root/drivers/media/usb/em28xx/em28xx-i2c.c

DEFINITIONS

1. em28xx_i2c_timeout
2. em2800_i2c_send_bytes
3. em2800_i2c_recv_bytes
4. em2800_i2c_check_for_device
5. em28xx_i2c_send_bytes
6. em28xx_i2c_recv_bytes
7. em28xx_i2c_check_for_device
8. em25xx_bus_B_send_bytes
9. em25xx_bus_B_recv_bytes
10. em25xx_bus_B_check_for_device
11. i2c_check_for_device
12. i2c_recv_bytes
13. i2c_send_bytes
14. em28xx_i2c_xfer
15. em28xx_hash_mem
16. em28xx_i2c_read_block
17. em28xx_i2c_eeprom
18. functionality
19. em28xx_do_i2c_scan
20. em28xx_i2c_register
21. em28xx_i2c_unregister

   1 // SPDX-License-Identifier: GPL-2.0+
   2 //
   3 // em28xx-i2c.c - driver for Empia EM2800/EM2820/2840 USB video capture devices
   4 //
   5 // Copyright (C) 2005 Ludovico Cavedon <cavedon@sssup.it>
   6 //                    Markus Rechberger <mrechberger@gmail.com>
   7 //                    Mauro Carvalho Chehab <mchehab@kernel.org>
   8 //                    Sascha Sommer <saschasommer@freenet.de>
   9 // Copyright (C) 2013 Frank Schäfer <fschaefer.oss@googlemail.com>
  10 //
  11 // This program is free software; you can redistribute it and/or modify
  12 // it under the terms of the GNU General Public License as published by
  13 // the Free Software Foundation; either version 2 of the License, or
  14 // (at your option) any later version.
  15 //
  16 // This program is distributed in the hope that it will be useful,
  17 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 // GNU General Public License for more details.
  20 
  21 #include "em28xx.h"
  22 
  23 #include <linux/module.h>
  24 #include <linux/kernel.h>
  25 #include <linux/usb.h>
  26 #include <linux/i2c.h>
  27 #include <linux/jiffies.h>
  28 
  29 #include "tuner-xc2028.h"
  30 #include <media/v4l2-common.h>
  31 #include <media/tuner.h>
  32 
  33 /* ----------------------------------------------------------- */
  34 
  35 static unsigned int i2c_scan;
  36 module_param(i2c_scan, int, 0444);
  37 MODULE_PARM_DESC(i2c_scan, "scan i2c bus at insmod time");
  38 
  39 static unsigned int i2c_debug;
  40 module_param(i2c_debug, int, 0644);
  41 MODULE_PARM_DESC(i2c_debug, "i2c debug message level (1: normal debug, 2: show I2C transfers)");
  42 
  43 #define dprintk(level, fmt, arg...) do {                                \
  44         if (i2c_debug > level)                                          \
  45                 dev_printk(KERN_DEBUG, &dev->intf->dev,                 \
  46                            "i2c: %s: " fmt, __func__, ## arg);          \
  47 } while (0)
  48 
  49 /*
  50  * Time in msecs to wait for i2c xfers to finish.
  51  * 35ms is the maximum time a SMBUS device could wait when
  52  * clock stretching is used. As the transfer itself will take
  53  * some time to happen, set it to 35 ms.
  54  *
  55  * Ok, I2C doesn't specify any limit. So, eventually, we may need
  56  * to increase this timeout.
  57  */
  58 #define EM28XX_I2C_XFER_TIMEOUT         35 /* ms */
  59 
  60 static int em28xx_i2c_timeout(struct em28xx *dev)
  61 {
  62         int time = EM28XX_I2C_XFER_TIMEOUT;
  63 
  64         switch (dev->i2c_speed & 0x03) {
  65         case EM28XX_I2C_FREQ_25_KHZ:
  66                 time += 4;              /* Assume 4 ms for transfers */
  67                 break;
  68         case EM28XX_I2C_FREQ_100_KHZ:
  69         case EM28XX_I2C_FREQ_400_KHZ:
  70                 time += 1;              /* Assume 1 ms for transfers */
  71                 break;
  72         default: /* EM28XX_I2C_FREQ_1_5_MHZ */
  73                 break;
  74         }
  75 
  76         return msecs_to_jiffies(time);
  77 }
  78 
  79 /*
  80  * em2800_i2c_send_bytes()
  81  * send up to 4 bytes to the em2800 i2c device
  82  */
  83 static int em2800_i2c_send_bytes(struct em28xx *dev, u8 addr, u8 *buf, u16 len)
  84 {
  85         unsigned long timeout = jiffies + em28xx_i2c_timeout(dev);
  86         int ret;
  87         u8 b2[6];
  88 
  89         if (len < 1 || len > 4)
  90                 return -EOPNOTSUPP;
  91 
  92         b2[5] = 0x80 + len - 1;
  93         b2[4] = addr;
  94         b2[3] = buf[0];
  95         if (len > 1)
  96                 b2[2] = buf[1];
  97         if (len > 2)
  98                 b2[1] = buf[2];
  99         if (len > 3)
 100                 b2[0] = buf[3];
 101 
 102         /* trigger write */
 103         ret = dev->em28xx_write_regs(dev, 4 - len, &b2[4 - len], 2 + len);
 104         if (ret != 2 + len) {
 105                 dev_warn(&dev->intf->dev,
 106                          "failed to trigger write to i2c address 0x%x (error=%i)\n",
 107                             addr, ret);
 108                 return (ret < 0) ? ret : -EIO;
 109         }
 110         /* wait for completion */
 111         while (time_is_after_jiffies(timeout)) {
 112                 ret = dev->em28xx_read_reg(dev, 0x05);
 113                 if (ret == 0x80 + len - 1)
 114                         return len;
 115                 if (ret == 0x94 + len - 1) {
 116                         dprintk(1, "R05 returned 0x%02x: I2C ACK error\n", ret);
 117                         return -ENXIO;
 118                 }
 119                 if (ret < 0) {
 120                         dev_warn(&dev->intf->dev,
 121                                  "failed to get i2c transfer status from bridge register (error=%i)\n",
 122                                 ret);
 123                         return ret;
 124                 }
 125                 usleep_range(5000, 6000);
 126         }
 127         dprintk(0, "write to i2c device at 0x%x timed out\n", addr);
 128         return -ETIMEDOUT;
 129 }
 130 
 131 /*
 132  * em2800_i2c_recv_bytes()
 133  * read up to 4 bytes from the em2800 i2c device
 134  */
 135 static int em2800_i2c_recv_bytes(struct em28xx *dev, u8 addr, u8 *buf, u16 len)
 136 {
 137         unsigned long timeout = jiffies + em28xx_i2c_timeout(dev);
 138         u8 buf2[4];
 139         int ret;
 140         int i;
 141 
 142         if (len < 1 || len > 4)
 143                 return -EOPNOTSUPP;
 144 
 145         /* trigger read */
 146         buf2[1] = 0x84 + len - 1;
 147         buf2[0] = addr;
 148         ret = dev->em28xx_write_regs(dev, 0x04, buf2, 2);
 149         if (ret != 2) {
 150                 dev_warn(&dev->intf->dev,
 151                          "failed to trigger read from i2c address 0x%x (error=%i)\n",
 152                          addr, ret);
 153                 return (ret < 0) ? ret : -EIO;
 154         }
 155 
 156         /* wait for completion */
 157         while (time_is_after_jiffies(timeout)) {
 158                 ret = dev->em28xx_read_reg(dev, 0x05);
 159                 if (ret == 0x84 + len - 1)
 160                         break;
 161                 if (ret == 0x94 + len - 1) {
 162                         dprintk(1, "R05 returned 0x%02x: I2C ACK error\n",
 163                                 ret);
 164                         return -ENXIO;
 165                 }
 166                 if (ret < 0) {
 167                         dev_warn(&dev->intf->dev,
 168                                  "failed to get i2c transfer status from bridge register (error=%i)\n",
 169                                  ret);
 170                         return ret;
 171                 }
 172                 usleep_range(5000, 6000);
 173         }
 174         if (ret != 0x84 + len - 1)
 175                 dprintk(0, "read from i2c device at 0x%x timed out\n", addr);
 176 
 177         /* get the received message */
 178         ret = dev->em28xx_read_reg_req_len(dev, 0x00, 4 - len, buf2, len);
 179         if (ret != len) {
 180                 dev_warn(&dev->intf->dev,
 181                          "reading from i2c device at 0x%x failed: couldn't get the received message from the bridge (error=%i)\n",
 182                          addr, ret);
 183                 return (ret < 0) ? ret : -EIO;
 184         }
 185         for (i = 0; i < len; i++)
 186                 buf[i] = buf2[len - 1 - i];
 187 
 188         return ret;
 189 }
 190 
 191 /*
 192  * em2800_i2c_check_for_device()
 193  * check if there is an i2c device at the supplied address
 194  */
 195 static int em2800_i2c_check_for_device(struct em28xx *dev, u8 addr)
 196 {
 197         u8 buf;
 198         int ret;
 199 
 200         ret = em2800_i2c_recv_bytes(dev, addr, &buf, 1);
 201         if (ret == 1)
 202                 return 0;
 203         return (ret < 0) ? ret : -EIO;
 204 }
 205 
 206 /*
 207  * em28xx_i2c_send_bytes()
 208  */
 209 static int em28xx_i2c_send_bytes(struct em28xx *dev, u16 addr, u8 *buf,
 210                                  u16 len, int stop)
 211 {
 212         unsigned long timeout = jiffies + em28xx_i2c_timeout(dev);
 213         int ret;
 214 
 215         if (len < 1 || len > 64)
 216                 return -EOPNOTSUPP;
 217         /*
 218          * NOTE: limited by the USB ctrl message constraints
 219          * Zero length reads always succeed, even if no device is connected
 220          */
 221 
 222         /* Write to i2c device */
 223         ret = dev->em28xx_write_regs_req(dev, stop ? 2 : 3, addr, buf, len);
 224         if (ret != len) {
 225                 if (ret < 0) {
 226                         dev_warn(&dev->intf->dev,
 227                                  "writing to i2c device at 0x%x failed (error=%i)\n",
 228                                  addr, ret);
 229                         return ret;
 230                 }
 231                 dev_warn(&dev->intf->dev,
 232                          "%i bytes write to i2c device at 0x%x requested, but %i bytes written\n",
 233                                 len, addr, ret);
 234                 return -EIO;
 235         }
 236 
 237         /* wait for completion */
 238         while (time_is_after_jiffies(timeout)) {
 239                 ret = dev->em28xx_read_reg(dev, 0x05);
 240                 if (ret == 0) /* success */
 241                         return len;
 242                 if (ret == 0x10) {
 243                         dprintk(1, "I2C ACK error on writing to addr 0x%02x\n",
 244                                 addr);
 245                         return -ENXIO;
 246                 }
 247                 if (ret < 0) {
 248                         dev_warn(&dev->intf->dev,
 249                                  "failed to get i2c transfer status from bridge register (error=%i)\n",
 250                                  ret);
 251                         return ret;
 252                 }
 253                 usleep_range(5000, 6000);
 254                 /*
 255                  * NOTE: do we really have to wait for success ?
 256                  * Never seen anything else than 0x00 or 0x10
 257                  * (even with high payload) ...
 258                  */
 259         }
 260 
 261         if (ret == 0x02 || ret == 0x04) {
 262                 /* NOTE: these errors seem to be related to clock stretching */
 263                 dprintk(0,
 264                         "write to i2c device at 0x%x timed out (status=%i)\n",
 265                         addr, ret);
 266                 return -ETIMEDOUT;
 267         }
 268 
 269         dev_warn(&dev->intf->dev,
 270                  "write to i2c device at 0x%x failed with unknown error (status=%i)\n",
 271                  addr, ret);
 272         return -EIO;
 273 }
 274 
 275 /*
 276  * em28xx_i2c_recv_bytes()
 277  * read a byte from the i2c device
 278  */
 279 static int em28xx_i2c_recv_bytes(struct em28xx *dev, u16 addr, u8 *buf, u16 len)
 280 {
 281         int ret;
 282 
 283         if (len < 1 || len > 64)
 284                 return -EOPNOTSUPP;
 285         /*
 286          * NOTE: limited by the USB ctrl message constraints
 287          * Zero length reads always succeed, even if no device is connected
 288          */
 289 
 290         /* Read data from i2c device */
 291         ret = dev->em28xx_read_reg_req_len(dev, 2, addr, buf, len);
 292         if (ret < 0) {
 293                 dev_warn(&dev->intf->dev,
 294                          "reading from i2c device at 0x%x failed (error=%i)\n",
 295                          addr, ret);
 296                 return ret;
 297         }
 298         /*
 299          * NOTE: some devices with two i2c buses have the bad habit to return 0
 300          * bytes if we are on bus B AND there was no write attempt to the
 301          * specified slave address before AND no device is present at the
 302          * requested slave address.
 303          * Anyway, the next check will fail with -ENXIO in this case, so avoid
 304          * spamming the system log on device probing and do nothing here.
 305          */
 306 
 307         /* Check success of the i2c operation */
 308         ret = dev->em28xx_read_reg(dev, 0x05);
 309         if (ret == 0) /* success */
 310                 return len;
 311         if (ret < 0) {
 312                 dev_warn(&dev->intf->dev,
 313                          "failed to get i2c transfer status from bridge register (error=%i)\n",
 314                          ret);
 315                 return ret;
 316         }
 317         if (ret == 0x10) {
 318                 dprintk(1, "I2C ACK error on writing to addr 0x%02x\n",
 319                         addr);
 320                 return -ENXIO;
 321         }
 322 
 323         if (ret == 0x02 || ret == 0x04) {
 324                 /* NOTE: these errors seem to be related to clock stretching */
 325                 dprintk(0,
 326                         "write to i2c device at 0x%x timed out (status=%i)\n",
 327                         addr, ret);
 328                 return -ETIMEDOUT;
 329         }
 330 
 331         dev_warn(&dev->intf->dev,
 332                  "write to i2c device at 0x%x failed with unknown error (status=%i)\n",
 333                  addr, ret);
 334         return -EIO;
 335 }
 336 
 337 /*
 338  * em28xx_i2c_check_for_device()
 339  * check if there is a i2c_device at the supplied address
 340  */
 341 static int em28xx_i2c_check_for_device(struct em28xx *dev, u16 addr)
 342 {
 343         int ret;
 344         u8 buf;
 345 
 346         ret = em28xx_i2c_recv_bytes(dev, addr, &buf, 1);
 347         if (ret == 1)
 348                 return 0;
 349         return (ret < 0) ? ret : -EIO;
 350 }
 351 
 352 /*
 353  * em25xx_bus_B_send_bytes
 354  * write bytes to the i2c device
 355  */
 356 static int em25xx_bus_B_send_bytes(struct em28xx *dev, u16 addr, u8 *buf,
 357                                    u16 len)
 358 {
 359         int ret;
 360 
 361         if (len < 1 || len > 64)
 362                 return -EOPNOTSUPP;
 363         /*
 364          * NOTE: limited by the USB ctrl message constraints
 365          * Zero length reads always succeed, even if no device is connected
 366          */
 367 
 368         /* Set register and write value */
 369         ret = dev->em28xx_write_regs_req(dev, 0x06, addr, buf, len);
 370         if (ret != len) {
 371                 if (ret < 0) {
 372                         dev_warn(&dev->intf->dev,
 373                                  "writing to i2c device at 0x%x failed (error=%i)\n",
 374                                  addr, ret);
 375                         return ret;
 376                 }
 377 
 378                 dev_warn(&dev->intf->dev,
 379                          "%i bytes write to i2c device at 0x%x requested, but %i bytes written\n",
 380                          len, addr, ret);
 381                 return -EIO;
 382         }
 383         /* Check success */
 384         ret = dev->em28xx_read_reg_req(dev, 0x08, 0x0000);
 385         /*
 386          * NOTE: the only error we've seen so far is
 387          * 0x01 when the slave device is not present
 388          */
 389         if (!ret)
 390                 return len;
 391 
 392         if (ret > 0) {
 393                 dprintk(1, "Bus B R08 returned 0x%02x: I2C ACK error\n", ret);
 394                 return -ENXIO;
 395         }
 396 
 397         return ret;
 398         /*
 399          * NOTE: With chip types (other chip IDs) which actually don't support
 400          * this operation, it seems to succeed ALWAYS ! (even if there is no
 401          * slave device or even no second i2c bus provided)
 402          */
 403 }
 404 
 405 /*
 406  * em25xx_bus_B_recv_bytes
 407  * read bytes from the i2c device
 408  */
 409 static int em25xx_bus_B_recv_bytes(struct em28xx *dev, u16 addr, u8 *buf,
 410                                    u16 len)
 411 {
 412         int ret;
 413 
 414         if (len < 1 || len > 64)
 415                 return -EOPNOTSUPP;
 416         /*
 417          * NOTE: limited by the USB ctrl message constraints
 418          * Zero length reads always succeed, even if no device is connected
 419          */
 420 
 421         /* Read value */
 422         ret = dev->em28xx_read_reg_req_len(dev, 0x06, addr, buf, len);
 423         if (ret < 0) {
 424                 dev_warn(&dev->intf->dev,
 425                          "reading from i2c device at 0x%x failed (error=%i)\n",
 426                          addr, ret);
 427                 return ret;
 428         }
 429         /*
 430          * NOTE: some devices with two i2c buses have the bad habit to return 0
 431          * bytes if we are on bus B AND there was no write attempt to the
 432          * specified slave address before AND no device is present at the
 433          * requested slave address.
 434          * Anyway, the next check will fail with -ENXIO in this case, so avoid
 435          * spamming the system log on device probing and do nothing here.
 436          */
 437 
 438         /* Check success */
 439         ret = dev->em28xx_read_reg_req(dev, 0x08, 0x0000);
 440         /*
 441          * NOTE: the only error we've seen so far is
 442          * 0x01 when the slave device is not present
 443          */
 444         if (!ret)
 445                 return len;
 446 
 447         if (ret > 0) {
 448                 dprintk(1, "Bus B R08 returned 0x%02x: I2C ACK error\n", ret);
 449                 return -ENXIO;
 450         }
 451 
 452         return ret;
 453         /*
 454          * NOTE: With chip types (other chip IDs) which actually don't support
 455          * this operation, it seems to succeed ALWAYS ! (even if there is no
 456          * slave device or even no second i2c bus provided)
 457          */
 458 }
 459 
 460 /*
 461  * em25xx_bus_B_check_for_device()
 462  * check if there is a i2c device at the supplied address
 463  */
 464 static int em25xx_bus_B_check_for_device(struct em28xx *dev, u16 addr)
 465 {
 466         u8 buf;
 467         int ret;
 468 
 469         ret = em25xx_bus_B_recv_bytes(dev, addr, &buf, 1);
 470         if (ret < 0)
 471                 return ret;
 472 
 473         return 0;
 474         /*
 475          * NOTE: With chips which do not support this operation,
 476          * it seems to succeed ALWAYS ! (even if no device connected)
 477          */
 478 }
 479 
 480 static inline int i2c_check_for_device(struct em28xx_i2c_bus *i2c_bus, u16 addr)
 481 {
 482         struct em28xx *dev = i2c_bus->dev;
 483         int rc = -EOPNOTSUPP;
 484 
 485         if (i2c_bus->algo_type == EM28XX_I2C_ALGO_EM28XX)
 486                 rc = em28xx_i2c_check_for_device(dev, addr);
 487         else if (i2c_bus->algo_type == EM28XX_I2C_ALGO_EM2800)
 488                 rc = em2800_i2c_check_for_device(dev, addr);
 489         else if (i2c_bus->algo_type == EM28XX_I2C_ALGO_EM25XX_BUS_B)
 490                 rc = em25xx_bus_B_check_for_device(dev, addr);
 491         return rc;
 492 }
 493 
 494 static inline int i2c_recv_bytes(struct em28xx_i2c_bus *i2c_bus,
 495                                  struct i2c_msg msg)
 496 {
 497         struct em28xx *dev = i2c_bus->dev;
 498         u16 addr = msg.addr << 1;
 499         int rc = -EOPNOTSUPP;
 500 
 501         if (i2c_bus->algo_type == EM28XX_I2C_ALGO_EM28XX)
 502                 rc = em28xx_i2c_recv_bytes(dev, addr, msg.buf, msg.len);
 503         else if (i2c_bus->algo_type == EM28XX_I2C_ALGO_EM2800)
 504                 rc = em2800_i2c_recv_bytes(dev, addr, msg.buf, msg.len);
 505         else if (i2c_bus->algo_type == EM28XX_I2C_ALGO_EM25XX_BUS_B)
 506                 rc = em25xx_bus_B_recv_bytes(dev, addr, msg.buf, msg.len);
 507         return rc;
 508 }
 509 
 510 static inline int i2c_send_bytes(struct em28xx_i2c_bus *i2c_bus,
 511                                  struct i2c_msg msg, int stop)
 512 {
 513         struct em28xx *dev = i2c_bus->dev;
 514         u16 addr = msg.addr << 1;
 515         int rc = -EOPNOTSUPP;
 516 
 517         if (i2c_bus->algo_type == EM28XX_I2C_ALGO_EM28XX)
 518                 rc = em28xx_i2c_send_bytes(dev, addr, msg.buf, msg.len, stop);
 519         else if (i2c_bus->algo_type == EM28XX_I2C_ALGO_EM2800)
 520                 rc = em2800_i2c_send_bytes(dev, addr, msg.buf, msg.len);
 521         else if (i2c_bus->algo_type == EM28XX_I2C_ALGO_EM25XX_BUS_B)
 522                 rc = em25xx_bus_B_send_bytes(dev, addr, msg.buf, msg.len);
 523         return rc;
 524 }
 525 
 526 /*
 527  * em28xx_i2c_xfer()
 528  * the main i2c transfer function
 529  */
 530 static int em28xx_i2c_xfer(struct i2c_adapter *i2c_adap,
 531                            struct i2c_msg msgs[], int num)
 532 {
 533         struct em28xx_i2c_bus *i2c_bus = i2c_adap->algo_data;
 534         struct em28xx *dev = i2c_bus->dev;
 535         unsigned int bus = i2c_bus->bus;
 536         int addr, rc, i;
 537         u8 reg;
 538 
 539         /*
 540          * prevent i2c xfer attempts after device is disconnected
 541          * some fe's try to do i2c writes/reads from their release
 542          * interfaces when called in disconnect path
 543          */
 544         if (dev->disconnected)
 545                 return -ENODEV;
 546 
 547         if (!rt_mutex_trylock(&dev->i2c_bus_lock))
 548                 return -EAGAIN;
 549 
 550         /* Switch I2C bus if needed */
 551         if (bus != dev->cur_i2c_bus &&
 552             i2c_bus->algo_type == EM28XX_I2C_ALGO_EM28XX) {
 553                 if (bus == 1)
 554                         reg = EM2874_I2C_SECONDARY_BUS_SELECT;
 555                 else
 556                         reg = 0;
 557                 em28xx_write_reg_bits(dev, EM28XX_R06_I2C_CLK, reg,
 558                                       EM2874_I2C_SECONDARY_BUS_SELECT);
 559                 dev->cur_i2c_bus = bus;
 560         }
 561 
 562         for (i = 0; i < num; i++) {
 563                 addr = msgs[i].addr << 1;
 564                 if (!msgs[i].len) {
 565                         /*
 566                          * no len: check only for device presence
 567                          * This code is only called during device probe.
 568                          */
 569                         rc = i2c_check_for_device(i2c_bus, addr);
 570 
 571                         if (rc == -ENXIO)
 572                                 rc = -ENODEV;
 573                 } else if (msgs[i].flags & I2C_M_RD) {
 574                         /* read bytes */
 575                         rc = i2c_recv_bytes(i2c_bus, msgs[i]);
 576                 } else {
 577                         /* write bytes */
 578                         rc = i2c_send_bytes(i2c_bus, msgs[i], i == num - 1);
 579                 }
 580 
 581                 if (rc < 0)
 582                         goto error;
 583 
 584                 dprintk(2, "%s %s addr=%02x len=%d: %*ph\n",
 585                         (msgs[i].flags & I2C_M_RD) ? "read" : "write",
 586                         i == num - 1 ? "stop" : "nonstop",
 587                         addr, msgs[i].len,
 588                         msgs[i].len, msgs[i].buf);
 589         }
 590 
 591         rt_mutex_unlock(&dev->i2c_bus_lock);
 592         return num;
 593 
 594 error:
 595         dprintk(2, "%s %s addr=%02x len=%d: %sERROR: %i\n",
 596                 (msgs[i].flags & I2C_M_RD) ? "read" : "write",
 597                 i == num - 1 ? "stop" : "nonstop",
 598                 addr, msgs[i].len,
 599                 (rc == -ENODEV) ? "no device " : "",
 600                 rc);
 601 
 602         rt_mutex_unlock(&dev->i2c_bus_lock);
 603         return rc;
 604 }
 605 
 606 /*
 607  * based on linux/sunrpc/svcauth.h and linux/hash.h
 608  * The original hash function returns a different value, if arch is x86_64
 609  * or i386.
 610  */
 611 static inline unsigned long em28xx_hash_mem(char *buf, int length, int bits)
 612 {
 613         unsigned long hash = 0;
 614         unsigned long l = 0;
 615         int len = 0;
 616         unsigned char c;
 617 
 618         do {
 619                 if (len == length) {
 620                         c = (char)len;
 621                         len = -1;
 622                 } else {
 623                         c = *buf++;
 624                 }
 625                 l = (l << 8) | c;
 626                 len++;
 627                 if ((len & (32 / 8 - 1)) == 0)
 628                         hash = ((hash ^ l) * 0x9e370001UL);
 629         } while (len);
 630 
 631         return (hash >> (32 - bits)) & 0xffffffffUL;
 632 }
 633 
 634 /*
 635  * Helper function to read data blocks from i2c clients with 8 or 16 bit
 636  * address width, 8 bit register width and auto incrementation been activated
 637  */
 638 static int em28xx_i2c_read_block(struct em28xx *dev, unsigned int bus, u16 addr,
 639                                  bool addr_w16, u16 len, u8 *data)
 640 {
 641         int remain = len, rsize, rsize_max, ret;
 642         u8 buf[2];
 643 
 644         /* Sanity check */
 645         if (addr + remain > (addr_w16 * 0xff00 + 0xff + 1))
 646                 return -EINVAL;
 647         /* Select address */
 648         buf[0] = addr >> 8;
 649         buf[1] = addr & 0xff;
 650         ret = i2c_master_send(&dev->i2c_client[bus],
 651                               buf + !addr_w16, 1 + addr_w16);
 652         if (ret < 0)
 653                 return ret;
 654         /* Read data */
 655         if (dev->board.is_em2800)
 656                 rsize_max = 4;
 657         else
 658                 rsize_max = 64;
 659         while (remain > 0) {
 660                 if (remain > rsize_max)
 661                         rsize = rsize_max;
 662                 else
 663                         rsize = remain;
 664 
 665                 ret = i2c_master_recv(&dev->i2c_client[bus], data, rsize);
 666                 if (ret < 0)
 667                         return ret;
 668 
 669                 remain -= rsize;
 670                 data += rsize;
 671         }
 672 
 673         return len;
 674 }
 675 
 676 static int em28xx_i2c_eeprom(struct em28xx *dev, unsigned int bus,
 677                              u8 **eedata, u16 *eedata_len)
 678 {
 679         const u16 len = 256;
 680         /*
 681          * FIXME common length/size for bytes to read, to display, hash
 682          * calculation and returned device dataset. Simplifies the code a lot,
 683          * but we might have to deal with multiple sizes in the future !
 684          */
 685         int err;
 686         struct em28xx_eeprom *dev_config;
 687         u8 buf, *data;
 688 
 689         *eedata = NULL;
 690         *eedata_len = 0;
 691 
 692         /* EEPROM is always on i2c bus 0 on all known devices. */
 693 
 694         dev->i2c_client[bus].addr = 0xa0 >> 1;
 695 
 696         /* Check if board has eeprom */
 697         err = i2c_master_recv(&dev->i2c_client[bus], &buf, 0);
 698         if (err < 0) {
 699                 dev_info(&dev->intf->dev, "board has no eeprom\n");
 700                 return -ENODEV;
 701         }
 702 
 703         data = kzalloc(len, GFP_KERNEL);
 704         if (!data)
 705                 return -ENOMEM;
 706 
 707         /* Read EEPROM content */
 708         err = em28xx_i2c_read_block(dev, bus, 0x0000,
 709                                     dev->eeprom_addrwidth_16bit,
 710                                     len, data);
 711         if (err != len) {
 712                 dev_err(&dev->intf->dev,
 713                         "failed to read eeprom (err=%d)\n", err);
 714                 goto error;
 715         }
 716 
 717         if (i2c_debug) {
 718                 /* Display eeprom content */
 719                 print_hex_dump(KERN_DEBUG, "em28xx eeprom ", DUMP_PREFIX_OFFSET,
 720                                16, 1, data, len, true);
 721 
 722                 if (dev->eeprom_addrwidth_16bit)
 723                         dev_info(&dev->intf->dev,
 724                                  "eeprom %06x: ... (skipped)\n", 256);
 725         }
 726 
 727         if (dev->eeprom_addrwidth_16bit &&
 728             data[0] == 0x26 && data[3] == 0x00) {
 729                 /* new eeprom format; size 4-64kb */
 730                 u16 mc_start;
 731                 u16 hwconf_offset;
 732 
 733                 dev->hash = em28xx_hash_mem(data, len, 32);
 734                 mc_start = (data[1] << 8) + 4;  /* usually 0x0004 */
 735 
 736                 dev_info(&dev->intf->dev,
 737                          "EEPROM ID = %4ph, EEPROM hash = 0x%08lx\n",
 738                          data, dev->hash);
 739                 dev_info(&dev->intf->dev,
 740                          "EEPROM info:\n");
 741                 dev_info(&dev->intf->dev,
 742                          "\tmicrocode start address = 0x%04x, boot configuration = 0x%02x\n",
 743                          mc_start, data[2]);
 744                 /*
 745                  * boot configuration (address 0x0002):
 746                  * [0]   microcode download speed: 1 = 400 kHz; 0 = 100 kHz
 747                  * [1]   always selects 12 kb RAM
 748                  * [2]   USB device speed: 1 = force Full Speed; 0 = auto detect
 749                  * [4]   1 = force fast mode and no suspend for device testing
 750                  * [5:7] USB PHY tuning registers; determined by device
 751                  *       characterization
 752                  */
 753 
 754                 /*
 755                  * Read hardware config dataset offset from address
 756                  * (microcode start + 46)
 757                  */
 758                 err = em28xx_i2c_read_block(dev, bus, mc_start + 46, 1, 2,
 759                                             data);
 760                 if (err != 2) {
 761                         dev_err(&dev->intf->dev,
 762                                 "failed to read hardware configuration data from eeprom (err=%d)\n",
 763                                 err);
 764                         goto error;
 765                 }
 766 
 767                 /* Calculate hardware config dataset start address */
 768                 hwconf_offset = mc_start + data[0] + (data[1] << 8);
 769 
 770                 /* Read hardware config dataset */
 771                 /*
 772                  * NOTE: the microcode copy can be multiple pages long, but
 773                  * we assume the hardware config dataset is the same as in
 774                  * the old eeprom and not longer than 256 bytes.
 775                  * tveeprom is currently also limited to 256 bytes.
 776                  */
 777                 err = em28xx_i2c_read_block(dev, bus, hwconf_offset, 1, len,
 778                                             data);
 779                 if (err != len) {
 780                         dev_err(&dev->intf->dev,
 781                                 "failed to read hardware configuration data from eeprom (err=%d)\n",
 782                                 err);
 783                         goto error;
 784                 }
 785 
 786                 /* Verify hardware config dataset */
 787                 /* NOTE: not all devices provide this type of dataset */
 788                 if (data[0] != 0x1a || data[1] != 0xeb ||
 789                     data[2] != 0x67 || data[3] != 0x95) {
 790                         dev_info(&dev->intf->dev,
 791                                  "\tno hardware configuration dataset found in eeprom\n");
 792                         kfree(data);
 793                         return 0;
 794                 }
 795 
 796                 /*
 797                  * TODO: decrypt eeprom data for camera bridges
 798                  * (em25xx, em276x+)
 799                  */
 800 
 801         } else if (!dev->eeprom_addrwidth_16bit &&
 802                    data[0] == 0x1a && data[1] == 0xeb &&
 803                    data[2] == 0x67 && data[3] == 0x95) {
 804                 dev->hash = em28xx_hash_mem(data, len, 32);
 805                 dev_info(&dev->intf->dev,
 806                          "EEPROM ID = %4ph, EEPROM hash = 0x%08lx\n",
 807                          data, dev->hash);
 808                 dev_info(&dev->intf->dev,
 809                          "EEPROM info:\n");
 810         } else {
 811                 dev_info(&dev->intf->dev,
 812                          "unknown eeprom format or eeprom corrupted !\n");
 813                 err = -ENODEV;
 814                 goto error;
 815         }
 816 
 817         *eedata = data;
 818         *eedata_len = len;
 819         dev_config = (void *)*eedata;
 820 
 821         switch (le16_to_cpu(dev_config->chip_conf) >> 4 & 0x3) {
 822         case 0:
 823                 dev_info(&dev->intf->dev, "\tNo audio on board.\n");
 824                 break;
 825         case 1:
 826                 dev_info(&dev->intf->dev, "\tAC97 audio (5 sample rates)\n");
 827                 break;
 828         case 2:
 829                 if (dev->chip_id < CHIP_ID_EM2860)
 830                         dev_info(&dev->intf->dev,
 831                                  "\tI2S audio, sample rate=32k\n");
 832                 else
 833                         dev_info(&dev->intf->dev,
 834                                  "\tI2S audio, 3 sample rates\n");
 835                 break;
 836         case 3:
 837                 if (dev->chip_id < CHIP_ID_EM2860)
 838                         dev_info(&dev->intf->dev,
 839                                  "\tI2S audio, 3 sample rates\n");
 840                 else
 841                         dev_info(&dev->intf->dev,
 842                                  "\tI2S audio, 5 sample rates\n");
 843                 break;
 844         }
 845 
 846         if (le16_to_cpu(dev_config->chip_conf) & 1 << 3)
 847                 dev_info(&dev->intf->dev, "\tUSB Remote wakeup capable\n");
 848 
 849         if (le16_to_cpu(dev_config->chip_conf) & 1 << 2)
 850                 dev_info(&dev->intf->dev, "\tUSB Self power capable\n");
 851 
 852         switch (le16_to_cpu(dev_config->chip_conf) & 0x3) {
 853         case 0:
 854                 dev_info(&dev->intf->dev, "\t500mA max power\n");
 855                 break;
 856         case 1:
 857                 dev_info(&dev->intf->dev, "\t400mA max power\n");
 858                 break;
 859         case 2:
 860                 dev_info(&dev->intf->dev, "\t300mA max power\n");
 861                 break;
 862         case 3:
 863                 dev_info(&dev->intf->dev, "\t200mA max power\n");
 864                 break;
 865         }
 866         dev_info(&dev->intf->dev,
 867                  "\tTable at offset 0x%02x, strings=0x%04x, 0x%04x, 0x%04x\n",
 868                  dev_config->string_idx_table,
 869                  le16_to_cpu(dev_config->string1),
 870                  le16_to_cpu(dev_config->string2),
 871                  le16_to_cpu(dev_config->string3));
 872 
 873         return 0;
 874 
 875 error:
 876         kfree(data);
 877         return err;
 878 }
 879 
 880 /* ----------------------------------------------------------- */
 881 
 882 /*
 883  * functionality()
 884  */
 885 static u32 functionality(struct i2c_adapter *i2c_adap)
 886 {
 887         struct em28xx_i2c_bus *i2c_bus = i2c_adap->algo_data;
 888 
 889         if (i2c_bus->algo_type == EM28XX_I2C_ALGO_EM28XX ||
 890             i2c_bus->algo_type == EM28XX_I2C_ALGO_EM25XX_BUS_B) {
 891                 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 892         } else if (i2c_bus->algo_type == EM28XX_I2C_ALGO_EM2800)  {
 893                 return (I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL) &
 894                         ~I2C_FUNC_SMBUS_WRITE_BLOCK_DATA;
 895         }
 896 
 897         WARN(1, "Unknown i2c bus algorithm.\n");
 898         return 0;
 899 }
 900 
 901 static const struct i2c_algorithm em28xx_algo = {
 902         .master_xfer   = em28xx_i2c_xfer,
 903         .functionality = functionality,
 904 };
 905 
 906 static const struct i2c_adapter em28xx_adap_template = {
 907         .owner = THIS_MODULE,
 908         .name = "em28xx",
 909         .algo = &em28xx_algo,
 910 };
 911 
 912 static const struct i2c_client em28xx_client_template = {
 913         .name = "em28xx internal",
 914 };
 915 
 916 /* ----------------------------------------------------------- */
 917 
 918 /*
 919  * i2c_devs
 920  * incomplete list of known devices
 921  */
 922 static char *i2c_devs[128] = {
 923         [0x1c >> 1] = "lgdt330x",
 924         [0x3e >> 1] = "remote IR sensor",
 925         [0x4a >> 1] = "saa7113h",
 926         [0x52 >> 1] = "drxk",
 927         [0x60 >> 1] = "remote IR sensor",
 928         [0x8e >> 1] = "remote IR sensor",
 929         [0x86 >> 1] = "tda9887",
 930         [0x80 >> 1] = "msp34xx",
 931         [0x88 >> 1] = "msp34xx",
 932         [0xa0 >> 1] = "eeprom",
 933         [0xb0 >> 1] = "tda9874",
 934         [0xb8 >> 1] = "tvp5150a",
 935         [0xba >> 1] = "webcam sensor or tvp5150a",
 936         [0xc0 >> 1] = "tuner (analog)",
 937         [0xc2 >> 1] = "tuner (analog)",
 938         [0xc4 >> 1] = "tuner (analog)",
 939         [0xc6 >> 1] = "tuner (analog)",
 940 };
 941 
 942 /*
 943  * do_i2c_scan()
 944  * check i2c address range for devices
 945  */
 946 void em28xx_do_i2c_scan(struct em28xx *dev, unsigned int bus)
 947 {
 948         u8 i2c_devicelist[128];
 949         unsigned char buf;
 950         int i, rc;
 951 
 952         memset(i2c_devicelist, 0, ARRAY_SIZE(i2c_devicelist));
 953 
 954         for (i = 0; i < ARRAY_SIZE(i2c_devs); i++) {
 955                 dev->i2c_client[bus].addr = i;
 956                 rc = i2c_master_recv(&dev->i2c_client[bus], &buf, 0);
 957                 if (rc < 0)
 958                         continue;
 959                 i2c_devicelist[i] = i;
 960                 dev_info(&dev->intf->dev,
 961                          "found i2c device @ 0x%x on bus %d [%s]\n",
 962                          i << 1, bus, i2c_devs[i] ? i2c_devs[i] : "???");
 963         }
 964 
 965         if (bus == dev->def_i2c_bus)
 966                 dev->i2c_hash = em28xx_hash_mem(i2c_devicelist,
 967                                                 ARRAY_SIZE(i2c_devicelist), 32);
 968 }
 969 
 970 /*
 971  * em28xx_i2c_register()
 972  * register i2c bus
 973  */
 974 int em28xx_i2c_register(struct em28xx *dev, unsigned int bus,
 975                         enum em28xx_i2c_algo_type algo_type)
 976 {
 977         int retval;
 978 
 979         if (WARN_ON(!dev->em28xx_write_regs || !dev->em28xx_read_reg ||
 980                     !dev->em28xx_write_regs_req || !dev->em28xx_read_reg_req))
 981                 return -ENODEV;
 982 
 983         if (bus >= NUM_I2C_BUSES)
 984                 return -ENODEV;
 985 
 986         dev->i2c_adap[bus] = em28xx_adap_template;
 987         dev->i2c_adap[bus].dev.parent = &dev->intf->dev;
 988         strscpy(dev->i2c_adap[bus].name, dev_name(&dev->intf->dev),
 989                 sizeof(dev->i2c_adap[bus].name));
 990 
 991         dev->i2c_bus[bus].bus = bus;
 992         dev->i2c_bus[bus].algo_type = algo_type;
 993         dev->i2c_bus[bus].dev = dev;
 994         dev->i2c_adap[bus].algo_data = &dev->i2c_bus[bus];
 995 
 996         retval = i2c_add_adapter(&dev->i2c_adap[bus]);
 997         if (retval < 0) {
 998                 dev_err(&dev->intf->dev,
 999                         "%s: i2c_add_adapter failed! retval [%d]\n",
1000                         __func__, retval);
1001                 return retval;
1002         }
1003 
1004         dev->i2c_client[bus] = em28xx_client_template;
1005         dev->i2c_client[bus].adapter = &dev->i2c_adap[bus];
1006 
1007         /* Up to now, all eeproms are at bus 0 */
1008         if (!bus) {
1009                 retval = em28xx_i2c_eeprom(dev, bus,
1010                                            &dev->eedata, &dev->eedata_len);
1011                 if (retval < 0 && retval != -ENODEV) {
1012                         dev_err(&dev->intf->dev,
1013                                 "%s: em28xx_i2_eeprom failed! retval [%d]\n",
1014                                 __func__, retval);
1015                 }
1016         }
1017 
1018         if (i2c_scan)
1019                 em28xx_do_i2c_scan(dev, bus);
1020 
1021         return 0;
1022 }
1023 
1024 /*
1025  * em28xx_i2c_unregister()
1026  * unregister i2c_bus
1027  */
1028 int em28xx_i2c_unregister(struct em28xx *dev, unsigned int bus)
1029 {
1030         if (bus >= NUM_I2C_BUSES)
1031                 return -ENODEV;
1032 
1033         i2c_del_adapter(&dev->i2c_adap[bus]);
1034         return 0;
1035 }