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 31static 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 62static int dw_reg_read(void *context, unsigned int reg, unsigned int *val) 63{ 64 struct dw_i2c_dev *dev = context; 65 66 *val = readl(dev->base + reg); 67 68 return 0; 69} 70 71static int dw_reg_write(void *context, unsigned int reg, unsigned int val) 72{ 73 struct dw_i2c_dev *dev = context; 74 75 writel(val, dev->base + reg); 76 77 return 0; 78} 79 80static 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(dev->base + reg)); 85 86 return 0; 87} 88 89static int dw_reg_write_swab(void *context, unsigned int reg, unsigned int val) 90{ 91 struct dw_i2c_dev *dev = context; 92 93 writel(swab32(val), dev->base + reg); 94 95 return 0; 96} 97 98static 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(dev->base + reg) | 103 (readw(dev->base + reg + 2) << 16); 104 105 return 0; 106} 107 108static int dw_reg_write_word(void *context, unsigned int reg, unsigned int val) 109{ 110 struct dw_i2c_dev *dev = context; 111 112 writew(val, dev->base + reg); 113 writew(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 */ 126int 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 (reg == swab32(DW_IC_COMP_TYPE_VALUE)) { 155 map_cfg.reg_read = dw_reg_read_swab; 156 map_cfg.reg_write = dw_reg_write_swab; 157 } else if (reg == (DW_IC_COMP_TYPE_VALUE & 0x0000ffff)) { 158 map_cfg.reg_read = dw_reg_read_word; 159 map_cfg.reg_write = dw_reg_write_word; 160 } else if (reg != DW_IC_COMP_TYPE_VALUE) { 161 dev_err(dev->dev, 162 "Unknown Synopsys component type: 0x%08x\n", reg); 163 return -ENODEV; 164 } 165 166 /* 167 * Note we'll check the return value of the regmap IO accessors only 168 * at the probe stage. The rest of the code won't do this because 169 * basically we have MMIO-based regmap so non of the read/write methods 170 * can fail. 171 */ 172 dev->map = devm_regmap_init(dev->dev, NULL, dev, &map_cfg); 173 if (IS_ERR(dev->map)) { 174 dev_err(dev->dev, "Failed to init the registers map\n"); 175 return PTR_ERR(dev->map); 176 } 177 178 return 0; 179} 180 181static const u32 supported_speeds[] = { 182 I2C_MAX_HIGH_SPEED_MODE_FREQ, 183 I2C_MAX_FAST_MODE_PLUS_FREQ, 184 I2C_MAX_FAST_MODE_FREQ, 185 I2C_MAX_STANDARD_MODE_FREQ, 186}; 187 188int i2c_dw_validate_speed(struct dw_i2c_dev *dev) 189{ 190 struct i2c_timings *t = &dev->timings; 191 unsigned int i; 192 193 /* 194 * Only standard mode at 100kHz, fast mode at 400kHz, 195 * fast mode plus at 1MHz and high speed mode at 3.4MHz are supported. 196 */ 197 for (i = 0; i < ARRAY_SIZE(supported_speeds); i++) { 198 if (t->bus_freq_hz == supported_speeds[i]) 199 return 0; 200 } 201 202 dev_err(dev->dev, 203 "%d Hz is unsupported, only 100kHz, 400kHz, 1MHz and 3.4MHz are supported\n", 204 t->bus_freq_hz); 205 206 return -EINVAL; 207} 208EXPORT_SYMBOL_GPL(i2c_dw_validate_speed); 209 210#ifdef CONFIG_ACPI 211 212#include <linux/dmi.h> 213 214/* 215 * The HCNT/LCNT information coming from ACPI should be the most accurate 216 * for given platform. However, some systems get it wrong. On such systems 217 * we get better results by calculating those based on the input clock. 218 */ 219static const struct dmi_system_id i2c_dw_no_acpi_params[] = { 220 { 221 .ident = "Dell Inspiron 7348", 222 .matches = { 223 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), 224 DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 7348"), 225 }, 226 }, 227 {} 228}; 229 230static void i2c_dw_acpi_params(struct device *device, char method[], 231 u16 *hcnt, u16 *lcnt, u32 *sda_hold) 232{ 233 struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER }; 234 acpi_handle handle = ACPI_HANDLE(device); 235 union acpi_object *obj; 236 237 if (dmi_check_system(i2c_dw_no_acpi_params)) 238 return; 239 240 if (ACPI_FAILURE(acpi_evaluate_object(handle, method, NULL, &buf))) 241 return; 242 243 obj = (union acpi_object *)buf.pointer; 244 if (obj->type == ACPI_TYPE_PACKAGE && obj->package.count == 3) { 245 const union acpi_object *objs = obj->package.elements; 246 247 *hcnt = (u16)objs[0].integer.value; 248 *lcnt = (u16)objs[1].integer.value; 249 *sda_hold = (u32)objs[2].integer.value; 250 } 251 252 kfree(buf.pointer); 253} 254 255int i2c_dw_acpi_configure(struct device *device) 256{ 257 struct dw_i2c_dev *dev = dev_get_drvdata(device); 258 struct i2c_timings *t = &dev->timings; 259 u32 ss_ht = 0, fp_ht = 0, hs_ht = 0, fs_ht = 0; 260 261 /* 262 * Try to get SDA hold time and *CNT values from an ACPI method for 263 * selected speed modes. 264 */ 265 i2c_dw_acpi_params(device, "SSCN", &dev->ss_hcnt, &dev->ss_lcnt, &ss_ht); 266 i2c_dw_acpi_params(device, "FPCN", &dev->fp_hcnt, &dev->fp_lcnt, &fp_ht); 267 i2c_dw_acpi_params(device, "HSCN", &dev->hs_hcnt, &dev->hs_lcnt, &hs_ht); 268 i2c_dw_acpi_params(device, "FMCN", &dev->fs_hcnt, &dev->fs_lcnt, &fs_ht); 269 270 switch (t->bus_freq_hz) { 271 case I2C_MAX_STANDARD_MODE_FREQ: 272 dev->sda_hold_time = ss_ht; 273 break; 274 case I2C_MAX_FAST_MODE_PLUS_FREQ: 275 dev->sda_hold_time = fp_ht; 276 break; 277 case I2C_MAX_HIGH_SPEED_MODE_FREQ: 278 dev->sda_hold_time = hs_ht; 279 break; 280 case I2C_MAX_FAST_MODE_FREQ: 281 default: 282 dev->sda_hold_time = fs_ht; 283 break; 284 } 285 286 return 0; 287} 288EXPORT_SYMBOL_GPL(i2c_dw_acpi_configure); 289 290static u32 i2c_dw_acpi_round_bus_speed(struct device *device) 291{ 292 u32 acpi_speed; 293 int i; 294 295 acpi_speed = i2c_acpi_find_bus_speed(device); 296 /* 297 * Some DSTDs use a non standard speed, round down to the lowest 298 * standard speed. 299 */ 300 for (i = 0; i < ARRAY_SIZE(supported_speeds); i++) { 301 if (acpi_speed >= supported_speeds[i]) 302 return supported_speeds[i]; 303 } 304 305 return 0; 306} 307 308#else /* CONFIG_ACPI */ 309 310static inline u32 i2c_dw_acpi_round_bus_speed(struct device *device) { return 0; } 311 312#endif /* CONFIG_ACPI */ 313 314void i2c_dw_adjust_bus_speed(struct dw_i2c_dev *dev) 315{ 316 u32 acpi_speed = i2c_dw_acpi_round_bus_speed(dev->dev); 317 struct i2c_timings *t = &dev->timings; 318 319 /* 320 * Find bus speed from the "clock-frequency" device property, ACPI 321 * or by using fast mode if neither is set. 322 */ 323 if (acpi_speed && t->bus_freq_hz) 324 t->bus_freq_hz = min(t->bus_freq_hz, acpi_speed); 325 else if (acpi_speed || t->bus_freq_hz) 326 t->bus_freq_hz = max(t->bus_freq_hz, acpi_speed); 327 else 328 t->bus_freq_hz = I2C_MAX_FAST_MODE_FREQ; 329} 330EXPORT_SYMBOL_GPL(i2c_dw_adjust_bus_speed); 331 332u32 i2c_dw_scl_hcnt(u32 ic_clk, u32 tSYMBOL, u32 tf, int cond, int offset) 333{ 334 /* 335 * DesignWare I2C core doesn't seem to have solid strategy to meet 336 * the tHD;STA timing spec. Configuring _HCNT based on tHIGH spec 337 * will result in violation of the tHD;STA spec. 338 */ 339 if (cond) 340 /* 341 * Conditional expression: 342 * 343 * IC_[FS]S_SCL_HCNT + (1+4+3) >= IC_CLK * tHIGH 344 * 345 * This is based on the DW manuals, and represents an ideal 346 * configuration. The resulting I2C bus speed will be 347 * faster than any of the others. 348 * 349 * If your hardware is free from tHD;STA issue, try this one. 350 */ 351 return DIV_ROUND_CLOSEST_ULL((u64)ic_clk * tSYMBOL, MICRO) - 352 8 + offset; 353 else 354 /* 355 * Conditional expression: 356 * 357 * IC_[FS]S_SCL_HCNT + 3 >= IC_CLK * (tHD;STA + tf) 358 * 359 * This is just experimental rule; the tHD;STA period turned 360 * out to be proportinal to (_HCNT + 3). With this setting, 361 * we could meet both tHIGH and tHD;STA timing specs. 362 * 363 * If unsure, you'd better to take this alternative. 364 * 365 * The reason why we need to take into account "tf" here, 366 * is the same as described in i2c_dw_scl_lcnt(). 367 */ 368 return DIV_ROUND_CLOSEST_ULL((u64)ic_clk * (tSYMBOL + tf), MICRO) - 369 3 + offset; 370} 371 372u32 i2c_dw_scl_lcnt(u32 ic_clk, u32 tLOW, u32 tf, int offset) 373{ 374 /* 375 * Conditional expression: 376 * 377 * IC_[FS]S_SCL_LCNT + 1 >= IC_CLK * (tLOW + tf) 378 * 379 * DW I2C core starts counting the SCL CNTs for the LOW period 380 * of the SCL clock (tLOW) as soon as it pulls the SCL line. 381 * In order to meet the tLOW timing spec, we need to take into 382 * account the fall time of SCL signal (tf). Default tf value 383 * should be 0.3 us, for safety. 384 */ 385 return DIV_ROUND_CLOSEST_ULL((u64)ic_clk * (tLOW + tf), MICRO) - 386 1 + offset; 387} 388 389int i2c_dw_set_sda_hold(struct dw_i2c_dev *dev) 390{ 391 u32 reg; 392 int ret; 393 394 ret = i2c_dw_acquire_lock(dev); 395 if (ret) 396 return ret; 397 398 /* Configure SDA Hold Time if required */ 399 ret = regmap_read(dev->map, DW_IC_COMP_VERSION, ®); 400 if (ret) 401 goto err_release_lock; 402 403 if (reg >= DW_IC_SDA_HOLD_MIN_VERS) { 404 if (!dev->sda_hold_time) { 405 /* Keep previous hold time setting if no one set it */ 406 ret = regmap_read(dev->map, DW_IC_SDA_HOLD, 407 &dev->sda_hold_time); 408 if (ret) 409 goto err_release_lock; 410 } 411 412 /* 413 * Workaround for avoiding TX arbitration lost in case I2C 414 * slave pulls SDA down "too quickly" after falling edge of 415 * SCL by enabling non-zero SDA RX hold. Specification says it 416 * extends incoming SDA low to high transition while SCL is 417 * high but it appears to help also above issue. 418 */ 419 if (!(dev->sda_hold_time & DW_IC_SDA_HOLD_RX_MASK)) 420 dev->sda_hold_time |= 1 << DW_IC_SDA_HOLD_RX_SHIFT; 421 422 dev_dbg(dev->dev, "SDA Hold Time TX:RX = %d:%d\n", 423 dev->sda_hold_time & ~(u32)DW_IC_SDA_HOLD_RX_MASK, 424 dev->sda_hold_time >> DW_IC_SDA_HOLD_RX_SHIFT); 425 } else if (dev->set_sda_hold_time) { 426 dev->set_sda_hold_time(dev); 427 } else if (dev->sda_hold_time) { 428 dev_warn(dev->dev, 429 "Hardware too old to adjust SDA hold time.\n"); 430 dev->sda_hold_time = 0; 431 } 432 433err_release_lock: 434 i2c_dw_release_lock(dev); 435 436 return ret; 437} 438 439void __i2c_dw_disable(struct dw_i2c_dev *dev) 440{ 441 int timeout = 100; 442 u32 status; 443 444 do { 445 __i2c_dw_disable_nowait(dev); 446 /* 447 * The enable status register may be unimplemented, but 448 * in that case this test reads zero and exits the loop. 449 */ 450 regmap_read(dev->map, DW_IC_ENABLE_STATUS, &status); 451 if ((status & 1) == 0) 452 return; 453 454 /* 455 * Wait 10 times the signaling period of the highest I2C 456 * transfer supported by the driver (for 400KHz this is 457 * 25us) as described in the DesignWare I2C databook. 458 */ 459 usleep_range(25, 250); 460 } while (timeout--); 461 462 dev_warn(dev->dev, "timeout in disabling adapter\n"); 463} 464 465unsigned long i2c_dw_clk_rate(struct dw_i2c_dev *dev) 466{ 467 /* 468 * Clock is not necessary if we got LCNT/HCNT values directly from 469 * the platform code. 470 */ 471 if (WARN_ON_ONCE(!dev->get_clk_rate_khz)) 472 return 0; 473 return dev->get_clk_rate_khz(dev); 474} 475 476int i2c_dw_prepare_clk(struct dw_i2c_dev *dev, bool prepare) 477{ 478 int ret; 479 480 if (prepare) { 481 /* Optional interface clock */ 482 ret = clk_prepare_enable(dev->pclk); 483 if (ret) 484 return ret; 485 486 ret = clk_prepare_enable(dev->clk); 487 if (ret) 488 clk_disable_unprepare(dev->pclk); 489 490 return ret; 491 } 492 493 clk_disable_unprepare(dev->clk); 494 clk_disable_unprepare(dev->pclk); 495 496 return 0; 497} 498EXPORT_SYMBOL_GPL(i2c_dw_prepare_clk); 499 500int i2c_dw_acquire_lock(struct dw_i2c_dev *dev) 501{ 502 int ret; 503 504 if (!dev->acquire_lock) 505 return 0; 506 507 ret = dev->acquire_lock(); 508 if (!ret) 509 return 0; 510 511 dev_err(dev->dev, "couldn't acquire bus ownership\n"); 512 513 return ret; 514} 515 516void i2c_dw_release_lock(struct dw_i2c_dev *dev) 517{ 518 if (dev->release_lock) 519 dev->release_lock(); 520} 521 522/* 523 * Waiting for bus not busy 524 */ 525int i2c_dw_wait_bus_not_busy(struct dw_i2c_dev *dev) 526{ 527 u32 status; 528 int ret; 529 530 ret = regmap_read_poll_timeout(dev->map, DW_IC_STATUS, status, 531 !(status & DW_IC_STATUS_ACTIVITY), 532 1100, 20000); 533 if (ret) { 534 dev_warn(dev->dev, "timeout waiting for bus ready\n"); 535 536 i2c_recover_bus(&dev->adapter); 537 538 regmap_read(dev->map, DW_IC_STATUS, &status); 539 if (!(status & DW_IC_STATUS_ACTIVITY)) 540 ret = 0; 541 } 542 543 return ret; 544} 545 546int i2c_dw_handle_tx_abort(struct dw_i2c_dev *dev) 547{ 548 unsigned long abort_source = dev->abort_source; 549 int i; 550 551 if (abort_source & DW_IC_TX_ABRT_NOACK) { 552 for_each_set_bit(i, &abort_source, ARRAY_SIZE(abort_sources)) 553 dev_dbg(dev->dev, 554 "%s: %s\n", __func__, abort_sources[i]); 555 return -EREMOTEIO; 556 } 557 558 for_each_set_bit(i, &abort_source, ARRAY_SIZE(abort_sources)) 559 dev_err(dev->dev, "%s: %s\n", __func__, abort_sources[i]); 560 561 if (abort_source & DW_IC_TX_ARB_LOST) 562 return -EAGAIN; 563 else if (abort_source & DW_IC_TX_ABRT_GCALL_READ) 564 return -EINVAL; /* wrong msgs[] data */ 565 else 566 return -EIO; 567} 568 569int i2c_dw_set_fifo_size(struct dw_i2c_dev *dev) 570{ 571 u32 param, tx_fifo_depth, rx_fifo_depth; 572 int ret; 573 574 /* 575 * Try to detect the FIFO depth if not set by interface driver, 576 * the depth could be from 2 to 256 from HW spec. 577 */ 578 ret = regmap_read(dev->map, DW_IC_COMP_PARAM_1, ¶m); 579 if (ret) 580 return ret; 581 582 tx_fifo_depth = ((param >> 16) & 0xff) + 1; 583 rx_fifo_depth = ((param >> 8) & 0xff) + 1; 584 if (!dev->tx_fifo_depth) { 585 dev->tx_fifo_depth = tx_fifo_depth; 586 dev->rx_fifo_depth = rx_fifo_depth; 587 } else if (tx_fifo_depth >= 2) { 588 dev->tx_fifo_depth = min_t(u32, dev->tx_fifo_depth, 589 tx_fifo_depth); 590 dev->rx_fifo_depth = min_t(u32, dev->rx_fifo_depth, 591 rx_fifo_depth); 592 } 593 594 return 0; 595} 596 597u32 i2c_dw_func(struct i2c_adapter *adap) 598{ 599 struct dw_i2c_dev *dev = i2c_get_adapdata(adap); 600 601 return dev->functionality; 602} 603 604void i2c_dw_disable(struct dw_i2c_dev *dev) 605{ 606 u32 dummy; 607 608 /* Disable controller */ 609 __i2c_dw_disable(dev); 610 611 /* Disable all interrupts */ 612 regmap_write(dev->map, DW_IC_INTR_MASK, 0); 613 regmap_read(dev->map, DW_IC_CLR_INTR, &dummy); 614} 615 616void i2c_dw_disable_int(struct dw_i2c_dev *dev) 617{ 618 regmap_write(dev->map, DW_IC_INTR_MASK, 0); 619} 620 621MODULE_DESCRIPTION("Synopsys DesignWare I2C bus adapter core"); 622MODULE_LICENSE("GPL"); 623