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 "%s %s [irq]: timed out waiting for end of xfer\n",
 206                                 dev->name, __FUNCTION__);
 207                         return -EIO;
 208                 }
 209                 status = saa7146_read(dev, I2C_STATUS);
 210         } else {
 211                 saa7146_write(dev, I2C_STATUS,   dev->i2c_bitrate);
 212                 saa7146_write(dev, I2C_TRANSFER, *dword);
 213                 saa7146_write(dev, MC2, (MASK_00 | MASK_16));
 214
 215                 /* do not poll for i2c-status before upload is complete */
 216                 timeout = jiffies + HZ/100 + 1; /* 10ms */
 217                 while(1) {
 218                         mc2 = (saa7146_read(dev, MC2) & 0x1);
 219                         if( 0 != mc2 ) {
 220                                 break;
 221                         }
 222                         if (time_after(jiffies,timeout)) {
 223                                 printk(KERN_WARNING "%s %s: timed out waiting for MC2\n",
 224                                         dev->name, __FUNCTION__);
 225                                 return -EIO;
 226                         }
 227                 }
 228                 /* wait until we get a transfer done or error */
 229                 timeout = jiffies + HZ/100 + 1; /* 10ms */
 230                 /* first read usually delivers bogus results... */
 231                 saa7146_i2c_status(dev);
 232                 while(1) {
 233                         status = saa7146_i2c_status(dev);
 234                         if ((status & 0x3) != 1)
 235                                 break;
 236                         if (time_after(jiffies,timeout)) {
 237                                 /* this is normal when probing the bus
 238                                  * (no answer from nonexisistant device...)
 239                                  */
 240                                 printk(KERN_WARNING "%s %s [poll]: timed out waiting for end of xfer\n",
 241                                         dev->name, __FUNCTION__);
 242                                 return -EIO;
 243                         }
 244                         if (++trial < 50 && short_delay)
 245                                 udelay(10);
 246                         else
 247                                 msleep(1);
 248                 }
 249         }
 250
 251         /* give a detailed status report */
 252         if ( 0 != (status & (SAA7146_I2C_SPERR | SAA7146_I2C_APERR |
 253                              SAA7146_I2C_DTERR | SAA7146_I2C_DRERR |
 254                              SAA7146_I2C_AL    | SAA7146_I2C_ERR   |
 255                              SAA7146_I2C_BUSY)) ) {
 256
 257                 if ( 0 == (status & SAA7146_I2C_ERR) ||
 258                      0 == (status & SAA7146_I2C_BUSY) ) {
 259                         /* it may take some time until ERR goes high - ignore */
 260                         DEB_I2C(("unexpected i2c status %04x\n", status));
 261                 }
 262                 if( 0 != (status & SAA7146_I2C_SPERR) ) {
 263                         DEB_I2C(("error due to invalid start/stop condition.\n"));
 264                 }
 265                 if( 0 != (status & SAA7146_I2C_DTERR) ) {
 266                         DEB_I2C(("error in data transmission.\n"));
 267                 }
 268                 if( 0 != (status & SAA7146_I2C_DRERR) ) {
 269                         DEB_I2C(("error when receiving data.\n"));
 270                 }
 271                 if( 0 != (status & SAA7146_I2C_AL) ) {
 272                         DEB_I2C(("error because arbitration lost.\n"));
 273                 }
 274
 275                 /* we handle address-errors here */
 276                 if( 0 != (status & SAA7146_I2C_APERR) ) {
 277                         DEB_I2C(("error in address phase.\n"));
 278                         return -EREMOTEIO;
 279                 }
 280
 281                 return -EIO;
 282         }
 283
 284         /* read back data, just in case we were reading ... */
 285         *dword = saa7146_read(dev, I2C_TRANSFER);
 286
 287         DEB_I2C(("after: 0x%08x\n",*dword));
 288         return 0;
 289 }
 290
 291 static int saa7146_i2c_transfer(struct saa7146_dev *dev, const struct i2c_msg *msgs, int num, int retries)
 292 {
 293         int i = 0, count = 0;
 294         u32* buffer = dev->d_i2c.cpu_addr;
 295         int err = 0;
 296         int address_err = 0;
 297         int short_delay = 0;
 298
 299         if (mutex_lock_interruptible(&dev->i2c_lock))
 300                 return -ERESTARTSYS;
 301
 302         for(i=0;i<num;i++) {
 303                 DEB_I2C(("msg:%d/%d\n",i+1,num));
 304         }
 305
 306         /* prepare the message(s), get number of u32s to transfer */
 307         count = saa7146_i2c_msg_prepare(msgs, num, buffer);
 308         if ( 0 > count ) {
 309                 err = -1;
 310                 goto out;
 311         }
 312
 313         if ( count > 3 || 0 != (SAA7146_I2C_SHORT_DELAY & dev->ext->flags) )
 314                 short_delay = 1;
 315
 316         do {
 317                 /* reset the i2c-device if necessary */
 318                 err = saa7146_i2c_reset(dev);
 319                 if ( 0 > err ) {
 320                         DEB_I2C(("could not reset i2c-device.\n"));
 321                         goto out;
 322                 }
 323
 324                 /* write out the u32s one after another */
 325                 for(i = 0; i < count; i++) {
 326                         err = saa7146_i2c_writeout(dev, &buffer[i], short_delay);
 327                         if ( 0 != err) {
 328                                 /* this one is unsatisfying: some i2c slaves on some
 329                                    dvb cards don't acknowledge correctly, so the saa7146
 330                                    thinks that an address error occured. in that case, the
 331                                    transaction should be retrying, even if an address error
 332                                    occured. analog saa7146 based cards extensively rely on
 333                                    i2c address probing, however, and address errors indicate that a
 334                                    device is really *not* there. retrying in that case
 335                                    increases the time the device needs to probe greatly, so
 336                                    it should be avoided. because of the fact, that only
 337                                    analog based cards use irq based i2c transactions (for dvb
 338                                    cards, this screwes up other interrupt sources), we bail out
 339                                    completely for analog cards after an address error and trust
 340                                    the saa7146 address error detection. */
 341                                 if ( -EREMOTEIO == err ) {
 342                                         if( 0 != (SAA7146_USE_I2C_IRQ & dev->ext->flags)) {
 343                                                 goto out;
 344                                         }
 345                                         address_err++;
 346                                 }
 347                                 DEB_I2C(("error while sending message(s). starting again.\n"));
 348                                 break;
 349                         }
 350                 }
 351                 if( 0 == err ) {
 352                         err = num;
 353                         break;
 354                 }
 355
 356                 /* delay a bit before retrying */
 357                 msleep(10);
 358
 359         } while (err != num && retries--);
 360
 361         /* if every retry had an address error, exit right away */
 362         if (address_err == retries) {
 363                 goto out;
 364         }
 365
 366         /* if any things had to be read, get the results */
 367         if ( 0 != saa7146_i2c_msg_cleanup(msgs, num, buffer)) {
 368                 DEB_I2C(("could not cleanup i2c-message.\n"));
 369                 err = -1;
 370                 goto out;
 371         }
 372
 373         /* return the number of delivered messages */
 374         DEB_I2C(("transmission successful. (msg:%d).\n",err));
 375 out:
 376         /* another bug in revision 0: the i2c-registers get uploaded randomly by other
 377            uploads, so we better clear them out before continueing */
 378         if( 0 == dev->revision ) {
 379                 u32 zero = 0;
 380                 saa7146_i2c_reset(dev);
 381                 if( 0 != saa7146_i2c_writeout(dev, &zero, short_delay)) {
 382                         INFO(("revision 0 error. this should never happen.\n"));
 383                 }
 384         }
 385
 386         mutex_unlock(&dev->i2c_lock);
 387         return err;
 388 }
 389
 390 /* utility functions */
 391 static int saa7146_i2c_xfer(struct i2c_adapter* adapter, struct i2c_msg *msg, int num)
 392 {
 393         struct saa7146_dev* dev = i2c_get_adapdata(adapter);
 394
 395         /* use helper function to transfer data */
 396         return saa7146_i2c_transfer(dev, msg, num, adapter->retries);
 397 }
 398
 399
 400 /*****************************************************************************/
 401 /* i2c-adapter helper functions                                              */
 402 #include <linux/i2c-id.h>
 403
 404 /* exported algorithm data */
 405 static struct i2c_algorithm saa7146_algo = {
 406         .master_xfer    = saa7146_i2c_xfer,
 407         .functionality  = saa7146_i2c_func,
 408 };
 409
 410 int saa7146_i2c_adapter_prepare(struct saa7146_dev *dev, struct i2c_adapter *i2c_adapter, u32 bitrate)
 411 {
 412         DEB_EE(("bitrate: 0x%08x\n",bitrate));
 413
 414         /* enable i2c-port pins */
 415         saa7146_write(dev, MC1, (MASK_08 | MASK_24));
 416
 417         dev->i2c_bitrate = bitrate;
 418         saa7146_i2c_reset(dev);
 419
 420         if( NULL != i2c_adapter ) {
 421                 BUG_ON(!i2c_adapter->class);
 422                 i2c_set_adapdata(i2c_adapter,dev);
 423                 i2c_adapter->dev.parent    = &dev->pci->dev;
 424                 i2c_adapter->algo          = &saa7146_algo;
 425                 i2c_adapter->algo_data     = NULL;
 426                 i2c_adapter->id            = I2C_HW_SAA7146;
 427                 i2c_adapter->timeout = SAA7146_I2C_TIMEOUT;
 428                 i2c_adapter->retries = SAA7146_I2C_RETRIES;
 429         }
 430
 431         return 0;
 432 }