drivers/i2c/busses/i2c-designware-common.c

   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
  28 #include "i2c-designware-core.h"
  29
  30 static char *abort_sources[] = {
  31         [ABRT_7B_ADDR_NOACK] =
  32                 "slave address not acknowledged (7bit mode)",
  33         [ABRT_10ADDR1_NOACK] =
  34                 "first address byte not acknowledged (10bit mode)",
  35         [ABRT_10ADDR2_NOACK] =
  36                 "second address byte not acknowledged (10bit mode)",
  37         [ABRT_TXDATA_NOACK] =
  38                 "data not acknowledged",
  39         [ABRT_GCALL_NOACK] =
  40                 "no acknowledgement for a general call",
  41         [ABRT_GCALL_READ] =
  42                 "read after general call",
  43         [ABRT_SBYTE_ACKDET] =
  44                 "start byte acknowledged",
  45         [ABRT_SBYTE_NORSTRT] =
  46                 "trying to send start byte when restart is disabled",
  47         [ABRT_10B_RD_NORSTRT] =
  48                 "trying to read when restart is disabled (10bit mode)",
  49         [ABRT_MASTER_DIS] =
  50                 "trying to use disabled adapter",
  51         [ARB_LOST] =
  52                 "lost arbitration",
  53         [ABRT_SLAVE_FLUSH_TXFIFO] =
  54                 "read command so flush old data in the TX FIFO",
  55         [ABRT_SLAVE_ARBLOST] =
  56                 "slave lost the bus while transmitting data to a remote master",
  57         [ABRT_SLAVE_RD_INTX] =
  58                 "incorrect slave-transmitter mode configuration",
  59 };
  60
  61 static int dw_reg_read(void *context, unsigned int reg, unsigned int *val)
  62 {
  63         struct dw_i2c_dev *dev = context;
  64
  65         *val = readl_relaxed(dev->base + reg);
  66
  67         return 0;
  68 }
  69
  70 static int dw_reg_write(void *context, unsigned int reg, unsigned int val)
  71 {
  72         struct dw_i2c_dev *dev = context;
  73
  74         writel_relaxed(val, dev->base + reg);
  75
  76         return 0;
  77 }
  78
  79 static int dw_reg_read_swab(void *context, unsigned int reg, unsigned int *val)
  80 {
  81         struct dw_i2c_dev *dev = context;
  82
  83         *val = swab32(readl_relaxed(dev->base + reg));
  84
  85         return 0;
  86 }
  87
  88 static int dw_reg_write_swab(void *context, unsigned int reg, unsigned int val)
  89 {
  90         struct dw_i2c_dev *dev = context;
  91
  92         writel_relaxed(swab32(val), dev->base + reg);
  93
  94         return 0;
  95 }
  96
  97 static int dw_reg_read_word(void *context, unsigned int reg, unsigned int *val)
  98 {
  99         struct dw_i2c_dev *dev = context;
 100
 101         *val = readw_relaxed(dev->base + reg) |
 102                 (readw_relaxed(dev->base + reg + 2) << 16);
 103
 104         return 0;
 105 }
 106
 107 static int dw_reg_write_word(void *context, unsigned int reg, unsigned int val)
 108 {
 109         struct dw_i2c_dev *dev = context;
 110
 111         writew_relaxed(val, dev->base + reg);
 112         writew_relaxed(val >> 16, dev->base + reg + 2);
 113
 114         return 0;
 115 }
 116
 117 /**
 118  * i2c_dw_init_regmap() - Initialize registers map
 119  * @dev: device private data
 120  *
 121  * Autodetects needed register access mode and creates the regmap with
 122  * corresponding read/write callbacks. This must be called before doing any
 123  * other register access.
 124  */
 125 int i2c_dw_init_regmap(struct dw_i2c_dev *dev)
 126 {
 127         struct regmap_config map_cfg = {
 128                 .reg_bits = 32,
 129                 .val_bits = 32,
 130                 .reg_stride = 4,
 131                 .disable_locking = true,
 132                 .reg_read = dw_reg_read,
 133                 .reg_write = dw_reg_write,
 134                 .max_register = DW_IC_COMP_TYPE,
 135         };
 136         u32 reg;
 137         int ret;
 138
 139         /*
 140          * Skip detecting the registers map configuration if the regmap has
 141          * already been provided by a higher code.
 142          */
 143         if (dev->map)
 144                 return 0;
 145
 146         ret = i2c_dw_acquire_lock(dev);
 147         if (ret)
 148                 return ret;
 149
 150         reg = readl(dev->base + DW_IC_COMP_TYPE);
 151         i2c_dw_release_lock(dev);
 152
 153         if (reg == swab32(DW_IC_COMP_TYPE_VALUE)) {
 154                 map_cfg.reg_read = dw_reg_read_swab;
 155                 map_cfg.reg_write = dw_reg_write_swab;
 156         } else if (reg == (DW_IC_COMP_TYPE_VALUE & 0x0000ffff)) {
 157                 map_cfg.reg_read = dw_reg_read_word;
 158                 map_cfg.reg_write = dw_reg_write_word;
 159         } else if (reg != DW_IC_COMP_TYPE_VALUE) {
 160                 dev_err(dev->dev,
 161                         "Unknown Synopsys component type: 0x%08x\n", reg);
 162                 return -ENODEV;
 163         }
 164
 165         /*
 166          * Note we'll check the return value of the regmap IO accessors only
 167          * at the probe stage. The rest of the code won't do this because
 168          * basically we have MMIO-based regmap so non of the read/write methods
 169          * can fail.
 170          */
 171         dev->map = devm_regmap_init(dev->dev, NULL, dev, &map_cfg);
 172         if (IS_ERR(dev->map)) {
 173                 dev_err(dev->dev, "Failed to init the registers map\n");
 174                 return PTR_ERR(dev->map);
 175         }
 176
 177         return 0;
 178 }
 179
 180 static const u32 supported_speeds[] = {
 181         I2C_MAX_HIGH_SPEED_MODE_FREQ,
 182         I2C_MAX_FAST_MODE_PLUS_FREQ,
 183         I2C_MAX_FAST_MODE_FREQ,
 184         I2C_MAX_STANDARD_MODE_FREQ,
 185 };
 186
 187 int i2c_dw_validate_speed(struct dw_i2c_dev *dev)
 188 {
 189         struct i2c_timings *t = &dev->timings;
 190         unsigned int i;
 191
 192         /*
 193          * Only standard mode at 100kHz, fast mode at 400kHz,
 194          * fast mode plus at 1MHz and high speed mode at 3.4MHz are supported.
 195          */
 196         for (i = 0; i < ARRAY_SIZE(supported_speeds); i++) {
 197                 if (t->bus_freq_hz == supported_speeds[i])
 198                         return 0;
 199         }
 200
 201         dev_err(dev->dev,
 202                 "%d Hz is unsupported, only 100kHz, 400kHz, 1MHz and 3.4MHz are supported\n",
 203                 t->bus_freq_hz);
 204
 205         return -EINVAL;
 206 }
 207 EXPORT_SYMBOL_GPL(i2c_dw_validate_speed);
 208
 209 #ifdef CONFIG_ACPI
 210
 211 #include <linux/dmi.h>
 212
 213 /*
 214  * The HCNT/LCNT information coming from ACPI should be the most accurate
 215  * for given platform. However, some systems get it wrong. On such systems
 216  * we get better results by calculating those based on the input clock.
 217  */
 218 static const struct dmi_system_id i2c_dw_no_acpi_params[] = {
 219         {
 220                 .ident = "Dell Inspiron 7348",
 221                 .matches = {
 222                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 223                         DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 7348"),
 224                 },
 225         },
 226         {}
 227 };
 228
 229 static void i2c_dw_acpi_params(struct device *device, char method[],
 230                                u16 *hcnt, u16 *lcnt, u32 *sda_hold)
 231 {
 232         struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER };
 233         acpi_handle handle = ACPI_HANDLE(device);
 234         union acpi_object *obj;
 235
 236         if (dmi_check_system(i2c_dw_no_acpi_params))
 237                 return;
 238
 239         if (ACPI_FAILURE(acpi_evaluate_object(handle, method, NULL, &buf)))
 240                 return;
 241
 242         obj = (union acpi_object *)buf.pointer;
 243         if (obj->type == ACPI_TYPE_PACKAGE && obj->package.count == 3) {
 244                 const union acpi_object *objs = obj->package.elements;
 245
 246                 *hcnt = (u16)objs[0].integer.value;
 247                 *lcnt = (u16)objs[1].integer.value;
 248                 *sda_hold = (u32)objs[2].integer.value;
 249         }
 250
 251         kfree(buf.pointer);
 252 }
 253
 254 int i2c_dw_acpi_configure(struct device *device)
 255 {
 256         struct dw_i2c_dev *dev = dev_get_drvdata(device);
 257         struct i2c_timings *t = &dev->timings;
 258         u32 ss_ht = 0, fp_ht = 0, hs_ht = 0, fs_ht = 0;
 259
 260         /*
 261          * Try to get SDA hold time and *CNT values from an ACPI method for
 262          * selected speed modes.
 263          */
 264         i2c_dw_acpi_params(device, "SSCN", &dev->ss_hcnt, &dev->ss_lcnt, &ss_ht);
 265         i2c_dw_acpi_params(device, "FPCN", &dev->fp_hcnt, &dev->fp_lcnt, &fp_ht);
 266         i2c_dw_acpi_params(device, "HSCN", &dev->hs_hcnt, &dev->hs_lcnt, &hs_ht);
 267         i2c_dw_acpi_params(device, "FMCN", &dev->fs_hcnt, &dev->fs_lcnt, &fs_ht);
 268
 269         switch (t->bus_freq_hz) {
 270         case I2C_MAX_STANDARD_MODE_FREQ:
 271                 dev->sda_hold_time = ss_ht;
 272                 break;
 273         case I2C_MAX_FAST_MODE_PLUS_FREQ:
 274                 dev->sda_hold_time = fp_ht;
 275                 break;
 276         case I2C_MAX_HIGH_SPEED_MODE_FREQ:
 277                 dev->sda_hold_time = hs_ht;
 278                 break;
 279         case I2C_MAX_FAST_MODE_FREQ:
 280         default:
 281                 dev->sda_hold_time = fs_ht;
 282                 break;
 283         }
 284
 285         return 0;
 286 }
 287 EXPORT_SYMBOL_GPL(i2c_dw_acpi_configure);
 288
 289 static u32 i2c_dw_acpi_round_bus_speed(struct device *device)
 290 {
 291         u32 acpi_speed;
 292         int i;
 293
 294         acpi_speed = i2c_acpi_find_bus_speed(device);
 295         /*
 296          * Some DSTDs use a non standard speed, round down to the lowest
 297          * standard speed.
 298          */
 299         for (i = 0; i < ARRAY_SIZE(supported_speeds); i++) {
 300                 if (acpi_speed >= supported_speeds[i])
 301                         return supported_speeds[i];
 302         }
 303
 304         return 0;
 305 }
 306
 307 #else   /* CONFIG_ACPI */
 308
 309 static inline u32 i2c_dw_acpi_round_bus_speed(struct device *device) { return 0; }
 310
 311 #endif  /* CONFIG_ACPI */
 312
 313 void i2c_dw_adjust_bus_speed(struct dw_i2c_dev *dev)
 314 {
 315         u32 acpi_speed = i2c_dw_acpi_round_bus_speed(dev->dev);
 316         struct i2c_timings *t = &dev->timings;
 317
 318         /*
 319          * Find bus speed from the "clock-frequency" device property, ACPI
 320          * or by using fast mode if neither is set.
 321          */
 322         if (acpi_speed && t->bus_freq_hz)
 323                 t->bus_freq_hz = min(t->bus_freq_hz, acpi_speed);
 324         else if (acpi_speed || t->bus_freq_hz)
 325                 t->bus_freq_hz = max(t->bus_freq_hz, acpi_speed);
 326         else
 327                 t->bus_freq_hz = I2C_MAX_FAST_MODE_FREQ;
 328 }
 329 EXPORT_SYMBOL_GPL(i2c_dw_adjust_bus_speed);
 330
 331 u32 i2c_dw_scl_hcnt(u32 ic_clk, u32 tSYMBOL, u32 tf, int cond, int offset)
 332 {
 333         /*
 334          * DesignWare I2C core doesn't seem to have solid strategy to meet
 335          * the tHD;STA timing spec.  Configuring _HCNT based on tHIGH spec
 336          * will result in violation of the tHD;STA spec.
 337          */
 338         if (cond)
 339                 /*
 340                  * Conditional expression:
 341                  *
 342                  *   IC_[FS]S_SCL_HCNT + (1+4+3) >= IC_CLK * tHIGH
 343                  *
 344                  * This is based on the DW manuals, and represents an ideal
 345                  * configuration.  The resulting I2C bus speed will be
 346                  * faster than any of the others.
 347                  *
 348                  * If your hardware is free from tHD;STA issue, try this one.
 349                  */
 350                 return (ic_clk * tSYMBOL + 500000) / 1000000 - 8 + offset;
 351         else
 352                 /*
 353                  * Conditional expression:
 354                  *
 355                  *   IC_[FS]S_SCL_HCNT + 3 >= IC_CLK * (tHD;STA + tf)
 356                  *
 357                  * This is just experimental rule; the tHD;STA period turned
 358                  * out to be proportinal to (_HCNT + 3).  With this setting,
 359                  * we could meet both tHIGH and tHD;STA timing specs.
 360                  *
 361                  * If unsure, you'd better to take this alternative.
 362                  *
 363                  * The reason why we need to take into account "tf" here,
 364                  * is the same as described in i2c_dw_scl_lcnt().
 365                  */
 366                 return (ic_clk * (tSYMBOL + tf) + 500000) / 1000000
 367                         - 3 + offset;
 368 }
 369
 370 u32 i2c_dw_scl_lcnt(u32 ic_clk, u32 tLOW, u32 tf, int offset)
 371 {
 372         /*
 373          * Conditional expression:
 374          *
 375          *   IC_[FS]S_SCL_LCNT + 1 >= IC_CLK * (tLOW + tf)
 376          *
 377          * DW I2C core starts counting the SCL CNTs for the LOW period
 378          * of the SCL clock (tLOW) as soon as it pulls the SCL line.
 379          * In order to meet the tLOW timing spec, we need to take into
 380          * account the fall time of SCL signal (tf).  Default tf value
 381          * should be 0.3 us, for safety.
 382          */
 383         return ((ic_clk * (tLOW + tf) + 500000) / 1000000) - 1 + offset;
 384 }
 385
 386 int i2c_dw_set_sda_hold(struct dw_i2c_dev *dev)
 387 {
 388         u32 reg;
 389         int ret;
 390
 391         ret = i2c_dw_acquire_lock(dev);
 392         if (ret)
 393                 return ret;
 394
 395         /* Configure SDA Hold Time if required */
 396         ret = regmap_read(dev->map, DW_IC_COMP_VERSION, &reg);
 397         if (ret)
 398                 goto err_release_lock;
 399
 400         if (reg >= DW_IC_SDA_HOLD_MIN_VERS) {
 401                 if (!dev->sda_hold_time) {
 402                         /* Keep previous hold time setting if no one set it */
 403                         ret = regmap_read(dev->map, DW_IC_SDA_HOLD,
 404                                           &dev->sda_hold_time);
 405                         if (ret)
 406                                 goto err_release_lock;
 407                 }
 408
 409                 /*
 410                  * Workaround for avoiding TX arbitration lost in case I2C
 411                  * slave pulls SDA down "too quickly" after falling edge of
 412                  * SCL by enabling non-zero SDA RX hold. Specification says it
 413                  * extends incoming SDA low to high transition while SCL is
 414                  * high but it appears to help also above issue.
 415                  */
 416                 if (!(dev->sda_hold_time & DW_IC_SDA_HOLD_RX_MASK))
 417                         dev->sda_hold_time |= 1 << DW_IC_SDA_HOLD_RX_SHIFT;
 418
 419                 dev_dbg(dev->dev, "SDA Hold Time TX:RX = %d:%d\n",
 420                         dev->sda_hold_time & ~(u32)DW_IC_SDA_HOLD_RX_MASK,
 421                         dev->sda_hold_time >> DW_IC_SDA_HOLD_RX_SHIFT);
 422         } else if (dev->set_sda_hold_time) {
 423                 dev->set_sda_hold_time(dev);
 424         } else if (dev->sda_hold_time) {
 425                 dev_warn(dev->dev,
 426                         "Hardware too old to adjust SDA hold time.\n");
 427                 dev->sda_hold_time = 0;
 428         }
 429
 430 err_release_lock:
 431         i2c_dw_release_lock(dev);
 432
 433         return ret;
 434 }
 435
 436 void __i2c_dw_disable(struct dw_i2c_dev *dev)
 437 {
 438         int timeout = 100;
 439         u32 status;
 440
 441         do {
 442                 __i2c_dw_disable_nowait(dev);
 443                 /*
 444                  * The enable status register may be unimplemented, but
 445                  * in that case this test reads zero and exits the loop.
 446                  */
 447                 regmap_read(dev->map, DW_IC_ENABLE_STATUS, &status);
 448                 if ((status & 1) == 0)
 449                         return;
 450
 451                 /*
 452                  * Wait 10 times the signaling period of the highest I2C
 453                  * transfer supported by the driver (for 400KHz this is
 454                  * 25us) as described in the DesignWare I2C databook.
 455                  */
 456                 usleep_range(25, 250);
 457         } while (timeout--);
 458
 459         dev_warn(dev->dev, "timeout in disabling adapter\n");
 460 }
 461
 462 unsigned long i2c_dw_clk_rate(struct dw_i2c_dev *dev)
 463 {
 464         /*
 465          * Clock is not necessary if we got LCNT/HCNT values directly from
 466          * the platform code.
 467          */
 468         if (WARN_ON_ONCE(!dev->get_clk_rate_khz))
 469                 return 0;
 470         return dev->get_clk_rate_khz(dev);
 471 }
 472
 473 int i2c_dw_prepare_clk(struct dw_i2c_dev *dev, bool prepare)
 474 {
 475         int ret;
 476
 477         if (IS_ERR(dev->clk))
 478                 return PTR_ERR(dev->clk);
 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 }
 498 EXPORT_SYMBOL_GPL(i2c_dw_prepare_clk);
 499
 500 int 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
 516 void 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  */
 525 int 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
 546 int 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
 569 int 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, &param);
 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
 597 u32 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
 604 void 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
 616 void i2c_dw_disable_int(struct dw_i2c_dev *dev)
 617 {
 618         regmap_write(dev->map, DW_IC_INTR_MASK, 0);
 619 }
 620
 621 MODULE_DESCRIPTION("Synopsys DesignWare I2C bus adapter core");
 622 MODULE_LICENSE("GPL");