1 /* ------------------------------------------------------------------------- */ 2 /* i2c-algo-pcf.c i2c driver algorithms for PCF8584 adapters */ 3 /* ------------------------------------------------------------------------- */ 4 /* Copyright (C) 1995-1997 Simon G. Vogl 5 1998-2000 Hans Berglund 6 7 This program is free software; you can redistribute it and/or modify 8 it under the terms of the GNU General Public License as published by 9 the Free Software Foundation; either version 2 of the License, or 10 (at your option) any later version. 11 12 This program is distributed in the hope that it will be useful, 13 but WITHOUT ANY WARRANTY; without even the implied warranty of 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 GNU General Public License for more details. 16 17 You should have received a copy of the GNU General Public License 18 along with this program; if not, write to the Free Software 19 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ 20 /* ------------------------------------------------------------------------- */ 21 22 /* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi> and 23 Frodo Looijaard <frodol@dds.nl> ,and also from Martin Bailey 24 <mbailey@littlefeet-inc.com> */ 25 26 /* Partially rewriten by Oleg I. Vdovikin <vdovikin@jscc.ru> to handle multiple 27 messages, proper stop/repstart signaling during receive, 28 added detect code */ 29 30 #include <linux/kernel.h> 31 #include <linux/module.h> 32 #include <linux/delay.h> 33 #include <linux/slab.h> 34 #include <linux/init.h> 35 #include <linux/errno.h> 36 #include <linux/i2c.h> 37 #include <linux/i2c-algo-pcf.h> 38 #include "i2c-algo-pcf.h" 39 40 41 #define DEB2(x) if (i2c_debug>=2) x 42 #define DEB3(x) if (i2c_debug>=3) x /* print several statistical values*/ 43 #define DEBPROTO(x) if (i2c_debug>=9) x; 44 /* debug the protocol by showing transferred bits */ 45 #define DEF_TIMEOUT 16 46 47 /* module parameters: 48 */ 49 static int i2c_debug; 50 51 /* --- setting states on the bus with the right timing: --------------- */ 52 53 #define set_pcf(adap, ctl, val) adap->setpcf(adap->data, ctl, val) 54 #define get_pcf(adap, ctl) adap->getpcf(adap->data, ctl) 55 #define get_own(adap) adap->getown(adap->data) 56 #define get_clock(adap) adap->getclock(adap->data) 57 #define i2c_outb(adap, val) adap->setpcf(adap->data, 0, val) 58 #define i2c_inb(adap) adap->getpcf(adap->data, 0) 59 60 /* --- other auxiliary functions -------------------------------------- */ 61 62 static void i2c_start(struct i2c_algo_pcf_data *adap) 63 { 64 DEBPROTO(printk("S ")); 65 set_pcf(adap, 1, I2C_PCF_START); 66 } 67 68 static void i2c_repstart(struct i2c_algo_pcf_data *adap) 69 { 70 DEBPROTO(printk(" Sr ")); 71 set_pcf(adap, 1, I2C_PCF_REPSTART); 72 } 73 74 75 static void i2c_stop(struct i2c_algo_pcf_data *adap) 76 { 77 DEBPROTO(printk("P\n")); 78 set_pcf(adap, 1, I2C_PCF_STOP); 79 } 80 81 static void handle_lab(struct i2c_algo_pcf_data *adap, const int *status) 82 { 83 DEB2(printk(KERN_INFO 84 "i2c-algo-pcf.o: lost arbitration (CSR 0x%02x)\n", 85 *status)); 86 87 /* Cleanup from LAB -- reset and enable ESO. 88 * This resets the PCF8584; since we've lost the bus, no 89 * further attempts should be made by callers to clean up 90 * (no i2c_stop() etc.) 91 */ 92 set_pcf(adap, 1, I2C_PCF_PIN); 93 set_pcf(adap, 1, I2C_PCF_ESO); 94 95 /* We pause for a time period sufficient for any running 96 * I2C transaction to complete -- the arbitration logic won't 97 * work properly until the next START is seen. 98 * It is assumed the bus driver or client has set a proper value. 99 * 100 * REVISIT: should probably use msleep instead of mdelay if we 101 * know we can sleep. 102 */ 103 if (adap->lab_mdelay) 104 mdelay(adap->lab_mdelay); 105 106 DEB2(printk(KERN_INFO 107 "i2c-algo-pcf.o: reset LAB condition (CSR 0x%02x)\n", 108 get_pcf(adap, 1))); 109 } 110 111 static int wait_for_bb(struct i2c_algo_pcf_data *adap) { 112 113 int timeout = DEF_TIMEOUT; 114 int status; 115 116 status = get_pcf(adap, 1); 117 #ifndef STUB_I2C 118 while (timeout-- && !(status & I2C_PCF_BB)) { 119 udelay(100); /* wait for 100 us */ 120 status = get_pcf(adap, 1); 121 } 122 #endif 123 if (timeout <= 0) { 124 printk(KERN_ERR "Timeout waiting for Bus Busy\n"); 125 } 126 127 return (timeout<=0); 128 } 129 130 131 static int wait_for_pin(struct i2c_algo_pcf_data *adap, int *status) { 132 133 int timeout = DEF_TIMEOUT; 134 135 *status = get_pcf(adap, 1); 136 #ifndef STUB_I2C 137 while (timeout-- && (*status & I2C_PCF_PIN)) { 138 adap->waitforpin(adap->data); 139 *status = get_pcf(adap, 1); 140 } 141 if (*status & I2C_PCF_LAB) { 142 handle_lab(adap, status); 143 return(-EINTR); 144 } 145 #endif 146 if (timeout <= 0) 147 return(-1); 148 else 149 return(0); 150 } 151 152 /* 153 * This should perform the 'PCF8584 initialization sequence' as described 154 * in the Philips IC12 data book (1995, Aug 29). 155 * There should be a 30 clock cycle wait after reset, I assume this 156 * has been fulfilled. 157 * There should be a delay at the end equal to the longest I2C message 158 * to synchronize the BB-bit (in multimaster systems). How long is 159 * this? I assume 1 second is always long enough. 160 * 161 * vdovikin: added detect code for PCF8584 162 */ 163 static int pcf_init_8584 (struct i2c_algo_pcf_data *adap) 164 { 165 unsigned char temp; 166 167 DEB3(printk(KERN_DEBUG "i2c-algo-pcf.o: PCF state 0x%02x\n", get_pcf(adap, 1))); 168 169 /* S1=0x80: S0 selected, serial interface off */ 170 set_pcf(adap, 1, I2C_PCF_PIN); 171 /* check to see S1 now used as R/W ctrl - 172 PCF8584 does that when ESO is zero */ 173 if (((temp = get_pcf(adap, 1)) & 0x7f) != (0)) { 174 DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't select S0 (0x%02x).\n", temp)); 175 return -ENXIO; /* definetly not PCF8584 */ 176 } 177 178 /* load own address in S0, effective address is (own << 1) */ 179 i2c_outb(adap, get_own(adap)); 180 /* check it's really written */ 181 if ((temp = i2c_inb(adap)) != get_own(adap)) { 182 DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't set S0 (0x%02x).\n", temp)); 183 return -ENXIO; 184 } 185 186 /* S1=0xA0, next byte in S2 */ 187 set_pcf(adap, 1, I2C_PCF_PIN | I2C_PCF_ES1); 188 /* check to see S2 now selected */ 189 if (((temp = get_pcf(adap, 1)) & 0x7f) != I2C_PCF_ES1) { 190 DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't select S2 (0x%02x).\n", temp)); 191 return -ENXIO; 192 } 193 194 /* load clock register S2 */ 195 i2c_outb(adap, get_clock(adap)); 196 /* check it's really written, the only 5 lowest bits does matter */ 197 if (((temp = i2c_inb(adap)) & 0x1f) != get_clock(adap)) { 198 DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't set S2 (0x%02x).\n", temp)); 199 return -ENXIO; 200 } 201 202 /* Enable serial interface, idle, S0 selected */ 203 set_pcf(adap, 1, I2C_PCF_IDLE); 204 205 /* check to see PCF is really idled and we can access status register */ 206 if ((temp = get_pcf(adap, 1)) != (I2C_PCF_PIN | I2C_PCF_BB)) { 207 DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't select S1` (0x%02x).\n", temp)); 208 return -ENXIO; 209 } 210 211 printk(KERN_DEBUG "i2c-algo-pcf.o: detected and initialized PCF8584.\n"); 212 213 return 0; 214 } 215 216 217 /* ----- Utility functions 218 */ 219 220 static int pcf_sendbytes(struct i2c_adapter *i2c_adap, const char *buf, 221 int count, int last) 222 { 223 struct i2c_algo_pcf_data *adap = i2c_adap->algo_data; 224 int wrcount, status, timeout; 225 226 for (wrcount=0; wrcount<count; ++wrcount) { 227 DEB2(dev_dbg(&i2c_adap->dev, "i2c_write: writing %2.2X\n", 228 buf[wrcount]&0xff)); 229 i2c_outb(adap, buf[wrcount]); 230 timeout = wait_for_pin(adap, &status); 231 if (timeout) { 232 if (timeout == -EINTR) { 233 /* arbitration lost */ 234 return -EINTR; 235 } 236 i2c_stop(adap); 237 dev_err(&i2c_adap->dev, "i2c_write: error - timeout.\n"); 238 return -EREMOTEIO; /* got a better one ?? */ 239 } 240 #ifndef STUB_I2C 241 if (status & I2C_PCF_LRB) { 242 i2c_stop(adap); 243 dev_err(&i2c_adap->dev, "i2c_write: error - no ack.\n"); 244 return -EREMOTEIO; /* got a better one ?? */ 245 } 246 #endif 247 } 248 if (last) { 249 i2c_stop(adap); 250 } 251 else { 252 i2c_repstart(adap); 253 } 254 255 return (wrcount); 256 } 257 258 259 static int pcf_readbytes(struct i2c_adapter *i2c_adap, char *buf, 260 int count, int last) 261 { 262 int i, status; 263 struct i2c_algo_pcf_data *adap = i2c_adap->algo_data; 264 int wfp; 265 266 /* increment number of bytes to read by one -- read dummy byte */ 267 for (i = 0; i <= count; i++) { 268 269 if ((wfp = wait_for_pin(adap, &status))) { 270 if (wfp == -EINTR) { 271 /* arbitration lost */ 272 return -EINTR; 273 } 274 i2c_stop(adap); 275 dev_err(&i2c_adap->dev, "pcf_readbytes timed out.\n"); 276 return (-1); 277 } 278 279 #ifndef STUB_I2C 280 if ((status & I2C_PCF_LRB) && (i != count)) { 281 i2c_stop(adap); 282 dev_err(&i2c_adap->dev, "i2c_read: i2c_inb, No ack.\n"); 283 return (-1); 284 } 285 #endif 286 287 if (i == count - 1) { 288 set_pcf(adap, 1, I2C_PCF_ESO); 289 } else 290 if (i == count) { 291 if (last) { 292 i2c_stop(adap); 293 } else { 294 i2c_repstart(adap); 295 } 296 }; 297 298 if (i) { 299 buf[i - 1] = i2c_inb(adap); 300 } else { 301 i2c_inb(adap); /* dummy read */ 302 } 303 } 304 305 return (i - 1); 306 } 307 308 309 static int pcf_doAddress(struct i2c_algo_pcf_data *adap, 310 struct i2c_msg *msg) 311 { 312 unsigned short flags = msg->flags; 313 unsigned char addr; 314 315 addr = msg->addr << 1; 316 if (flags & I2C_M_RD) 317 addr |= 1; 318 if (flags & I2C_M_REV_DIR_ADDR) 319 addr ^= 1; 320 i2c_outb(adap, addr); 321 322 return 0; 323 } 324 325 static int pcf_xfer(struct i2c_adapter *i2c_adap, 326 struct i2c_msg *msgs, 327 int num) 328 { 329 struct i2c_algo_pcf_data *adap = i2c_adap->algo_data; 330 struct i2c_msg *pmsg; 331 int i; 332 int ret=0, timeout, status; 333 334 if (adap->xfer_begin) 335 adap->xfer_begin(adap->data); 336 337 /* Check for bus busy */ 338 timeout = wait_for_bb(adap); 339 if (timeout) { 340 DEB2(printk(KERN_ERR "i2c-algo-pcf.o: " 341 "Timeout waiting for BB in pcf_xfer\n");) 342 i = -EIO; 343 goto out; 344 } 345 346 for (i = 0;ret >= 0 && i < num; i++) { 347 pmsg = &msgs[i]; 348 349 DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: Doing %s %d bytes to 0x%02x - %d of %d messages\n", 350 pmsg->flags & I2C_M_RD ? "read" : "write", 351 pmsg->len, pmsg->addr, i + 1, num);) 352 353 ret = pcf_doAddress(adap, pmsg); 354 355 /* Send START */ 356 if (i == 0) { 357 i2c_start(adap); 358 } 359 360 /* Wait for PIN (pending interrupt NOT) */ 361 timeout = wait_for_pin(adap, &status); 362 if (timeout) { 363 if (timeout == -EINTR) { 364 /* arbitration lost */ 365 i = -EINTR; 366 goto out; 367 } 368 i2c_stop(adap); 369 DEB2(printk(KERN_ERR "i2c-algo-pcf.o: Timeout waiting " 370 "for PIN(1) in pcf_xfer\n");) 371 i = -EREMOTEIO; 372 goto out; 373 } 374 375 #ifndef STUB_I2C 376 /* Check LRB (last rcvd bit - slave ack) */ 377 if (status & I2C_PCF_LRB) { 378 i2c_stop(adap); 379 DEB2(printk(KERN_ERR "i2c-algo-pcf.o: No LRB(1) in pcf_xfer\n");) 380 i = -EREMOTEIO; 381 goto out; 382 } 383 #endif 384 385 DEB3(printk(KERN_DEBUG "i2c-algo-pcf.o: Msg %d, addr=0x%x, flags=0x%x, len=%d\n", 386 i, msgs[i].addr, msgs[i].flags, msgs[i].len);) 387 388 /* Read */ 389 if (pmsg->flags & I2C_M_RD) { 390 /* read bytes into buffer*/ 391 ret = pcf_readbytes(i2c_adap, pmsg->buf, pmsg->len, 392 (i + 1 == num)); 393 394 if (ret != pmsg->len) { 395 DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: fail: " 396 "only read %d bytes.\n",ret)); 397 } else { 398 DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: read %d bytes.\n",ret)); 399 } 400 } else { /* Write */ 401 ret = pcf_sendbytes(i2c_adap, pmsg->buf, pmsg->len, 402 (i + 1 == num)); 403 404 if (ret != pmsg->len) { 405 DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: fail: " 406 "only wrote %d bytes.\n",ret)); 407 } else { 408 DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: wrote %d bytes.\n",ret)); 409 } 410 } 411 } 412 413 out: 414 if (adap->xfer_end) 415 adap->xfer_end(adap->data); 416 return (i); 417 } 418 419 static u32 pcf_func(struct i2c_adapter *adap) 420 { 421 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | 422 I2C_FUNC_PROTOCOL_MANGLING; 423 } 424 425 /* -----exported algorithm data: ------------------------------------- */ 426 427 static const struct i2c_algorithm pcf_algo = { 428 .master_xfer = pcf_xfer, 429 .functionality = pcf_func, 430 }; 431 432 /* 433 * registering functions to load algorithms at runtime 434 */ 435 int i2c_pcf_add_bus(struct i2c_adapter *adap) 436 { 437 struct i2c_algo_pcf_data *pcf_adap = adap->algo_data; 438 int rval; 439 440 DEB2(dev_dbg(&adap->dev, "hw routines registered.\n")); 441 442 /* register new adapter to i2c module... */ 443 adap->algo = &pcf_algo; 444 adap->timeout = 100; 445 446 if ((rval = pcf_init_8584(pcf_adap))) 447 return rval; 448 449 rval = i2c_add_adapter(adap); 450 451 return rval; 452 } 453 EXPORT_SYMBOL(i2c_pcf_add_bus); 454 455 MODULE_AUTHOR("Hans Berglund <hb@spacetec.no>"); 456 MODULE_DESCRIPTION("I2C-Bus PCF8584 algorithm"); 457 MODULE_LICENSE("GPL"); 458 459 module_param(i2c_debug, int, S_IRUGO | S_IWUSR); 460 MODULE_PARM_DESC(i2c_debug, 461 "debug level - 0 off; 1 normal; 2,3 more verbose; 9 pcf-protocol"); 462