1 /*- 2 * Copyright (C) 2008-2009 Semihalf, Michal Hajduk 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27 #include <sys/cdefs.h> 28 __FBSDID("$FreeBSD$"); 29 30 #include <sys/param.h> 31 #include <sys/systm.h> 32 #include <sys/bus.h> 33 #include <sys/kernel.h> 34 #include <sys/module.h> 35 #include <sys/resource.h> 36 37 #include <machine/bus.h> 38 #include <machine/resource.h> 39 #include <machine/ocpbus.h> 40 #include <sys/rman.h> 41 42 #include <sys/lock.h> 43 #include <sys/mutex.h> 44 45 #include <dev/iicbus/iiconf.h> 46 #include <dev/iicbus/iicbus.h> 47 #include "iicbus_if.h" 48 49 #include <powerpc/mpc85xx/ocpbus.h> 50 51 #define I2C_ADDR_REG 0x00 /* I2C slave address register */ 52 #define I2C_FDR_REG 0x04 /* I2C frequency divider register */ 53 #define I2C_CONTROL_REG 0x08 /* I2C control register */ 54 #define I2C_STATUS_REG 0x0C /* I2C status register */ 55 #define I2C_DATA_REG 0x10 /* I2C data register */ 56 #define I2C_DFSRR_REG 0x14 /* I2C Digital Filter Sampling rate */ 57 #define I2C_ENABLE 0x80 /* Module enable - interrupt disable */ 58 #define I2CSR_RXAK 0x01 /* Received acknowledge */ 59 #define I2CSR_MCF (1<<7) /* Data transfer */ 60 #define I2CSR_MASS (1<<6) /* Addressed as a slave */ 61 #define I2CSR_MBB (1<<5) /* Bus busy */ 62 #define I2CSR_MAL (1<<4) /* Arbitration lost */ 63 #define I2CSR_SRW (1<<2) /* Slave read/write */ 64 #define I2CSR_MIF (1<<1) /* Module interrupt */ 65 #define I2CCR_MEN (1<<7) /* Module enable */ 66 #define I2CCR_MSTA (1<<5) /* Master/slave mode */ 67 #define I2CCR_MTX (1<<4) /* Transmit/receive mode */ 68 #define I2CCR_TXAK (1<<3) /* Transfer acknowledge */ 69 #define I2CCR_RSTA (1<<2) /* Repeated START */ 70 71 #define I2C_BAUD_RATE_FAST 0x31 72 #define I2C_BAUD_RATE_DEF 0x3F 73 #define I2C_DFSSR_DIV 0x10 74 75 #define DEBUG 76 #undef DEBUG 77 78 #ifdef DEBUG 79 #define debugf(fmt, args...) do { printf("%s(): ", __func__); printf(fmt,##args); } while (0) 80 #else 81 #define debugf(fmt, args...) 82 #endif 83 84 struct i2c_softc { 85 device_t dev; 86 device_t iicbus; 87 struct resource *res; 88 struct mtx mutex; 89 int rid; 90 bus_space_handle_t bsh; 91 bus_space_tag_t bst; 92 }; 93 94 static int i2c_probe(device_t); 95 static int i2c_attach(device_t); 96 97 static int i2c_repeated_start(device_t dev, u_char slave, int timeout); 98 static int i2c_start(device_t dev, u_char slave, int timeout); 99 static int i2c_stop(device_t dev); 100 static int i2c_reset(device_t dev, u_char speed, u_char addr, u_char *oldaddr); 101 static int i2c_read(device_t dev, char *buf, int len, int *read, int last, int delay); 102 static int i2c_write(device_t dev, const char *buf, int len, int *sent, int timeout); 103 104 static device_method_t i2c_methods[] = { 105 DEVMETHOD(device_probe, i2c_probe), 106 DEVMETHOD(device_attach, i2c_attach), 107 108 DEVMETHOD(iicbus_callback, iicbus_null_callback), 109 DEVMETHOD(iicbus_repeated_start, i2c_repeated_start), 110 DEVMETHOD(iicbus_start, i2c_start), 111 DEVMETHOD(iicbus_stop, i2c_stop), 112 DEVMETHOD(iicbus_reset, i2c_reset), 113 DEVMETHOD(iicbus_read, i2c_read), 114 DEVMETHOD(iicbus_write, i2c_write), 115 DEVMETHOD(iicbus_transfer, iicbus_transfer_gen), 116 117 { 0, 0 } 118 }; 119 120 static driver_t i2c_driver = { 121 "i2c", 122 i2c_methods, 123 sizeof(struct i2c_softc), 124 }; 125 static devclass_t i2c_devclass; 126 127 DRIVER_MODULE(i2c, ocpbus, i2c_driver, i2c_devclass, 0, 0); 128 DRIVER_MODULE(iicbus, i2c, iicbus_driver, iicbus_devclass, 0, 0); 129 130 static __inline void 131 i2c_write_reg(struct i2c_softc *sc, bus_size_t off, uint8_t val) 132 { 133 134 bus_space_write_1(sc->bst, sc->bsh, off, val); 135 } 136 137 static __inline uint8_t 138 i2c_read_reg(struct i2c_softc *sc, bus_size_t off) 139 { 140 141 return (bus_space_read_1(sc->bst, sc->bsh, off)); 142 } 143 144 static __inline void 145 i2c_flag_set(struct i2c_softc *sc, bus_size_t off, uint8_t mask) 146 { 147 uint8_t status; 148 149 status = i2c_read_reg(sc, off); 150 status |= mask; 151 i2c_write_reg(sc, off, status); 152 } 153 154 static int 155 i2c_do_wait(device_t dev, struct i2c_softc *sc, int write, int start) 156 { 157 int err; 158 uint8_t status; 159 160 status = i2c_read_reg(sc,I2C_STATUS_REG); 161 if (status & I2CSR_MIF) { 162 if (write && start && (status & I2CSR_RXAK)) { 163 debugf("no ack %s", start ? 164 "after sending slave address" : ""); 165 err = IIC_ENOACK; 166 goto error; 167 } 168 if (status & I2CSR_MAL) { 169 debugf("arbitration lost"); 170 err = IIC_EBUSERR; 171 goto error; 172 } 173 if (!write && !(status & I2CSR_MCF)) { 174 debugf("transfer unfinished"); 175 err = IIC_EBUSERR; 176 goto error; 177 } 178 } 179 180 return (IIC_NOERR); 181 182 error: 183 i2c_write_reg(sc, I2C_STATUS_REG, 0x0); 184 i2c_write_reg(sc, I2C_CONTROL_REG, I2CCR_MEN | I2CCR_TXAK); 185 return (err); 186 } 187 188 static int 189 i2c_probe(device_t dev) 190 { 191 device_t parent; 192 struct i2c_softc *sc; 193 uintptr_t devtype; 194 int error; 195 196 parent = device_get_parent(dev); 197 198 error = BUS_READ_IVAR(parent, dev, OCPBUS_IVAR_DEVTYPE, &devtype); 199 200 if (error) 201 return (error); 202 203 if (devtype != OCPBUS_DEVTYPE_I2C) 204 return (ENXIO); 205 206 sc = device_get_softc(dev); 207 sc->rid = 0; 208 209 sc->res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &sc->rid, 210 RF_ACTIVE); 211 if (sc->res == NULL) { 212 device_printf(dev, "could not allocate resources"); 213 return (ENXIO); 214 } 215 216 sc->bst = rman_get_bustag(sc->res); 217 sc->bsh = rman_get_bushandle(sc->res); 218 219 /* Enable I2C */ 220 i2c_write_reg(sc, I2C_CONTROL_REG, I2C_ENABLE); 221 bus_release_resource(dev, SYS_RES_MEMORY, sc->rid, sc->res); 222 device_set_desc(dev, "I2C bus controller"); 223 224 return (BUS_PROBE_DEFAULT); 225 } 226 227 static int 228 i2c_attach(device_t dev) 229 { 230 struct i2c_softc *sc; 231 sc = device_get_softc(dev); 232 233 sc->dev = dev; 234 sc->rid = 0; 235 236 mtx_init(&sc->mutex, device_get_nameunit(dev), "I2C", MTX_DEF); 237 238 sc->res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &sc->rid, 239 RF_ACTIVE); 240 if (sc->res == NULL) { 241 device_printf(dev, "could not allocate resources"); 242 mtx_destroy(&sc->mutex); 243 return (ENXIO); 244 } 245 246 sc->bst = rman_get_bustag(sc->res); 247 sc->bsh = rman_get_bushandle(sc->res); 248 249 sc->iicbus = device_add_child(dev, "iicbus", -1); 250 if (sc->iicbus == NULL) { 251 device_printf(dev, "could not add iicbus child"); 252 mtx_destroy(&sc->mutex); 253 return (ENXIO); 254 } 255 256 bus_generic_attach(dev); 257 return (IIC_NOERR); 258 } 259 static int 260 i2c_repeated_start(device_t dev, u_char slave, int timeout) 261 { 262 struct i2c_softc *sc; 263 int error; 264 265 sc = device_get_softc(dev); 266 267 mtx_lock(&sc->mutex); 268 /* Set repeated start condition */ 269 i2c_flag_set(sc, I2C_CONTROL_REG ,I2CCR_RSTA); 270 /* Write target address - LSB is R/W bit */ 271 i2c_write_reg(sc, I2C_DATA_REG, slave); 272 DELAY(1250); 273 274 error = i2c_do_wait(dev, sc, 1, 1); 275 mtx_unlock(&sc->mutex); 276 277 if (error) 278 return (error); 279 280 return (IIC_NOERR); 281 } 282 283 static int 284 i2c_start(device_t dev, u_char slave, int timeout) 285 { 286 struct i2c_softc *sc; 287 uint8_t status; 288 int error; 289 290 sc = device_get_softc(dev); 291 DELAY(1000); 292 293 mtx_lock(&sc->mutex); 294 status = i2c_read_reg(sc, I2C_STATUS_REG); 295 /* Check if bus is idle or busy */ 296 if (status & I2CSR_MBB) { 297 debugf("bus busy"); 298 mtx_unlock(&sc->mutex); 299 i2c_stop(dev); 300 return (IIC_EBUSBSY); 301 } 302 303 /* Set start condition */ 304 i2c_write_reg(sc, I2C_CONTROL_REG, I2CCR_MEN | I2CCR_MSTA | I2CCR_MTX); 305 /* Write target address - LSB is R/W bit */ 306 i2c_write_reg(sc, I2C_DATA_REG, slave); 307 DELAY(1250); 308 309 error = i2c_do_wait(dev, sc, 1, 1); 310 311 mtx_unlock(&sc->mutex); 312 if (error) 313 return (error); 314 315 return (IIC_NOERR); 316 } 317 318 static int 319 i2c_stop(device_t dev) 320 { 321 struct i2c_softc *sc; 322 323 sc = device_get_softc(dev); 324 mtx_lock(&sc->mutex); 325 i2c_write_reg(sc, I2C_CONTROL_REG, I2CCR_MEN | I2CCR_TXAK); 326 DELAY(1000); 327 mtx_unlock(&sc->mutex); 328 329 return (IIC_NOERR); 330 } 331 332 static int 333 i2c_reset(device_t dev, u_char speed, u_char addr, u_char *oldadr) 334 { 335 struct i2c_softc *sc; 336 uint8_t baud_rate; 337 338 sc = device_get_softc(dev); 339 340 switch (speed) { 341 case IIC_FAST: 342 baud_rate = I2C_BAUD_RATE_FAST; 343 break; 344 case IIC_SLOW: 345 case IIC_UNKNOWN: 346 case IIC_FASTEST: 347 default: 348 baud_rate = I2C_BAUD_RATE_DEF; 349 break; 350 } 351 352 mtx_lock(&sc->mutex); 353 i2c_write_reg(sc, I2C_CONTROL_REG, 0x0); 354 i2c_write_reg(sc, I2C_STATUS_REG, 0x0); 355 DELAY(1000); 356 i2c_write_reg(sc, I2C_FDR_REG, baud_rate); 357 i2c_write_reg(sc, I2C_DFSRR_REG, I2C_DFSSR_DIV); 358 i2c_write_reg(sc, I2C_CONTROL_REG, I2C_ENABLE); 359 DELAY(1000); 360 mtx_unlock(&sc->mutex); 361 362 return (IIC_NOERR); 363 } 364 365 static int 366 i2c_read(device_t dev, char *buf, int len, int *read, int last, int delay) 367 { 368 struct i2c_softc *sc; 369 int error; 370 371 sc = device_get_softc(dev); 372 *read = 0; 373 374 mtx_lock(&sc->mutex); 375 if (len) { 376 if (len == 1) 377 i2c_write_reg(sc, I2C_CONTROL_REG, I2CCR_MEN | 378 I2CCR_MSTA | I2CCR_TXAK); 379 380 else 381 i2c_write_reg(sc, I2C_CONTROL_REG, I2CCR_MEN | 382 I2CCR_MSTA); 383 384 /* dummy read */ 385 i2c_read_reg(sc, I2C_DATA_REG); 386 DELAY(1000); 387 } 388 389 while (*read < len) { 390 DELAY(1000); 391 error = i2c_do_wait(dev, sc, 0, 0); 392 if (error) { 393 mtx_unlock(&sc->mutex); 394 return (error); 395 } 396 if ((*read == len - 2) && last) { 397 i2c_write_reg(sc, I2C_CONTROL_REG, I2CCR_MEN | 398 I2CCR_MSTA | I2CCR_TXAK); 399 } 400 401 if ((*read == len - 1) && last) { 402 i2c_write_reg(sc, I2C_CONTROL_REG, I2CCR_MEN | 403 I2CCR_TXAK); 404 } 405 406 *buf++ = i2c_read_reg(sc, I2C_DATA_REG); 407 (*read)++; 408 DELAY(1250); 409 } 410 mtx_unlock(&sc->mutex); 411 412 return (IIC_NOERR); 413 } 414 415 static int 416 i2c_write(device_t dev, const char *buf, int len, int *sent, int timeout) 417 { 418 struct i2c_softc *sc; 419 int error; 420 421 sc = device_get_softc(dev); 422 *sent = 0; 423 424 mtx_lock(&sc->mutex); 425 while (*sent < len) { 426 i2c_write_reg(sc, I2C_DATA_REG, *buf++); 427 DELAY(1250); 428 429 error = i2c_do_wait(dev, sc, 1, 0); 430 if (error) { 431 mtx_unlock(&sc->mutex); 432 return (error); 433 } 434 435 (*sent)++; 436 } 437 mtx_unlock(&sc->mutex); 438 439 return (IIC_NOERR); 440 } 441