drivers/media/common/saa7146/saa7146_i2c.c

   1 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   2
   3 #include <media/saa7146_vv.h>
   4
   5 static u32 saa7146_i2c_func(struct i2c_adapter *adapter)
   6 {
   7         /* DEB_I2C("'%s'\n", adapter->name); */
   8
   9         return    I2C_FUNC_I2C
  10                 | I2C_FUNC_SMBUS_QUICK
  11                 | I2C_FUNC_SMBUS_READ_BYTE      | I2C_FUNC_SMBUS_WRITE_BYTE
  12                 | I2C_FUNC_SMBUS_READ_BYTE_DATA | I2C_FUNC_SMBUS_WRITE_BYTE_DATA;
  13 }
  14
  15 /* this function returns the status-register of our i2c-device */
  16 static inline u32 saa7146_i2c_status(struct saa7146_dev *dev)
  17 {
  18         u32 iicsta = saa7146_read(dev, I2C_STATUS);
  19         /* DEB_I2C("status: 0x%08x\n", iicsta); */
  20         return iicsta;
  21 }
  22
  23 /* this function runs through the i2c-messages and prepares the data to be
  24    sent through the saa7146. have a look at the specifications p. 122 ff
  25    to understand this. it returns the number of u32s to send, or -1
  26    in case of an error. */
  27 static int saa7146_i2c_msg_prepare(const struct i2c_msg *m, int num, __le32 *op)
  28 {
  29         int h1, h2;
  30         int i, j, addr;
  31         int mem = 0, op_count = 0;
  32
  33         /* first determine size of needed memory */
  34         for(i = 0; i < num; i++) {
  35                 mem += m[i].len + 1;
  36         }
  37
  38         /* worst case: we need one u32 for three bytes to be send
  39            plus one extra byte to address the device */
  40         mem = 1 + ((mem-1) / 3);
  41
  42         /* we assume that op points to a memory of at least
  43          * SAA7146_I2C_MEM bytes size. if we exceed this limit...
  44          */
  45         if ((4 * mem) > SAA7146_I2C_MEM) {
  46                 /* DEB_I2C("cannot prepare i2c-message\n"); */
  47                 return -ENOMEM;
  48         }
  49
  50         /* be careful: clear out the i2c-mem first */
  51         memset(op,0,sizeof(__le32)*mem);
  52
  53         /* loop through all messages */
  54         for(i = 0; i < num; i++) {
  55
  56                 /* insert the address of the i2c-slave.
  57                    note: we get 7 bit i2c-addresses,
  58                    so we have to perform a translation */
  59                 addr = (m[i].addr*2) + ( (0 != (m[i].flags & I2C_M_RD)) ? 1 : 0);
  60                 h1 = op_count/3; h2 = op_count%3;
  61                 op[h1] |= cpu_to_le32(      (u8)addr << ((3-h2)*8));
  62                 op[h1] |= cpu_to_le32(SAA7146_I2C_START << ((3-h2)*2));
  63                 op_count++;
  64
  65                 /* loop through all bytes of message i */
  66                 for(j = 0; j < m[i].len; j++) {
  67                         /* insert the data bytes */
  68                         h1 = op_count/3; h2 = op_count%3;
  69                         op[h1] |= cpu_to_le32( (u32)((u8)m[i].buf[j]) << ((3-h2)*8));
  70                         op[h1] |= cpu_to_le32(       SAA7146_I2C_CONT << ((3-h2)*2));
  71                         op_count++;
  72                 }
  73
  74         }
  75
  76         /* have a look at the last byte inserted:
  77           if it was: ...CONT change it to ...STOP */
  78         h1 = (op_count-1)/3; h2 = (op_count-1)%3;
  79         if ( SAA7146_I2C_CONT == (0x3 & (le32_to_cpu(op[h1]) >> ((3-h2)*2))) ) {
  80                 op[h1] &= ~cpu_to_le32(0x2 << ((3-h2)*2));
  81                 op[h1] |= cpu_to_le32(SAA7146_I2C_STOP << ((3-h2)*2));
  82         }
  83
  84         /* return the number of u32s to send */
  85         return mem;
  86 }
  87
  88 /* this functions loops through all i2c-messages. normally, it should determine
  89    which bytes were read through the adapter and write them back to the corresponding
  90    i2c-message. but instead, we simply write back all bytes.
  91    fixme: this could be improved. */
  92 static int saa7146_i2c_msg_cleanup(const struct i2c_msg *m, int num, __le32 *op)
  93 {
  94         int i, j;
  95         int op_count = 0;
  96
  97         /* loop through all messages */
  98         for(i = 0; i < num; i++) {
  99
 100                 op_count++;
 101
 102                 /* loop through all bytes of message i */
 103                 for(j = 0; j < m[i].len; j++) {
 104                         /* write back all bytes that could have been read */
 105                         m[i].buf[j] = (le32_to_cpu(op[op_count/3]) >> ((3-(op_count%3))*8));
 106                         op_count++;
 107                 }
 108         }
 109
 110         return 0;
 111 }
 112
 113 /* this functions resets the i2c-device and returns 0 if everything was fine, otherwise -1 */
 114 static int saa7146_i2c_reset(struct saa7146_dev *dev)
 115 {
 116         /* get current status */
 117         u32 status = saa7146_i2c_status(dev);
 118
 119         /* clear registers for sure */
 120         saa7146_write(dev, I2C_STATUS, dev->i2c_bitrate);
 121         saa7146_write(dev, I2C_TRANSFER, 0);
 122
 123         /* check if any operation is still in progress */
 124         if ( 0 != ( status & SAA7146_I2C_BUSY) ) {
 125
 126                 /* yes, kill ongoing operation */
 127                 DEB_I2C("busy_state detected\n");
 128
 129                 /* set "ABORT-OPERATION"-bit (bit 7)*/
 130                 saa7146_write(dev, I2C_STATUS, (dev->i2c_bitrate | MASK_07));
 131                 saa7146_write(dev, MC2, (MASK_00 | MASK_16));
 132                 msleep(SAA7146_I2C_DELAY);
 133
 134                 /* clear all error-bits pending; this is needed because p.123, note 1 */
 135                 saa7146_write(dev, I2C_STATUS, dev->i2c_bitrate);
 136                 saa7146_write(dev, MC2, (MASK_00 | MASK_16));
 137                 msleep(SAA7146_I2C_DELAY);
 138         }
 139
 140         /* check if any error is (still) present. (this can be necessary because p.123, note 1) */
 141         status = saa7146_i2c_status(dev);
 142
 143         if ( dev->i2c_bitrate != status ) {
 144
 145                 DEB_I2C("error_state detected. status:0x%08x\n", status);
 146
 147                 /* Repeat the abort operation. This seems to be necessary
 148                    after serious protocol errors caused by e.g. the SAA7740 */
 149                 saa7146_write(dev, I2C_STATUS, (dev->i2c_bitrate | MASK_07));
 150                 saa7146_write(dev, MC2, (MASK_00 | MASK_16));
 151                 msleep(SAA7146_I2C_DELAY);
 152
 153                 /* clear all error-bits pending */
 154                 saa7146_write(dev, I2C_STATUS, dev->i2c_bitrate);
 155                 saa7146_write(dev, MC2, (MASK_00 | MASK_16));
 156                 msleep(SAA7146_I2C_DELAY);
 157
 158                 /* the data sheet says it might be necessary to clear the status
 159                    twice after an abort */
 160                 saa7146_write(dev, I2C_STATUS, dev->i2c_bitrate);
 161                 saa7146_write(dev, MC2, (MASK_00 | MASK_16));
 162                 msleep(SAA7146_I2C_DELAY);
 163         }
 164
 165         /* if any error is still present, a fatal error has occurred ... */
 166         status = saa7146_i2c_status(dev);
 167         if ( dev->i2c_bitrate != status ) {
 168                 DEB_I2C("fatal error. status:0x%08x\n", status);
 169                 return -1;
 170         }
 171
 172         return 0;
 173 }
 174
 175 /* this functions writes out the data-byte 'dword' to the i2c-device.
 176    it returns 0 if ok, -1 if the transfer failed, -2 if the transfer
 177    failed badly (e.g. address error) */
 178 static int saa7146_i2c_writeout(struct saa7146_dev *dev, __le32 *dword, int short_delay)
 179 {
 180         u32 status = 0, mc2 = 0;
 181         int trial = 0;
 182         unsigned long timeout;
 183
 184         /* write out i2c-command */
 185         DEB_I2C("before: 0x%08x (status: 0x%08x), %d\n",
 186                 *dword, saa7146_read(dev, I2C_STATUS), dev->i2c_op);
 187
 188         if( 0 != (SAA7146_USE_I2C_IRQ & dev->ext->flags)) {
 189
 190                 saa7146_write(dev, I2C_STATUS,   dev->i2c_bitrate);
 191                 saa7146_write(dev, I2C_TRANSFER, le32_to_cpu(*dword));
 192
 193                 dev->i2c_op = 1;
 194                 SAA7146_ISR_CLEAR(dev, MASK_16|MASK_17);
 195                 SAA7146_IER_ENABLE(dev, MASK_16|MASK_17);
 196                 saa7146_write(dev, MC2, (MASK_00 | MASK_16));
 197
 198                 timeout = HZ/100 + 1; /* 10ms */
 199                 timeout = wait_event_interruptible_timeout(dev->i2c_wq, dev->i2c_op == 0, timeout);
 200                 if (timeout == -ERESTARTSYS || dev->i2c_op) {
 201                         SAA7146_IER_DISABLE(dev, MASK_16|MASK_17);
 202                         SAA7146_ISR_CLEAR(dev, MASK_16|MASK_17);
 203                         if (timeout == -ERESTARTSYS)
 204                                 /* a signal arrived */
 205                                 return -ERESTARTSYS;
 206
 207                         pr_warn("%s %s [irq]: timed out waiting for end of xfer\n",
 208                                 dev->name, __func__);
 209                         return -EIO;
 210                 }
 211                 status = saa7146_read(dev, I2C_STATUS);
 212         } else {
 213                 saa7146_write(dev, I2C_STATUS,   dev->i2c_bitrate);
 214                 saa7146_write(dev, I2C_TRANSFER, le32_to_cpu(*dword));
 215                 saa7146_write(dev, MC2, (MASK_00 | MASK_16));
 216
 217                 /* do not poll for i2c-status before upload is complete */
 218                 timeout = jiffies + HZ/100 + 1; /* 10ms */
 219                 while(1) {
 220                         mc2 = (saa7146_read(dev, MC2) & 0x1);
 221                         if( 0 != mc2 ) {
 222                                 break;
 223                         }
 224                         if (time_after(jiffies,timeout)) {
 225                                 pr_warn("%s %s: timed out waiting for MC2\n",
 226                                         dev->name, __func__);
 227                                 return -EIO;
 228                         }
 229                 }
 230                 /* wait until we get a transfer done or error */
 231                 timeout = jiffies + HZ/100 + 1; /* 10ms */
 232                 /* first read usually delivers bogus results... */
 233                 saa7146_i2c_status(dev);
 234                 while(1) {
 235                         status = saa7146_i2c_status(dev);
 236                         if ((status & 0x3) != 1)
 237                                 break;
 238                         if (time_after(jiffies,timeout)) {
 239                                 /* this is normal when probing the bus
 240                                  * (no answer from nonexisistant device...)
 241                                  */
 242                                 pr_warn("%s %s [poll]: timed out waiting for end of xfer\n",
 243                                         dev->name, __func__);
 244                                 return -EIO;
 245                         }
 246                         if (++trial < 50 && short_delay)
 247                                 udelay(10);
 248                         else
 249                                 msleep(1);
 250                 }
 251         }
 252
 253         /* give a detailed status report */
 254         if ( 0 != (status & (SAA7146_I2C_SPERR | SAA7146_I2C_APERR |
 255                              SAA7146_I2C_DTERR | SAA7146_I2C_DRERR |
 256                              SAA7146_I2C_AL    | SAA7146_I2C_ERR   |
 257                              SAA7146_I2C_BUSY)) ) {
 258
 259                 if ( 0 == (status & SAA7146_I2C_ERR) ||
 260                      0 == (status & SAA7146_I2C_BUSY) ) {
 261                         /* it may take some time until ERR goes high - ignore */
 262                         DEB_I2C("unexpected i2c status %04x\n", status);
 263                 }
 264                 if( 0 != (status & SAA7146_I2C_SPERR) ) {
 265                         DEB_I2C("error due to invalid start/stop condition\n");
 266                 }
 267                 if( 0 != (status & SAA7146_I2C_DTERR) ) {
 268                         DEB_I2C("error in data transmission\n");
 269                 }
 270                 if( 0 != (status & SAA7146_I2C_DRERR) ) {
 271                         DEB_I2C("error when receiving data\n");
 272                 }
 273                 if( 0 != (status & SAA7146_I2C_AL) ) {
 274                         DEB_I2C("error because arbitration lost\n");
 275                 }
 276
 277                 /* we handle address-errors here */
 278                 if( 0 != (status & SAA7146_I2C_APERR) ) {
 279                         DEB_I2C("error in address phase\n");
 280                         return -EREMOTEIO;
 281                 }
 282
 283                 return -EIO;
 284         }
 285
 286         /* read back data, just in case we were reading ... */
 287         *dword = cpu_to_le32(saa7146_read(dev, I2C_TRANSFER));
 288
 289         DEB_I2C("after: 0x%08x\n", *dword);
 290         return 0;
 291 }
 292
 293 static int saa7146_i2c_transfer(struct saa7146_dev *dev, const struct i2c_msg *msgs, int num, int retries)
 294 {
 295         int i = 0, count = 0;
 296         __le32 *buffer = dev->d_i2c.cpu_addr;
 297         int err = 0;
 298         int short_delay = 0;
 299
 300         if (mutex_lock_interruptible(&dev->i2c_lock))
 301                 return -ERESTARTSYS;
 302
 303         for(i=0;i<num;i++) {
 304                 DEB_I2C("msg:%d/%d\n", i+1, num);
 305         }
 306
 307         /* prepare the message(s), get number of u32s to transfer */
 308         count = saa7146_i2c_msg_prepare(msgs, num, buffer);
 309         if ( 0 > count ) {
 310                 err = -1;
 311                 goto out;
 312         }
 313
 314         if ( count > 3 || 0 != (SAA7146_I2C_SHORT_DELAY & dev->ext->flags) )
 315                 short_delay = 1;
 316
 317         do {
 318                 /* reset the i2c-device if necessary */
 319                 err = saa7146_i2c_reset(dev);
 320                 if ( 0 > err ) {
 321                         DEB_I2C("could not reset i2c-device\n");
 322                         goto out;
 323                 }
 324
 325                 /* write out the u32s one after another */
 326                 for(i = 0; i < count; i++) {
 327                         err = saa7146_i2c_writeout(dev, &buffer[i], short_delay);
 328                         if ( 0 != err) {
 329                                 /* this one is unsatisfying: some i2c slaves on some
 330                                    dvb cards don't acknowledge correctly, so the saa7146
 331                                    thinks that an address error occurred. in that case, the
 332                                    transaction should be retrying, even if an address error
 333                                    occurred. analog saa7146 based cards extensively rely on
 334                                    i2c address probing, however, and address errors indicate that a
 335                                    device is really *not* there. retrying in that case
 336                                    increases the time the device needs to probe greatly, so
 337                                    it should be avoided. So we bail out in irq mode after an
 338                                    address error and trust the saa7146 address error detection. */
 339                                 if (-EREMOTEIO == err && 0 != (SAA7146_USE_I2C_IRQ & dev->ext->flags))
 340                                         goto out;
 341                                 DEB_I2C("error while sending message(s). starting again\n");
 342                                 break;
 343                         }
 344                 }
 345                 if( 0 == err ) {
 346                         err = num;
 347                         break;
 348                 }
 349
 350                 /* delay a bit before retrying */
 351                 msleep(10);
 352
 353         } while (err != num && retries--);
 354
 355         /* quit if any error occurred */
 356         if (err != num)
 357                 goto out;
 358
 359         /* if any things had to be read, get the results */
 360         if ( 0 != saa7146_i2c_msg_cleanup(msgs, num, buffer)) {
 361                 DEB_I2C("could not cleanup i2c-message\n");
 362                 err = -1;
 363                 goto out;
 364         }
 365
 366         /* return the number of delivered messages */
 367         DEB_I2C("transmission successful. (msg:%d)\n", err);
 368 out:
 369         /* another bug in revision 0: the i2c-registers get uploaded randomly by other
 370            uploads, so we better clear them out before continuing */
 371         if( 0 == dev->revision ) {
 372                 __le32 zero = 0;
 373                 saa7146_i2c_reset(dev);
 374                 if( 0 != saa7146_i2c_writeout(dev, &zero, short_delay)) {
 375                         pr_info("revision 0 error. this should never happen\n");
 376                 }
 377         }
 378
 379         mutex_unlock(&dev->i2c_lock);
 380         return err;
 381 }
 382
 383 /* utility functions */
 384 static int saa7146_i2c_xfer(struct i2c_adapter* adapter, struct i2c_msg *msg, int num)
 385 {
 386         struct v4l2_device *v4l2_dev = i2c_get_adapdata(adapter);
 387         struct saa7146_dev *dev = to_saa7146_dev(v4l2_dev);
 388
 389         /* use helper function to transfer data */
 390         return saa7146_i2c_transfer(dev, msg, num, adapter->retries);
 391 }
 392
 393
 394 /*****************************************************************************/
 395 /* i2c-adapter helper functions                                              */
 396
 397 /* exported algorithm data */
 398 static struct i2c_algorithm saa7146_algo = {
 399         .master_xfer    = saa7146_i2c_xfer,
 400         .functionality  = saa7146_i2c_func,
 401 };
 402
 403 int saa7146_i2c_adapter_prepare(struct saa7146_dev *dev, struct i2c_adapter *i2c_adapter, u32 bitrate)
 404 {
 405         DEB_EE("bitrate: 0x%08x\n", bitrate);
 406
 407         /* enable i2c-port pins */
 408         saa7146_write(dev, MC1, (MASK_08 | MASK_24));
 409
 410         dev->i2c_bitrate = bitrate;
 411         saa7146_i2c_reset(dev);
 412
 413         if (i2c_adapter) {
 414                 i2c_set_adapdata(i2c_adapter, &dev->v4l2_dev);
 415                 i2c_adapter->dev.parent    = &dev->pci->dev;
 416                 i2c_adapter->algo          = &saa7146_algo;
 417                 i2c_adapter->algo_data     = NULL;
 418                 i2c_adapter->timeout = SAA7146_I2C_TIMEOUT;
 419                 i2c_adapter->retries = SAA7146_I2C_RETRIES;
 420         }
 421
 422         return 0;
 423 }