1 // SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0 2 /* 3 * Mellanox i2c driver 4 * 5 * Copyright (C) 2016-2020 Mellanox Technologies 6 */ 7 8 #include <linux/delay.h> 9 #include <linux/i2c.h> 10 #include <linux/init.h> 11 #include <linux/io.h> 12 #include <linux/kernel.h> 13 #include <linux/module.h> 14 #include <linux/platform_data/mlxreg.h> 15 #include <linux/platform_device.h> 16 #include <linux/regmap.h> 17 18 /* General defines */ 19 #define MLXPLAT_CPLD_LPC_I2C_BASE_ADDR 0x2000 20 #define MLXCPLD_I2C_DEVICE_NAME "i2c_mlxcpld" 21 #define MLXCPLD_I2C_VALID_FLAG (I2C_M_RECV_LEN | I2C_M_RD) 22 #define MLXCPLD_I2C_BUS_NUM 1 23 #define MLXCPLD_I2C_DATA_REG_SZ 36 24 #define MLXCPLD_I2C_DATA_SZ_BIT BIT(5) 25 #define MLXCPLD_I2C_DATA_SZ_MASK GENMASK(6, 5) 26 #define MLXCPLD_I2C_SMBUS_BLK_BIT BIT(7) 27 #define MLXCPLD_I2C_MAX_ADDR_LEN 4 28 #define MLXCPLD_I2C_RETR_NUM 2 29 #define MLXCPLD_I2C_XFER_TO 500000 /* usec */ 30 #define MLXCPLD_I2C_POLL_TIME 200 /* usec */ 31 32 /* LPC I2C registers */ 33 #define MLXCPLD_LPCI2C_CPBLTY_REG 0x0 34 #define MLXCPLD_LPCI2C_CTRL_REG 0x1 35 #define MLXCPLD_LPCI2C_HALF_CYC_REG 0x4 36 #define MLXCPLD_LPCI2C_I2C_HOLD_REG 0x5 37 #define MLXCPLD_LPCI2C_CMD_REG 0x6 38 #define MLXCPLD_LPCI2C_NUM_DAT_REG 0x7 39 #define MLXCPLD_LPCI2C_NUM_ADDR_REG 0x8 40 #define MLXCPLD_LPCI2C_STATUS_REG 0x9 41 #define MLXCPLD_LPCI2C_DATA_REG 0xa 42 43 /* LPC I2C masks and parameters */ 44 #define MLXCPLD_LPCI2C_RST_SEL_MASK 0x1 45 #define MLXCPLD_LPCI2C_TRANS_END 0x1 46 #define MLXCPLD_LPCI2C_STATUS_NACK 0x10 47 #define MLXCPLD_LPCI2C_NO_IND 0 48 #define MLXCPLD_LPCI2C_ACK_IND 1 49 #define MLXCPLD_LPCI2C_NACK_IND 2 50 51 #define MLXCPLD_I2C_FREQ_1000KHZ_SET 0x04 52 #define MLXCPLD_I2C_FREQ_400KHZ_SET 0x0e 53 #define MLXCPLD_I2C_FREQ_100KHZ_SET 0x42 54 55 enum mlxcpld_i2c_frequency { 56 MLXCPLD_I2C_FREQ_1000KHZ = 1, 57 MLXCPLD_I2C_FREQ_400KHZ = 2, 58 MLXCPLD_I2C_FREQ_100KHZ = 3, 59 }; 60 61 struct mlxcpld_i2c_curr_xfer { 62 u8 cmd; 63 u8 addr_width; 64 u8 data_len; 65 u8 msg_num; 66 struct i2c_msg *msg; 67 }; 68 69 struct mlxcpld_i2c_priv { 70 struct i2c_adapter adap; 71 u32 base_addr; 72 struct mutex lock; 73 struct mlxcpld_i2c_curr_xfer xfer; 74 struct device *dev; 75 bool smbus_block; 76 int polling_time; 77 }; 78 79 static void mlxcpld_i2c_lpc_write_buf(u8 *data, u8 len, u32 addr) 80 { 81 int i; 82 83 for (i = 0; i < len - len % 4; i += 4) 84 outl(*(u32 *)(data + i), addr + i); 85 for (; i < len; ++i) 86 outb(*(data + i), addr + i); 87 } 88 89 static void mlxcpld_i2c_lpc_read_buf(u8 *data, u8 len, u32 addr) 90 { 91 int i; 92 93 for (i = 0; i < len - len % 4; i += 4) 94 *(u32 *)(data + i) = inl(addr + i); 95 for (; i < len; ++i) 96 *(data + i) = inb(addr + i); 97 } 98 99 static void mlxcpld_i2c_read_comm(struct mlxcpld_i2c_priv *priv, u8 offs, 100 u8 *data, u8 datalen) 101 { 102 u32 addr = priv->base_addr + offs; 103 104 switch (datalen) { 105 case 1: 106 *(data) = inb(addr); 107 break; 108 case 2: 109 *((u16 *)data) = inw(addr); 110 break; 111 case 3: 112 *((u16 *)data) = inw(addr); 113 *(data + 2) = inb(addr + 2); 114 break; 115 case 4: 116 *((u32 *)data) = inl(addr); 117 break; 118 default: 119 mlxcpld_i2c_lpc_read_buf(data, datalen, addr); 120 break; 121 } 122 } 123 124 static void mlxcpld_i2c_write_comm(struct mlxcpld_i2c_priv *priv, u8 offs, 125 u8 *data, u8 datalen) 126 { 127 u32 addr = priv->base_addr + offs; 128 129 switch (datalen) { 130 case 1: 131 outb(*(data), addr); 132 break; 133 case 2: 134 outw(*((u16 *)data), addr); 135 break; 136 case 3: 137 outw(*((u16 *)data), addr); 138 outb(*(data + 2), addr + 2); 139 break; 140 case 4: 141 outl(*((u32 *)data), addr); 142 break; 143 default: 144 mlxcpld_i2c_lpc_write_buf(data, datalen, addr); 145 break; 146 } 147 } 148 149 /* 150 * Check validity of received i2c messages parameters. 151 * Returns 0 if OK, other - in case of invalid parameters. 152 */ 153 static int mlxcpld_i2c_check_msg_params(struct mlxcpld_i2c_priv *priv, 154 struct i2c_msg *msgs, int num) 155 { 156 int i; 157 158 if (!num) { 159 dev_err(priv->dev, "Incorrect 0 num of messages\n"); 160 return -EINVAL; 161 } 162 163 if (unlikely(msgs[0].addr > 0x7f)) { 164 dev_err(priv->dev, "Invalid address 0x%03x\n", 165 msgs[0].addr); 166 return -EINVAL; 167 } 168 169 for (i = 0; i < num; ++i) { 170 if (unlikely(!msgs[i].buf)) { 171 dev_err(priv->dev, "Invalid buf in msg[%d]\n", 172 i); 173 return -EINVAL; 174 } 175 if (unlikely(msgs[0].addr != msgs[i].addr)) { 176 dev_err(priv->dev, "Invalid addr in msg[%d]\n", 177 i); 178 return -EINVAL; 179 } 180 } 181 182 return 0; 183 } 184 185 /* 186 * Check if transfer is completed and status of operation. 187 * Returns 0 - transfer completed (both ACK or NACK), 188 * negative - transfer isn't finished. 189 */ 190 static int mlxcpld_i2c_check_status(struct mlxcpld_i2c_priv *priv, int *status) 191 { 192 u8 val; 193 194 mlxcpld_i2c_read_comm(priv, MLXCPLD_LPCI2C_STATUS_REG, &val, 1); 195 196 if (val & MLXCPLD_LPCI2C_TRANS_END) { 197 if (val & MLXCPLD_LPCI2C_STATUS_NACK) 198 /* 199 * The slave is unable to accept the data. No such 200 * slave, command not understood, or unable to accept 201 * any more data. 202 */ 203 *status = MLXCPLD_LPCI2C_NACK_IND; 204 else 205 *status = MLXCPLD_LPCI2C_ACK_IND; 206 return 0; 207 } 208 *status = MLXCPLD_LPCI2C_NO_IND; 209 210 return -EIO; 211 } 212 213 static void mlxcpld_i2c_set_transf_data(struct mlxcpld_i2c_priv *priv, 214 struct i2c_msg *msgs, int num, 215 u8 comm_len) 216 { 217 priv->xfer.msg = msgs; 218 priv->xfer.msg_num = num; 219 220 /* 221 * All upper layers currently are never use transfer with more than 222 * 2 messages. Actually, it's also not so relevant in Mellanox systems 223 * because of HW limitation. Max size of transfer is not more than 32 224 * or 68 bytes in the current x86 LPCI2C bridge. 225 */ 226 priv->xfer.cmd = msgs[num - 1].flags & I2C_M_RD; 227 228 if (priv->xfer.cmd == I2C_M_RD && comm_len != msgs[0].len) { 229 priv->xfer.addr_width = msgs[0].len; 230 priv->xfer.data_len = comm_len - priv->xfer.addr_width; 231 } else { 232 priv->xfer.addr_width = 0; 233 priv->xfer.data_len = comm_len; 234 } 235 } 236 237 /* Reset CPLD LPCI2C block */ 238 static void mlxcpld_i2c_reset(struct mlxcpld_i2c_priv *priv) 239 { 240 u8 val; 241 242 mutex_lock(&priv->lock); 243 244 mlxcpld_i2c_read_comm(priv, MLXCPLD_LPCI2C_CTRL_REG, &val, 1); 245 val &= ~MLXCPLD_LPCI2C_RST_SEL_MASK; 246 mlxcpld_i2c_write_comm(priv, MLXCPLD_LPCI2C_CTRL_REG, &val, 1); 247 248 mutex_unlock(&priv->lock); 249 } 250 251 /* Make sure the CPLD is ready to start transmitting. */ 252 static int mlxcpld_i2c_check_busy(struct mlxcpld_i2c_priv *priv) 253 { 254 u8 val; 255 256 mlxcpld_i2c_read_comm(priv, MLXCPLD_LPCI2C_STATUS_REG, &val, 1); 257 258 if (val & MLXCPLD_LPCI2C_TRANS_END) 259 return 0; 260 261 return -EIO; 262 } 263 264 static int mlxcpld_i2c_wait_for_free(struct mlxcpld_i2c_priv *priv) 265 { 266 int timeout = 0; 267 268 do { 269 if (!mlxcpld_i2c_check_busy(priv)) 270 break; 271 usleep_range(priv->polling_time / 2, priv->polling_time); 272 timeout += priv->polling_time; 273 } while (timeout <= MLXCPLD_I2C_XFER_TO); 274 275 if (timeout > MLXCPLD_I2C_XFER_TO) 276 return -ETIMEDOUT; 277 278 return 0; 279 } 280 281 /* 282 * Wait for master transfer to complete. 283 * It puts current process to sleep until we get interrupt or timeout expires. 284 * Returns the number of transferred or read bytes or error (<0). 285 */ 286 static int mlxcpld_i2c_wait_for_tc(struct mlxcpld_i2c_priv *priv) 287 { 288 int status, i, timeout = 0; 289 u8 datalen, val; 290 291 do { 292 usleep_range(priv->polling_time / 2, priv->polling_time); 293 if (!mlxcpld_i2c_check_status(priv, &status)) 294 break; 295 timeout += priv->polling_time; 296 } while (status == 0 && timeout < MLXCPLD_I2C_XFER_TO); 297 298 switch (status) { 299 case MLXCPLD_LPCI2C_NO_IND: 300 return -ETIMEDOUT; 301 302 case MLXCPLD_LPCI2C_ACK_IND: 303 if (priv->xfer.cmd != I2C_M_RD) 304 return (priv->xfer.addr_width + priv->xfer.data_len); 305 306 if (priv->xfer.msg_num == 1) 307 i = 0; 308 else 309 i = 1; 310 311 if (!priv->xfer.msg[i].buf) 312 return -EINVAL; 313 314 /* 315 * Actual read data len will be always the same as 316 * requested len. 0xff (line pull-up) will be returned 317 * if slave has no data to return. Thus don't read 318 * MLXCPLD_LPCI2C_NUM_DAT_REG reg from CPLD. Only in case of 319 * SMBus block read transaction data len can be different, 320 * check this case. 321 */ 322 mlxcpld_i2c_read_comm(priv, MLXCPLD_LPCI2C_NUM_ADDR_REG, &val, 323 1); 324 if (priv->smbus_block && (val & MLXCPLD_I2C_SMBUS_BLK_BIT)) { 325 mlxcpld_i2c_read_comm(priv, MLXCPLD_LPCI2C_NUM_DAT_REG, 326 &datalen, 1); 327 if (unlikely(datalen > I2C_SMBUS_BLOCK_MAX)) { 328 dev_err(priv->dev, "Incorrect smbus block read message len\n"); 329 return -EPROTO; 330 } 331 } else { 332 datalen = priv->xfer.data_len; 333 } 334 335 mlxcpld_i2c_read_comm(priv, MLXCPLD_LPCI2C_DATA_REG, 336 priv->xfer.msg[i].buf, datalen); 337 338 return datalen; 339 340 case MLXCPLD_LPCI2C_NACK_IND: 341 return -ENXIO; 342 343 default: 344 return -EINVAL; 345 } 346 } 347 348 static void mlxcpld_i2c_xfer_msg(struct mlxcpld_i2c_priv *priv) 349 { 350 int i, len = 0; 351 u8 cmd, val; 352 353 mlxcpld_i2c_write_comm(priv, MLXCPLD_LPCI2C_NUM_DAT_REG, 354 &priv->xfer.data_len, 1); 355 356 val = priv->xfer.addr_width; 357 /* Notify HW about SMBus block read transaction */ 358 if (priv->smbus_block && priv->xfer.msg_num >= 2 && 359 priv->xfer.msg[1].len == 1 && 360 (priv->xfer.msg[1].flags & I2C_M_RECV_LEN) && 361 (priv->xfer.msg[1].flags & I2C_M_RD)) 362 val |= MLXCPLD_I2C_SMBUS_BLK_BIT; 363 364 mlxcpld_i2c_write_comm(priv, MLXCPLD_LPCI2C_NUM_ADDR_REG, &val, 1); 365 366 for (i = 0; i < priv->xfer.msg_num; i++) { 367 if ((priv->xfer.msg[i].flags & I2C_M_RD) != I2C_M_RD) { 368 /* Don't write to CPLD buffer in read transaction */ 369 mlxcpld_i2c_write_comm(priv, MLXCPLD_LPCI2C_DATA_REG + 370 len, priv->xfer.msg[i].buf, 371 priv->xfer.msg[i].len); 372 len += priv->xfer.msg[i].len; 373 } 374 } 375 376 /* 377 * Set target slave address with command for master transfer. 378 * It should be latest executed function before CPLD transaction. 379 */ 380 cmd = (priv->xfer.msg[0].addr << 1) | priv->xfer.cmd; 381 mlxcpld_i2c_write_comm(priv, MLXCPLD_LPCI2C_CMD_REG, &cmd, 1); 382 } 383 384 /* 385 * Generic lpc-i2c transfer. 386 * Returns the number of processed messages or error (<0). 387 */ 388 static int mlxcpld_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, 389 int num) 390 { 391 struct mlxcpld_i2c_priv *priv = i2c_get_adapdata(adap); 392 u8 comm_len = 0; 393 int i, err; 394 395 err = mlxcpld_i2c_check_msg_params(priv, msgs, num); 396 if (err) { 397 dev_err(priv->dev, "Incorrect message\n"); 398 return err; 399 } 400 401 for (i = 0; i < num; ++i) 402 comm_len += msgs[i].len; 403 404 /* Check bus state */ 405 if (mlxcpld_i2c_wait_for_free(priv)) { 406 dev_err(priv->dev, "LPCI2C bridge is busy\n"); 407 408 /* 409 * Usually it means something serious has happened. 410 * We can not have unfinished previous transfer 411 * so it doesn't make any sense to try to stop it. 412 * Probably we were not able to recover from the 413 * previous error. 414 * The only reasonable thing - is soft reset. 415 */ 416 mlxcpld_i2c_reset(priv); 417 if (mlxcpld_i2c_check_busy(priv)) { 418 dev_err(priv->dev, "LPCI2C bridge is busy after reset\n"); 419 return -EIO; 420 } 421 } 422 423 mlxcpld_i2c_set_transf_data(priv, msgs, num, comm_len); 424 425 mutex_lock(&priv->lock); 426 427 /* Do real transfer. Can't fail */ 428 mlxcpld_i2c_xfer_msg(priv); 429 430 /* Wait for transaction complete */ 431 err = mlxcpld_i2c_wait_for_tc(priv); 432 433 mutex_unlock(&priv->lock); 434 435 return err < 0 ? err : num; 436 } 437 438 static u32 mlxcpld_i2c_func(struct i2c_adapter *adap) 439 { 440 struct mlxcpld_i2c_priv *priv = i2c_get_adapdata(adap); 441 442 if (priv->smbus_block) 443 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | 444 I2C_FUNC_SMBUS_I2C_BLOCK | I2C_FUNC_SMBUS_BLOCK_DATA; 445 else 446 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | 447 I2C_FUNC_SMBUS_I2C_BLOCK; 448 } 449 450 static const struct i2c_algorithm mlxcpld_i2c_algo = { 451 .master_xfer = mlxcpld_i2c_xfer, 452 .functionality = mlxcpld_i2c_func 453 }; 454 455 static const struct i2c_adapter_quirks mlxcpld_i2c_quirks = { 456 .flags = I2C_AQ_COMB_WRITE_THEN_READ, 457 .max_read_len = MLXCPLD_I2C_DATA_REG_SZ - MLXCPLD_I2C_MAX_ADDR_LEN, 458 .max_write_len = MLXCPLD_I2C_DATA_REG_SZ, 459 .max_comb_1st_msg_len = 4, 460 }; 461 462 static const struct i2c_adapter_quirks mlxcpld_i2c_quirks_ext = { 463 .flags = I2C_AQ_COMB_WRITE_THEN_READ, 464 .max_read_len = MLXCPLD_I2C_DATA_REG_SZ * 2 - MLXCPLD_I2C_MAX_ADDR_LEN, 465 .max_write_len = MLXCPLD_I2C_DATA_REG_SZ * 2, 466 .max_comb_1st_msg_len = 4, 467 }; 468 469 static struct i2c_adapter mlxcpld_i2c_adapter = { 470 .owner = THIS_MODULE, 471 .name = "i2c-mlxcpld", 472 .class = I2C_CLASS_HWMON | I2C_CLASS_SPD, 473 .algo = &mlxcpld_i2c_algo, 474 .quirks = &mlxcpld_i2c_quirks, 475 .retries = MLXCPLD_I2C_RETR_NUM, 476 .nr = MLXCPLD_I2C_BUS_NUM, 477 }; 478 479 static int 480 mlxcpld_i2c_set_frequency(struct mlxcpld_i2c_priv *priv, 481 struct mlxreg_core_hotplug_platform_data *pdata) 482 { 483 struct mlxreg_core_item *item = pdata->items; 484 struct mlxreg_core_data *data; 485 u32 regval; 486 u8 freq; 487 int err; 488 489 if (!item) 490 return 0; 491 492 /* Read frequency setting. */ 493 data = item->data; 494 err = regmap_read(pdata->regmap, data->reg, ®val); 495 if (err) 496 return err; 497 498 /* Set frequency only if it is not 100KHz, which is default. */ 499 switch ((regval & data->mask) >> data->bit) { 500 case MLXCPLD_I2C_FREQ_1000KHZ: 501 freq = MLXCPLD_I2C_FREQ_1000KHZ_SET; 502 priv->polling_time /= 4; 503 break; 504 case MLXCPLD_I2C_FREQ_400KHZ: 505 freq = MLXCPLD_I2C_FREQ_400KHZ_SET; 506 priv->polling_time /= 4; 507 break; 508 default: 509 return 0; 510 } 511 512 mlxcpld_i2c_write_comm(priv, MLXCPLD_LPCI2C_HALF_CYC_REG, &freq, 1); 513 514 return 0; 515 } 516 517 static int mlxcpld_i2c_probe(struct platform_device *pdev) 518 { 519 struct mlxreg_core_hotplug_platform_data *pdata; 520 struct mlxcpld_i2c_priv *priv; 521 int err; 522 u8 val; 523 524 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); 525 if (!priv) 526 return -ENOMEM; 527 528 mutex_init(&priv->lock); 529 platform_set_drvdata(pdev, priv); 530 531 priv->dev = &pdev->dev; 532 priv->base_addr = MLXPLAT_CPLD_LPC_I2C_BASE_ADDR; 533 priv->polling_time = MLXCPLD_I2C_POLL_TIME; 534 535 /* Set I2C bus frequency if platform data provides this info. */ 536 pdata = dev_get_platdata(&pdev->dev); 537 if (pdata) { 538 err = mlxcpld_i2c_set_frequency(priv, pdata); 539 if (err) 540 goto mlxcpld_i2_probe_failed; 541 } 542 543 /* Register with i2c layer */ 544 mlxcpld_i2c_adapter.timeout = usecs_to_jiffies(MLXCPLD_I2C_XFER_TO); 545 /* Read capability register */ 546 mlxcpld_i2c_read_comm(priv, MLXCPLD_LPCI2C_CPBLTY_REG, &val, 1); 547 /* Check support for extended transaction length */ 548 if ((val & MLXCPLD_I2C_DATA_SZ_MASK) == MLXCPLD_I2C_DATA_SZ_BIT) 549 mlxcpld_i2c_adapter.quirks = &mlxcpld_i2c_quirks_ext; 550 /* Check support for smbus block transaction */ 551 if (val & MLXCPLD_I2C_SMBUS_BLK_BIT) 552 priv->smbus_block = true; 553 if (pdev->id >= -1) 554 mlxcpld_i2c_adapter.nr = pdev->id; 555 priv->adap = mlxcpld_i2c_adapter; 556 priv->adap.dev.parent = &pdev->dev; 557 i2c_set_adapdata(&priv->adap, priv); 558 559 err = i2c_add_numbered_adapter(&priv->adap); 560 if (err) 561 goto mlxcpld_i2_probe_failed; 562 563 /* Notify caller when adapter is added. */ 564 if (pdata && pdata->completion_notify) 565 pdata->completion_notify(pdata->handle, mlxcpld_i2c_adapter.nr); 566 567 return 0; 568 569 mlxcpld_i2_probe_failed: 570 mutex_destroy(&priv->lock); 571 return err; 572 } 573 574 static int mlxcpld_i2c_remove(struct platform_device *pdev) 575 { 576 struct mlxcpld_i2c_priv *priv = platform_get_drvdata(pdev); 577 578 i2c_del_adapter(&priv->adap); 579 mutex_destroy(&priv->lock); 580 581 return 0; 582 } 583 584 static struct platform_driver mlxcpld_i2c_driver = { 585 .probe = mlxcpld_i2c_probe, 586 .remove = mlxcpld_i2c_remove, 587 .driver = { 588 .name = MLXCPLD_I2C_DEVICE_NAME, 589 }, 590 }; 591 592 module_platform_driver(mlxcpld_i2c_driver); 593 594 MODULE_AUTHOR("Michael Shych <michaels@mellanox.com>"); 595 MODULE_DESCRIPTION("Mellanox I2C-CPLD controller driver"); 596 MODULE_LICENSE("Dual BSD/GPL"); 597 MODULE_ALIAS("platform:i2c-mlxcpld"); 598