at91_twi.c revision 164503
1/*- 2 * Copyright (c) 2006 M. Warner Losh. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 14 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 15 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 16 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 17 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 18 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 19 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 20 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 21 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 22 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 23 */ 24 25#include <sys/cdefs.h> 26__FBSDID("$FreeBSD: head/sys/arm/at91/at91_twi.c 164503 2006-11-22 06:51:59Z imp $"); 27 28#include <sys/param.h> 29#include <sys/systm.h> 30#include <sys/bus.h> 31#include <sys/conf.h> 32#include <sys/kernel.h> 33#include <sys/lock.h> 34#include <sys/mbuf.h> 35#include <sys/malloc.h> 36#include <sys/module.h> 37#include <sys/mutex.h> 38#include <sys/rman.h> 39#include <machine/bus.h> 40 41#include <arm/at91/at91rm92reg.h> 42#include <arm/at91/at91_twireg.h> 43 44#include <dev/iicbus/iiconf.h> 45#include <dev/iicbus/iicbus.h> 46#include "iicbus_if.h" 47 48struct at91_twi_softc 49{ 50 device_t dev; /* Myself */ 51 void *intrhand; /* Interrupt handle */ 52 struct resource *irq_res; /* IRQ resource */ 53 struct resource *mem_res; /* Memory resource */ 54 struct mtx sc_mtx; /* basically a perimeter lock */ 55 volatile int flags; 56#define RXRDY 4 57#define TXRDY 0x10 58 uint32_t cwgr; 59 int sc_started; 60 int twi_addr; 61 device_t iicbus; 62}; 63 64static inline uint32_t 65RD4(struct at91_twi_softc *sc, bus_size_t off) 66{ 67 return bus_read_4(sc->mem_res, off); 68} 69 70static inline void 71WR4(struct at91_twi_softc *sc, bus_size_t off, uint32_t val) 72{ 73 bus_write_4(sc->mem_res, off, val); 74} 75 76#define AT91_TWI_LOCK(_sc) mtx_lock(&(_sc)->sc_mtx) 77#define AT91_TWI_UNLOCK(_sc) mtx_unlock(&(_sc)->sc_mtx) 78#define AT91_TWI_LOCK_INIT(_sc) \ 79 mtx_init(&_sc->sc_mtx, device_get_nameunit(_sc->dev), \ 80 "twi", MTX_DEF) 81#define AT91_TWI_LOCK_DESTROY(_sc) mtx_destroy(&_sc->sc_mtx); 82#define AT91_TWI_ASSERT_LOCKED(_sc) mtx_assert(&_sc->sc_mtx, MA_OWNED); 83#define AT91_TWI_ASSERT_UNLOCKED(_sc) mtx_assert(&_sc->sc_mtx, MA_NOTOWNED); 84#define TWI_DEF_CLK 100000 85 86static devclass_t at91_twi_devclass; 87 88/* bus entry points */ 89 90static int at91_twi_probe(device_t dev); 91static int at91_twi_attach(device_t dev); 92static int at91_twi_detach(device_t dev); 93static void at91_twi_intr(void *); 94 95/* helper routines */ 96static int at91_twi_activate(device_t dev); 97static void at91_twi_deactivate(device_t dev); 98 99static int 100at91_twi_probe(device_t dev) 101{ 102 device_set_desc(dev, "TWI"); 103 return (0); 104} 105 106static int 107at91_twi_attach(device_t dev) 108{ 109 struct at91_twi_softc *sc = device_get_softc(dev); 110 int err; 111 112 sc->dev = dev; 113 err = at91_twi_activate(dev); 114 if (err) 115 goto out; 116 117 AT91_TWI_LOCK_INIT(sc); 118 119 /* 120 * Activate the interrupt 121 */ 122 err = bus_setup_intr(dev, sc->irq_res, INTR_TYPE_MISC | INTR_MPSAFE, 123 at91_twi_intr, sc, &sc->intrhand); 124 if (err) { 125 AT91_TWI_LOCK_DESTROY(sc); 126 goto out; 127 } 128 sc->cwgr = TWI_CWGR_CKDIV(8 * AT91C_MASTER_CLOCK / 90000) | 129 TWI_CWGR_CHDIV(TWI_CWGR_DIV(TWI_DEF_CLK)) | 130 TWI_CWGR_CLDIV(TWI_CWGR_DIV(TWI_DEF_CLK)); 131 WR4(sc, TWI_CR, TWI_CR_SWRST); 132 WR4(sc, TWI_CR, TWI_CR_MSEN | TWI_CR_SVDIS); 133 WR4(sc, TWI_CWGR, sc->cwgr); 134// WR4(sc, TWI_IER, TWI_SR_RXRDY | TWI_SR_OVRE | TWI_SR_UNRE | 135// TWI_SR_NACK); 136 137 if ((sc->iicbus = device_add_child(dev, "iicbus", -1)) == NULL) 138 device_printf(dev, "could not allocate iicbus instance\n"); 139 /* probe and attach the iicbus */ 140 bus_generic_attach(dev); 141out:; 142 if (err) 143 at91_twi_deactivate(dev); 144 return (err); 145} 146 147static int 148at91_twi_detach(device_t dev) 149{ 150 struct at91_twi_softc *sc; 151 int rv; 152 153 sc = device_get_softc(dev); 154 at91_twi_deactivate(dev); 155 if (sc->iicbus && (rv = device_delete_child(dev, sc->iicbus)) != 0) 156 return (rv); 157 158 return (0); 159} 160 161static int 162at91_twi_activate(device_t dev) 163{ 164 struct at91_twi_softc *sc; 165 int rid; 166 167 sc = device_get_softc(dev); 168 rid = 0; 169 sc->mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid, 170 RF_ACTIVE); 171 if (sc->mem_res == NULL) 172 goto errout; 173 rid = 0; 174 sc->irq_res = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid, 175 RF_ACTIVE); 176 if (sc->irq_res == NULL) 177 goto errout; 178 return (0); 179errout: 180 at91_twi_deactivate(dev); 181 return (ENOMEM); 182} 183 184static void 185at91_twi_deactivate(device_t dev) 186{ 187 struct at91_twi_softc *sc; 188 189 sc = device_get_softc(dev); 190 if (sc->intrhand) 191 bus_teardown_intr(dev, sc->irq_res, sc->intrhand); 192 sc->intrhand = 0; 193 bus_generic_detach(sc->dev); 194 if (sc->mem_res) 195 bus_release_resource(dev, SYS_RES_IOPORT, 196 rman_get_rid(sc->mem_res), sc->mem_res); 197 sc->mem_res = 0; 198 if (sc->irq_res) 199 bus_release_resource(dev, SYS_RES_IRQ, 200 rman_get_rid(sc->irq_res), sc->irq_res); 201 sc->irq_res = 0; 202 return; 203} 204 205static void 206at91_twi_intr(void *xsc) 207{ 208 struct at91_twi_softc *sc = xsc; 209 uint32_t status; 210 211 /* Reading the status also clears the interrupt */ 212 status = RD4(sc, TWI_SR); 213 printf("status %x\n", status); 214 if (status == 0) 215 return; 216 AT91_TWI_LOCK(sc); 217 if (status & TWI_SR_RXRDY) 218 sc->flags |= RXRDY; 219 if (status & TWI_SR_TXRDY) 220 sc->flags |= TXRDY; 221 AT91_TWI_UNLOCK(sc); 222 wakeup(sc); 223 return; 224} 225 226static int 227at91_twi_wait(struct at91_twi_softc *sc, uint32_t bit) 228{ 229 int err = 0; 230 int counter = 100000; 231 232 while (!(RD4(sc, TWI_SR) & bit) && counter-- >= 0) 233 continue; 234 if (counter <= 0) 235 err = EIO; 236 return (err); 237} 238 239static int 240at91_twi_rst_card(device_t dev, u_char speed, u_char addr, u_char *oldaddr) 241{ 242 struct at91_twi_softc *sc; 243 int ckdiv, rate; 244 245 sc = device_get_softc(dev); 246 if (oldaddr) 247 *oldaddr = sc->twi_addr; 248 if (addr != 0) 249 sc->twi_addr = 0; 250 else 251 sc->twi_addr = addr; 252 253 rate = 1; 254 255 /* 256 * speeds are for 1.5kb/s, 45kb/s and 90kb/s. 257 */ 258 switch (speed) { 259 case IIC_SLOW: 260 ckdiv = AT91C_MASTER_CLOCK / (1500 * 4) - 2; 261 break; 262 263 case IIC_FAST: 264 ckdiv = AT91C_MASTER_CLOCK / (45000 * 4) - 2; 265 break; 266 267 case IIC_UNKNOWN: 268 case IIC_FASTEST: 269 default: 270 ckdiv = AT91C_MASTER_CLOCK / (90000 * 4) - 2; 271 break; 272 } 273 274 sc->cwgr = TWI_CWGR_CKDIV(ckdiv) | TWI_CWGR_CHDIV(TWI_CWGR_DIV(rate)) | 275 TWI_CWGR_CLDIV(TWI_CWGR_DIV(rate)); 276 WR4(sc, TWI_CR, TWI_CR_SWRST); 277 WR4(sc, TWI_CR, TWI_CR_MSEN | TWI_CR_SVDIS); 278 WR4(sc, TWI_CWGR, sc->cwgr); 279 280 return 0; 281} 282 283static int 284at91_twi_callback(device_t dev, int index, caddr_t *data) 285{ 286 int error = 0; 287 288 switch (index) { 289 case IIC_REQUEST_BUS: 290 break; 291 292 case IIC_RELEASE_BUS: 293 break; 294 295 default: 296 error = EINVAL; 297 } 298 299 return (error); 300} 301 302static int 303at91_twi_transfer(device_t dev, struct iic_msg *msgs, uint32_t nmsgs) 304{ 305 struct at91_twi_softc *sc; 306 int i, len; 307 uint32_t rdwr; 308 uint8_t *buf; 309 310 sc = device_get_softc(dev); 311 for (i = 0; i < nmsgs; i++) { 312 /* 313 * The linux atmel driver doesn't use the internal device 314 * address feature of twi. A separate i2c message needs to 315 * be written to use this. 316 * See http://lists.arm.linux.org.uk/pipermail/linux-arm-kernel/2004-September/024411.html 317 * for details. 318 */ 319 rdwr = (msgs[i].flags & IIC_M_RD) ? TWI_MMR_MREAD : 0; 320 WR4(sc, TWI_MMR, TWI_MMR_DADR(msgs[i].slave) | rdwr); 321 len = msgs[i].len; 322 buf = msgs[i].buf; 323 if (len == 0 || buf == NULL) 324 return (EINVAL); 325 WR4(sc, TWI_CR, TWI_CR_START); 326 if (msgs[i].flags & IIC_M_RD) { 327 while (len--) { 328 if (len == 0) 329 WR4(sc, TWI_CR, TWI_CR_STOP); 330 if (at91_twi_wait(sc, TWI_SR_RXRDY)) 331 return (EIO); 332 *buf++ = RD4(sc, TWI_RHR) & 0xff; 333 } 334 } else { 335 while (len--) { 336 WR4(sc, TWI_THR, *buf++); 337 if (len == 0) 338 WR4(sc, TWI_CR, TWI_CR_STOP); 339 if (at91_twi_wait(sc, TWI_SR_TXRDY)) 340 return (EIO); 341 } 342 } 343 if (at91_twi_wait(sc, TWI_SR_TXCOMP)) 344 return (EIO); 345 } 346 return (0); 347} 348 349static device_method_t at91_twi_methods[] = { 350 /* Device interface */ 351 DEVMETHOD(device_probe, at91_twi_probe), 352 DEVMETHOD(device_attach, at91_twi_attach), 353 DEVMETHOD(device_detach, at91_twi_detach), 354 355 /* iicbus interface */ 356 DEVMETHOD(iicbus_callback, at91_twi_callback), 357 DEVMETHOD(iicbus_reset, at91_twi_rst_card), 358 DEVMETHOD(iicbus_transfer, at91_twi_transfer), 359 { 0, 0 } 360}; 361 362static driver_t at91_twi_driver = { 363 "at91_twi", 364 at91_twi_methods, 365 sizeof(struct at91_twi_softc), 366}; 367 368DRIVER_MODULE(at91_twi, atmelarm, at91_twi_driver, at91_twi_devclass, 0, 0); 369DRIVER_MODULE(iicbus, at91_twi, iicbus_driver, iicbus_devclass, 0, 0); 370