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_ISR_CLEAR(dev, MASK_16|MASK_17);
 193                 SAA7146_IER_ENABLE(dev, MASK_16|MASK_17);
 194                 saa7146_write(dev, MC2, (MASK_00 | MASK_16));
 195
 196                 timeout = HZ/100 + 1; /* 10ms */
 197                 timeout = wait_event_interruptible_timeout(dev->i2c_wq, dev->i2c_op == 0, timeout);
 198                 if (timeout == -ERESTARTSYS || dev->i2c_op) {
 199                         SAA7146_IER_DISABLE(dev, MASK_16|MASK_17);
 200                         SAA7146_ISR_CLEAR(dev, MASK_16|MASK_17);
 201                         if (timeout == -ERESTARTSYS)
 202                                 /* a signal arrived */
 203                                 return -ERESTARTSYS;
 204
 205                         printk(KERN_WARNING "saa7146_i2c_writeout: timed out waiting for end of xfer\n");
 206                         return -EIO;
 207                 }
 208                 status = saa7146_read(dev, I2C_STATUS);
 209         } else {
 210                 saa7146_write(dev, I2C_STATUS,   dev->i2c_bitrate);
 211                 saa7146_write(dev, I2C_TRANSFER, *dword);
 212                 saa7146_write(dev, MC2, (MASK_00 | MASK_16));
 213
 214                 /* do not poll for i2c-status before upload is complete */
 215                 timeout = jiffies + HZ/100 + 1; /* 10ms */
 216                 while(1) {
 217                         mc2 = (saa7146_read(dev, MC2) & 0x1);
 218                         if( 0 != mc2 ) {
 219                                 break;
 220                         }
 221                         if (time_after(jiffies,timeout)) {
 222                                 printk(KERN_WARNING "saa7146_i2c_writeout: timed out waiting for MC2\n");
 223                                 return -EIO;
 224                         }
 225                 }
 226                 /* wait until we get a transfer done or error */
 227                 timeout = jiffies + HZ/100 + 1; /* 10ms */
 228                 /* first read usually delivers bogus results... */
 229                 saa7146_i2c_status(dev);
 230                 while(1) {
 231                         status = saa7146_i2c_status(dev);
 232                         if ((status & 0x3) != 1)
 233                                 break;
 234                         if (time_after(jiffies,timeout)) {
 235                                 /* this is normal when probing the bus
 236                                  * (no answer from nonexisistant device...)
 237                                  */
 238                                 DEB_I2C(("saa7146_i2c_writeout: timed out waiting for end of xfer\n"));
 239                                 return -EIO;
 240                         }
 241                         if (++trial < 50 && short_delay)
 242                                 udelay(10);
 243                         else
 244                                 msleep(1);
 245                 }
 246         }
 247
 248         /* give a detailed status report */
 249         if ( 0 != (status & SAA7146_I2C_ERR)) {
 250
 251                 if( 0 != (status & SAA7146_I2C_SPERR) ) {
 252                         DEB_I2C(("error due to invalid start/stop condition.\n"));
 253                 }
 254                 if( 0 != (status & SAA7146_I2C_DTERR) ) {
 255                         DEB_I2C(("error in data transmission.\n"));
 256                 }
 257                 if( 0 != (status & SAA7146_I2C_DRERR) ) {
 258                         DEB_I2C(("error when receiving data.\n"));
 259                 }
 260                 if( 0 != (status & SAA7146_I2C_AL) ) {
 261                         DEB_I2C(("error because arbitration lost.\n"));
 262                 }
 263
 264                 /* we handle address-errors here */
 265                 if( 0 != (status & SAA7146_I2C_APERR) ) {
 266                         DEB_I2C(("error in address phase.\n"));
 267                         return -EREMOTEIO;
 268                 }
 269
 270                 return -EIO;
 271         }
 272
 273         /* read back data, just in case we were reading ... */
 274         *dword = saa7146_read(dev, I2C_TRANSFER);
 275
 276         DEB_I2C(("after: 0x%08x\n",*dword));
 277         return 0;
 278 }
 279
 280 int saa7146_i2c_transfer(struct saa7146_dev *dev, const struct i2c_msg *msgs, int num, int retries)
 281 {
 282         int i = 0, count = 0;
 283         u32* buffer = dev->d_i2c.cpu_addr;
 284         int err = 0;
 285         int address_err = 0;
 286         int short_delay = 0;
 287
 288         if (mutex_lock_interruptible(&dev->i2c_lock))
 289                 return -ERESTARTSYS;
 290
 291         for(i=0;i<num;i++) {
 292                 DEB_I2C(("msg:%d/%d\n",i+1,num));
 293         }
 294
 295         /* prepare the message(s), get number of u32s to transfer */
 296         count = saa7146_i2c_msg_prepare(msgs, num, buffer);
 297         if ( 0 > count ) {
 298                 err = -1;
 299                 goto out;
 300         }
 301
 302         if ( count > 3 || 0 != (SAA7146_I2C_SHORT_DELAY & dev->ext->flags) )
 303                 short_delay = 1;
 304
 305         do {
 306                 /* reset the i2c-device if necessary */
 307                 err = saa7146_i2c_reset(dev);
 308                 if ( 0 > err ) {
 309                         DEB_I2C(("could not reset i2c-device.\n"));
 310                         goto out;
 311                 }
 312
 313                 /* write out the u32s one after another */
 314                 for(i = 0; i < count; i++) {
 315                         err = saa7146_i2c_writeout(dev, &buffer[i], short_delay);
 316                         if ( 0 != err) {
 317                                 /* this one is unsatisfying: some i2c slaves on some
 318                                    dvb cards don't acknowledge correctly, so the saa7146
 319                                    thinks that an address error occured. in that case, the
 320                                    transaction should be retrying, even if an address error
 321                                    occured. analog saa7146 based cards extensively rely on
 322                                    i2c address probing, however, and address errors indicate that a
 323                                    device is really *not* there. retrying in that case
 324                                    increases the time the device needs to probe greatly, so
 325                                    it should be avoided. because of the fact, that only
 326                                    analog based cards use irq based i2c transactions (for dvb
 327                                    cards, this screwes up other interrupt sources), we bail out
 328                                    completely for analog cards after an address error and trust
 329                                    the saa7146 address error detection. */
 330                                 if ( -EREMOTEIO == err ) {
 331                                         if( 0 != (SAA7146_USE_I2C_IRQ & dev->ext->flags)) {
 332                                                 goto out;
 333                                         }
 334                                         address_err++;
 335                                 }
 336                                 DEB_I2C(("error while sending message(s). starting again.\n"));
 337                                 break;
 338                         }
 339                 }
 340                 if( 0 == err ) {
 341                         err = num;
 342                         break;
 343                 }
 344
 345                 /* delay a bit before retrying */
 346                 msleep(10);
 347
 348         } while (err != num && retries--);
 349
 350         /* if every retry had an address error, exit right away */
 351         if (address_err == retries) {
 352                 goto out;
 353         }
 354
 355         /* if any things had to be read, get the results */
 356         if ( 0 != saa7146_i2c_msg_cleanup(msgs, num, buffer)) {
 357                 DEB_I2C(("could not cleanup i2c-message.\n"));
 358                 err = -1;
 359                 goto out;
 360         }
 361
 362         /* return the number of delivered messages */
 363         DEB_I2C(("transmission successful. (msg:%d).\n",err));
 364 out:
 365         /* another bug in revision 0: the i2c-registers get uploaded randomly by other
 366            uploads, so we better clear them out before continueing */
 367         if( 0 == dev->revision ) {
 368                 u32 zero = 0;
 369                 saa7146_i2c_reset(dev);
 370                 if( 0 != saa7146_i2c_writeout(dev, &zero, short_delay)) {
 371                         INFO(("revision 0 error. this should never happen.\n"));
 372                 }
 373         }
 374
 375         mutex_unlock(&dev->i2c_lock);
 376         return err;
 377 }
 378
 379 /* utility functions */
 380 static int saa7146_i2c_xfer(struct i2c_adapter* adapter, struct i2c_msg *msg, int num)
 381 {
 382         struct saa7146_dev* dev = i2c_get_adapdata(adapter);
 383
 384         /* use helper function to transfer data */
 385         return saa7146_i2c_transfer(dev, msg, num, adapter->retries);
 386 }
 387
 388
 389 /*****************************************************************************/
 390 /* i2c-adapter helper functions                                              */
 391 #include <linux/i2c-id.h>
 392
 393 /* exported algorithm data */
 394 static struct i2c_algorithm saa7146_algo = {
 395         .master_xfer    = saa7146_i2c_xfer,
 396         .functionality  = saa7146_i2c_func,
 397 };
 398
 399 int saa7146_i2c_adapter_prepare(struct saa7146_dev *dev, struct i2c_adapter *i2c_adapter, u32 bitrate)
 400 {
 401         DEB_EE(("bitrate: 0x%08x\n",bitrate));
 402
 403         /* enable i2c-port pins */
 404         saa7146_write(dev, MC1, (MASK_08 | MASK_24));
 405
 406         dev->i2c_bitrate = bitrate;
 407         saa7146_i2c_reset(dev);
 408
 409         if( NULL != i2c_adapter ) {
 410                 BUG_ON(!i2c_adapter->class);
 411                 i2c_set_adapdata(i2c_adapter,dev);
 412                 i2c_adapter->dev.parent    = &dev->pci->dev;
 413                 i2c_adapter->algo          = &saa7146_algo;
 414                 i2c_adapter->algo_data     = NULL;
 415                 i2c_adapter->id            = I2C_HW_SAA7146;
 416                 i2c_adapter->timeout = SAA7146_I2C_TIMEOUT;
 417                 i2c_adapter->retries = SAA7146_I2C_RETRIES;
 418         }
 419
 420         return 0;
 421 }