drivers/media/common/saa7146/saa7146_i2c.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   3
   4 #include <media/drv-intf/saa7146_vv.h>
   5
   6 static u32 saa7146_i2c_func(struct i2c_adapter *adapter)
   7 {
   8         /* DEB_I2C("'%s'\n", adapter->name); */
   9
  10         return    I2C_FUNC_I2C
  11                 | I2C_FUNC_SMBUS_QUICK
  12                 | I2C_FUNC_SMBUS_READ_BYTE      | I2C_FUNC_SMBUS_WRITE_BYTE
  13                 | I2C_FUNC_SMBUS_READ_BYTE_DATA | I2C_FUNC_SMBUS_WRITE_BYTE_DATA;
  14 }
  15
  16 /* this function returns the status-register of our i2c-device */
  17 static inline u32 saa7146_i2c_status(struct saa7146_dev *dev)
  18 {
  19         u32 iicsta = saa7146_read(dev, I2C_STATUS);
  20         /* DEB_I2C("status: 0x%08x\n", iicsta); */
  21         return iicsta;
  22 }
  23
  24 /* this function runs through the i2c-messages and prepares the data to be
  25    sent through the saa7146. have a look at the specifications p. 122 ff
  26    to understand this. it returns the number of u32s to send, or -1
  27    in case of an error. */
  28 static int saa7146_i2c_msg_prepare(const struct i2c_msg *m, int num, __le32 *op)
  29 {
  30         int h1, h2;
  31         int i, j, addr;
  32         int mem = 0, op_count = 0;
  33
  34         /* first determine size of needed memory */
  35         for(i = 0; i < num; i++) {
  36                 mem += m[i].len + 1;
  37         }
  38
  39         /* worst case: we need one u32 for three bytes to be send
  40            plus one extra byte to address the device */
  41         mem = 1 + ((mem-1) / 3);
  42
  43         /* we assume that op points to a memory of at least
  44          * SAA7146_I2C_MEM bytes size. if we exceed this limit...
  45          */
  46         if ((4 * mem) > SAA7146_I2C_MEM) {
  47                 /* DEB_I2C("cannot prepare i2c-message\n"); */
  48                 return -ENOMEM;
  49         }
  50
  51         /* be careful: clear out the i2c-mem first */
  52         memset(op,0,sizeof(__le32)*mem);
  53
  54         /* loop through all messages */
  55         for(i = 0; i < num; i++) {
  56
  57                 /* insert the address of the i2c-slave.
  58                    note: we get 7 bit i2c-addresses,
  59                    so we have to perform a translation */
  60                 addr = (m[i].addr*2) + ( (0 != (m[i].flags & I2C_M_RD)) ? 1 : 0);
  61                 h1 = op_count/3; h2 = op_count%3;
  62                 op[h1] |= cpu_to_le32(      (u8)addr << ((3-h2)*8));
  63                 op[h1] |= cpu_to_le32(SAA7146_I2C_START << ((3-h2)*2));
  64                 op_count++;
  65
  66                 /* loop through all bytes of message i */
  67                 for(j = 0; j < m[i].len; j++) {
  68                         /* insert the data bytes */
  69                         h1 = op_count/3; h2 = op_count%3;
  70                         op[h1] |= cpu_to_le32( (u32)((u8)m[i].buf[j]) << ((3-h2)*8));
  71                         op[h1] |= cpu_to_le32(       SAA7146_I2C_CONT << ((3-h2)*2));
  72                         op_count++;
  73                 }
  74
  75         }
  76
  77         /* have a look at the last byte inserted:
  78           if it was: ...CONT change it to ...STOP */
  79         h1 = (op_count-1)/3; h2 = (op_count-1)%3;
  80         if ( SAA7146_I2C_CONT == (0x3 & (le32_to_cpu(op[h1]) >> ((3-h2)*2))) ) {
  81                 op[h1] &= ~cpu_to_le32(0x2 << ((3-h2)*2));
  82                 op[h1] |= cpu_to_le32(SAA7146_I2C_STOP << ((3-h2)*2));
  83         }
  84
  85         /* return the number of u32s to send */
  86         return mem;
  87 }
  88
  89 /* this functions loops through all i2c-messages. normally, it should determine
  90    which bytes were read through the adapter and write them back to the corresponding
  91    i2c-message. but instead, we simply write back all bytes.
  92    fixme: this could be improved. */
  93 static int saa7146_i2c_msg_cleanup(const struct i2c_msg *m, int num, __le32 *op)
  94 {
  95         int i, j;
  96         int op_count = 0;
  97
  98         /* loop through all messages */
  99         for(i = 0; i < num; i++) {
 100
 101                 op_count++;
 102
 103                 /* loop through all bytes of message i */
 104                 for(j = 0; j < m[i].len; j++) {
 105                         /* write back all bytes that could have been read */
 106                         m[i].buf[j] = (le32_to_cpu(op[op_count/3]) >> ((3-(op_count%3))*8));
 107                         op_count++;
 108                 }
 109         }
 110
 111         return 0;
 112 }
 113
 114 /* this functions resets the i2c-device and returns 0 if everything was fine, otherwise -1 */
 115 static int saa7146_i2c_reset(struct saa7146_dev *dev)
 116 {
 117         /* get current status */
 118         u32 status = saa7146_i2c_status(dev);
 119
 120         /* clear registers for sure */
 121         saa7146_write(dev, I2C_STATUS, dev->i2c_bitrate);
 122         saa7146_write(dev, I2C_TRANSFER, 0);
 123
 124         /* check if any operation is still in progress */
 125         if ( 0 != ( status & SAA7146_I2C_BUSY) ) {
 126
 127                 /* yes, kill ongoing operation */
 128                 DEB_I2C("busy_state detected\n");
 129
 130                 /* set "ABORT-OPERATION"-bit (bit 7)*/
 131                 saa7146_write(dev, I2C_STATUS, (dev->i2c_bitrate | MASK_07));
 132                 saa7146_write(dev, MC2, (MASK_00 | MASK_16));
 133                 msleep(SAA7146_I2C_DELAY);
 134
 135                 /* clear all error-bits pending; this is needed because p.123, note 1 */
 136                 saa7146_write(dev, I2C_STATUS, dev->i2c_bitrate);
 137                 saa7146_write(dev, MC2, (MASK_00 | MASK_16));
 138                 msleep(SAA7146_I2C_DELAY);
 139         }
 140
 141         /* check if any error is (still) present. (this can be necessary because p.123, note 1) */
 142         status = saa7146_i2c_status(dev);
 143
 144         if ( dev->i2c_bitrate != status ) {
 145
 146                 DEB_I2C("error_state detected. status:0x%08x\n", status);
 147
 148                 /* Repeat the abort operation. This seems to be necessary
 149                    after serious protocol errors caused by e.g. the SAA7740 */
 150                 saa7146_write(dev, I2C_STATUS, (dev->i2c_bitrate | MASK_07));
 151                 saa7146_write(dev, MC2, (MASK_00 | MASK_16));
 152                 msleep(SAA7146_I2C_DELAY);
 153
 154                 /* clear all error-bits pending */
 155                 saa7146_write(dev, I2C_STATUS, dev->i2c_bitrate);
 156                 saa7146_write(dev, MC2, (MASK_00 | MASK_16));
 157                 msleep(SAA7146_I2C_DELAY);
 158
 159                 /* the data sheet says it might be necessary to clear the status
 160                    twice after an abort */
 161                 saa7146_write(dev, I2C_STATUS, dev->i2c_bitrate);
 162                 saa7146_write(dev, MC2, (MASK_00 | MASK_16));
 163                 msleep(SAA7146_I2C_DELAY);
 164         }
 165
 166         /* if any error is still present, a fatal error has occurred ... */
 167         status = saa7146_i2c_status(dev);
 168         if ( dev->i2c_bitrate != status ) {
 169                 DEB_I2C("fatal error. status:0x%08x\n", status);
 170                 return -1;
 171         }
 172
 173         return 0;
 174 }
 175
 176 /* this functions writes out the data-byte 'dword' to the i2c-device.
 177    it returns 0 if ok, -1 if the transfer failed, -2 if the transfer
 178    failed badly (e.g. address error) */
 179 static int saa7146_i2c_writeout(struct saa7146_dev *dev, __le32 *dword, int short_delay)
 180 {
 181         u32 status = 0, mc2 = 0;
 182         int trial = 0;
 183         unsigned long timeout;
 184
 185         /* write out i2c-command */
 186         DEB_I2C("before: 0x%08x (status: 0x%08x), %d\n",
 187                 *dword, saa7146_read(dev, I2C_STATUS), dev->i2c_op);
 188
 189         if( 0 != (SAA7146_USE_I2C_IRQ & dev->ext->flags)) {
 190
 191                 saa7146_write(dev, I2C_STATUS,   dev->i2c_bitrate);
 192                 saa7146_write(dev, I2C_TRANSFER, le32_to_cpu(*dword));
 193
 194                 dev->i2c_op = 1;
 195                 SAA7146_ISR_CLEAR(dev, MASK_16|MASK_17);
 196                 SAA7146_IER_ENABLE(dev, MASK_16|MASK_17);
 197                 saa7146_write(dev, MC2, (MASK_00 | MASK_16));
 198
 199                 timeout = HZ/100 + 1; /* 10ms */
 200                 timeout = wait_event_interruptible_timeout(dev->i2c_wq, dev->i2c_op == 0, timeout);
 201                 if (timeout == -ERESTARTSYS || dev->i2c_op) {
 202                         SAA7146_IER_DISABLE(dev, MASK_16|MASK_17);
 203                         SAA7146_ISR_CLEAR(dev, MASK_16|MASK_17);
 204                         if (timeout == -ERESTARTSYS)
 205                                 /* a signal arrived */
 206                                 return -ERESTARTSYS;
 207
 208                         pr_warn("%s %s [irq]: timed out waiting for end of xfer\n",
 209                                 dev->name, __func__);
 210                         return -EIO;
 211                 }
 212                 status = saa7146_read(dev, I2C_STATUS);
 213         } else {
 214                 saa7146_write(dev, I2C_STATUS,   dev->i2c_bitrate);
 215                 saa7146_write(dev, I2C_TRANSFER, le32_to_cpu(*dword));
 216                 saa7146_write(dev, MC2, (MASK_00 | MASK_16));
 217
 218                 /* do not poll for i2c-status before upload is complete */
 219                 timeout = jiffies + HZ/100 + 1; /* 10ms */
 220                 while(1) {
 221                         mc2 = (saa7146_read(dev, MC2) & 0x1);
 222                         if( 0 != mc2 ) {
 223                                 break;
 224                         }
 225                         if (time_after(jiffies,timeout)) {
 226                                 pr_warn("%s %s: timed out waiting for MC2\n",
 227                                         dev->name, __func__);
 228                                 return -EIO;
 229                         }
 230                 }
 231                 /* wait until we get a transfer done or error */
 232                 timeout = jiffies + HZ/100 + 1; /* 10ms */
 233                 /* first read usually delivers bogus results... */
 234                 saa7146_i2c_status(dev);
 235                 while(1) {
 236                         status = saa7146_i2c_status(dev);
 237                         if ((status & 0x3) != 1)
 238                                 break;
 239                         if (time_after(jiffies,timeout)) {
 240                                 /* this is normal when probing the bus
 241                                  * (no answer from nonexisistant device...)
 242                                  */
 243                                 pr_warn("%s %s [poll]: timed out waiting for end of xfer\n",
 244                                         dev->name, __func__);
 245                                 return -EIO;
 246                         }
 247                         if (++trial < 50 && short_delay)
 248                                 udelay(10);
 249                         else
 250                                 msleep(1);
 251                 }
 252         }
 253
 254         /* give a detailed status report */
 255         if ( 0 != (status & (SAA7146_I2C_SPERR | SAA7146_I2C_APERR |
 256                              SAA7146_I2C_DTERR | SAA7146_I2C_DRERR |
 257                              SAA7146_I2C_AL    | SAA7146_I2C_ERR   |
 258                              SAA7146_I2C_BUSY)) ) {
 259
 260                 if ( 0 == (status & SAA7146_I2C_ERR) ||
 261                      0 == (status & SAA7146_I2C_BUSY) ) {
 262                         /* it may take some time until ERR goes high - ignore */
 263                         DEB_I2C("unexpected i2c status %04x\n", status);
 264                 }
 265                 if( 0 != (status & SAA7146_I2C_SPERR) ) {
 266                         DEB_I2C("error due to invalid start/stop condition\n");
 267                 }
 268                 if( 0 != (status & SAA7146_I2C_DTERR) ) {
 269                         DEB_I2C("error in data transmission\n");
 270                 }
 271                 if( 0 != (status & SAA7146_I2C_DRERR) ) {
 272                         DEB_I2C("error when receiving data\n");
 273                 }
 274                 if( 0 != (status & SAA7146_I2C_AL) ) {
 275                         DEB_I2C("error because arbitration lost\n");
 276                 }
 277
 278                 /* we handle address-errors here */
 279                 if( 0 != (status & SAA7146_I2C_APERR) ) {
 280                         DEB_I2C("error in address phase\n");
 281                         return -EREMOTEIO;
 282                 }
 283
 284                 return -EIO;
 285         }
 286
 287         /* read back data, just in case we were reading ... */
 288         *dword = cpu_to_le32(saa7146_read(dev, I2C_TRANSFER));
 289
 290         DEB_I2C("after: 0x%08x\n", *dword);
 291         return 0;
 292 }
 293
 294 static int saa7146_i2c_transfer(struct saa7146_dev *dev, const struct i2c_msg *msgs, int num, int retries)
 295 {
 296         int i = 0, count = 0;
 297         __le32 *buffer = dev->d_i2c.cpu_addr;
 298         int err = 0;
 299         int short_delay = 0;
 300
 301         if (mutex_lock_interruptible(&dev->i2c_lock))
 302                 return -ERESTARTSYS;
 303
 304         for(i=0;i<num;i++) {
 305                 DEB_I2C("msg:%d/%d\n", i+1, num);
 306         }
 307
 308         /* prepare the message(s), get number of u32s to transfer */
 309         count = saa7146_i2c_msg_prepare(msgs, num, buffer);
 310         if ( 0 > count ) {
 311                 err = -1;
 312                 goto out;
 313         }
 314
 315         if ( count > 3 || 0 != (SAA7146_I2C_SHORT_DELAY & dev->ext->flags) )
 316                 short_delay = 1;
 317
 318         do {
 319                 /* reset the i2c-device if necessary */
 320                 err = saa7146_i2c_reset(dev);
 321                 if ( 0 > err ) {
 322                         DEB_I2C("could not reset i2c-device\n");
 323                         goto out;
 324                 }
 325
 326                 /* write out the u32s one after another */
 327                 for(i = 0; i < count; i++) {
 328                         err = saa7146_i2c_writeout(dev, &buffer[i], short_delay);
 329                         if ( 0 != err) {
 330                                 /* this one is unsatisfying: some i2c slaves on some
 331                                    dvb cards don't acknowledge correctly, so the saa7146
 332                                    thinks that an address error occurred. in that case, the
 333                                    transaction should be retrying, even if an address error
 334                                    occurred. analog saa7146 based cards extensively rely on
 335                                    i2c address probing, however, and address errors indicate that a
 336                                    device is really *not* there. retrying in that case
 337                                    increases the time the device needs to probe greatly, so
 338                                    it should be avoided. So we bail out in irq mode after an
 339                                    address error and trust the saa7146 address error detection. */
 340                                 if (-EREMOTEIO == err && 0 != (SAA7146_USE_I2C_IRQ & dev->ext->flags))
 341                                         goto out;
 342                                 DEB_I2C("error while sending message(s). starting again\n");
 343                                 break;
 344                         }
 345                 }
 346                 if( 0 == err ) {
 347                         err = num;
 348                         break;
 349                 }
 350
 351                 /* delay a bit before retrying */
 352                 msleep(10);
 353
 354         } while (err != num && retries--);
 355
 356         /* quit if any error occurred */
 357         if (err != num)
 358                 goto out;
 359
 360         /* if any things had to be read, get the results */
 361         if ( 0 != saa7146_i2c_msg_cleanup(msgs, num, buffer)) {
 362                 DEB_I2C("could not cleanup i2c-message\n");
 363                 err = -1;
 364                 goto out;
 365         }
 366
 367         /* return the number of delivered messages */
 368         DEB_I2C("transmission successful. (msg:%d)\n", err);
 369 out:
 370         /* another bug in revision 0: the i2c-registers get uploaded randomly by other
 371            uploads, so we better clear them out before continuing */
 372         if( 0 == dev->revision ) {
 373                 __le32 zero = 0;
 374                 saa7146_i2c_reset(dev);
 375                 if( 0 != saa7146_i2c_writeout(dev, &zero, short_delay)) {
 376                         pr_info("revision 0 error. this should never happen\n");
 377                 }
 378         }
 379
 380         mutex_unlock(&dev->i2c_lock);
 381         return err;
 382 }
 383
 384 /* utility functions */
 385 static int saa7146_i2c_xfer(struct i2c_adapter* adapter, struct i2c_msg *msg, int num)
 386 {
 387         struct v4l2_device *v4l2_dev = i2c_get_adapdata(adapter);
 388         struct saa7146_dev *dev = to_saa7146_dev(v4l2_dev);
 389
 390         /* use helper function to transfer data */
 391         return saa7146_i2c_transfer(dev, msg, num, adapter->retries);
 392 }
 393
 394
 395 /*****************************************************************************/
 396 /* i2c-adapter helper functions                                              */
 397
 398 /* exported algorithm data */
 399 static const struct i2c_algorithm saa7146_algo = {
 400         .master_xfer    = saa7146_i2c_xfer,
 401         .functionality  = saa7146_i2c_func,
 402 };
 403
 404 int saa7146_i2c_adapter_prepare(struct saa7146_dev *dev, struct i2c_adapter *i2c_adapter, u32 bitrate)
 405 {
 406         DEB_EE("bitrate: 0x%08x\n", bitrate);
 407
 408         /* enable i2c-port pins */
 409         saa7146_write(dev, MC1, (MASK_08 | MASK_24));
 410
 411         dev->i2c_bitrate = bitrate;
 412         saa7146_i2c_reset(dev);
 413
 414         if (i2c_adapter) {
 415                 i2c_set_adapdata(i2c_adapter, &dev->v4l2_dev);
 416                 i2c_adapter->dev.parent    = &dev->pci->dev;
 417                 i2c_adapter->algo          = &saa7146_algo;
 418                 i2c_adapter->algo_data     = NULL;
 419                 i2c_adapter->timeout = SAA7146_I2C_TIMEOUT;
 420                 i2c_adapter->retries = SAA7146_I2C_RETRIES;
 421         }
 422
 423         return 0;
 424 }