drivers/i2c/i2c-cdns.c

   1 /*
   2  * Copyright (C) 2015 Moritz Fischer <moritz.fischer@ettus.com>
   3  * IP from Cadence (ID T-CS-PE-0007-100, Version R1p10f2)
   4  *
   5  * This file is based on: drivers/i2c/zynq_i2c.c,
   6  * with added driver-model support and code cleanup.
   7  *
   8  * SPDX-License-Identifier:     GPL-2.0+
   9  */
  10
  11 #include <common.h>
  12 #include <linux/types.h>
  13 #include <linux/io.h>
  14 #include <linux/errno.h>
  15 #include <dm/device.h>
  16 #include <dm/root.h>
  17 #include <i2c.h>
  18 #include <fdtdec.h>
  19 #include <mapmem.h>
  20 #include <wait_bit.h>
  21
  22 DECLARE_GLOBAL_DATA_PTR;
  23
  24 /* i2c register set */
  25 struct cdns_i2c_regs {
  26         u32 control;
  27         u32 status;
  28         u32 address;
  29         u32 data;
  30         u32 interrupt_status;
  31         u32 transfer_size;
  32         u32 slave_mon_pause;
  33         u32 time_out;
  34         u32 interrupt_mask;
  35         u32 interrupt_enable;
  36         u32 interrupt_disable;
  37 };
  38
  39 /* Control register fields */
  40 #define CDNS_I2C_CONTROL_RW             0x00000001
  41 #define CDNS_I2C_CONTROL_MS             0x00000002
  42 #define CDNS_I2C_CONTROL_NEA            0x00000004
  43 #define CDNS_I2C_CONTROL_ACKEN          0x00000008
  44 #define CDNS_I2C_CONTROL_HOLD           0x00000010
  45 #define CDNS_I2C_CONTROL_SLVMON         0x00000020
  46 #define CDNS_I2C_CONTROL_CLR_FIFO       0x00000040
  47 #define CDNS_I2C_CONTROL_DIV_B_SHIFT    8
  48 #define CDNS_I2C_CONTROL_DIV_B_MASK     0x00003F00
  49 #define CDNS_I2C_CONTROL_DIV_A_SHIFT    14
  50 #define CDNS_I2C_CONTROL_DIV_A_MASK     0x0000C000
  51
  52 /* Status register values */
  53 #define CDNS_I2C_STATUS_RXDV    0x00000020
  54 #define CDNS_I2C_STATUS_TXDV    0x00000040
  55 #define CDNS_I2C_STATUS_RXOVF   0x00000080
  56 #define CDNS_I2C_STATUS_BA      0x00000100
  57
  58 /* Interrupt register fields */
  59 #define CDNS_I2C_INTERRUPT_COMP         0x00000001
  60 #define CDNS_I2C_INTERRUPT_DATA         0x00000002
  61 #define CDNS_I2C_INTERRUPT_NACK         0x00000004
  62 #define CDNS_I2C_INTERRUPT_TO           0x00000008
  63 #define CDNS_I2C_INTERRUPT_SLVRDY       0x00000010
  64 #define CDNS_I2C_INTERRUPT_RXOVF        0x00000020
  65 #define CDNS_I2C_INTERRUPT_TXOVF        0x00000040
  66 #define CDNS_I2C_INTERRUPT_RXUNF        0x00000080
  67 #define CDNS_I2C_INTERRUPT_ARBLOST      0x00000200
  68
  69 #define CDNS_I2C_FIFO_DEPTH             16
  70 #define CDNS_I2C_TRANSFER_SIZE_MAX      255 /* Controller transfer limit */
  71 #define CDNS_I2C_TRANSFER_SIZE          (CDNS_I2C_TRANSFER_SIZE_MAX - 3)
  72
  73 #define CDNS_I2C_BROKEN_HOLD_BIT        BIT(0)
  74
  75 #ifdef DEBUG
  76 static void cdns_i2c_debug_status(struct cdns_i2c_regs *cdns_i2c)
  77 {
  78         int int_status;
  79         int status;
  80         int_status = readl(&cdns_i2c->interrupt_status);
  81
  82         status = readl(&cdns_i2c->status);
  83         if (int_status || status) {
  84                 debug("Status: ");
  85                 if (int_status & CDNS_I2C_INTERRUPT_COMP)
  86                         debug("COMP ");
  87                 if (int_status & CDNS_I2C_INTERRUPT_DATA)
  88                         debug("DATA ");
  89                 if (int_status & CDNS_I2C_INTERRUPT_NACK)
  90                         debug("NACK ");
  91                 if (int_status & CDNS_I2C_INTERRUPT_TO)
  92                         debug("TO ");
  93                 if (int_status & CDNS_I2C_INTERRUPT_SLVRDY)
  94                         debug("SLVRDY ");
  95                 if (int_status & CDNS_I2C_INTERRUPT_RXOVF)
  96                         debug("RXOVF ");
  97                 if (int_status & CDNS_I2C_INTERRUPT_TXOVF)
  98                         debug("TXOVF ");
  99                 if (int_status & CDNS_I2C_INTERRUPT_RXUNF)
 100                         debug("RXUNF ");
 101                 if (int_status & CDNS_I2C_INTERRUPT_ARBLOST)
 102                         debug("ARBLOST ");
 103                 if (status & CDNS_I2C_STATUS_RXDV)
 104                         debug("RXDV ");
 105                 if (status & CDNS_I2C_STATUS_TXDV)
 106                         debug("TXDV ");
 107                 if (status & CDNS_I2C_STATUS_RXOVF)
 108                         debug("RXOVF ");
 109                 if (status & CDNS_I2C_STATUS_BA)
 110                         debug("BA ");
 111                 debug("TS%d ", readl(&cdns_i2c->transfer_size));
 112                 debug("\n");
 113         }
 114 }
 115 #endif
 116
 117 struct i2c_cdns_bus {
 118         int id;
 119         unsigned int input_freq;
 120         struct cdns_i2c_regs __iomem *regs;     /* register base */
 121
 122         int hold_flag;
 123         u32 quirks;
 124 };
 125
 126 struct cdns_i2c_platform_data {
 127         u32 quirks;
 128 };
 129
 130 /* Wait for an interrupt */
 131 static u32 cdns_i2c_wait(struct cdns_i2c_regs *cdns_i2c, u32 mask)
 132 {
 133         int timeout, int_status;
 134
 135         for (timeout = 0; timeout < 100; timeout++) {
 136                 int_status = readl(&cdns_i2c->interrupt_status);
 137                 if (int_status & mask)
 138                         break;
 139                 udelay(100);
 140         }
 141
 142         /* Clear interrupt status flags */
 143         writel(int_status & mask, &cdns_i2c->interrupt_status);
 144
 145         return int_status & mask;
 146 }
 147
 148 #define CDNS_I2C_DIVA_MAX       4
 149 #define CDNS_I2C_DIVB_MAX       64
 150
 151 static int cdns_i2c_calc_divs(unsigned long *f, unsigned long input_clk,
 152                 unsigned int *a, unsigned int *b)
 153 {
 154         unsigned long fscl = *f, best_fscl = *f, actual_fscl, temp;
 155         unsigned int div_a, div_b, calc_div_a = 0, calc_div_b = 0;
 156         unsigned int last_error, current_error;
 157
 158         /* calculate (divisor_a+1) x (divisor_b+1) */
 159         temp = input_clk / (22 * fscl);
 160
 161         /*
 162          * If the calculated value is negative or 0CDNS_I2C_DIVA_MAX,
 163          * the fscl input is out of range. Return error.
 164          */
 165         if (!temp || (temp > (CDNS_I2C_DIVA_MAX * CDNS_I2C_DIVB_MAX)))
 166                 return -EINVAL;
 167
 168         last_error = -1;
 169         for (div_a = 0; div_a < CDNS_I2C_DIVA_MAX; div_a++) {
 170                 div_b = DIV_ROUND_UP(input_clk, 22 * fscl * (div_a + 1));
 171
 172                 if ((div_b < 1) || (div_b > CDNS_I2C_DIVB_MAX))
 173                         continue;
 174                 div_b--;
 175
 176                 actual_fscl = input_clk / (22 * (div_a + 1) * (div_b + 1));
 177
 178                 if (actual_fscl > fscl)
 179                         continue;
 180
 181                 current_error = ((actual_fscl > fscl) ? (actual_fscl - fscl) :
 182                                                         (fscl - actual_fscl));
 183
 184                 if (last_error > current_error) {
 185                         calc_div_a = div_a;
 186                         calc_div_b = div_b;
 187                         best_fscl = actual_fscl;
 188                         last_error = current_error;
 189                 }
 190         }
 191
 192         *a = calc_div_a;
 193         *b = calc_div_b;
 194         *f = best_fscl;
 195
 196         return 0;
 197 }
 198
 199 static int cdns_i2c_set_bus_speed(struct udevice *dev, unsigned int speed)
 200 {
 201         struct i2c_cdns_bus *bus = dev_get_priv(dev);
 202         u32 div_a = 0, div_b = 0;
 203         unsigned long speed_p = speed;
 204         int ret = 0;
 205
 206         if (speed > 400000) {
 207                 debug("%s, failed to set clock speed to %u\n", __func__,
 208                       speed);
 209                 return -EINVAL;
 210         }
 211
 212         ret = cdns_i2c_calc_divs(&speed_p, bus->input_freq, &div_a, &div_b);
 213         if (ret)
 214                 return ret;
 215
 216         debug("%s: div_a: %d, div_b: %d, input freq: %d, speed: %d/%ld\n",
 217               __func__, div_a, div_b, bus->input_freq, speed, speed_p);
 218
 219         writel((div_b << CDNS_I2C_CONTROL_DIV_B_SHIFT) |
 220                (div_a << CDNS_I2C_CONTROL_DIV_A_SHIFT), &bus->regs->control);
 221
 222         /* Enable master mode, ack, and 7-bit addressing */
 223         setbits_le32(&bus->regs->control, CDNS_I2C_CONTROL_MS |
 224                 CDNS_I2C_CONTROL_ACKEN | CDNS_I2C_CONTROL_NEA);
 225
 226         return 0;
 227 }
 228
 229 static int cdns_i2c_write_data(struct i2c_cdns_bus *i2c_bus, u32 addr, u8 *data,
 230                                u32 len)
 231 {
 232         u8 *cur_data = data;
 233         struct cdns_i2c_regs *regs = i2c_bus->regs;
 234
 235         /* Set the controller in Master transmit mode and clear FIFO */
 236         setbits_le32(&regs->control, CDNS_I2C_CONTROL_CLR_FIFO);
 237         clrbits_le32(&regs->control, CDNS_I2C_CONTROL_RW);
 238
 239         /* Check message size against FIFO depth, and set hold bus bit
 240          * if it is greater than FIFO depth
 241          */
 242         if (len > CDNS_I2C_FIFO_DEPTH)
 243                 setbits_le32(&regs->control, CDNS_I2C_CONTROL_HOLD);
 244
 245         /* Clear the interrupts in status register */
 246         writel(0xFF, &regs->interrupt_status);
 247
 248         writel(addr, &regs->address);
 249
 250         while (len--) {
 251                 writel(*(cur_data++), &regs->data);
 252                 if (readl(&regs->transfer_size) == CDNS_I2C_FIFO_DEPTH) {
 253                         if (!cdns_i2c_wait(regs, CDNS_I2C_INTERRUPT_COMP)) {
 254                                 /* Release the bus */
 255                                 clrbits_le32(&regs->control,
 256                                              CDNS_I2C_CONTROL_HOLD);
 257                                 return -ETIMEDOUT;
 258                         }
 259                 }
 260         }
 261
 262         /* All done... release the bus */
 263         if (!i2c_bus->hold_flag)
 264                 clrbits_le32(&regs->control, CDNS_I2C_CONTROL_HOLD);
 265
 266         /* Wait for the address and data to be sent */
 267         if (!cdns_i2c_wait(regs, CDNS_I2C_INTERRUPT_COMP))
 268                 return -ETIMEDOUT;
 269         return 0;
 270 }
 271
 272 static inline bool cdns_is_hold_quirk(int hold_quirk, int curr_recv_count)
 273 {
 274         return hold_quirk && (curr_recv_count == CDNS_I2C_FIFO_DEPTH + 1);
 275 }
 276
 277 static int cdns_i2c_read_data(struct i2c_cdns_bus *i2c_bus, u32 addr, u8 *data,
 278                               u32 recv_count)
 279 {
 280         u8 *cur_data = data;
 281         struct cdns_i2c_regs *regs = i2c_bus->regs;
 282         int curr_recv_count;
 283         int updatetx, hold_quirk;
 284
 285         /* Check the hardware can handle the requested bytes */
 286         if ((recv_count < 0))
 287                 return -EINVAL;
 288
 289         curr_recv_count = recv_count;
 290
 291         /* Check for the message size against the FIFO depth */
 292         if (recv_count > CDNS_I2C_FIFO_DEPTH)
 293                 setbits_le32(&regs->control, CDNS_I2C_CONTROL_HOLD);
 294
 295         setbits_le32(&regs->control, CDNS_I2C_CONTROL_CLR_FIFO |
 296                 CDNS_I2C_CONTROL_RW);
 297
 298         if (recv_count > CDNS_I2C_TRANSFER_SIZE) {
 299                 curr_recv_count = CDNS_I2C_TRANSFER_SIZE;
 300                 writel(curr_recv_count, &regs->transfer_size);
 301         } else {
 302                 writel(recv_count, &regs->transfer_size);
 303         }
 304
 305         /* Start reading data */
 306         writel(addr, &regs->address);
 307
 308         updatetx = recv_count > curr_recv_count;
 309
 310         hold_quirk = (i2c_bus->quirks & CDNS_I2C_BROKEN_HOLD_BIT) && updatetx;
 311
 312         while (recv_count) {
 313                 while (readl(&regs->status) & CDNS_I2C_STATUS_RXDV) {
 314                         if (recv_count < CDNS_I2C_FIFO_DEPTH &&
 315                             !i2c_bus->hold_flag) {
 316                                 clrbits_le32(&regs->control,
 317                                              CDNS_I2C_CONTROL_HOLD);
 318                         }
 319                         *(cur_data)++ = readl(&regs->data);
 320                         recv_count--;
 321                         curr_recv_count--;
 322
 323                         if (cdns_is_hold_quirk(hold_quirk, curr_recv_count))
 324                                 break;
 325                 }
 326
 327                 if (cdns_is_hold_quirk(hold_quirk, curr_recv_count)) {
 328                         /* wait while fifo is full */
 329                         while (readl(&regs->transfer_size) !=
 330                                      (curr_recv_count - CDNS_I2C_FIFO_DEPTH))
 331                                 ;
 332                         /*
 333                          * Check number of bytes to be received against maximum
 334                          * transfer size and update register accordingly.
 335                          */
 336                         if ((recv_count - CDNS_I2C_FIFO_DEPTH) >
 337                             CDNS_I2C_TRANSFER_SIZE) {
 338                                 writel(CDNS_I2C_TRANSFER_SIZE,
 339                                        &regs->transfer_size);
 340                                 curr_recv_count = CDNS_I2C_TRANSFER_SIZE +
 341                                         CDNS_I2C_FIFO_DEPTH;
 342                         } else {
 343                                 writel(recv_count - CDNS_I2C_FIFO_DEPTH,
 344                                        &regs->transfer_size);
 345                                 curr_recv_count = recv_count;
 346                         }
 347                 } else if (recv_count && !hold_quirk && !curr_recv_count) {
 348                         writel(addr, &regs->address);
 349                         if (recv_count > CDNS_I2C_TRANSFER_SIZE) {
 350                                 writel(CDNS_I2C_TRANSFER_SIZE,
 351                                        &regs->transfer_size);
 352                                 curr_recv_count = CDNS_I2C_TRANSFER_SIZE;
 353                         } else {
 354                                 writel(recv_count, &regs->transfer_size);
 355                                 curr_recv_count = recv_count;
 356                         }
 357                 }
 358         }
 359
 360         /* Wait for the address and data to be sent */
 361         if (!cdns_i2c_wait(regs, CDNS_I2C_INTERRUPT_COMP))
 362                 return -ETIMEDOUT;
 363
 364         return 0;
 365 }
 366
 367 static int cdns_i2c_xfer(struct udevice *dev, struct i2c_msg *msg,
 368                          int nmsgs)
 369 {
 370         struct i2c_cdns_bus *i2c_bus = dev_get_priv(dev);
 371         int ret, count;
 372         bool hold_quirk;
 373
 374         hold_quirk = !!(i2c_bus->quirks & CDNS_I2C_BROKEN_HOLD_BIT);
 375
 376         if (nmsgs > 1) {
 377                 /*
 378                  * This controller does not give completion interrupt after a
 379                  * master receive message if HOLD bit is set (repeated start),
 380                  * resulting in SW timeout. Hence, if a receive message is
 381                  * followed by any other message, an error is returned
 382                  * indicating that this sequence is not supported.
 383                  */
 384                 for (count = 0; (count < nmsgs - 1) && hold_quirk; count++) {
 385                         if (msg[count].flags & I2C_M_RD) {
 386                                 printf("Can't do repeated start after a receive message\n");
 387                                 return -EOPNOTSUPP;
 388                         }
 389                 }
 390
 391                 i2c_bus->hold_flag = 1;
 392                 setbits_le32(&i2c_bus->regs->control, CDNS_I2C_CONTROL_HOLD);
 393         } else {
 394                 i2c_bus->hold_flag = 0;
 395         }
 396
 397         debug("i2c_xfer: %d messages\n", nmsgs);
 398         for (; nmsgs > 0; nmsgs--, msg++) {
 399                 debug("i2c_xfer: chip=0x%x, len=0x%x\n", msg->addr, msg->len);
 400                 if (msg->flags & I2C_M_RD) {
 401                         ret = cdns_i2c_read_data(i2c_bus, msg->addr, msg->buf,
 402                                                  msg->len);
 403                 } else {
 404                         ret = cdns_i2c_write_data(i2c_bus, msg->addr, msg->buf,
 405                                                   msg->len);
 406                 }
 407                 if (ret) {
 408                         debug("i2c_write: error sending\n");
 409                         return -EREMOTEIO;
 410                 }
 411         }
 412
 413         return 0;
 414 }
 415
 416 static int cdns_i2c_ofdata_to_platdata(struct udevice *dev)
 417 {
 418         struct i2c_cdns_bus *i2c_bus = dev_get_priv(dev);
 419         struct cdns_i2c_platform_data *pdata =
 420                 (struct cdns_i2c_platform_data *)dev_get_driver_data(dev);
 421
 422         i2c_bus->regs = (struct cdns_i2c_regs *)dev_get_addr(dev);
 423         if (!i2c_bus->regs)
 424                 return -ENOMEM;
 425
 426         if (pdata)
 427                 i2c_bus->quirks = pdata->quirks;
 428
 429         i2c_bus->input_freq = 100000000; /* TODO hardcode input freq for now */
 430
 431         return 0;
 432 }
 433
 434 static const struct dm_i2c_ops cdns_i2c_ops = {
 435         .xfer = cdns_i2c_xfer,
 436         .set_bus_speed = cdns_i2c_set_bus_speed,
 437 };
 438
 439 static const struct cdns_i2c_platform_data r1p10_i2c_def = {
 440         .quirks = CDNS_I2C_BROKEN_HOLD_BIT,
 441 };
 442
 443 static const struct udevice_id cdns_i2c_of_match[] = {
 444         { .compatible = "cdns,i2c-r1p10", .data = (ulong)&r1p10_i2c_def },
 445         { .compatible = "cdns,i2c-r1p14" },
 446         { /* end of table */ }
 447 };
 448
 449 U_BOOT_DRIVER(cdns_i2c) = {
 450         .name = "i2c-cdns",
 451         .id = UCLASS_I2C,
 452         .of_match = cdns_i2c_of_match,
 453         .ofdata_to_platdata = cdns_i2c_ofdata_to_platdata,
 454         .priv_auto_alloc_size = sizeof(struct i2c_cdns_bus),
 455         .ops = &cdns_i2c_ops,
 456 };