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 int wait_for_bb(struct i2c_algo_pcf_data *adap) { 82 83 int timeout = DEF_TIMEOUT; 84 int status; 85 86 status = get_pcf(adap, 1); 87 #ifndef STUB_I2C 88 while (timeout-- && !(status & I2C_PCF_BB)) { 89 udelay(100); /* wait for 100 us */ 90 status = get_pcf(adap, 1); 91 } 92 #endif 93 if (timeout <= 0) { 94 printk(KERN_ERR "Timeout waiting for Bus Busy\n"); 95 } 96 97 return (timeout<=0); 98 } 99 100 101 static int wait_for_pin(struct i2c_algo_pcf_data *adap, int *status) { 102 103 int timeout = DEF_TIMEOUT; 104 105 *status = get_pcf(adap, 1); 106 #ifndef STUB_I2C 107 while (timeout-- && (*status & I2C_PCF_PIN)) { 108 adap->waitforpin(); 109 *status = get_pcf(adap, 1); 110 } 111 if (*status & I2C_PCF_LAB) { 112 DEB2(printk(KERN_INFO 113 "i2c-algo-pcf.o: lost arbitration (CSR 0x%02x)\n", 114 *status)); 115 /* Cleanup from LAB-- reset and enable ESO. 116 * This resets the PCF8584; since we've lost the bus, no 117 * further attempts should be made by callers to clean up 118 * (no i2c_stop() etc.) 119 */ 120 set_pcf(adap, 1, I2C_PCF_PIN); 121 set_pcf(adap, 1, I2C_PCF_ESO); 122 /* TODO: we should pause for a time period sufficient for any 123 * running I2C transaction to complete-- the arbitration 124 * logic won't work properly until the next START is seen. 125 */ 126 DEB2(printk(KERN_INFO 127 "i2c-algo-pcf.o: reset LAB condition (CSR 0x%02x)\n", 128 get_pcf(adap,1))); 129 return(-EINTR); 130 } 131 #endif 132 if (timeout <= 0) 133 return(-1); 134 else 135 return(0); 136 } 137 138 /* 139 * This should perform the 'PCF8584 initialization sequence' as described 140 * in the Philips IC12 data book (1995, Aug 29). 141 * There should be a 30 clock cycle wait after reset, I assume this 142 * has been fulfilled. 143 * There should be a delay at the end equal to the longest I2C message 144 * to synchronize the BB-bit (in multimaster systems). How long is 145 * this? I assume 1 second is always long enough. 146 * 147 * vdovikin: added detect code for PCF8584 148 */ 149 static int pcf_init_8584 (struct i2c_algo_pcf_data *adap) 150 { 151 unsigned char temp; 152 153 DEB3(printk(KERN_DEBUG "i2c-algo-pcf.o: PCF state 0x%02x\n", get_pcf(adap, 1))); 154 155 /* S1=0x80: S0 selected, serial interface off */ 156 set_pcf(adap, 1, I2C_PCF_PIN); 157 /* check to see S1 now used as R/W ctrl - 158 PCF8584 does that when ESO is zero */ 159 if (((temp = get_pcf(adap, 1)) & 0x7f) != (0)) { 160 DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't select S0 (0x%02x).\n", temp)); 161 return -ENXIO; /* definetly not PCF8584 */ 162 } 163 164 /* load own address in S0, effective address is (own << 1) */ 165 i2c_outb(adap, get_own(adap)); 166 /* check it's really written */ 167 if ((temp = i2c_inb(adap)) != get_own(adap)) { 168 DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't set S0 (0x%02x).\n", temp)); 169 return -ENXIO; 170 } 171 172 /* S1=0xA0, next byte in S2 */ 173 set_pcf(adap, 1, I2C_PCF_PIN | I2C_PCF_ES1); 174 /* check to see S2 now selected */ 175 if (((temp = get_pcf(adap, 1)) & 0x7f) != I2C_PCF_ES1) { 176 DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't select S2 (0x%02x).\n", temp)); 177 return -ENXIO; 178 } 179 180 /* load clock register S2 */ 181 i2c_outb(adap, get_clock(adap)); 182 /* check it's really written, the only 5 lowest bits does matter */ 183 if (((temp = i2c_inb(adap)) & 0x1f) != get_clock(adap)) { 184 DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't set S2 (0x%02x).\n", temp)); 185 return -ENXIO; 186 } 187 188 /* Enable serial interface, idle, S0 selected */ 189 set_pcf(adap, 1, I2C_PCF_IDLE); 190 191 /* check to see PCF is really idled and we can access status register */ 192 if ((temp = get_pcf(adap, 1)) != (I2C_PCF_PIN | I2C_PCF_BB)) { 193 DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't select S1` (0x%02x).\n", temp)); 194 return -ENXIO; 195 } 196 197 printk(KERN_DEBUG "i2c-algo-pcf.o: deteted and initialized PCF8584.\n"); 198 199 return 0; 200 } 201 202 203 /* ----- Utility functions 204 */ 205 206 static int pcf_sendbytes(struct i2c_adapter *i2c_adap, const char *buf, 207 int count, int last) 208 { 209 struct i2c_algo_pcf_data *adap = i2c_adap->algo_data; 210 int wrcount, status, timeout; 211 212 for (wrcount=0; wrcount<count; ++wrcount) { 213 DEB2(dev_dbg(&i2c_adap->dev, "i2c_write: writing %2.2X\n", 214 buf[wrcount]&0xff)); 215 i2c_outb(adap, buf[wrcount]); 216 timeout = wait_for_pin(adap, &status); 217 if (timeout) { 218 if (timeout == -EINTR) { 219 /* arbitration lost */ 220 return -EINTR; 221 } 222 i2c_stop(adap); 223 dev_err(&i2c_adap->dev, "i2c_write: error - timeout.\n"); 224 return -EREMOTEIO; /* got a better one ?? */ 225 } 226 #ifndef STUB_I2C 227 if (status & I2C_PCF_LRB) { 228 i2c_stop(adap); 229 dev_err(&i2c_adap->dev, "i2c_write: error - no ack.\n"); 230 return -EREMOTEIO; /* got a better one ?? */ 231 } 232 #endif 233 } 234 if (last) { 235 i2c_stop(adap); 236 } 237 else { 238 i2c_repstart(adap); 239 } 240 241 return (wrcount); 242 } 243 244 245 static int pcf_readbytes(struct i2c_adapter *i2c_adap, char *buf, 246 int count, int last) 247 { 248 int i, status; 249 struct i2c_algo_pcf_data *adap = i2c_adap->algo_data; 250 int wfp; 251 252 /* increment number of bytes to read by one -- read dummy byte */ 253 for (i = 0; i <= count; i++) { 254 255 if ((wfp = wait_for_pin(adap, &status))) { 256 if (wfp == -EINTR) { 257 /* arbitration lost */ 258 return -EINTR; 259 } 260 i2c_stop(adap); 261 dev_err(&i2c_adap->dev, "pcf_readbytes timed out.\n"); 262 return (-1); 263 } 264 265 #ifndef STUB_I2C 266 if ((status & I2C_PCF_LRB) && (i != count)) { 267 i2c_stop(adap); 268 dev_err(&i2c_adap->dev, "i2c_read: i2c_inb, No ack.\n"); 269 return (-1); 270 } 271 #endif 272 273 if (i == count - 1) { 274 set_pcf(adap, 1, I2C_PCF_ESO); 275 } else 276 if (i == count) { 277 if (last) { 278 i2c_stop(adap); 279 } else { 280 i2c_repstart(adap); 281 } 282 }; 283 284 if (i) { 285 buf[i - 1] = i2c_inb(adap); 286 } else { 287 i2c_inb(adap); /* dummy read */ 288 } 289 } 290 291 return (i - 1); 292 } 293 294 295 static int pcf_doAddress(struct i2c_algo_pcf_data *adap, 296 struct i2c_msg *msg) 297 { 298 unsigned short flags = msg->flags; 299 unsigned char addr; 300 301 addr = msg->addr << 1; 302 if (flags & I2C_M_RD) 303 addr |= 1; 304 if (flags & I2C_M_REV_DIR_ADDR) 305 addr ^= 1; 306 i2c_outb(adap, addr); 307 308 return 0; 309 } 310 311 static int pcf_xfer(struct i2c_adapter *i2c_adap, 312 struct i2c_msg *msgs, 313 int num) 314 { 315 struct i2c_algo_pcf_data *adap = i2c_adap->algo_data; 316 struct i2c_msg *pmsg; 317 int i; 318 int ret=0, timeout, status; 319 320 321 /* Check for bus busy */ 322 timeout = wait_for_bb(adap); 323 if (timeout) { 324 DEB2(printk(KERN_ERR "i2c-algo-pcf.o: " 325 "Timeout waiting for BB in pcf_xfer\n");) 326 return -EIO; 327 } 328 329 for (i = 0;ret >= 0 && i < num; i++) { 330 pmsg = &msgs[i]; 331 332 DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: Doing %s %d bytes to 0x%02x - %d of %d messages\n", 333 pmsg->flags & I2C_M_RD ? "read" : "write", 334 pmsg->len, pmsg->addr, i + 1, num);) 335 336 ret = pcf_doAddress(adap, pmsg); 337 338 /* Send START */ 339 if (i == 0) { 340 i2c_start(adap); 341 } 342 343 /* Wait for PIN (pending interrupt NOT) */ 344 timeout = wait_for_pin(adap, &status); 345 if (timeout) { 346 if (timeout == -EINTR) { 347 /* arbitration lost */ 348 return (-EINTR); 349 } 350 i2c_stop(adap); 351 DEB2(printk(KERN_ERR "i2c-algo-pcf.o: Timeout waiting " 352 "for PIN(1) in pcf_xfer\n");) 353 return (-EREMOTEIO); 354 } 355 356 #ifndef STUB_I2C 357 /* Check LRB (last rcvd bit - slave ack) */ 358 if (status & I2C_PCF_LRB) { 359 i2c_stop(adap); 360 DEB2(printk(KERN_ERR "i2c-algo-pcf.o: No LRB(1) in pcf_xfer\n");) 361 return (-EREMOTEIO); 362 } 363 #endif 364 365 DEB3(printk(KERN_DEBUG "i2c-algo-pcf.o: Msg %d, addr=0x%x, flags=0x%x, len=%d\n", 366 i, msgs[i].addr, msgs[i].flags, msgs[i].len);) 367 368 /* Read */ 369 if (pmsg->flags & I2C_M_RD) { 370 /* read bytes into buffer*/ 371 ret = pcf_readbytes(i2c_adap, pmsg->buf, pmsg->len, 372 (i + 1 == num)); 373 374 if (ret != pmsg->len) { 375 DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: fail: " 376 "only read %d bytes.\n",ret)); 377 } else { 378 DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: read %d bytes.\n",ret)); 379 } 380 } else { /* Write */ 381 ret = pcf_sendbytes(i2c_adap, pmsg->buf, pmsg->len, 382 (i + 1 == num)); 383 384 if (ret != pmsg->len) { 385 DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: fail: " 386 "only wrote %d bytes.\n",ret)); 387 } else { 388 DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: wrote %d bytes.\n",ret)); 389 } 390 } 391 } 392 393 return (i); 394 } 395 396 static u32 pcf_func(struct i2c_adapter *adap) 397 { 398 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | 399 I2C_FUNC_PROTOCOL_MANGLING; 400 } 401 402 /* -----exported algorithm data: ------------------------------------- */ 403 404 static const struct i2c_algorithm pcf_algo = { 405 .master_xfer = pcf_xfer, 406 .functionality = pcf_func, 407 }; 408 409 /* 410 * registering functions to load algorithms at runtime 411 */ 412 int i2c_pcf_add_bus(struct i2c_adapter *adap) 413 { 414 struct i2c_algo_pcf_data *pcf_adap = adap->algo_data; 415 int rval; 416 417 DEB2(dev_dbg(&adap->dev, "hw routines registered.\n")); 418 419 /* register new adapter to i2c module... */ 420 adap->algo = &pcf_algo; 421 adap->timeout = 100; 422 423 if ((rval = pcf_init_8584(pcf_adap))) 424 return rval; 425 426 rval = i2c_add_adapter(adap); 427 428 return rval; 429 } 430 EXPORT_SYMBOL(i2c_pcf_add_bus); 431 432 MODULE_AUTHOR("Hans Berglund <hb@spacetec.no>"); 433 MODULE_DESCRIPTION("I2C-Bus PCF8584 algorithm"); 434 MODULE_LICENSE("GPL"); 435 436 module_param(i2c_debug, int, S_IRUGO | S_IWUSR); 437 MODULE_PARM_DESC(i2c_debug, 438 "debug level - 0 off; 1 normal; 2,3 more verbose; 9 pcf-protocol"); 439