max6900.c revision 1.19
1 /* $NetBSD: max6900.c,v 1.19 2025/01/07 17:39:45 andvar Exp $ */ 2 3 /* 4 * Copyright (c) 2003 Wasabi Systems, Inc. 5 * All rights reserved. 6 * 7 * Written by Steve C. Woodford and Jason R. Thorpe for Wasabi Systems, Inc. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgement: 19 * This product includes software developed for the NetBSD Project by 20 * Wasabi Systems, Inc. 21 * 4. The name of Wasabi Systems, Inc. may not be used to endorse 22 * or promote products derived from this software without specific prior 23 * written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 27 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 28 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL WASABI SYSTEMS, INC 29 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 30 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 31 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 32 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 33 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 34 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 35 * POSSIBILITY OF SUCH DAMAGE. 36 */ 37 38 #include <sys/cdefs.h> 39 __KERNEL_RCSID(0, "$NetBSD: max6900.c,v 1.19 2025/01/07 17:39:45 andvar Exp $"); 40 41 #include <sys/param.h> 42 #include <sys/systm.h> 43 #include <sys/device.h> 44 #include <sys/kernel.h> 45 #include <sys/fcntl.h> 46 #include <sys/uio.h> 47 #include <sys/conf.h> 48 #include <sys/event.h> 49 50 #include <dev/clock_subr.h> 51 52 #include <dev/i2c/i2cvar.h> 53 #include <dev/i2c/max6900reg.h> 54 55 struct maxrtc_softc { 56 device_t sc_dev; 57 i2c_tag_t sc_tag; 58 int sc_address; 59 int sc_open; 60 struct todr_chip_handle sc_todr; 61 }; 62 63 static int maxrtc_match(device_t, cfdata_t, void *); 64 static void maxrtc_attach(device_t, device_t, void *); 65 66 CFATTACH_DECL_NEW(maxrtc, sizeof(struct maxrtc_softc), 67 maxrtc_match, maxrtc_attach, NULL, NULL); 68 extern struct cfdriver maxrtc_cd; 69 70 dev_type_open(maxrtc_open); 71 dev_type_close(maxrtc_close); 72 dev_type_read(maxrtc_read); 73 dev_type_write(maxrtc_write); 74 75 const struct cdevsw maxrtc_cdevsw = { 76 .d_open = maxrtc_open, 77 .d_close = maxrtc_close, 78 .d_read = maxrtc_read, 79 .d_write = maxrtc_write, 80 .d_ioctl = noioctl, 81 .d_stop = nostop, 82 .d_tty = notty, 83 .d_poll = nopoll, 84 .d_mmap = nommap, 85 .d_kqfilter = nokqfilter, 86 .d_discard = nodiscard, 87 .d_flag = D_OTHER 88 }; 89 90 static int maxrtc_gettime_ymdhms(struct todr_chip_handle *, 91 struct clock_ymdhms *); 92 static int maxrtc_settime_ymdhms(struct todr_chip_handle *, 93 struct clock_ymdhms *); 94 95 int 96 maxrtc_match(device_t parent, cfdata_t cf, void *aux) 97 { 98 struct i2c_attach_args *ia = aux; 99 100 if ((ia->ia_addr & MAX6900_ADDRMASK) == MAX6900_ADDR) 101 return (I2C_MATCH_ADDRESS_ONLY); 102 103 return (0); 104 } 105 106 void 107 maxrtc_attach(device_t parent, device_t self, void *aux) 108 { 109 struct maxrtc_softc *sc = device_private(self); 110 struct i2c_attach_args *ia = aux; 111 112 sc->sc_tag = ia->ia_tag; 113 sc->sc_address = ia->ia_addr; 114 sc->sc_dev = self; 115 116 aprint_naive(": Real-time Clock/NVRAM\n"); 117 aprint_normal(": MAX6900 Real-time Clock/NVRAM\n"); 118 119 sc->sc_open = 0; 120 121 sc->sc_todr.cookie = sc; 122 sc->sc_todr.todr_gettime = NULL; 123 sc->sc_todr.todr_settime = NULL; 124 sc->sc_todr.todr_gettime_ymdhms = maxrtc_gettime_ymdhms; 125 sc->sc_todr.todr_settime_ymdhms = maxrtc_settime_ymdhms; 126 sc->sc_todr.todr_setwen = NULL; 127 128 todr_attach(&sc->sc_todr); 129 } 130 131 /*ARGSUSED*/ 132 int 133 maxrtc_open(dev_t dev, int flag, int fmt, struct lwp *l) 134 { 135 struct maxrtc_softc *sc; 136 137 if ((sc = device_lookup_private(&maxrtc_cd, minor(dev))) == NULL) 138 return (ENXIO); 139 140 /* XXX: Locking */ 141 142 if (sc->sc_open) 143 return (EBUSY); 144 145 sc->sc_open = 1; 146 return (0); 147 } 148 149 /*ARGSUSED*/ 150 int 151 maxrtc_close(dev_t dev, int flag, int fmt, struct lwp *l) 152 { 153 struct maxrtc_softc *sc; 154 155 if ((sc = device_lookup_private(&maxrtc_cd, minor(dev))) == NULL) 156 return (ENXIO); 157 158 sc->sc_open = 0; 159 return (0); 160 } 161 162 /*ARGSUSED*/ 163 int 164 maxrtc_read(dev_t dev, struct uio *uio, int flags) 165 { 166 struct maxrtc_softc *sc; 167 u_int8_t ch, cmdbuf[1]; 168 int a, error; 169 170 if ((sc = device_lookup_private(&maxrtc_cd, minor(dev))) == NULL) 171 return (ENXIO); 172 173 if (uio->uio_offset >= MAX6900_RAM_BYTES) 174 return (EINVAL); 175 176 if ((error = iic_acquire_bus(sc->sc_tag, 0)) != 0) 177 return (error); 178 179 while (uio->uio_resid && uio->uio_offset < MAX6900_RAM_BYTES) { 180 a = (int)uio->uio_offset; 181 cmdbuf[0] = MAX6900_REG_RAM(a) | MAX6900_CMD_READ; 182 if ((error = iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP, 183 sc->sc_address, cmdbuf, 1, 184 &ch, 1, 0)) != 0) { 185 iic_release_bus(sc->sc_tag, 0); 186 aprint_error_dev(sc->sc_dev, 187 "maxrtc_read: read failed at 0x%x\n", a); 188 return (error); 189 } 190 if ((error = uiomove(&ch, 1, uio)) != 0) { 191 iic_release_bus(sc->sc_tag, 0); 192 return (error); 193 } 194 } 195 196 iic_release_bus(sc->sc_tag, 0); 197 198 return (0); 199 } 200 201 /*ARGSUSED*/ 202 int 203 maxrtc_write(dev_t dev, struct uio *uio, int flags) 204 { 205 struct maxrtc_softc *sc; 206 u_int8_t cmdbuf[2]; 207 int a, error, sverror; 208 209 if ((sc = device_lookup_private(&maxrtc_cd, minor(dev))) == NULL) 210 return (ENXIO); 211 212 if (uio->uio_offset >= MAX6900_RAM_BYTES) 213 return (EINVAL); 214 215 if ((error = iic_acquire_bus(sc->sc_tag, 0)) != 0) 216 return (error); 217 218 /* Start by clearing the control register's write-protect bit. */ 219 cmdbuf[0] = MAX6900_REG_CONTROL | MAX6900_CMD_WRITE; 220 cmdbuf[1] = 0; 221 222 if ((error = iic_exec(sc->sc_tag, I2C_OP_WRITE, sc->sc_address, 223 cmdbuf, 1, &cmdbuf[1], 1, 0)) != 0) { 224 iic_release_bus(sc->sc_tag, 0); 225 aprint_error_dev(sc->sc_dev, 226 "maxrtc_write: failed to clear WP bit\n"); 227 return (error); 228 } 229 230 while (uio->uio_resid && uio->uio_offset < MAX6900_RAM_BYTES) { 231 a = (int)uio->uio_offset; 232 233 cmdbuf[0] = MAX6900_REG_RAM(a) | MAX6900_CMD_WRITE; 234 if ((error = uiomove(&cmdbuf[1], 1, uio)) != 0) 235 break; 236 237 if ((error = iic_exec(sc->sc_tag, I2C_OP_WRITE, sc->sc_address, 238 cmdbuf, 1, &cmdbuf[1], 1, 0)) != 0) { 239 aprint_error_dev(sc->sc_dev, 240 "maxrtc_write: write failed at 0x%x\n", a); 241 break; 242 } 243 } 244 245 /* Set the write-protect bit again. */ 246 cmdbuf[0] = MAX6900_REG_CONTROL | MAX6900_CMD_WRITE; 247 cmdbuf[1] = MAX6900_CONTROL_WP; 248 249 sverror = error; 250 if ((error = iic_exec(sc->sc_tag, I2C_OP_WRITE_WITH_STOP, 251 sc->sc_address, cmdbuf, 1, 252 &cmdbuf[1], 1, 0)) != 0) { 253 if (sverror != 0) 254 error = sverror; 255 aprint_error_dev(sc->sc_dev, 256 "maxrtc_write: failed to set WP bit\n"); 257 } 258 259 iic_release_bus(sc->sc_tag, 0); 260 261 return (error); 262 } 263 264 /* 265 * While the MAX6900 has a nice Clock Burst Read/Write command, 266 * we can't use it, since some I2C controllers do not support 267 * anything other than single-byte transfers. 268 */ 269 static int max6900_rtc_offset[] = { 270 MAX6900_REG_SECOND, 271 MAX6900_REG_MINUTE, 272 MAX6900_REG_HOUR, 273 MAX6900_REG_DATE, 274 MAX6900_REG_MONTH, 275 MAX6900_REG_DAY, 276 MAX6900_REG_YEAR, 277 MAX6900_REG_CENTURY, /* control, if burst */ 278 }; 279 280 static int 281 maxrtc_gettime_ymdhms(struct todr_chip_handle *ch, struct clock_ymdhms *dt) 282 { 283 struct maxrtc_softc *sc = ch->cookie; 284 u_int8_t bcd[MAX6900_BURST_LEN], cmdbuf[1]; 285 int i, error; 286 287 if ((error = iic_acquire_bus(sc->sc_tag, 0)) != 0) { 288 aprint_error_dev(sc->sc_dev, 289 "maxrtc_clock_read: failed to acquire I2C bus\n"); 290 return (error); 291 } 292 293 /* Read each timekeeping register in order. */ 294 for (i = 0; i < MAX6900_BURST_LEN; i++) { 295 cmdbuf[0] = max6900_rtc_offset[i] | MAX6900_CMD_READ; 296 297 if ((error = iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP, 298 sc->sc_address, cmdbuf, 1, 299 &bcd[i], 1, 0)) != 0) { 300 iic_release_bus(sc->sc_tag, 0); 301 aprint_error_dev(sc->sc_dev, 302 "maxrtc_clock_read: failed to read rtc " 303 "at 0x%x\n", 304 max6900_rtc_offset[i]); 305 return (error); 306 } 307 } 308 309 /* Done with I2C */ 310 iic_release_bus(sc->sc_tag, 0); 311 312 /* 313 * Convert the MAX6900's register values into something useable 314 */ 315 dt->dt_sec = bcdtobin(bcd[MAX6900_BURST_SECOND] & MAX6900_SECOND_MASK); 316 dt->dt_min = bcdtobin(bcd[MAX6900_BURST_MINUTE] & MAX6900_MINUTE_MASK); 317 318 if (bcd[MAX6900_BURST_HOUR] & MAX6900_HOUR_12HRS) { 319 dt->dt_hour = bcdtobin(bcd[MAX6900_BURST_HOUR] & 320 MAX6900_HOUR_12MASK); 321 if (bcd[MAX6900_BURST_HOUR] & MAX6900_HOUR_12HRS_PM) 322 dt->dt_hour += 12; 323 } else { 324 dt->dt_hour = bcdtobin(bcd[MAX6900_BURST_HOUR] & 325 MAX6900_HOUR_24MASK); 326 } 327 328 dt->dt_day = bcdtobin(bcd[MAX6900_BURST_DATE] & MAX6900_DATE_MASK); 329 dt->dt_mon = bcdtobin(bcd[MAX6900_BURST_MONTH] & MAX6900_MONTH_MASK); 330 dt->dt_year = bcdtobin(bcd[MAX6900_BURST_YEAR]); 331 /* century in the burst control slot */ 332 dt->dt_year += (int)bcdtobin(bcd[MAX6900_BURST_CONTROL]) * 100; 333 334 return (0); 335 } 336 337 static int 338 maxrtc_settime_ymdhms(struct todr_chip_handle *ch, struct clock_ymdhms *dt) 339 { 340 struct maxrtc_softc *sc = ch->cookie; 341 uint8_t bcd[MAX6900_BURST_LEN], cmdbuf[2]; 342 uint8_t init_seconds, final_seconds; 343 int i, error; 344 345 /* 346 * Convert our time representation into something the MAX6900 347 * can understand. 348 */ 349 bcd[MAX6900_BURST_SECOND] = bintobcd(dt->dt_sec); 350 bcd[MAX6900_BURST_MINUTE] = bintobcd(dt->dt_min); 351 bcd[MAX6900_BURST_HOUR] = bintobcd(dt->dt_hour) & MAX6900_HOUR_24MASK; 352 bcd[MAX6900_BURST_DATE] = bintobcd(dt->dt_day); 353 bcd[MAX6900_BURST_WDAY] = bintobcd(dt->dt_wday); 354 bcd[MAX6900_BURST_MONTH] = bintobcd(dt->dt_mon); 355 bcd[MAX6900_BURST_YEAR] = bintobcd(dt->dt_year % 100); 356 /* century in control slot */ 357 bcd[MAX6900_BURST_CONTROL] = bintobcd(dt->dt_year / 100); 358 359 if ((error = iic_acquire_bus(sc->sc_tag, 0)) != 0) { 360 aprint_error_dev(sc->sc_dev, 361 "maxrtc_clock_write: failed to acquire I2C bus\n"); 362 return (error); 363 } 364 365 /* Start by clearing the control register's write-protect bit. */ 366 cmdbuf[0] = MAX6900_REG_CONTROL | MAX6900_CMD_WRITE; 367 cmdbuf[1] = 0; 368 369 if ((error = iic_exec(sc->sc_tag, I2C_OP_WRITE, sc->sc_address, 370 cmdbuf, 1, &cmdbuf[1], 1, 0)) != 0) { 371 iic_release_bus(sc->sc_tag, 0); 372 aprint_error_dev(sc->sc_dev, 373 "maxrtc_clock_write: failed to clear WP bit\n"); 374 return (error); 375 } 376 377 /* 378 * The MAX6900 RTC manual recommends ensuring "atomicity" of 379 * a non-burst write by: 380 * 381 * - writing SECONDS 382 * - reading back SECONDS, remembering it as "initial seconds" 383 * - write the remaining RTC registers 384 * - read back SECONDS as "final seconds" 385 * - if "initial seconds" == 59, ensure "final seconds" == 59 386 * - else, ensure "final seconds" is no more than one second 387 * beyond "initial seconds". 388 */ 389 again: 390 cmdbuf[0] = MAX6900_REG_SECOND | MAX6900_CMD_WRITE; 391 if ((error = iic_exec(sc->sc_tag, I2C_OP_WRITE, sc->sc_address, 392 cmdbuf, 1, &bcd[MAX6900_BURST_SECOND], 1, 0)) != 0) { 393 iic_release_bus(sc->sc_tag, 0); 394 aprint_error_dev(sc->sc_dev, 395 "maxrtc_clock_write: failed to write SECONDS\n"); 396 return (error); 397 } 398 399 cmdbuf[0] = MAX6900_REG_SECOND | MAX6900_CMD_READ; 400 if ((error = iic_exec(sc->sc_tag, I2C_OP_READ, sc->sc_address, 401 cmdbuf, 1, &init_seconds, 1, 0)) != 0) { 402 iic_release_bus(sc->sc_tag, 0); 403 aprint_error_dev(sc->sc_dev, 404 "maxrtc_clock_write: failed to read " 405 "INITIAL SECONDS\n"); 406 return (error); 407 } 408 409 for (i = 1; i < MAX6900_BURST_LEN; i++) { 410 cmdbuf[0] = max6900_rtc_offset[i] | MAX6900_CMD_WRITE; 411 if ((error = iic_exec(sc->sc_tag, 412 i != MAX6900_BURST_LEN - 1 ? I2C_OP_WRITE : 413 I2C_OP_WRITE_WITH_STOP, sc->sc_address, 414 cmdbuf, 1, &bcd[i], 1, 0)) != 0) { 415 iic_release_bus(sc->sc_tag, 0); 416 aprint_error_dev(sc->sc_dev, 417 "maxrtc_clock_write: failed to write rtc " 418 " at 0x%x\n", 419 max6900_rtc_offset[i]); 420 return (error); 421 } 422 } 423 424 cmdbuf[0] = MAX6900_REG_SECOND | MAX6900_CMD_READ; 425 if ((error = iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP, sc->sc_address, 426 cmdbuf, 1, &final_seconds, 1, 0)) != 0) { 427 iic_release_bus(sc->sc_tag, 0); 428 aprint_error_dev(sc->sc_dev, 429 "maxrtc_clock_write: failed to read " 430 "FINAL SECONDS\n"); 431 return (error); 432 } 433 434 if ((init_seconds == 59 && final_seconds != 59) || 435 (init_seconds != 59 && final_seconds != init_seconds + 1)) { 436 #if 1 437 printf("%s: maxrtc_clock_write: init %d, final %d, try again\n", 438 device_xname(sc->sc_dev), init_seconds, final_seconds); 439 #endif 440 goto again; 441 } 442 443 /* Finish by setting the control register's write-protect bit. */ 444 cmdbuf[0] = MAX6900_REG_CONTROL | MAX6900_CMD_WRITE; 445 cmdbuf[1] = MAX6900_CONTROL_WP; 446 447 if ((error = iic_exec(sc->sc_tag, I2C_OP_WRITE_WITH_STOP, 448 sc->sc_address, cmdbuf, 1, &cmdbuf[1], 1, 449 0)) != 0) { 450 iic_release_bus(sc->sc_tag, 0); 451 aprint_error_dev(sc->sc_dev, 452 "maxrtc_clock_write: failed to set WP bit\n"); 453 return (error); 454 } 455 456 iic_release_bus(sc->sc_tag, 0); 457 458 return (0); 459 } 460
Indexes created Mon Sep 22 13:09:51 GMT 2025