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 <sys/rman.h> 40 41 #include <sys/lock.h> 42 #include <sys/mutex.h> 43 44 #include <dev/iicbus/iiconf.h> 45 #include <dev/iicbus/iicbus.h> 46 #include "iicbus_if.h" 47 48 #include <dev/ofw/ofw_bus.h> 49 #include <dev/ofw/ofw_bus_subr.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 #ifdef DEBUG 76 #define debugf(fmt, args...) do { printf("%s(): ", __func__); printf(fmt,##args); } while (0) 77 #else 78 #define debugf(fmt, args...) 79 #endif 80 81 struct i2c_softc { 82 device_t dev; 83 device_t iicbus; 84 struct resource *res; 85 struct mtx mutex; 86 int rid; 87 bus_space_handle_t bsh; 88 bus_space_tag_t bst; 89 }; 90 91 static int i2c_probe(device_t); 92 static int i2c_attach(device_t); 93 94 static int i2c_repeated_start(device_t dev, u_char slave, int timeout); 95 static int i2c_start(device_t dev, u_char slave, int timeout); 96 static int i2c_stop(device_t dev); 97 static int i2c_reset(device_t dev, u_char speed, u_char addr, u_char *oldaddr); 98 static int i2c_read(device_t dev, char *buf, int len, int *read, int last, int delay); 99 static int i2c_write(device_t dev, const char *buf, int len, int *sent, int timeout); 100 101 static device_method_t i2c_methods[] = { 102 DEVMETHOD(device_probe, i2c_probe), 103 DEVMETHOD(device_attach, i2c_attach), 104 105 DEVMETHOD(iicbus_callback, iicbus_null_callback), 106 DEVMETHOD(iicbus_repeated_start, i2c_repeated_start), 107 DEVMETHOD(iicbus_start, i2c_start), 108 DEVMETHOD(iicbus_stop, i2c_stop), 109 DEVMETHOD(iicbus_reset, i2c_reset), 110 DEVMETHOD(iicbus_read, i2c_read), 111 DEVMETHOD(iicbus_write, i2c_write), 112 DEVMETHOD(iicbus_transfer, iicbus_transfer_gen), 113 114 { 0, 0 } 115 }; 116 117 static driver_t i2c_driver = { 118 "i2c", 119 i2c_methods, 120 sizeof(struct i2c_softc), 121 }; 122 static devclass_t i2c_devclass; 123 124 DRIVER_MODULE(i2c, simplebus, i2c_driver, i2c_devclass, 0, 0); 125 DRIVER_MODULE(iicbus, i2c, iicbus_driver, iicbus_devclass, 0, 0); 126 127 static __inline void 128 i2c_write_reg(struct i2c_softc *sc, bus_size_t off, uint8_t val) 129 { 130 131 bus_space_write_1(sc->bst, sc->bsh, off, val); 132 } 133 134 static __inline uint8_t 135 i2c_read_reg(struct i2c_softc *sc, bus_size_t off) 136 { 137 138 return (bus_space_read_1(sc->bst, sc->bsh, off)); 139 } 140 141 static __inline void 142 i2c_flag_set(struct i2c_softc *sc, bus_size_t off, uint8_t mask) 143 { 144 uint8_t status; 145 146 status = i2c_read_reg(sc, off); 147 status |= mask; 148 i2c_write_reg(sc, off, status); 149 } 150 151 static int 152 i2c_do_wait(device_t dev, struct i2c_softc *sc, int write, int start) 153 { 154 int err; 155 uint8_t status; 156 157 status = i2c_read_reg(sc, I2C_STATUS_REG); 158 if (status & I2CSR_MIF) { 159 if (write && start && (status & I2CSR_RXAK)) { 160 debugf("no ack %s", start ? 161 "after sending slave address" : ""); 162 err = IIC_ENOACK; 163 goto error; 164 } 165 if (status & I2CSR_MAL) { 166 debugf("arbitration lost"); 167 err = IIC_EBUSERR; 168 goto error; 169 } 170 if (!write && !(status & I2CSR_MCF)) { 171 debugf("transfer unfinished"); 172 err = IIC_EBUSERR; 173 goto error; 174 } 175 } 176 177 return (IIC_NOERR); 178 179 error: 180 i2c_write_reg(sc, I2C_STATUS_REG, 0x0); 181 i2c_write_reg(sc, I2C_CONTROL_REG, I2CCR_MEN | I2CCR_TXAK); 182 return (err); 183 } 184 185 static int 186 i2c_probe(device_t dev) 187 { 188 struct i2c_softc *sc; 189 190 if (!ofw_bus_is_compatible(dev, "fsl-i2c")) 191 return (ENXIO); 192 193 sc = device_get_softc(dev); 194 sc->rid = 0; 195 196 sc->res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &sc->rid, 197 RF_ACTIVE); 198 if (sc->res == NULL) { 199 device_printf(dev, "could not allocate resources\n"); 200 return (ENXIO); 201 } 202 203 sc->bst = rman_get_bustag(sc->res); 204 sc->bsh = rman_get_bushandle(sc->res); 205 206 /* Enable I2C */ 207 i2c_write_reg(sc, I2C_CONTROL_REG, I2C_ENABLE); 208 bus_release_resource(dev, SYS_RES_MEMORY, sc->rid, sc->res); 209 device_set_desc(dev, "I2C bus controller"); 210 211 return (BUS_PROBE_DEFAULT); 212 } 213 214 static int 215 i2c_attach(device_t dev) 216 { 217 struct i2c_softc *sc; 218 sc = device_get_softc(dev); 219 220 sc->dev = dev; 221 sc->rid = 0; 222 223 mtx_init(&sc->mutex, device_get_nameunit(dev), "I2C", MTX_DEF); 224 225 sc->res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &sc->rid, 226 RF_ACTIVE); 227 if (sc->res == NULL) { 228 device_printf(dev, "could not allocate resources"); 229 mtx_destroy(&sc->mutex); 230 return (ENXIO); 231 } 232 233 sc->bst = rman_get_bustag(sc->res); 234 sc->bsh = rman_get_bushandle(sc->res); 235 236 sc->iicbus = device_add_child(dev, "iicbus", -1); 237 if (sc->iicbus == NULL) { 238 device_printf(dev, "could not add iicbus child"); 239 mtx_destroy(&sc->mutex); 240 return (ENXIO); 241 } 242 243 bus_generic_attach(dev); 244 return (IIC_NOERR); 245 } 246 static int 247 i2c_repeated_start(device_t dev, u_char slave, int timeout) 248 { 249 struct i2c_softc *sc; 250 int error; 251 252 sc = device_get_softc(dev); 253 254 mtx_lock(&sc->mutex); 255 /* Set repeated start condition */ 256 i2c_flag_set(sc, I2C_CONTROL_REG ,I2CCR_RSTA); 257 /* Write target address - LSB is R/W bit */ 258 i2c_write_reg(sc, I2C_DATA_REG, slave); 259 DELAY(1250); 260 261 error = i2c_do_wait(dev, sc, 1, 1); 262 mtx_unlock(&sc->mutex); 263 264 if (error) 265 return (error); 266 267 return (IIC_NOERR); 268 } 269 270 static int 271 i2c_start(device_t dev, u_char slave, int timeout) 272 { 273 struct i2c_softc *sc; 274 uint8_t status; 275 int error; 276 277 sc = device_get_softc(dev); 278 DELAY(1000); 279 280 mtx_lock(&sc->mutex); 281 status = i2c_read_reg(sc, I2C_STATUS_REG); 282 /* Check if bus is idle or busy */ 283 if (status & I2CSR_MBB) { 284 debugf("bus busy"); 285 mtx_unlock(&sc->mutex); 286 i2c_stop(dev); 287 return (IIC_EBUSERR); 288 } 289 290 /* Set start condition */ 291 i2c_write_reg(sc, I2C_CONTROL_REG, I2CCR_MEN | I2CCR_MSTA | I2CCR_MTX); 292 /* Write target address - LSB is R/W bit */ 293 i2c_write_reg(sc, I2C_DATA_REG, slave); 294 DELAY(1250); 295 296 error = i2c_do_wait(dev, sc, 1, 1); 297 298 mtx_unlock(&sc->mutex); 299 if (error) 300 return (error); 301 302 return (IIC_NOERR); 303 } 304 305 static int 306 i2c_stop(device_t dev) 307 { 308 struct i2c_softc *sc; 309 310 sc = device_get_softc(dev); 311 mtx_lock(&sc->mutex); 312 i2c_write_reg(sc, I2C_CONTROL_REG, I2CCR_MEN | I2CCR_TXAK); 313 DELAY(1000); 314 mtx_unlock(&sc->mutex); 315 316 return (IIC_NOERR); 317 } 318 319 static int 320 i2c_reset(device_t dev, u_char speed, u_char addr, u_char *oldadr) 321 { 322 struct i2c_softc *sc; 323 uint8_t baud_rate; 324 325 sc = device_get_softc(dev); 326 327 switch (speed) { 328 case IIC_FAST: 329 baud_rate = I2C_BAUD_RATE_FAST; 330 break; 331 case IIC_SLOW: 332 case IIC_UNKNOWN: 333 case IIC_FASTEST: 334 default: 335 baud_rate = I2C_BAUD_RATE_DEF; 336 break; 337 } 338 339 mtx_lock(&sc->mutex); 340 i2c_write_reg(sc, I2C_CONTROL_REG, 0x0); 341 i2c_write_reg(sc, I2C_STATUS_REG, 0x0); 342 DELAY(1000); 343 i2c_write_reg(sc, I2C_FDR_REG, baud_rate); 344 i2c_write_reg(sc, I2C_DFSRR_REG, I2C_DFSSR_DIV); 345 i2c_write_reg(sc, I2C_CONTROL_REG, I2C_ENABLE); 346 DELAY(1000); 347 mtx_unlock(&sc->mutex); 348 349 return (IIC_NOERR); 350 } 351 352 static int 353 i2c_read(device_t dev, char *buf, int len, int *read, int last, int delay) 354 { 355 struct i2c_softc *sc; 356 int error; 357 358 sc = device_get_softc(dev); 359 *read = 0; 360 361 mtx_lock(&sc->mutex); 362 if (len) { 363 if (len == 1) 364 i2c_write_reg(sc, I2C_CONTROL_REG, I2CCR_MEN | 365 I2CCR_MSTA | I2CCR_TXAK); 366 367 else 368 i2c_write_reg(sc, I2C_CONTROL_REG, I2CCR_MEN | 369 I2CCR_MSTA); 370 371 /* dummy read */ 372 i2c_read_reg(sc, I2C_DATA_REG); 373 DELAY(1000); 374 } 375 376 while (*read < len) { 377 DELAY(1000); 378 error = i2c_do_wait(dev, sc, 0, 0); 379 if (error) { 380 mtx_unlock(&sc->mutex); 381 return (error); 382 } 383 if ((*read == len - 2) && last) { 384 i2c_write_reg(sc, I2C_CONTROL_REG, I2CCR_MEN | 385 I2CCR_MSTA | I2CCR_TXAK); 386 } 387 388 if ((*read == len - 1) && last) { 389 i2c_write_reg(sc, I2C_CONTROL_REG, I2CCR_MEN | 390 I2CCR_TXAK); 391 } 392 393 *buf++ = i2c_read_reg(sc, I2C_DATA_REG); 394 (*read)++; 395 DELAY(1250); 396 } 397 mtx_unlock(&sc->mutex); 398 399 return (IIC_NOERR); 400 } 401 402 static int 403 i2c_write(device_t dev, const char *buf, int len, int *sent, int timeout) 404 { 405 struct i2c_softc *sc; 406 int error; 407 408 sc = device_get_softc(dev); 409 *sent = 0; 410 411 mtx_lock(&sc->mutex); 412 while (*sent < len) { 413 i2c_write_reg(sc, I2C_DATA_REG, *buf++); 414 DELAY(1250); 415 416 error = i2c_do_wait(dev, sc, 1, 0); 417 if (error) { 418 mtx_unlock(&sc->mutex); 419 return (error); 420 } 421 422 (*sent)++; 423 } 424 mtx_unlock(&sc->mutex); 425 426 return (IIC_NOERR); 427 } 428