1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Synopsys DesignWare I2C adapter driver. 4 * 5 * Based on the TI DAVINCI I2C adapter driver. 6 * 7 * Copyright (C) 2006 Texas Instruments. 8 * Copyright (C) 2007 MontaVista Software Inc. 9 * Copyright (C) 2009 Provigent Ltd. 10 */ 11 #include <linux/acpi.h> 12 #include <linux/clk.h> 13 #include <linux/delay.h> 14 #include <linux/device.h> 15 #include <linux/err.h> 16 #include <linux/errno.h> 17 #include <linux/export.h> 18 #include <linux/i2c.h> 19 #include <linux/interrupt.h> 20 #include <linux/io.h> 21 #include <linux/kernel.h> 22 #include <linux/module.h> 23 #include <linux/pm_runtime.h> 24 #include <linux/regmap.h> 25 #include <linux/swab.h> 26 #include <linux/types.h> 27 #include <linux/units.h> 28 29 #include "i2c-designware-core.h" 30 31 static char *abort_sources[] = { 32 [ABRT_7B_ADDR_NOACK] = 33 "slave address not acknowledged (7bit mode)", 34 [ABRT_10ADDR1_NOACK] = 35 "first address byte not acknowledged (10bit mode)", 36 [ABRT_10ADDR2_NOACK] = 37 "second address byte not acknowledged (10bit mode)", 38 [ABRT_TXDATA_NOACK] = 39 "data not acknowledged", 40 [ABRT_GCALL_NOACK] = 41 "no acknowledgement for a general call", 42 [ABRT_GCALL_READ] = 43 "read after general call", 44 [ABRT_SBYTE_ACKDET] = 45 "start byte acknowledged", 46 [ABRT_SBYTE_NORSTRT] = 47 "trying to send start byte when restart is disabled", 48 [ABRT_10B_RD_NORSTRT] = 49 "trying to read when restart is disabled (10bit mode)", 50 [ABRT_MASTER_DIS] = 51 "trying to use disabled adapter", 52 [ARB_LOST] = 53 "lost arbitration", 54 [ABRT_SLAVE_FLUSH_TXFIFO] = 55 "read command so flush old data in the TX FIFO", 56 [ABRT_SLAVE_ARBLOST] = 57 "slave lost the bus while transmitting data to a remote master", 58 [ABRT_SLAVE_RD_INTX] = 59 "incorrect slave-transmitter mode configuration", 60 }; 61 62 static int dw_reg_read(void *context, unsigned int reg, unsigned int *val) 63 { 64 struct dw_i2c_dev *dev = context; 65 66 *val = readl_relaxed(dev->base + reg); 67 68 return 0; 69 } 70 71 static int dw_reg_write(void *context, unsigned int reg, unsigned int val) 72 { 73 struct dw_i2c_dev *dev = context; 74 75 writel_relaxed(val, dev->base + reg); 76 77 return 0; 78 } 79 80 static int dw_reg_read_swab(void *context, unsigned int reg, unsigned int *val) 81 { 82 struct dw_i2c_dev *dev = context; 83 84 *val = swab32(readl_relaxed(dev->base + reg)); 85 86 return 0; 87 } 88 89 static int dw_reg_write_swab(void *context, unsigned int reg, unsigned int val) 90 { 91 struct dw_i2c_dev *dev = context; 92 93 writel_relaxed(swab32(val), dev->base + reg); 94 95 return 0; 96 } 97 98 static int dw_reg_read_word(void *context, unsigned int reg, unsigned int *val) 99 { 100 struct dw_i2c_dev *dev = context; 101 102 *val = readw_relaxed(dev->base + reg) | 103 (readw_relaxed(dev->base + reg + 2) << 16); 104 105 return 0; 106 } 107 108 static int dw_reg_write_word(void *context, unsigned int reg, unsigned int val) 109 { 110 struct dw_i2c_dev *dev = context; 111 112 writew_relaxed(val, dev->base + reg); 113 writew_relaxed(val >> 16, dev->base + reg + 2); 114 115 return 0; 116 } 117 118 /** 119 * i2c_dw_init_regmap() - Initialize registers map 120 * @dev: device private data 121 * 122 * Autodetects needed register access mode and creates the regmap with 123 * corresponding read/write callbacks. This must be called before doing any 124 * other register access. 125 */ 126 int i2c_dw_init_regmap(struct dw_i2c_dev *dev) 127 { 128 struct regmap_config map_cfg = { 129 .reg_bits = 32, 130 .val_bits = 32, 131 .reg_stride = 4, 132 .disable_locking = true, 133 .reg_read = dw_reg_read, 134 .reg_write = dw_reg_write, 135 .max_register = DW_IC_COMP_TYPE, 136 }; 137 u32 reg; 138 int ret; 139 140 /* 141 * Skip detecting the registers map configuration if the regmap has 142 * already been provided by a higher code. 143 */ 144 if (dev->map) 145 return 0; 146 147 ret = i2c_dw_acquire_lock(dev); 148 if (ret) 149 return ret; 150 151 reg = readl(dev->base + DW_IC_COMP_TYPE); 152 i2c_dw_release_lock(dev); 153 154 if ((dev->flags & MODEL_MASK) == MODEL_AMD_NAVI_GPU) 155 map_cfg.max_register = AMD_UCSI_INTR_REG; 156 157 if (reg == swab32(DW_IC_COMP_TYPE_VALUE)) { 158 map_cfg.reg_read = dw_reg_read_swab; 159 map_cfg.reg_write = dw_reg_write_swab; 160 } else if (reg == (DW_IC_COMP_TYPE_VALUE & 0x0000ffff)) { 161 map_cfg.reg_read = dw_reg_read_word; 162 map_cfg.reg_write = dw_reg_write_word; 163 } else if (reg != DW_IC_COMP_TYPE_VALUE) { 164 dev_err(dev->dev, 165 "Unknown Synopsys component type: 0x%08x\n", reg); 166 return -ENODEV; 167 } 168 169 /* 170 * Note we'll check the return value of the regmap IO accessors only 171 * at the probe stage. The rest of the code won't do this because 172 * basically we have MMIO-based regmap so non of the read/write methods 173 * can fail. 174 */ 175 dev->map = devm_regmap_init(dev->dev, NULL, dev, &map_cfg); 176 if (IS_ERR(dev->map)) { 177 dev_err(dev->dev, "Failed to init the registers map\n"); 178 return PTR_ERR(dev->map); 179 } 180 181 return 0; 182 } 183 184 static const u32 supported_speeds[] = { 185 I2C_MAX_HIGH_SPEED_MODE_FREQ, 186 I2C_MAX_FAST_MODE_PLUS_FREQ, 187 I2C_MAX_FAST_MODE_FREQ, 188 I2C_MAX_STANDARD_MODE_FREQ, 189 }; 190 191 int i2c_dw_validate_speed(struct dw_i2c_dev *dev) 192 { 193 struct i2c_timings *t = &dev->timings; 194 unsigned int i; 195 196 /* 197 * Only standard mode at 100kHz, fast mode at 400kHz, 198 * fast mode plus at 1MHz and high speed mode at 3.4MHz are supported. 199 */ 200 for (i = 0; i < ARRAY_SIZE(supported_speeds); i++) { 201 if (t->bus_freq_hz == supported_speeds[i]) 202 return 0; 203 } 204 205 dev_err(dev->dev, 206 "%d Hz is unsupported, only 100kHz, 400kHz, 1MHz and 3.4MHz are supported\n", 207 t->bus_freq_hz); 208 209 return -EINVAL; 210 } 211 EXPORT_SYMBOL_GPL(i2c_dw_validate_speed); 212 213 #ifdef CONFIG_ACPI 214 215 #include <linux/dmi.h> 216 217 /* 218 * The HCNT/LCNT information coming from ACPI should be the most accurate 219 * for given platform. However, some systems get it wrong. On such systems 220 * we get better results by calculating those based on the input clock. 221 */ 222 static const struct dmi_system_id i2c_dw_no_acpi_params[] = { 223 { 224 .ident = "Dell Inspiron 7348", 225 .matches = { 226 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), 227 DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 7348"), 228 }, 229 }, 230 {} 231 }; 232 233 static void i2c_dw_acpi_params(struct device *device, char method[], 234 u16 *hcnt, u16 *lcnt, u32 *sda_hold) 235 { 236 struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER }; 237 acpi_handle handle = ACPI_HANDLE(device); 238 union acpi_object *obj; 239 240 if (dmi_check_system(i2c_dw_no_acpi_params)) 241 return; 242 243 if (ACPI_FAILURE(acpi_evaluate_object(handle, method, NULL, &buf))) 244 return; 245 246 obj = (union acpi_object *)buf.pointer; 247 if (obj->type == ACPI_TYPE_PACKAGE && obj->package.count == 3) { 248 const union acpi_object *objs = obj->package.elements; 249 250 *hcnt = (u16)objs[0].integer.value; 251 *lcnt = (u16)objs[1].integer.value; 252 *sda_hold = (u32)objs[2].integer.value; 253 } 254 255 kfree(buf.pointer); 256 } 257 258 int i2c_dw_acpi_configure(struct device *device) 259 { 260 struct dw_i2c_dev *dev = dev_get_drvdata(device); 261 struct i2c_timings *t = &dev->timings; 262 u32 ss_ht = 0, fp_ht = 0, hs_ht = 0, fs_ht = 0; 263 264 /* 265 * Try to get SDA hold time and *CNT values from an ACPI method for 266 * selected speed modes. 267 */ 268 i2c_dw_acpi_params(device, "SSCN", &dev->ss_hcnt, &dev->ss_lcnt, &ss_ht); 269 i2c_dw_acpi_params(device, "FMCN", &dev->fs_hcnt, &dev->fs_lcnt, &fs_ht); 270 i2c_dw_acpi_params(device, "FPCN", &dev->fp_hcnt, &dev->fp_lcnt, &fp_ht); 271 i2c_dw_acpi_params(device, "HSCN", &dev->hs_hcnt, &dev->hs_lcnt, &hs_ht); 272 273 switch (t->bus_freq_hz) { 274 case I2C_MAX_STANDARD_MODE_FREQ: 275 dev->sda_hold_time = ss_ht; 276 break; 277 case I2C_MAX_FAST_MODE_PLUS_FREQ: 278 dev->sda_hold_time = fp_ht; 279 break; 280 case I2C_MAX_HIGH_SPEED_MODE_FREQ: 281 dev->sda_hold_time = hs_ht; 282 break; 283 case I2C_MAX_FAST_MODE_FREQ: 284 default: 285 dev->sda_hold_time = fs_ht; 286 break; 287 } 288 289 return 0; 290 } 291 EXPORT_SYMBOL_GPL(i2c_dw_acpi_configure); 292 293 static u32 i2c_dw_acpi_round_bus_speed(struct device *device) 294 { 295 u32 acpi_speed; 296 int i; 297 298 acpi_speed = i2c_acpi_find_bus_speed(device); 299 /* 300 * Some DSTDs use a non standard speed, round down to the lowest 301 * standard speed. 302 */ 303 for (i = 0; i < ARRAY_SIZE(supported_speeds); i++) { 304 if (acpi_speed >= supported_speeds[i]) 305 return supported_speeds[i]; 306 } 307 308 return 0; 309 } 310 311 #else /* CONFIG_ACPI */ 312 313 static inline u32 i2c_dw_acpi_round_bus_speed(struct device *device) { return 0; } 314 315 #endif /* CONFIG_ACPI */ 316 317 void i2c_dw_adjust_bus_speed(struct dw_i2c_dev *dev) 318 { 319 u32 acpi_speed = i2c_dw_acpi_round_bus_speed(dev->dev); 320 struct i2c_timings *t = &dev->timings; 321 322 /* 323 * Find bus speed from the "clock-frequency" device property, ACPI 324 * or by using fast mode if neither is set. 325 */ 326 if (acpi_speed && t->bus_freq_hz) 327 t->bus_freq_hz = min(t->bus_freq_hz, acpi_speed); 328 else if (acpi_speed || t->bus_freq_hz) 329 t->bus_freq_hz = max(t->bus_freq_hz, acpi_speed); 330 else 331 t->bus_freq_hz = I2C_MAX_FAST_MODE_FREQ; 332 } 333 EXPORT_SYMBOL_GPL(i2c_dw_adjust_bus_speed); 334 335 u32 i2c_dw_scl_hcnt(u32 ic_clk, u32 tSYMBOL, u32 tf, int cond, int offset) 336 { 337 /* 338 * DesignWare I2C core doesn't seem to have solid strategy to meet 339 * the tHD;STA timing spec. Configuring _HCNT based on tHIGH spec 340 * will result in violation of the tHD;STA spec. 341 */ 342 if (cond) 343 /* 344 * Conditional expression: 345 * 346 * IC_[FS]S_SCL_HCNT + (1+4+3) >= IC_CLK * tHIGH 347 * 348 * This is based on the DW manuals, and represents an ideal 349 * configuration. The resulting I2C bus speed will be 350 * faster than any of the others. 351 * 352 * If your hardware is free from tHD;STA issue, try this one. 353 */ 354 return DIV_ROUND_CLOSEST_ULL((u64)ic_clk * tSYMBOL, MICRO) - 355 8 + offset; 356 else 357 /* 358 * Conditional expression: 359 * 360 * IC_[FS]S_SCL_HCNT + 3 >= IC_CLK * (tHD;STA + tf) 361 * 362 * This is just experimental rule; the tHD;STA period turned 363 * out to be proportinal to (_HCNT + 3). With this setting, 364 * we could meet both tHIGH and tHD;STA timing specs. 365 * 366 * If unsure, you'd better to take this alternative. 367 * 368 * The reason why we need to take into account "tf" here, 369 * is the same as described in i2c_dw_scl_lcnt(). 370 */ 371 return DIV_ROUND_CLOSEST_ULL((u64)ic_clk * (tSYMBOL + tf), MICRO) - 372 3 + offset; 373 } 374 375 u32 i2c_dw_scl_lcnt(u32 ic_clk, u32 tLOW, u32 tf, int offset) 376 { 377 /* 378 * Conditional expression: 379 * 380 * IC_[FS]S_SCL_LCNT + 1 >= IC_CLK * (tLOW + tf) 381 * 382 * DW I2C core starts counting the SCL CNTs for the LOW period 383 * of the SCL clock (tLOW) as soon as it pulls the SCL line. 384 * In order to meet the tLOW timing spec, we need to take into 385 * account the fall time of SCL signal (tf). Default tf value 386 * should be 0.3 us, for safety. 387 */ 388 return DIV_ROUND_CLOSEST_ULL((u64)ic_clk * (tLOW + tf), MICRO) - 389 1 + offset; 390 } 391 392 int i2c_dw_set_sda_hold(struct dw_i2c_dev *dev) 393 { 394 unsigned int reg; 395 int ret; 396 397 ret = i2c_dw_acquire_lock(dev); 398 if (ret) 399 return ret; 400 401 /* Configure SDA Hold Time if required */ 402 ret = regmap_read(dev->map, DW_IC_COMP_VERSION, ®); 403 if (ret) 404 goto err_release_lock; 405 406 if (reg >= DW_IC_SDA_HOLD_MIN_VERS) { 407 if (!dev->sda_hold_time) { 408 /* Keep previous hold time setting if no one set it */ 409 ret = regmap_read(dev->map, DW_IC_SDA_HOLD, 410 &dev->sda_hold_time); 411 if (ret) 412 goto err_release_lock; 413 } 414 415 /* 416 * Workaround for avoiding TX arbitration lost in case I2C 417 * slave pulls SDA down "too quickly" after falling edge of 418 * SCL by enabling non-zero SDA RX hold. Specification says it 419 * extends incoming SDA low to high transition while SCL is 420 * high but it appears to help also above issue. 421 */ 422 if (!(dev->sda_hold_time & DW_IC_SDA_HOLD_RX_MASK)) 423 dev->sda_hold_time |= 1 << DW_IC_SDA_HOLD_RX_SHIFT; 424 425 dev_dbg(dev->dev, "SDA Hold Time TX:RX = %d:%d\n", 426 dev->sda_hold_time & ~(u32)DW_IC_SDA_HOLD_RX_MASK, 427 dev->sda_hold_time >> DW_IC_SDA_HOLD_RX_SHIFT); 428 } else if (dev->set_sda_hold_time) { 429 dev->set_sda_hold_time(dev); 430 } else if (dev->sda_hold_time) { 431 dev_warn(dev->dev, 432 "Hardware too old to adjust SDA hold time.\n"); 433 dev->sda_hold_time = 0; 434 } 435 436 err_release_lock: 437 i2c_dw_release_lock(dev); 438 439 return ret; 440 } 441 442 void __i2c_dw_disable(struct dw_i2c_dev *dev) 443 { 444 int timeout = 100; 445 unsigned int status; 446 447 do { 448 __i2c_dw_disable_nowait(dev); 449 /* 450 * The enable status register may be unimplemented, but 451 * in that case this test reads zero and exits the loop. 452 */ 453 regmap_read(dev->map, DW_IC_ENABLE_STATUS, &status); 454 if ((status & 1) == 0) 455 return; 456 457 /* 458 * Wait 10 times the signaling period of the highest I2C 459 * transfer supported by the driver (for 400KHz this is 460 * 25us) as described in the DesignWare I2C databook. 461 */ 462 usleep_range(25, 250); 463 } while (timeout--); 464 465 dev_warn(dev->dev, "timeout in disabling adapter\n"); 466 } 467 468 u32 i2c_dw_clk_rate(struct dw_i2c_dev *dev) 469 { 470 /* 471 * Clock is not necessary if we got LCNT/HCNT values directly from 472 * the platform code. 473 */ 474 if (WARN_ON_ONCE(!dev->get_clk_rate_khz)) 475 return 0; 476 return dev->get_clk_rate_khz(dev); 477 } 478 479 int i2c_dw_prepare_clk(struct dw_i2c_dev *dev, bool prepare) 480 { 481 int ret; 482 483 if (prepare) { 484 /* Optional interface clock */ 485 ret = clk_prepare_enable(dev->pclk); 486 if (ret) 487 return ret; 488 489 ret = clk_prepare_enable(dev->clk); 490 if (ret) 491 clk_disable_unprepare(dev->pclk); 492 493 return ret; 494 } 495 496 clk_disable_unprepare(dev->clk); 497 clk_disable_unprepare(dev->pclk); 498 499 return 0; 500 } 501 EXPORT_SYMBOL_GPL(i2c_dw_prepare_clk); 502 503 int i2c_dw_acquire_lock(struct dw_i2c_dev *dev) 504 { 505 int ret; 506 507 if (!dev->acquire_lock) 508 return 0; 509 510 ret = dev->acquire_lock(); 511 if (!ret) 512 return 0; 513 514 dev_err(dev->dev, "couldn't acquire bus ownership\n"); 515 516 return ret; 517 } 518 519 void i2c_dw_release_lock(struct dw_i2c_dev *dev) 520 { 521 if (dev->release_lock) 522 dev->release_lock(); 523 } 524 525 /* 526 * Waiting for bus not busy 527 */ 528 int i2c_dw_wait_bus_not_busy(struct dw_i2c_dev *dev) 529 { 530 unsigned int status; 531 int ret; 532 533 ret = regmap_read_poll_timeout(dev->map, DW_IC_STATUS, status, 534 !(status & DW_IC_STATUS_ACTIVITY), 535 1100, 20000); 536 if (ret) { 537 dev_warn(dev->dev, "timeout waiting for bus ready\n"); 538 539 i2c_recover_bus(&dev->adapter); 540 541 regmap_read(dev->map, DW_IC_STATUS, &status); 542 if (!(status & DW_IC_STATUS_ACTIVITY)) 543 ret = 0; 544 } 545 546 return ret; 547 } 548 549 int i2c_dw_handle_tx_abort(struct dw_i2c_dev *dev) 550 { 551 unsigned long abort_source = dev->abort_source; 552 int i; 553 554 if (abort_source & DW_IC_TX_ABRT_NOACK) { 555 for_each_set_bit(i, &abort_source, ARRAY_SIZE(abort_sources)) 556 dev_dbg(dev->dev, 557 "%s: %s\n", __func__, abort_sources[i]); 558 return -EREMOTEIO; 559 } 560 561 for_each_set_bit(i, &abort_source, ARRAY_SIZE(abort_sources)) 562 dev_err(dev->dev, "%s: %s\n", __func__, abort_sources[i]); 563 564 if (abort_source & DW_IC_TX_ARB_LOST) 565 return -EAGAIN; 566 else if (abort_source & DW_IC_TX_ABRT_GCALL_READ) 567 return -EINVAL; /* wrong msgs[] data */ 568 else 569 return -EIO; 570 } 571 572 int i2c_dw_set_fifo_size(struct dw_i2c_dev *dev) 573 { 574 u32 tx_fifo_depth, rx_fifo_depth; 575 unsigned int param; 576 int ret; 577 578 /* 579 * Try to detect the FIFO depth if not set by interface driver, 580 * the depth could be from 2 to 256 from HW spec. 581 */ 582 ret = i2c_dw_acquire_lock(dev); 583 if (ret) 584 return ret; 585 586 ret = regmap_read(dev->map, DW_IC_COMP_PARAM_1, ¶m); 587 i2c_dw_release_lock(dev); 588 if (ret) 589 return ret; 590 591 tx_fifo_depth = ((param >> 16) & 0xff) + 1; 592 rx_fifo_depth = ((param >> 8) & 0xff) + 1; 593 if (!dev->tx_fifo_depth) { 594 dev->tx_fifo_depth = tx_fifo_depth; 595 dev->rx_fifo_depth = rx_fifo_depth; 596 } else if (tx_fifo_depth >= 2) { 597 dev->tx_fifo_depth = min_t(u32, dev->tx_fifo_depth, 598 tx_fifo_depth); 599 dev->rx_fifo_depth = min_t(u32, dev->rx_fifo_depth, 600 rx_fifo_depth); 601 } 602 603 return 0; 604 } 605 606 u32 i2c_dw_func(struct i2c_adapter *adap) 607 { 608 struct dw_i2c_dev *dev = i2c_get_adapdata(adap); 609 610 return dev->functionality; 611 } 612 613 void i2c_dw_disable(struct dw_i2c_dev *dev) 614 { 615 unsigned int dummy; 616 int ret; 617 618 ret = i2c_dw_acquire_lock(dev); 619 if (ret) 620 return; 621 622 /* Disable controller */ 623 __i2c_dw_disable(dev); 624 625 /* Disable all interrupts */ 626 regmap_write(dev->map, DW_IC_INTR_MASK, 0); 627 regmap_read(dev->map, DW_IC_CLR_INTR, &dummy); 628 629 i2c_dw_release_lock(dev); 630 } 631 632 MODULE_DESCRIPTION("Synopsys DesignWare I2C bus adapter core"); 633 MODULE_LICENSE("GPL"); 634