drivers/media/common/saa7146_i2c.c

   1 #include <media/saa7146_vv.h>
   2
   3 static u32 saa7146_i2c_func(struct i2c_adapter *adapter)
   4 {
   5 //fm    DEB_I2C(("'%s'.\n", adapter->name));
   6
   7         return    I2C_FUNC_I2C
   8                 | I2C_FUNC_SMBUS_QUICK
   9                 | I2C_FUNC_SMBUS_READ_BYTE      | I2C_FUNC_SMBUS_WRITE_BYTE
  10                 | I2C_FUNC_SMBUS_READ_BYTE_DATA | I2C_FUNC_SMBUS_WRITE_BYTE_DATA;
  11 }
  12
  13 /* this function returns the status-register of our i2c-device */
  14 static inline u32 saa7146_i2c_status(struct saa7146_dev *dev)
  15 {
  16         u32 iicsta = saa7146_read(dev, I2C_STATUS);
  17 /*
  18         DEB_I2C(("status: 0x%08x\n",iicsta));
  19 */
  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, u32 *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 SAA7146_I2C_MEM bytes
  43            size. if we exceed this limit... */
  44         if ( (4*mem) > SAA7146_I2C_MEM ) {
  45 //fm            DEB_I2C(("cannot prepare i2c-message.\n"));
  46                 return -ENOMEM;
  47         }
  48
  49         /* be careful: clear out the i2c-mem first */
  50         memset(op,0,sizeof(u32)*mem);
  51
  52         /* loop through all messages */
  53         for(i = 0; i < num; i++) {
  54
  55                 /* insert the address of the i2c-slave.
  56                    note: we get 7 bit i2c-addresses,
  57                    so we have to perform a translation */
  58                 addr = (m[i].addr*2) + ( (0 != (m[i].flags & I2C_M_RD)) ? 1 : 0);
  59                 h1 = op_count/3; h2 = op_count%3;
  60                 op[h1] |= (         (u8)addr << ((3-h2)*8));
  61                 op[h1] |= (SAA7146_I2C_START << ((3-h2)*2));
  62                 op_count++;
  63
  64                 /* loop through all bytes of message i */
  65                 for(j = 0; j < m[i].len; j++) {
  66                         /* insert the data bytes */
  67                         h1 = op_count/3; h2 = op_count%3;
  68                         op[h1] |= ( (u32)((u8)m[i].buf[j]) << ((3-h2)*8));
  69                         op[h1] |= (       SAA7146_I2C_CONT << ((3-h2)*2));
  70                         op_count++;
  71                 }
  72
  73         }
  74
  75         /* have a look at the last byte inserted:
  76           if it was: ...CONT change it to ...STOP */
  77         h1 = (op_count-1)/3; h2 = (op_count-1)%3;
  78         if ( SAA7146_I2C_CONT == (0x3 & (op[h1] >> ((3-h2)*2))) ) {
  79                 op[h1] &= ~(0x2 << ((3-h2)*2));
  80                 op[h1] |= (SAA7146_I2C_STOP << ((3-h2)*2));
  81         }
  82
  83         /* return the number of u32s to send */
  84         return mem;
  85 }
  86
  87 /* this functions loops through all i2c-messages. normally, it should determine
  88    which bytes were read through the adapter and write them back to the corresponding
  89    i2c-message. but instead, we simply write back all bytes.
  90    fixme: this could be improved. */
  91 static int saa7146_i2c_msg_cleanup(const struct i2c_msg *m, int num, u32 *op)
  92 {
  93         int i, j;
  94         int op_count = 0;
  95
  96         /* loop through all messages */
  97         for(i = 0; i < num; i++) {
  98
  99                 op_count++;
 100
 101                 /* loop throgh all bytes of message i */
 102                 for(j = 0; j < m[i].len; j++) {
 103                         /* write back all bytes that could have been read */
 104                         m[i].buf[j] = (op[op_count/3] >> ((3-(op_count%3))*8));
 105                         op_count++;
 106                 }
 107         }
 108
 109         return 0;
 110 }
 111
 112 /* this functions resets the i2c-device and returns 0 if everything was fine, otherwise -1 */
 113 static int saa7146_i2c_reset(struct saa7146_dev *dev)
 114 {
 115         /* get current status */
 116         u32 status = saa7146_i2c_status(dev);
 117
 118         /* clear registers for sure */
 119         saa7146_write(dev, I2C_STATUS, dev->i2c_bitrate);
 120         saa7146_write(dev, I2C_TRANSFER, 0);
 121
 122         /* check if any operation is still in progress */
 123         if ( 0 != ( status & SAA7146_I2C_BUSY) ) {
 124
 125                 /* yes, kill ongoing operation */
 126                 DEB_I2C(("busy_state detected.\n"));
 127
 128                 /* set "ABORT-OPERATION"-bit (bit 7)*/
 129                 saa7146_write(dev, I2C_STATUS, (dev->i2c_bitrate | MASK_07));
 130                 saa7146_write(dev, MC2, (MASK_00 | MASK_16));
 131                 msleep(SAA7146_I2C_DELAY);
 132
 133                 /* clear all error-bits pending; this is needed because p.123, note 1 */
 134                 saa7146_write(dev, I2C_STATUS, dev->i2c_bitrate);
 135                 saa7146_write(dev, MC2, (MASK_00 | MASK_16));
 136                 msleep(SAA7146_I2C_DELAY);
 137         }
 138
 139         /* check if any error is (still) present. (this can be necessary because p.123, note 1) */
 140         status = saa7146_i2c_status(dev);
 141
 142         if ( dev->i2c_bitrate != status ) {
 143
 144                 DEB_I2C(("error_state detected. status:0x%08x\n",status));
 145
 146                 /* Repeat the abort operation. This seems to be necessary
 147                    after serious protocol errors caused by e.g. the SAA7740 */
 148                 saa7146_write(dev, I2C_STATUS, (dev->i2c_bitrate | MASK_07));
 149                 saa7146_write(dev, MC2, (MASK_00 | MASK_16));
 150                 msleep(SAA7146_I2C_DELAY);
 151
 152                 /* clear all error-bits pending */
 153                 saa7146_write(dev, I2C_STATUS, dev->i2c_bitrate);
 154                 saa7146_write(dev, MC2, (MASK_00 | MASK_16));
 155                 msleep(SAA7146_I2C_DELAY);
 156
 157                 /* the data sheet says it might be necessary to clear the status
 158                    twice after an abort */
 159                 saa7146_write(dev, I2C_STATUS, dev->i2c_bitrate);
 160                 saa7146_write(dev, MC2, (MASK_00 | MASK_16));
 161                 msleep(SAA7146_I2C_DELAY);
 162         }
 163
 164         /* if any error is still present, a fatal error has occured ... */
 165         status = saa7146_i2c_status(dev);
 166         if ( dev->i2c_bitrate != status ) {
 167                 DEB_I2C(("fatal error. status:0x%08x\n",status));
 168                 return -1;
 169         }
 170
 171         return 0;
 172 }
 173
 174 /* this functions writes out the data-byte 'dword' to the i2c-device.
 175    it returns 0 if ok, -1 if the transfer failed, -2 if the transfer
 176    failed badly (e.g. address error) */
 177 static int saa7146_i2c_writeout(struct saa7146_dev *dev, u32* dword, int short_delay)
 178 {
 179         u32 status = 0, mc2 = 0;
 180         int trial = 0;
 181         unsigned long timeout;
 182
 183         /* write out i2c-command */
 184         DEB_I2C(("before: 0x%08x (status: 0x%08x), %d\n",*dword,saa7146_read(dev, I2C_STATUS), dev->i2c_op));
 185
 186         if( 0 != (SAA7146_USE_I2C_IRQ & dev->ext->flags)) {
 187
 188                 saa7146_write(dev, I2C_STATUS,   dev->i2c_bitrate);
 189                 saa7146_write(dev, I2C_TRANSFER, *dword);
 190
 191                 dev->i2c_op = 1;
 192                 SAA7146_IER_ENABLE(dev, MASK_16|MASK_17);
 193                 saa7146_write(dev, MC2, (MASK_00 | MASK_16));
 194
 195                 wait_event_interruptible(dev->i2c_wq, dev->i2c_op == 0);
 196                 if (signal_pending (current)) {
 197                         /* a signal arrived */
 198                         return -ERESTARTSYS;
 199                 }
 200                 status = saa7146_read(dev, I2C_STATUS);
 201         } else {
 202                 saa7146_write(dev, I2C_STATUS,   dev->i2c_bitrate);
 203                 saa7146_write(dev, I2C_TRANSFER, *dword);
 204                 saa7146_write(dev, MC2, (MASK_00 | MASK_16));
 205
 206                 /* do not poll for i2c-status before upload is complete */
 207                 timeout = jiffies + HZ/100 + 1; /* 10ms */
 208                 while(1) {
 209                         mc2 = (saa7146_read(dev, MC2) & 0x1);
 210                         if( 0 != mc2 ) {
 211                                 break;
 212                         }
 213                         if (time_after(jiffies,timeout)) {
 214                                 printk(KERN_WARNING "saa7146_i2c_writeout: timed out waiting for MC2\n");
 215                                 return -EIO;
 216                         }
 217                 }
 218                 /* wait until we get a transfer done or error */
 219                 timeout = jiffies + HZ/100 + 1; /* 10ms */
 220                 /* first read usually delivers bogus results... */
 221                 saa7146_i2c_status(dev);
 222                 while(1) {
 223                         status = saa7146_i2c_status(dev);
 224                         if ((status & 0x3) != 1)
 225                                 break;
 226                         if (time_after(jiffies,timeout)) {
 227                                 /* this is normal when probing the bus
 228                                  * (no answer from nonexisistant device...)
 229                                  */
 230                                 DEB_I2C(("saa7146_i2c_writeout: timed out waiting for end of xfer\n"));
 231                                 return -EIO;
 232                         }
 233                         if (++trial < 50 && short_delay)
 234                                 udelay(10);
 235                         else
 236                                 msleep(1);
 237                 }
 238         }
 239
 240         /* give a detailed status report */
 241         if ( 0 != (status & SAA7146_I2C_ERR)) {
 242
 243                 if( 0 != (status & SAA7146_I2C_SPERR) ) {
 244                         DEB_I2C(("error due to invalid start/stop condition.\n"));
 245                 }
 246                 if( 0 != (status & SAA7146_I2C_DTERR) ) {
 247                         DEB_I2C(("error in data transmission.\n"));
 248                 }
 249                 if( 0 != (status & SAA7146_I2C_DRERR) ) {
 250                         DEB_I2C(("error when receiving data.\n"));
 251                 }
 252                 if( 0 != (status & SAA7146_I2C_AL) ) {
 253                         DEB_I2C(("error because arbitration lost.\n"));
 254                 }
 255
 256                 /* we handle address-errors here */
 257                 if( 0 != (status & SAA7146_I2C_APERR) ) {
 258                         DEB_I2C(("error in address phase.\n"));
 259                         return -EREMOTEIO;
 260                 }
 261
 262                 return -EIO;
 263         }
 264
 265         /* read back data, just in case we were reading ... */
 266         *dword = saa7146_read(dev, I2C_TRANSFER);
 267
 268         DEB_I2C(("after: 0x%08x\n",*dword));
 269         return 0;
 270 }
 271
 272 int saa7146_i2c_transfer(struct saa7146_dev *dev, const struct i2c_msg *msgs, int num, int retries)
 273 {
 274         int i = 0, count = 0;
 275         u32* buffer = dev->d_i2c.cpu_addr;
 276         int err = 0;
 277         int address_err = 0;
 278         int short_delay = 0;
 279
 280         if (mutex_lock_interruptible(&dev->i2c_lock))
 281                 return -ERESTARTSYS;
 282
 283         for(i=0;i<num;i++) {
 284                 DEB_I2C(("msg:%d/%d\n",i+1,num));
 285         }
 286
 287         /* prepare the message(s), get number of u32s to transfer */
 288         count = saa7146_i2c_msg_prepare(msgs, num, buffer);
 289         if ( 0 > count ) {
 290                 err = -1;
 291                 goto out;
 292         }
 293
 294         if ( count > 3 || 0 != (SAA7146_I2C_SHORT_DELAY & dev->ext->flags) )
 295                 short_delay = 1;
 296
 297         do {
 298                 /* reset the i2c-device if necessary */
 299                 err = saa7146_i2c_reset(dev);
 300                 if ( 0 > err ) {
 301                         DEB_I2C(("could not reset i2c-device.\n"));
 302                         goto out;
 303                 }
 304
 305                 /* write out the u32s one after another */
 306                 for(i = 0; i < count; i++) {
 307                         err = saa7146_i2c_writeout(dev, &buffer[i], short_delay);
 308                         if ( 0 != err) {
 309                                 /* this one is unsatisfying: some i2c slaves on some
 310                                    dvb cards don't acknowledge correctly, so the saa7146
 311                                    thinks that an address error occured. in that case, the
 312                                    transaction should be retrying, even if an address error
 313                                    occured. analog saa7146 based cards extensively rely on
 314                                    i2c address probing, however, and address errors indicate that a
 315                                    device is really *not* there. retrying in that case
 316                                    increases the time the device needs to probe greatly, so
 317                                    it should be avoided. because of the fact, that only
 318                                    analog based cards use irq based i2c transactions (for dvb
 319                                    cards, this screwes up other interrupt sources), we bail out
 320                                    completely for analog cards after an address error and trust
 321                                    the saa7146 address error detection. */
 322                                 if ( -EREMOTEIO == err ) {
 323                                         if( 0 != (SAA7146_USE_I2C_IRQ & dev->ext->flags)) {
 324                                                 goto out;
 325                                         }
 326                                         address_err++;
 327                                 }
 328                                 DEB_I2C(("error while sending message(s). starting again.\n"));
 329                                 break;
 330                         }
 331                 }
 332                 if( 0 == err ) {
 333                         err = num;
 334                         break;
 335                 }
 336
 337                 /* delay a bit before retrying */
 338                 msleep(10);
 339
 340         } while (err != num && retries--);
 341
 342         /* if every retry had an address error, exit right away */
 343         if (address_err == retries) {
 344                 goto out;
 345         }
 346
 347         /* if any things had to be read, get the results */
 348         if ( 0 != saa7146_i2c_msg_cleanup(msgs, num, buffer)) {
 349                 DEB_I2C(("could not cleanup i2c-message.\n"));
 350                 err = -1;
 351                 goto out;
 352         }
 353
 354         /* return the number of delivered messages */
 355         DEB_I2C(("transmission successful. (msg:%d).\n",err));
 356 out:
 357         /* another bug in revision 0: the i2c-registers get uploaded randomly by other
 358            uploads, so we better clear them out before continueing */
 359         if( 0 == dev->revision ) {
 360                 u32 zero = 0;
 361                 saa7146_i2c_reset(dev);
 362                 if( 0 != saa7146_i2c_writeout(dev, &zero, short_delay)) {
 363                         INFO(("revision 0 error. this should never happen.\n"));
 364                 }
 365         }
 366
 367         mutex_unlock(&dev->i2c_lock);
 368         return err;
 369 }
 370
 371 /* utility functions */
 372 static int saa7146_i2c_xfer(struct i2c_adapter* adapter, struct i2c_msg *msg, int num)
 373 {
 374         struct saa7146_dev* dev = i2c_get_adapdata(adapter);
 375
 376         /* use helper function to transfer data */
 377         return saa7146_i2c_transfer(dev, msg, num, adapter->retries);
 378 }
 379
 380
 381 /*****************************************************************************/
 382 /* i2c-adapter helper functions                                              */
 383 #include <linux/i2c-id.h>
 384
 385 /* exported algorithm data */
 386 static struct i2c_algorithm saa7146_algo = {
 387         .master_xfer    = saa7146_i2c_xfer,
 388         .functionality  = saa7146_i2c_func,
 389 };
 390
 391 int saa7146_i2c_adapter_prepare(struct saa7146_dev *dev, struct i2c_adapter *i2c_adapter, u32 bitrate)
 392 {
 393         DEB_EE(("bitrate: 0x%08x\n",bitrate));
 394
 395         /* enable i2c-port pins */
 396         saa7146_write(dev, MC1, (MASK_08 | MASK_24));
 397
 398         dev->i2c_bitrate = bitrate;
 399         saa7146_i2c_reset(dev);
 400
 401         if( NULL != i2c_adapter ) {
 402                 BUG_ON(!i2c_adapter->class);
 403                 i2c_set_adapdata(i2c_adapter,dev);
 404                 i2c_adapter->dev.parent    = &dev->pci->dev;
 405                 i2c_adapter->algo          = &saa7146_algo;
 406                 i2c_adapter->algo_data     = NULL;
 407                 i2c_adapter->id            = I2C_HW_SAA7146;
 408                 i2c_adapter->timeout = SAA7146_I2C_TIMEOUT;
 409                 i2c_adapter->retries = SAA7146_I2C_RETRIES;
 410         }
 411
 412         return 0;
 413 }