saa7146_i2c.c revision afd1a0c9ac281eed3b22b293ccd92af7b0d60889
1#include <media/saa7146_vv.h> 2 3static 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 */ 14static 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. */ 27static 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. */ 91static 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 */ 113static 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) */ 177static 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 while(1) { 221 /** 222 * first read usually delivers bogus results... 223 */ 224 saa7146_i2c_status(dev); 225 status = saa7146_i2c_status(dev); 226 if ((status & 0x3) != 1) 227 break; 228 if (time_after(jiffies,timeout)) { 229 /* this is normal when probing the bus 230 * (no answer from nonexisistant device...) 231 */ 232 DEB_I2C(("saa7146_i2c_writeout: timed out waiting for end of xfer\n")); 233 return -EIO; 234 } 235 if ((++trial < 20) && short_delay) 236 udelay(10); 237 else 238 msleep(1); 239 } 240 } 241 242 /* give a detailed status report */ 243 if ( 0 != (status & SAA7146_I2C_ERR)) { 244 245 if( 0 != (status & SAA7146_I2C_SPERR) ) { 246 DEB_I2C(("error due to invalid start/stop condition.\n")); 247 } 248 if( 0 != (status & SAA7146_I2C_DTERR) ) { 249 DEB_I2C(("error in data transmission.\n")); 250 } 251 if( 0 != (status & SAA7146_I2C_DRERR) ) { 252 DEB_I2C(("error when receiving data.\n")); 253 } 254 if( 0 != (status & SAA7146_I2C_AL) ) { 255 DEB_I2C(("error because arbitration lost.\n")); 256 } 257 258 /* we handle address-errors here */ 259 if( 0 != (status & SAA7146_I2C_APERR) ) { 260 DEB_I2C(("error in address phase.\n")); 261 return -EREMOTEIO; 262 } 263 264 return -EIO; 265 } 266 267 /* read back data, just in case we were reading ... */ 268 *dword = saa7146_read(dev, I2C_TRANSFER); 269 270 DEB_I2C(("after: 0x%08x\n",*dword)); 271 return 0; 272} 273 274int saa7146_i2c_transfer(struct saa7146_dev *dev, const struct i2c_msg *msgs, int num, int retries) 275{ 276 int i = 0, count = 0; 277 u32* buffer = dev->d_i2c.cpu_addr; 278 int err = 0; 279 int address_err = 0; 280 int short_delay = 0; 281 282 if (down_interruptible (&dev->i2c_lock)) 283 return -ERESTARTSYS; 284 285 for(i=0;i<num;i++) { 286 DEB_I2C(("msg:%d/%d\n",i+1,num)); 287 } 288 289 /* prepare the message(s), get number of u32s to transfer */ 290 count = saa7146_i2c_msg_prepare(msgs, num, buffer); 291 if ( 0 > count ) { 292 err = -1; 293 goto out; 294 } 295 296 if ( count > 3 || 0 != (SAA7146_I2C_SHORT_DELAY & dev->ext->flags) ) 297 short_delay = 1; 298 299 do { 300 /* reset the i2c-device if necessary */ 301 err = saa7146_i2c_reset(dev); 302 if ( 0 > err ) { 303 DEB_I2C(("could not reset i2c-device.\n")); 304 goto out; 305 } 306 307 /* write out the u32s one after another */ 308 for(i = 0; i < count; i++) { 309 err = saa7146_i2c_writeout(dev, &buffer[i], short_delay); 310 if ( 0 != err) { 311 /* this one is unsatisfying: some i2c slaves on some 312 dvb cards don't acknowledge correctly, so the saa7146 313 thinks that an address error occured. in that case, the 314 transaction should be retrying, even if an address error 315 occured. analog saa7146 based cards extensively rely on 316 i2c address probing, however, and address errors indicate that a 317 device is really *not* there. retrying in that case 318 increases the time the device needs to probe greatly, so 319 it should be avoided. because of the fact, that only 320 analog based cards use irq based i2c transactions (for dvb 321 cards, this screwes up other interrupt sources), we bail out 322 completely for analog cards after an address error and trust 323 the saa7146 address error detection. */ 324 if ( -EREMOTEIO == err ) { 325 if( 0 != (SAA7146_USE_I2C_IRQ & dev->ext->flags)) { 326 goto out; 327 } 328 address_err++; 329 } 330 DEB_I2C(("error while sending message(s). starting again.\n")); 331 break; 332 } 333 } 334 if( 0 == err ) { 335 err = num; 336 break; 337 } 338 339 /* delay a bit before retrying */ 340 msleep(10); 341 342 } while (err != num && retries--); 343 344 /* if every retry had an address error, exit right away */ 345 if (address_err == retries) { 346 goto out; 347 } 348 349 /* if any things had to be read, get the results */ 350 if ( 0 != saa7146_i2c_msg_cleanup(msgs, num, buffer)) { 351 DEB_I2C(("could not cleanup i2c-message.\n")); 352 err = -1; 353 goto out; 354 } 355 356 /* return the number of delivered messages */ 357 DEB_I2C(("transmission successful. (msg:%d).\n",err)); 358out: 359 /* another bug in revision 0: the i2c-registers get uploaded randomly by other 360 uploads, so we better clear them out before continueing */ 361 if( 0 == dev->revision ) { 362 u32 zero = 0; 363 saa7146_i2c_reset(dev); 364 if( 0 != saa7146_i2c_writeout(dev, &zero, short_delay)) { 365 INFO(("revision 0 error. this should never happen.\n")); 366 } 367 } 368 369 up(&dev->i2c_lock); 370 return err; 371} 372 373/* utility functions */ 374static int saa7146_i2c_xfer(struct i2c_adapter* adapter, struct i2c_msg *msg, int num) 375{ 376 struct saa7146_dev* dev = i2c_get_adapdata(adapter); 377 378 /* use helper function to transfer data */ 379 return saa7146_i2c_transfer(dev, msg, num, adapter->retries); 380} 381 382 383/*****************************************************************************/ 384/* i2c-adapter helper functions */ 385#include <linux/i2c-id.h> 386 387/* exported algorithm data */ 388static struct i2c_algorithm saa7146_algo = { 389 .master_xfer = saa7146_i2c_xfer, 390 .functionality = saa7146_i2c_func, 391}; 392 393int saa7146_i2c_adapter_prepare(struct saa7146_dev *dev, struct i2c_adapter *i2c_adapter, u32 bitrate) 394{ 395 DEB_EE(("bitrate: 0x%08x\n",bitrate)); 396 397 /* enable i2c-port pins */ 398 saa7146_write(dev, MC1, (MASK_08 | MASK_24)); 399 400 dev->i2c_bitrate = bitrate; 401 saa7146_i2c_reset(dev); 402 403 if( NULL != i2c_adapter ) { 404 BUG_ON(!i2c_adapter->class); 405 i2c_set_adapdata(i2c_adapter,dev); 406 i2c_adapter->dev.parent = &dev->pci->dev; 407 i2c_adapter->algo = &saa7146_algo; 408 i2c_adapter->algo_data = NULL; 409 i2c_adapter->id = I2C_HW_SAA7146; 410 i2c_adapter->timeout = SAA7146_I2C_TIMEOUT; 411 i2c_adapter->retries = SAA7146_I2C_RETRIES; 412 } 413 414 return 0; 415} 416