mv_twsi.c revision 295567
1/*- 2 * Copyright (C) 2008 MARVELL INTERNATIONAL LTD. 3 * All rights reserved. 4 * 5 * Developed by Semihalf. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of MARVELL nor the names of contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32/* 33 * Driver for the TWSI (aka I2C, aka IIC) bus controller found on Marvell 34 * SoCs. Supports master operation only, and works in polling mode. 35 * 36 * Calls to DELAY() are needed per Application Note AN-179 "TWSI Software 37 * Guidelines for Discovery(TM), Horizon (TM) and Feroceon(TM) Devices". 38 */ 39 40#include <sys/cdefs.h> 41__FBSDID("$FreeBSD: head/sys/arm/mv/twsi.c 295567 2016-02-12 17:04:03Z andrew $"); 42 43#include <sys/param.h> 44#include <sys/systm.h> 45#include <sys/bus.h> 46#include <sys/kernel.h> 47#include <sys/module.h> 48#include <sys/resource.h> 49 50#include <machine/_inttypes.h> 51#include <machine/bus.h> 52#include <machine/resource.h> 53 54#include <sys/rman.h> 55 56#include <sys/lock.h> 57#include <sys/mutex.h> 58 59#include <dev/iicbus/iiconf.h> 60#include <dev/iicbus/iicbus.h> 61#include <dev/fdt/fdt_common.h> 62#include <dev/ofw/ofw_bus.h> 63#include <dev/ofw/ofw_bus_subr.h> 64 65#include <arm/mv/mvreg.h> 66#include <arm/mv/mvvar.h> 67 68#include "iicbus_if.h" 69 70#define MV_TWSI_NAME "twsi" 71#define IICBUS_DEVNAME "iicbus" 72 73#define TWSI_SLAVE_ADDR 0x00 74#define TWSI_EXT_SLAVE_ADDR 0x10 75#define TWSI_DATA 0x04 76 77#define TWSI_CONTROL 0x08 78#define TWSI_CONTROL_ACK (1 << 2) 79#define TWSI_CONTROL_IFLG (1 << 3) 80#define TWSI_CONTROL_STOP (1 << 4) 81#define TWSI_CONTROL_START (1 << 5) 82#define TWSI_CONTROL_TWSIEN (1 << 6) 83#define TWSI_CONTROL_INTEN (1 << 7) 84 85#define TWSI_STATUS 0x0c 86#define TWSI_STATUS_START 0x08 87#define TWSI_STATUS_RPTD_START 0x10 88#define TWSI_STATUS_ADDR_W_ACK 0x18 89#define TWSI_STATUS_DATA_WR_ACK 0x28 90#define TWSI_STATUS_ADDR_R_ACK 0x40 91#define TWSI_STATUS_DATA_RD_ACK 0x50 92#define TWSI_STATUS_DATA_RD_NOACK 0x58 93 94#define TWSI_BAUD_RATE 0x0c 95#define TWSI_BAUD_RATE_PARAM(M,N) ((((M) << 3) | ((N) & 0x7)) & 0x7f) 96#define TWSI_BAUD_RATE_RAW(C,M,N) ((C)/((10*(M+1))<<(N+1))) 97#define TWSI_BAUD_RATE_SLOW 50000 /* 50kHz */ 98#define TWSI_BAUD_RATE_FAST 100000 /* 100kHz */ 99 100#define TWSI_SOFT_RESET 0x1c 101 102#define TWSI_DEBUG 103#undef TWSI_DEBUG 104 105#ifdef TWSI_DEBUG 106#define debugf(fmt, args...) do { printf("%s(): ", __func__); printf(fmt,##args); } while (0) 107#else 108#define debugf(fmt, args...) 109#endif 110 111struct mv_twsi_softc { 112 device_t dev; 113 struct resource *res[1]; /* SYS_RES_MEMORY */ 114 struct mtx mutex; 115 device_t iicbus; 116}; 117 118static struct mv_twsi_baud_rate { 119 uint32_t raw; 120 int param; 121 int m; 122 int n; 123} baud_rate[IIC_FASTEST + 1]; 124 125static int mv_twsi_probe(device_t); 126static int mv_twsi_attach(device_t); 127static int mv_twsi_detach(device_t); 128 129static int mv_twsi_reset(device_t dev, u_char speed, u_char addr, 130 u_char *oldaddr); 131static int mv_twsi_repeated_start(device_t dev, u_char slave, int timeout); 132static int mv_twsi_start(device_t dev, u_char slave, int timeout); 133static int mv_twsi_stop(device_t dev); 134static int mv_twsi_read(device_t dev, char *buf, int len, int *read, int last, 135 int delay); 136static int mv_twsi_write(device_t dev, const char *buf, int len, int *sent, 137 int timeout); 138 139static struct resource_spec res_spec[] = { 140 { SYS_RES_MEMORY, 0, RF_ACTIVE }, 141 { -1, 0 } 142}; 143 144static struct ofw_compat_data compat_data[] = { 145 { "mrvl,twsi", true }, 146 { "marvell,mv64xxx-i2c", true }, 147 { NULL, false } 148}; 149 150static device_method_t mv_twsi_methods[] = { 151 /* device interface */ 152 DEVMETHOD(device_probe, mv_twsi_probe), 153 DEVMETHOD(device_attach, mv_twsi_attach), 154 DEVMETHOD(device_detach, mv_twsi_detach), 155 156 /* iicbus interface */ 157 DEVMETHOD(iicbus_callback, iicbus_null_callback), 158 DEVMETHOD(iicbus_repeated_start, mv_twsi_repeated_start), 159 DEVMETHOD(iicbus_start, mv_twsi_start), 160 DEVMETHOD(iicbus_stop, mv_twsi_stop), 161 DEVMETHOD(iicbus_write, mv_twsi_write), 162 DEVMETHOD(iicbus_read, mv_twsi_read), 163 DEVMETHOD(iicbus_reset, mv_twsi_reset), 164 DEVMETHOD(iicbus_transfer, iicbus_transfer_gen), 165 { 0, 0 } 166}; 167 168static devclass_t mv_twsi_devclass; 169 170static driver_t mv_twsi_driver = { 171 MV_TWSI_NAME, 172 mv_twsi_methods, 173 sizeof(struct mv_twsi_softc), 174}; 175 176DRIVER_MODULE(twsi, simplebus, mv_twsi_driver, mv_twsi_devclass, 0, 0); 177DRIVER_MODULE(iicbus, twsi, iicbus_driver, iicbus_devclass, 0, 0); 178MODULE_DEPEND(twsi, iicbus, 1, 1, 1); 179 180static __inline uint32_t 181TWSI_READ(struct mv_twsi_softc *sc, bus_size_t off) 182{ 183 184 return (bus_read_4(sc->res[0], off)); 185} 186 187static __inline void 188TWSI_WRITE(struct mv_twsi_softc *sc, bus_size_t off, uint32_t val) 189{ 190 191 bus_write_4(sc->res[0], off, val); 192} 193 194static __inline void 195twsi_control_clear(struct mv_twsi_softc *sc, uint32_t mask) 196{ 197 uint32_t val; 198 199 val = TWSI_READ(sc, TWSI_CONTROL); 200 val &= ~mask; 201 TWSI_WRITE(sc, TWSI_CONTROL, val); 202} 203 204static __inline void 205twsi_control_set(struct mv_twsi_softc *sc, uint32_t mask) 206{ 207 uint32_t val; 208 209 val = TWSI_READ(sc, TWSI_CONTROL); 210 val |= mask; 211 TWSI_WRITE(sc, TWSI_CONTROL, val); 212} 213 214static __inline void 215twsi_clear_iflg(struct mv_twsi_softc *sc) 216{ 217 218 DELAY(1000); 219 twsi_control_clear(sc, TWSI_CONTROL_IFLG); 220 DELAY(1000); 221} 222 223 224/* 225 * timeout given in us 226 * returns 227 * 0 on sucessfull mask change 228 * non-zero on timeout 229 */ 230static int 231twsi_poll_ctrl(struct mv_twsi_softc *sc, int timeout, uint32_t mask) 232{ 233 234 timeout /= 10; 235 while (!(TWSI_READ(sc, TWSI_CONTROL) & mask)) { 236 DELAY(10); 237 if (--timeout < 0) 238 return (timeout); 239 } 240 return (0); 241} 242 243 244/* 245 * 'timeout' is given in us. Note also that timeout handling is not exact -- 246 * twsi_locked_start() total wait can be more than 2 x timeout 247 * (twsi_poll_ctrl() is called twice). 'mask' can be either TWSI_STATUS_START 248 * or TWSI_STATUS_RPTD_START 249 */ 250static int 251twsi_locked_start(device_t dev, struct mv_twsi_softc *sc, int32_t mask, 252 u_char slave, int timeout) 253{ 254 int read_access, iflg_set = 0; 255 uint32_t status; 256 257 mtx_assert(&sc->mutex, MA_OWNED); 258 259 if (mask == TWSI_STATUS_RPTD_START) 260 /* read IFLG to know if it should be cleared later; from NBSD */ 261 iflg_set = TWSI_READ(sc, TWSI_CONTROL) & TWSI_CONTROL_IFLG; 262 263 twsi_control_set(sc, TWSI_CONTROL_START); 264 265 if (mask == TWSI_STATUS_RPTD_START && iflg_set) { 266 debugf("IFLG set, clearing\n"); 267 twsi_clear_iflg(sc); 268 } 269 270 /* 271 * Without this delay we timeout checking IFLG if the timeout is 0. 272 * NBSD driver always waits here too. 273 */ 274 DELAY(1000); 275 276 if (twsi_poll_ctrl(sc, timeout, TWSI_CONTROL_IFLG)) { 277 debugf("timeout sending %sSTART condition\n", 278 mask == TWSI_STATUS_START ? "" : "repeated "); 279 return (IIC_ETIMEOUT); 280 } 281 282 status = TWSI_READ(sc, TWSI_STATUS); 283 if (status != mask) { 284 debugf("wrong status (%02x) after sending %sSTART condition\n", 285 status, mask == TWSI_STATUS_START ? "" : "repeated "); 286 return (IIC_ESTATUS); 287 } 288 289 TWSI_WRITE(sc, TWSI_DATA, slave); 290 DELAY(1000); 291 twsi_clear_iflg(sc); 292 293 if (twsi_poll_ctrl(sc, timeout, TWSI_CONTROL_IFLG)) { 294 debugf("timeout sending slave address\n"); 295 return (IIC_ETIMEOUT); 296 } 297 298 read_access = (slave & 0x1) ? 1 : 0; 299 status = TWSI_READ(sc, TWSI_STATUS); 300 if (status != (read_access ? 301 TWSI_STATUS_ADDR_R_ACK : TWSI_STATUS_ADDR_W_ACK)) { 302 debugf("no ACK (status: %02x) after sending slave address\n", 303 status); 304 return (IIC_ENOACK); 305 } 306 307 return (IIC_NOERR); 308} 309 310static int 311mv_twsi_probe(device_t dev) 312{ 313 314 if (!ofw_bus_status_okay(dev)) 315 return (ENXIO); 316 317 if (!ofw_bus_search_compatible(dev, compat_data)->ocd_data) 318 return (ENXIO); 319 320 device_set_desc(dev, "Marvell Integrated I2C Bus Controller"); 321 return (BUS_PROBE_DEFAULT); 322} 323 324#define ABSSUB(a,b) (((a) > (b)) ? (a) - (b) : (b) - (a)) 325static void 326mv_twsi_cal_baud_rate(const uint32_t target, struct mv_twsi_baud_rate *rate) 327{ 328 uint32_t clk, cur, diff, diff0; 329 int m, n, m0, n0; 330 331 /* Calculate baud rate. */ 332 m0 = n0 = 4; /* Default values on reset */ 333 diff0 = 0xffffffff; 334 clk = get_tclk(); 335 336 for (n = 0; n < 8; n++) { 337 for (m = 0; m < 16; m++) { 338 cur = TWSI_BAUD_RATE_RAW(clk,m,n); 339 diff = ABSSUB(target, cur); 340 if (diff < diff0) { 341 m0 = m; 342 n0 = n; 343 diff0 = diff; 344 } 345 } 346 } 347 rate->raw = TWSI_BAUD_RATE_RAW(clk, m0, n0); 348 rate->param = TWSI_BAUD_RATE_PARAM(m0, n0); 349 rate->m = m0; 350 rate->n = n0; 351} 352 353static int 354mv_twsi_attach(device_t dev) 355{ 356 struct mv_twsi_softc *sc; 357 phandle_t child, iicbusnode; 358 device_t childdev; 359 struct iicbus_ivar *devi; 360 char dname[32]; /* 32 is taken from struct u_device */ 361 uint32_t paddr; 362 int len, error; 363 364 sc = device_get_softc(dev); 365 sc->dev = dev; 366 bzero(baud_rate, sizeof(baud_rate)); 367 368 mtx_init(&sc->mutex, device_get_nameunit(dev), MV_TWSI_NAME, MTX_DEF); 369 370 /* Allocate IO resources */ 371 if (bus_alloc_resources(dev, res_spec, sc->res)) { 372 device_printf(dev, "could not allocate resources\n"); 373 mv_twsi_detach(dev); 374 return (ENXIO); 375 } 376 377 mv_twsi_cal_baud_rate(TWSI_BAUD_RATE_SLOW, &baud_rate[IIC_SLOW]); 378 mv_twsi_cal_baud_rate(TWSI_BAUD_RATE_FAST, &baud_rate[IIC_FAST]); 379 if (bootverbose) 380 device_printf(dev, "calculated baud rates are:\n" 381 " %" PRIu32 " kHz (M=%d, N=%d) for slow,\n" 382 " %" PRIu32 " kHz (M=%d, N=%d) for fast.\n", 383 baud_rate[IIC_SLOW].raw / 1000, 384 baud_rate[IIC_SLOW].m, 385 baud_rate[IIC_SLOW].n, 386 baud_rate[IIC_FAST].raw / 1000, 387 baud_rate[IIC_FAST].m, 388 baud_rate[IIC_FAST].n); 389 390 sc->iicbus = device_add_child(dev, IICBUS_DEVNAME, -1); 391 if (sc->iicbus == NULL) { 392 device_printf(dev, "could not add iicbus child\n"); 393 mv_twsi_detach(dev); 394 return (ENXIO); 395 } 396 /* Attach iicbus. */ 397 bus_generic_attach(dev); 398 399 iicbusnode = 0; 400 /* Find iicbus as the child devices in the device tree. */ 401 for (child = OF_child(ofw_bus_get_node(dev)); child != 0; 402 child = OF_peer(child)) { 403 len = OF_getproplen(child, "model"); 404 if (len <= 0 || len > sizeof(dname)) 405 continue; 406 error = OF_getprop(child, "model", &dname, len); 407 if (error == -1) 408 continue; 409 len = strlen(dname); 410 if (len == strlen(IICBUS_DEVNAME) && 411 strncasecmp(dname, IICBUS_DEVNAME, len) == 0) { 412 iicbusnode = child; 413 break; 414 } 415 } 416 if (iicbusnode == 0) 417 goto attach_end; 418 419 /* Attach child devices onto iicbus. */ 420 for (child = OF_child(iicbusnode); child != 0; child = OF_peer(child)) { 421 /* Get slave address. */ 422 error = OF_getprop(child, "i2c-address", &paddr, sizeof(paddr)); 423 if (error == -1) 424 error = OF_getprop(child, "reg", &paddr, sizeof(paddr)); 425 if (error == -1) 426 continue; 427 428 /* Get device driver name. */ 429 len = OF_getproplen(child, "model"); 430 if (len <= 0 || len > sizeof(dname)) 431 continue; 432 OF_getprop(child, "model", &dname, len); 433 434 if (bootverbose) 435 device_printf(dev, "adding a device %s at %d.\n", 436 dname, fdt32_to_cpu(paddr)); 437 childdev = BUS_ADD_CHILD(sc->iicbus, 0, dname, -1); 438 devi = IICBUS_IVAR(childdev); 439 devi->addr = fdt32_to_cpu(paddr); 440 } 441 442attach_end: 443 bus_generic_attach(sc->iicbus); 444 445 return (0); 446} 447 448static int 449mv_twsi_detach(device_t dev) 450{ 451 struct mv_twsi_softc *sc; 452 int rv; 453 454 sc = device_get_softc(dev); 455 456 if ((rv = bus_generic_detach(dev)) != 0) 457 return (rv); 458 459 if (sc->iicbus != NULL) 460 if ((rv = device_delete_child(dev, sc->iicbus)) != 0) 461 return (rv); 462 463 bus_release_resources(dev, res_spec, sc->res); 464 465 mtx_destroy(&sc->mutex); 466 return (0); 467} 468 469/* 470 * Only slave mode supported, disregard [old]addr 471 */ 472static int 473mv_twsi_reset(device_t dev, u_char speed, u_char addr, u_char *oldaddr) 474{ 475 struct mv_twsi_softc *sc; 476 uint32_t param; 477 478 sc = device_get_softc(dev); 479 480 switch (speed) { 481 case IIC_SLOW: 482 case IIC_FAST: 483 param = baud_rate[speed].param; 484 break; 485 case IIC_FASTEST: 486 case IIC_UNKNOWN: 487 default: 488 param = baud_rate[IIC_FAST].param; 489 break; 490 } 491 492 mtx_lock(&sc->mutex); 493 TWSI_WRITE(sc, TWSI_SOFT_RESET, 0x0); 494 DELAY(2000); 495 TWSI_WRITE(sc, TWSI_BAUD_RATE, param); 496 TWSI_WRITE(sc, TWSI_CONTROL, TWSI_CONTROL_TWSIEN | TWSI_CONTROL_ACK); 497 DELAY(1000); 498 mtx_unlock(&sc->mutex); 499 500 return (0); 501} 502 503/* 504 * timeout is given in us 505 */ 506static int 507mv_twsi_repeated_start(device_t dev, u_char slave, int timeout) 508{ 509 struct mv_twsi_softc *sc; 510 int rv; 511 512 sc = device_get_softc(dev); 513 514 mtx_lock(&sc->mutex); 515 rv = twsi_locked_start(dev, sc, TWSI_STATUS_RPTD_START, slave, 516 timeout); 517 mtx_unlock(&sc->mutex); 518 519 if (rv) { 520 mv_twsi_stop(dev); 521 return (rv); 522 } else 523 return (IIC_NOERR); 524} 525 526/* 527 * timeout is given in us 528 */ 529static int 530mv_twsi_start(device_t dev, u_char slave, int timeout) 531{ 532 struct mv_twsi_softc *sc; 533 int rv; 534 535 sc = device_get_softc(dev); 536 537 mtx_lock(&sc->mutex); 538 rv = twsi_locked_start(dev, sc, TWSI_STATUS_START, slave, timeout); 539 mtx_unlock(&sc->mutex); 540 541 if (rv) { 542 mv_twsi_stop(dev); 543 return (rv); 544 } else 545 return (IIC_NOERR); 546} 547 548static int 549mv_twsi_stop(device_t dev) 550{ 551 struct mv_twsi_softc *sc; 552 553 sc = device_get_softc(dev); 554 555 mtx_lock(&sc->mutex); 556 twsi_control_set(sc, TWSI_CONTROL_STOP); 557 DELAY(1000); 558 twsi_clear_iflg(sc); 559 mtx_unlock(&sc->mutex); 560 561 return (IIC_NOERR); 562} 563 564static int 565mv_twsi_read(device_t dev, char *buf, int len, int *read, int last, int delay) 566{ 567 struct mv_twsi_softc *sc; 568 uint32_t status; 569 int last_byte, rv; 570 571 sc = device_get_softc(dev); 572 573 mtx_lock(&sc->mutex); 574 *read = 0; 575 while (*read < len) { 576 /* 577 * Check if we are reading last byte of the last buffer, 578 * do not send ACK then, per I2C specs 579 */ 580 last_byte = ((*read == len - 1) && last) ? 1 : 0; 581 if (last_byte) 582 twsi_control_clear(sc, TWSI_CONTROL_ACK); 583 else 584 twsi_control_set(sc, TWSI_CONTROL_ACK); 585 586 DELAY (1000); 587 twsi_clear_iflg(sc); 588 589 if (twsi_poll_ctrl(sc, delay, TWSI_CONTROL_IFLG)) { 590 debugf("timeout reading data\n"); 591 rv = IIC_ETIMEOUT; 592 goto out; 593 } 594 595 status = TWSI_READ(sc, TWSI_STATUS); 596 if (status != (last_byte ? 597 TWSI_STATUS_DATA_RD_NOACK : TWSI_STATUS_DATA_RD_ACK)) { 598 debugf("wrong status (%02x) while reading\n", status); 599 rv = IIC_ESTATUS; 600 goto out; 601 } 602 603 *buf++ = TWSI_READ(sc, TWSI_DATA); 604 (*read)++; 605 } 606 rv = IIC_NOERR; 607out: 608 mtx_unlock(&sc->mutex); 609 return (rv); 610} 611 612static int 613mv_twsi_write(device_t dev, const char *buf, int len, int *sent, int timeout) 614{ 615 struct mv_twsi_softc *sc; 616 uint32_t status; 617 int rv; 618 619 sc = device_get_softc(dev); 620 621 mtx_lock(&sc->mutex); 622 *sent = 0; 623 while (*sent < len) { 624 TWSI_WRITE(sc, TWSI_DATA, *buf++); 625 626 twsi_clear_iflg(sc); 627 if (twsi_poll_ctrl(sc, timeout, TWSI_CONTROL_IFLG)) { 628 debugf("timeout writing data\n"); 629 rv = IIC_ETIMEOUT; 630 goto out; 631 } 632 633 status = TWSI_READ(sc, TWSI_STATUS); 634 if (status != TWSI_STATUS_DATA_WR_ACK) { 635 debugf("wrong status (%02x) while writing\n", status); 636 rv = IIC_ESTATUS; 637 goto out; 638 } 639 (*sent)++; 640 } 641 rv = IIC_NOERR; 642out: 643 mtx_unlock(&sc->mutex); 644 return (rv); 645} 646