24 #define READ_IIN_EST 0x95 25 #define MFR_SVI3_IOUT_PRT 0x65 26 27 #define MP2891_TEMP_LIMIT_OFFSET 40 28 #define MP2891_PIN_LIMIT_UINT 2 29 #define MP2891_IOUT_LIMIT_UINT 8 30 #define MP2891_IOUT_SCALE_DIV 32 31 #define MP2891_VOUT_SCALE_DIV 100 32 #define MP2891_OVUV_DELTA_SCALE 50 33 #define MP2891_OV_LIMIT_SCALE 20 34 #define MP2891_UV_LIMIT_SCALE 5 35 36 #define MP2891_PAGE_NUM 2 37 38 #define MP2891_RAIL1_FUNC (PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT | \ 39 PMBUS_HAVE_IOUT | PMBUS_HAVE_TEMP | \ 40 PMBUS_HAVE_POUT | PMBUS_HAVE_PIN | \ 41 PMBUS_HAVE_IIN | PMBUS_HAVE_STATUS_VOUT | \ 42 PMBUS_HAVE_STATUS_IOUT | \ 43 PMBUS_HAVE_STATUS_INPUT | \ 44 PMBUS_HAVE_STATUS_TEMP) 45 46 #define MP2891_RAIL2_FUNC (PMBUS_HAVE_VOUT | PMBUS_HAVE_IOUT | \ 47 PMBUS_HAVE_TEMP | PMBUS_HAVE_POUT | \ 48 PMBUS_HAVE_PIN | PMBUS_HAVE_IIN | \ 49 PMBUS_HAVE_STATUS_VOUT | \ 50 PMBUS_HAVE_STATUS_IOUT | \ 51 PMBUS_HAVE_STATUS_INPUT | \ 52 PMBUS_HAVE_STATUS_TEMP) 53 54 struct mp2891_data { 55 struct pmbus_driver_info info; 56 int vout_scale[MP2891_PAGE_NUM]; 57 int iout_scale[MP2891_PAGE_NUM]; 58 }; 59 60 #define to_mp2891_data(x) container_of(x, struct mp2891_data, info) 61 62 /* Converts a LINEAR11 value to DIRECT format */ 63 static u16 mp2891_reg2data_linear11(u16 word) 64 { 65 s16 exponent; 66 s32 mantissa; 67 s64 val; 68 69 exponent = ((s16)word) >> 11; 70 mantissa = ((s16)((word & 0x7ff) << 5)) >> 5; 71 val = mantissa; 72 73 if (exponent >= 0) 74 val <<= exponent; 75 else 76 val >>= -exponent; 77 78 return val; 79 } 80 81 static int 82 mp2891_identify_vout_scale(struct i2c_client *client, struct pmbus_driver_info *info, 83 int page) 84 { 85 struct mp2891_data *data = to_mp2891_data(info); 86 int ret; 87 88 ret = i2c_smbus_write_byte_data(client, PMBUS_PAGE, page); 89 if (ret < 0) 90 return ret; 91 92 ret = i2c_smbus_read_word_data(client, MFR_VOUT_LOOP_CTRL); 93 if (ret < 0) 94 return ret; 95 96 /* 97 * The output voltage is equal to the READ_VOUT(0x8B) register value multiplied 98 * by vout_scale. 99 * Obtain vout scale from the register MFR_VOUT_LOOP_CTRL, bits 15-14,bit 13. 100 * If MFR_VOUT_LOOP_CTRL[13] = 1, the vout scale is below: 101 * 2.5mV/LSB 102 * If MFR_VOUT_LOOP_CTRL[13] = 0, the vout scale is decided by 103 * MFR_VOUT_LOOP_CTRL[15:14]: 104 * 00b - 6.25mV/LSB, 01b - 5mV/LSB, 10b - 2mV/LSB, 11b - 1mV 105 */ 106 if (ret & GENMASK(13, 13)) { 107 data->vout_scale[page] = 250; 108 } else { 109 ret = FIELD_GET(GENMASK(15, 14), ret); 110 if (ret == 0) 111 data->vout_scale[page] = 625; 112 else if (ret == 1) 113 data->vout_scale[page] = 500; 114 else if (ret == 2) 115 data->vout_scale[page] = 200; 116 else 117 data->vout_scale[page] = 100; 118 } 119 120 return 0; 121 } 122 123 static int 124 mp2891_identify_iout_scale(struct i2c_client *client, struct pmbus_driver_info *info, 125 int page) 126 { 127 struct mp2891_data *data = to_mp2891_data(info); 128 int ret; 129 130 ret = i2c_smbus_write_byte_data(client, PMBUS_PAGE, page); 131 if (ret < 0) 132 return ret; 133 134 ret = i2c_smbus_read_word_data(client, MFR_SVI3_IOUT_PRT); 135 if (ret < 0) 136 return ret; 137 138 /* 139 * The output current is equal to the READ_IOUT(0x8C) register value 140 * multiplied by iout_scale. 141 * Obtain iout_scale from the register MFR_SVI3_IOUT_PRT[2:0]. 142 * The value is selected as below: 143 * 000b - 1A/LSB, 001b - (1/32)A/LSB, 010b - (1/16)A/LSB, 144 * 011b - (1/8)A/LSB, 100b - (1/4)A/LSB, 101b - (1/2)A/LSB 145 * 110b - 1A/LSB, 111b - 2A/LSB 146 */ 147 switch (ret & GENMASK(2, 0)) { 148 case 0: 149 case 6: 150 data->iout_scale[page] = 32; 151 break; 152 case 1: 153 data->iout_scale[page] = 1; 154 break; 155 case 2: 156 data->iout_scale[page] = 2; 157 break; 158 case 3: 159 data->iout_scale[page] = 4; 160 break; 161 case 4: 162 data->iout_scale[page] = 8; 163 break; 164 case 5: 165 data->iout_scale[page] = 16; 166 break; 167 default: 168 data->iout_scale[page] = 64; 169 break; 170 } 171 172 return 0; 173 } 174 175 static int mp2891_identify(struct i2c_client *client, struct pmbus_driver_info *info) 176 { 177 int ret; 178 179 /* Identify vout scale for rail 1. */ 180 ret = mp2891_identify_vout_scale(client, info, 0); 181 if (ret < 0) 182 return ret; 183 184 /* Identify vout scale for rail 2. */ 185 ret = mp2891_identify_vout_scale(client, info, 1); 186 if (ret < 0) 187 return ret; 188 189 /* Identify iout scale for rail 1. */ 190 ret = mp2891_identify_iout_scale(client, info, 0); 191 if (ret < 0) 192 return ret; 193 194 /* Identify iout scale for rail 2. */ 195 return mp2891_identify_iout_scale(client, info, 1); 196 } 197 198 static int mp2891_read_byte_data(struct i2c_client *client, int page, int reg) 199 { 200 int ret; 201 202 switch (reg) { 203 case PMBUS_VOUT_MODE: 204 /* 205 * The MP2891 does not follow standard PMBus protocol completely, the 206 * PMBUS_VOUT_MODE(0x20) in MP2891 is reserved and 0x00 is always 207 * returned when the register is read. But the calculation of vout in 208 * this driver is based on direct format. As a result, the format of 209 * vout is enforced to direct. 210 */ 211 ret = PB_VOUT_MODE_DIRECT; 212 break; 213 default: 214 ret = -ENODATA; 215 break; 216 } 217 218 return ret; 219 } 220 221 static int mp2891_read_word_data(struct i2c_client *client, int page, 222 int phase, int reg) 223 { 224 const struct pmbus_driver_info *info = pmbus_get_driver_info(client); 225 struct mp2891_data *data = to_mp2891_data(info); 226 int ret; 227 228 switch (reg) { 229 case PMBUS_READ_VIN: 230 ret = pmbus_read_word_data(client, page, phase, reg); 231 if (ret < 0) 232 return ret; 233 234 ret = ret & GENMASK(9, 0); 235 break; 236 case PMBUS_READ_IIN: 237 /* 238 * The MP2891 does not have standard PMBUS_READ_IIN register(0x89), 239 * the iin telemetry can be obtained through the vender redefined 240 * register READ_IIN_EST(0x95). The MP2891 PMBUS_READ_IIN register 241 * is linear11 format, But the pout scale is set to 1A/Lsb(using 242 * r/m/b scale). As a result, the iin read from MP2891 should be 243 * calculated to A, then return the result to pmbus core. 244 */ 245 ret = pmbus_read_word_data(client, page, phase, READ_IIN_EST); 246 if (ret < 0) 247 return ret; 248 249 ret = mp2891_reg2data_linear11(ret); 250 break; 251 case PMBUS_READ_PIN: 252 /* 253 * The MP2891 has standard PMBUS_READ_PIN register(0x97), but this 254 * is not used to read the input power per rail. The input power 255 * per rail is read through the vender redefined register 256 * READ_PIN_EST(0x94). The MP2891 PMBUS_READ_PIN register is linear11 257 * format, But the pout scale is set to 1W/Lsb(using r/m/b scale). 258 * As a result, the pin read from MP2891 should be calculated to W, 259 * then return the result to pmbus core. 260 */ 261 ret = pmbus_read_word_data(client, page, phase, READ_PIN_EST); 262 if (ret < 0) 263 return ret; 264 265 ret = mp2891_reg2data_linear11(ret); 266 break; 267 case PMBUS_READ_POUT: 268 /* 269 * The MP2891 PMBUS_READ_POUT register is linear11 format, and the 270 * exponent is not a constant value. But the pout scale is set to 271 * 1W/Lsb(using r/m/b scale). As a result, the pout read from MP2891 272 * should be calculated to W, then return the result to pmbus core. 273 */ 274 ret = pmbus_read_word_data(client, page, phase, reg); 275 if (ret < 0) 276 return ret; 277 278 ret = mp2891_reg2data_linear11(ret); 279 break; 280 case PMBUS_READ_VOUT: 281 case PMBUS_VOUT_UV_WARN_LIMIT: 282 ret = pmbus_read_word_data(client, page, phase, reg); 283 if (ret < 0) 284 return ret; 285 286 ret = DIV_ROUND_CLOSEST(ret * data->vout_scale[page], MP2891_VOUT_SCALE_DIV); 287 break; 288 case PMBUS_READ_IOUT: 289 ret = pmbus_read_word_data(client, page, phase, reg); 290 if (ret < 0) 291 return ret; 292 293 ret = DIV_ROUND_CLOSEST((ret & GENMASK(10, 0)) * data->iout_scale[page], 294 MP2891_IOUT_SCALE_DIV); 295 break; 296 case PMBUS_OT_FAULT_LIMIT: 297 case PMBUS_OT_WARN_LIMIT: 298 /* 299 * The scale of MP2891 PMBUS_OT_FAULT_LIMIT and PMBUS_OT_WARN_LIMIT 300 * is 1°C/LSB and they have 40°C offset. 301 */ 302 ret = pmbus_read_word_data(client, page, phase, reg); 303 if (ret < 0) 304 return ret; 305 306 ret = (ret & GENMASK(7, 0)) - MP2891_TEMP_LIMIT_OFFSET; 307 break; 308 case PMBUS_VIN_OV_FAULT_LIMIT: 309 /* 310 * The MP2891 PMBUS_VIN_OV_FAULT_LIMIT scale is 125mV/Lsb. 311 * but the vin scale is set to 31.25mV/Lsb(using r/m/b scale). 312 * As a result, the limit value should be multiplied by 4. 313 */ 314 ret = pmbus_read_word_data(client, page, phase, reg); 315 if (ret < 0) 316 return ret; 317 318 ret = (ret & GENMASK(7, 0)) * 4; 319 break; 320 case PMBUS_VOUT_UV_FAULT_LIMIT: 321 ret = pmbus_read_word_data(client, page, phase, reg); 322 if (ret < 0) 323 return ret; 324 325 if (FIELD_GET(GENMASK(11, 8), ret)) 326 ret = FIELD_GET(GENMASK(7, 0), ret) * MP2891_UV_LIMIT_SCALE - 327 (FIELD_GET(GENMASK(11, 8), ret) + 1) * MP2891_OVUV_DELTA_SCALE; 328 else 329 ret = FIELD_GET(GENMASK(7, 0), ret) * MP2891_UV_LIMIT_SCALE; 330 331 ret = ret < 0 ? 0 : ret; 332 break; 333 case PMBUS_VOUT_OV_FAULT_LIMIT: 334 ret = pmbus_read_word_data(client, page, phase, reg); 335 if (ret < 0) 336 return ret; 337 338 if (FIELD_GET(GENMASK(11, 8), ret)) 339 ret = FIELD_GET(GENMASK(7, 0), ret) * MP2891_OV_LIMIT_SCALE + 340 (FIELD_GET(GENMASK(11, 8), ret) + 1) * MP2891_OVUV_DELTA_SCALE; 341 else 342 ret = FIELD_GET(GENMASK(7, 0), ret) * MP2891_OV_LIMIT_SCALE; 343 break; 344 case PMBUS_IOUT_OC_WARN_LIMIT: 345 case PMBUS_IOUT_OC_FAULT_LIMIT: 346 ret = pmbus_read_word_data(client, page, phase, reg); 347 if (ret < 0) 348 return ret; 349 350 ret = DIV_ROUND_CLOSEST((ret & GENMASK(7, 0)) * data->iout_scale[page] * 351 MP2891_IOUT_LIMIT_UINT, MP2891_IOUT_SCALE_DIV); 352 break; 353 case PMBUS_IIN_OC_WARN_LIMIT: 354 /* 355 * The scale of PMBUS_IIN_OC_WARN_LIMIT is 0.5A/Lsb, but the iin scale 356 * is set to 1A/Lsb(using r/m/b scale), so the word data should be 357 * divided by 2. 358 */ 359 ret = pmbus_read_word_data(client, 0, phase, reg); 360 if (ret < 0) 361 return ret; 362 363 ret = DIV_ROUND_CLOSEST((ret & GENMASK(9, 0)), 2); 364 break; 365 case PMBUS_PIN_OP_WARN_LIMIT: 366 /* 367 * The scale of PMBUS_PIN_OP_WARN_LIMIT is 2W/Lsb, but the pin scale 368 * is set to 1W/Lsb(using r/m/b scale), so the word data should be 369 * multiplied by 2. 370 */ 371 ret = pmbus_read_word_data(client, 0, phase, reg); 372 if (ret < 0) 373 return ret; 374 375 ret = (ret & GENMASK(9, 0)) * MP2891_PIN_LIMIT_UINT; 376 break; 377 case PMBUS_READ_TEMPERATURE_1: 378 case PMBUS_VIN_UV_FAULT_LIMIT: 379 case PMBUS_VIN_UV_WARN_LIMIT: 380 ret = -ENODATA; 381 break; 382 default: 383 ret = -EINVAL; 384 break; 385 } 386 387 return ret; 388 } 389 390 static int mp2891_write_word_data(struct i2c_client *client, int page, int reg, 391 u16 word) 392 { 393 const struct pmbus_driver_info *info = pmbus_get_driver_info(client); 394 struct mp2891_data *data = to_mp2891_data(info); 395 int ret; 396 397 switch (reg) { 398 case PMBUS_VOUT_UV_WARN_LIMIT: 399 ret = pmbus_write_word_data(client, page, reg, 400 DIV_ROUND_CLOSEST(word * MP2891_VOUT_SCALE_DIV, 401 data->vout_scale[page])); 402 break; 403 case PMBUS_VOUT_UV_FAULT_LIMIT: 404 /* 405 * The PMBUS_VOUT_UV_FAULT_LIMIT[7:0] is the limit value, and bit8-bit15 406 * should not be changed. 407 */ 408 ret = pmbus_read_word_data(client, page, 0xff, reg); 409 if (ret < 0) 410 return ret; 411 412 if (FIELD_GET(GENMASK(11, 8), ret)) 413 ret = pmbus_write_word_data(client, page, reg, 414 (ret & ~GENMASK(7, 0)) | 415 FIELD_PREP(GENMASK(7, 0), 416 DIV_ROUND_CLOSEST(word + 417 (FIELD_GET(GENMASK(11, 8), ret) + 1) * 418 MP2891_OVUV_DELTA_SCALE, 419 MP2891_UV_LIMIT_SCALE))); 420 else 421 ret = pmbus_write_word_data(client, page, reg, 422 (ret & ~GENMASK(7, 0)) | 423 FIELD_PREP(GENMASK(7, 0), 424 DIV_ROUND_CLOSEST(word, 425 MP2891_UV_LIMIT_SCALE))); 426 break; 427 case PMBUS_VOUT_OV_FAULT_LIMIT: 428 /* 429 * The PMBUS_VOUT_OV_FAULT_LIMIT[7:0] is the limit value, and bit8-bit15 430 * should not be changed. 431 */ 432 ret = pmbus_read_word_data(client, page, 0xff, reg); 433 if (ret < 0) 434 return ret; 435 436 if (FIELD_GET(GENMASK(11, 8), ret)) 437 ret = pmbus_write_word_data(client, page, reg, 438 (ret & ~GENMASK(7, 0)) | 439 FIELD_PREP(GENMASK(7, 0), 440 DIV_ROUND_CLOSEST(word - 441 (FIELD_GET(GENMASK(11, 8), ret) + 1) * 442 MP2891_OVUV_DELTA_SCALE, 443 MP2891_OV_LIMIT_SCALE))); 444 else 445 ret = pmbus_write_word_data(client, page, reg, 446 (ret & ~GENMASK(7, 0)) | 447 FIELD_PREP(GENMASK(7, 0), 448 DIV_ROUND_CLOSEST(word, 449 MP2891_OV_LIMIT_SCALE))); 450 break; 451 case PMBUS_VIN_OV_FAULT_LIMIT: 452 /* 453 * The PMBUS_VIN_OV_FAULT_LIMIT[7:0] is the limit value, and bit8-bit15 454 * should not be changed. The scale of PMBUS_VIN_OV_FAULT_LIMIT is 125mV/Lsb, 455 * but the vin scale is set to 31.25mV/Lsb(using r/m/b scale), so the word data 456 * should be divided by 4. 457 */ 458 ret = pmbus_read_word_data(client, page, 0xff, reg); 459 if (ret < 0) 460 return ret; 461 462 ret = pmbus_write_word_data(client, page, reg, 463 (ret & ~GENMASK(7, 0)) | 464 FIELD_PREP(GENMASK(7, 0), 465 DIV_ROUND_CLOSEST(word, 4))); 466 break; 467 case PMBUS_OT_FAULT_LIMIT: 468 case PMBUS_OT_WARN_LIMIT: 469 /* 470 * The scale of MP2891 PMBUS_OT_FAULT_LIMIT and PMBUS_OT_WARN_LIMIT 471 * have 40°C offset. The bit0-bit7 is the limit value, and bit8-bit15 472 * should not be changed. 473 */ 474 ret = pmbus_read_word_data(client, page, 0xff, reg); 475 if (ret < 0) 476 return ret; 477 478 ret = pmbus_write_word_data(client, page, reg, 479 (ret & ~GENMASK(7, 0)) | 480 FIELD_PREP(GENMASK(7, 0), word + MP2891_TEMP_LIMIT_OFFSET)); 481 break; 482 case PMBUS_IOUT_OC_WARN_LIMIT: 483 case PMBUS_IOUT_OC_FAULT_LIMIT: 484 ret = pmbus_write_word_data(client, page, reg, 485 DIV_ROUND_CLOSEST(word * MP2891_IOUT_SCALE_DIV, 486 MP2891_IOUT_LIMIT_UINT * 487 data->iout_scale[page])); 488 break; 489 case PMBUS_IIN_OC_WARN_LIMIT: 490 /* 491 * The scale of PMBUS_IIN_OC_WARN_LIMIT is 0.5A/Lsb, but the iin scale 492 * is set to 1A/Lsb(using r/m/b scale), so the word data should be 493 * multiplied by 2. 494 */ 495 ret = pmbus_write_word_data(client, page, reg, word * 2); 496 break; 497 case PMBUS_PIN_OP_WARN_LIMIT: 498 /* 499 * The scale of PMBUS_PIN_OP_WARN_LIMIT is 2W/Lsb, but the pin scale 500 * is set to 1W/Lsb(using r/m/b scale), so the word data should be 501 * divided by 2. 502 */ 503 ret = pmbus_write_word_data(client, page, reg, 504 DIV_ROUND_CLOSEST(word, MP2891_PIN_LIMIT_UINT)); 505 break; 506 case PMBUS_VIN_UV_FAULT_LIMIT: 507 case PMBUS_VIN_UV_WARN_LIMIT: 508 ret = -ENODATA; 509 break; 510 default: 511 ret = -EINVAL; 512 break; 513 } 514 515 return ret; 516 } 517 518 static const struct pmbus_driver_info mp2891_info = { 519 .pages = MP2891_PAGE_NUM, 520 .format[PSC_VOLTAGE_IN] = direct, 521 .format[PSC_CURRENT_IN] = direct, 522 .format[PSC_CURRENT_OUT] = direct, 523 .format[PSC_TEMPERATURE] = direct, 524 .format[PSC_POWER] = direct, 525 .format[PSC_VOLTAGE_OUT] = direct, 526 527 /* set vin scale 31.25mV/Lsb */ 528 .m[PSC_VOLTAGE_IN] = 32, 529 .R[PSC_VOLTAGE_IN] = 0, 530 .b[PSC_VOLTAGE_IN] = 0, 531 532 /* set temp scale 1000m°C/Lsb */ 533 .m[PSC_TEMPERATURE] = 1, 534 .R[PSC_TEMPERATURE] = 0, 535 .b[PSC_TEMPERATURE] = 0, 536 537 .m[PSC_CURRENT_IN] = 1, 538 .R[PSC_CURRENT_IN] = 0, 539 .b[PSC_CURRENT_IN] = 0, 540 541 .m[PSC_CURRENT_OUT] = 1, 542 .R[PSC_CURRENT_OUT] = 0, 543 .b[PSC_CURRENT_OUT] = 0, 544 545 .m[PSC_POWER] = 1, 546 .R[PSC_POWER] = 0, 547 .b[PSC_POWER] = 0, 548 549 .m[PSC_VOLTAGE_OUT] = 1, 550 .R[PSC_VOLTAGE_OUT] = 3, 551 .b[PSC_VOLTAGE_OUT] = 0, 552 553 .func[0] = MP2891_RAIL1_FUNC, 554 .func[1] = MP2891_RAIL2_FUNC, 555 .read_word_data = mp2891_read_word_data, 556 .write_word_data = mp2891_write_word_data, 557 .read_byte_data = mp2891_read_byte_data, 558 .identify = mp2891_identify, 559 }; 560 561 static int mp2891_probe(struct i2c_client *client) 562 { 563 struct mp2891_data *data; 564 565 data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL); 566 if (!data) 567 return -ENOMEM; 568 569 memcpy(&data->info, &mp2891_info, sizeof(mp2891_info)); 570 571 return pmbus_do_probe(client, &data->info); 572 } 573 574 static const struct i2c_device_id mp2891_id[] = { 575 {"mp2891", 0}, 576 {} 577 }; 578 MODULE_DEVICE_TABLE(i2c, mp2891_id); 579 580 static const struct of_device_id __maybe_unused mp2891_of_match[] = { 581 {.compatible = "mps,mp2891"}, 582 {} 583 }; 584 MODULE_DEVICE_TABLE(of, mp2891_of_match); 585 586 static struct i2c_driver mp2891_driver = { 587 .driver = { 588 .name = "mp2891", 589 .of_match_table = mp2891_of_match, 590 }, 591 .probe = mp2891_probe, 592 .id_table = mp2891_id, 593 }; 594 595 module_i2c_driver(mp2891_driver); 596 597 MODULE_AUTHOR("Noah Wang <noahwang.wang@outlook.com>"); 598 MODULE_DESCRIPTION("PMBus driver for MPS MP2891"); 599 MODULE_LICENSE("GPL"); 600 MODULE_IMPORT_NS(PMBUS); 601