1 /* 2 * Real Time Clock interface for StrongARM SA1x00 and XScale PXA2xx 3 * 4 * Copyright (c) 2000 Nils Faerber 5 * 6 * Based on rtc.c by Paul Gortmaker 7 * 8 * Original Driver by Nils Faerber <nils@kernelconcepts.de> 9 * 10 * Modifications from: 11 * CIH <cih@coventive.com> 12 * Nicolas Pitre <nico@fluxnic.net> 13 * Andrew Christian <andrew.christian@hp.com> 14 * 15 * Converted to the RTC subsystem and Driver Model 16 * by Richard Purdie <rpurdie@rpsys.net> 17 * 18 * This program is free software; you can redistribute it and/or 19 * modify it under the terms of the GNU General Public License 20 * as published by the Free Software Foundation; either version 21 * 2 of the License, or (at your option) any later version. 22 */ 23 24 #include <linux/platform_device.h> 25 #include <linux/module.h> 26 #include <linux/rtc.h> 27 #include <linux/init.h> 28 #include <linux/fs.h> 29 #include <linux/interrupt.h> 30 #include <linux/string.h> 31 #include <linux/pm.h> 32 #include <linux/bitops.h> 33 34 #include <mach/hardware.h> 35 #include <asm/irq.h> 36 37 #ifdef CONFIG_ARCH_PXA 38 #include <mach/regs-rtc.h> 39 #include <mach/regs-ost.h> 40 #endif 41 42 #define RTC_DEF_DIVIDER (32768 - 1) 43 #define RTC_DEF_TRIM 0 44 45 static const unsigned long RTC_FREQ = 1024; 46 static unsigned long timer_freq; 47 static struct rtc_time rtc_alarm; 48 static DEFINE_SPINLOCK(sa1100_rtc_lock); 49 50 static inline int rtc_periodic_alarm(struct rtc_time *tm) 51 { 52 return (tm->tm_year == -1) || 53 ((unsigned)tm->tm_mon >= 12) || 54 ((unsigned)(tm->tm_mday - 1) >= 31) || 55 ((unsigned)tm->tm_hour > 23) || 56 ((unsigned)tm->tm_min > 59) || 57 ((unsigned)tm->tm_sec > 59); 58 } 59 60 /* 61 * Calculate the next alarm time given the requested alarm time mask 62 * and the current time. 63 */ 64 static void rtc_next_alarm_time(struct rtc_time *next, struct rtc_time *now, 65 struct rtc_time *alrm) 66 { 67 unsigned long next_time; 68 unsigned long now_time; 69 70 next->tm_year = now->tm_year; 71 next->tm_mon = now->tm_mon; 72 next->tm_mday = now->tm_mday; 73 next->tm_hour = alrm->tm_hour; 74 next->tm_min = alrm->tm_min; 75 next->tm_sec = alrm->tm_sec; 76 77 rtc_tm_to_time(now, &now_time); 78 rtc_tm_to_time(next, &next_time); 79 80 if (next_time < now_time) { 81 /* Advance one day */ 82 next_time += 60 * 60 * 24; 83 rtc_time_to_tm(next_time, next); 84 } 85 } 86 87 static int rtc_update_alarm(struct rtc_time *alrm) 88 { 89 struct rtc_time alarm_tm, now_tm; 90 unsigned long now, time; 91 int ret; 92 93 do { 94 now = RCNR; 95 rtc_time_to_tm(now, &now_tm); 96 rtc_next_alarm_time(&alarm_tm, &now_tm, alrm); 97 ret = rtc_tm_to_time(&alarm_tm, &time); 98 if (ret != 0) 99 break; 100 101 RTSR = RTSR & (RTSR_HZE|RTSR_ALE|RTSR_AL); 102 RTAR = time; 103 } while (now != RCNR); 104 105 return ret; 106 } 107 108 static irqreturn_t sa1100_rtc_interrupt(int irq, void *dev_id) 109 { 110 struct platform_device *pdev = to_platform_device(dev_id); 111 struct rtc_device *rtc = platform_get_drvdata(pdev); 112 unsigned int rtsr; 113 unsigned long events = 0; 114 115 spin_lock(&sa1100_rtc_lock); 116 117 rtsr = RTSR; 118 /* clear interrupt sources */ 119 RTSR = 0; 120 /* Fix for a nasty initialization problem the in SA11xx RTSR register. 121 * See also the comments in sa1100_rtc_probe(). */ 122 if (rtsr & (RTSR_ALE | RTSR_HZE)) { 123 /* This is the original code, before there was the if test 124 * above. This code does not clear interrupts that were not 125 * enabled. */ 126 RTSR = (RTSR_AL | RTSR_HZ) & (rtsr >> 2); 127 } else { 128 /* For some reason, it is possible to enter this routine 129 * without interruptions enabled, it has been tested with 130 * several units (Bug in SA11xx chip?). 131 * 132 * This situation leads to an infinite "loop" of interrupt 133 * routine calling and as a result the processor seems to 134 * lock on its first call to open(). */ 135 RTSR = RTSR_AL | RTSR_HZ; 136 } 137 138 /* clear alarm interrupt if it has occurred */ 139 if (rtsr & RTSR_AL) 140 rtsr &= ~RTSR_ALE; 141 RTSR = rtsr & (RTSR_ALE | RTSR_HZE); 142 143 /* update irq data & counter */ 144 if (rtsr & RTSR_AL) 145 events |= RTC_AF | RTC_IRQF; 146 if (rtsr & RTSR_HZ) 147 events |= RTC_UF | RTC_IRQF; 148 149 rtc_update_irq(rtc, 1, events); 150 151 if (rtsr & RTSR_AL && rtc_periodic_alarm(&rtc_alarm)) 152 rtc_update_alarm(&rtc_alarm); 153 154 spin_unlock(&sa1100_rtc_lock); 155 156 return IRQ_HANDLED; 157 } 158 159 static int sa1100_irq_set_freq(struct device *dev, int freq) 160 { 161 if (freq < 1 || freq > timer_freq) { 162 return -EINVAL; 163 } else { 164 struct rtc_device *rtc = (struct rtc_device *)dev; 165 166 rtc->irq_freq = freq; 167 168 return 0; 169 } 170 } 171 172 static int rtc_timer1_count; 173 174 static int sa1100_irq_set_state(struct device *dev, int enabled) 175 { 176 spin_lock_irq(&sa1100_rtc_lock); 177 if (enabled) { 178 struct rtc_device *rtc = (struct rtc_device *)dev; 179 180 OSMR1 = timer_freq / rtc->irq_freq + OSCR; 181 OIER |= OIER_E1; 182 rtc_timer1_count = 1; 183 } else { 184 OIER &= ~OIER_E1; 185 } 186 spin_unlock_irq(&sa1100_rtc_lock); 187 188 return 0; 189 } 190 191 static inline int sa1100_timer1_retrigger(struct rtc_device *rtc) 192 { 193 unsigned long diff; 194 unsigned long period = timer_freq / rtc->irq_freq; 195 196 spin_lock_irq(&sa1100_rtc_lock); 197 198 do { 199 OSMR1 += period; 200 diff = OSMR1 - OSCR; 201 /* If OSCR > OSMR1, diff is a very large number (unsigned 202 * math). This means we have a lost interrupt. */ 203 } while (diff > period); 204 OIER |= OIER_E1; 205 206 spin_unlock_irq(&sa1100_rtc_lock); 207 208 return 0; 209 } 210 211 static irqreturn_t timer1_interrupt(int irq, void *dev_id) 212 { 213 struct platform_device *pdev = to_platform_device(dev_id); 214 struct rtc_device *rtc = platform_get_drvdata(pdev); 215 216 /* 217 * If we match for the first time, rtc_timer1_count will be 1. 218 * Otherwise, we wrapped around (very unlikely but 219 * still possible) so compute the amount of missed periods. 220 * The match reg is updated only when the data is actually retrieved 221 * to avoid unnecessary interrupts. 222 */ 223 OSSR = OSSR_M1; /* clear match on timer1 */ 224 225 rtc_update_irq(rtc, rtc_timer1_count, RTC_PF | RTC_IRQF); 226 227 if (rtc_timer1_count == 1) 228 rtc_timer1_count = 229 (rtc->irq_freq * ((1 << 30) / (timer_freq >> 2))); 230 231 /* retrigger. */ 232 sa1100_timer1_retrigger(rtc); 233 234 return IRQ_HANDLED; 235 } 236 237 static int sa1100_rtc_read_callback(struct device *dev, int data) 238 { 239 if (data & RTC_PF) { 240 struct rtc_device *rtc = (struct rtc_device *)dev; 241 242 /* interpolate missed periods and set match for the next */ 243 unsigned long period = timer_freq / rtc->irq_freq; 244 unsigned long oscr = OSCR; 245 unsigned long osmr1 = OSMR1; 246 unsigned long missed = (oscr - osmr1)/period; 247 data += missed << 8; 248 OSSR = OSSR_M1; /* clear match on timer 1 */ 249 OSMR1 = osmr1 + (missed + 1)*period; 250 /* Ensure we didn't miss another match in the mean time. 251 * Here we compare (match - OSCR) 8 instead of 0 -- 252 * see comment in pxa_timer_interrupt() for explanation. 253 */ 254 while ((signed long)((osmr1 = OSMR1) - OSCR) <= 8) { 255 data += 0x100; 256 OSSR = OSSR_M1; /* clear match on timer 1 */ 257 OSMR1 = osmr1 + period; 258 } 259 } 260 return data; 261 } 262 263 static int sa1100_rtc_open(struct device *dev) 264 { 265 int ret; 266 struct rtc_device *rtc = (struct rtc_device *)dev; 267 268 ret = request_irq(IRQ_RTC1Hz, sa1100_rtc_interrupt, IRQF_DISABLED, 269 "rtc 1Hz", dev); 270 if (ret) { 271 dev_err(dev, "IRQ %d already in use.\n", IRQ_RTC1Hz); 272 goto fail_ui; 273 } 274 ret = request_irq(IRQ_RTCAlrm, sa1100_rtc_interrupt, IRQF_DISABLED, 275 "rtc Alrm", dev); 276 if (ret) { 277 dev_err(dev, "IRQ %d already in use.\n", IRQ_RTCAlrm); 278 goto fail_ai; 279 } 280 ret = request_irq(IRQ_OST1, timer1_interrupt, IRQF_DISABLED, 281 "rtc timer", dev); 282 if (ret) { 283 dev_err(dev, "IRQ %d already in use.\n", IRQ_OST1); 284 goto fail_pi; 285 } 286 rtc->max_user_freq = RTC_FREQ; 287 sa1100_irq_set_freq(dev, RTC_FREQ); 288 289 return 0; 290 291 fail_pi: 292 free_irq(IRQ_RTCAlrm, dev); 293 fail_ai: 294 free_irq(IRQ_RTC1Hz, dev); 295 fail_ui: 296 return ret; 297 } 298 299 static void sa1100_rtc_release(struct device *dev) 300 { 301 spin_lock_irq(&sa1100_rtc_lock); 302 RTSR = 0; 303 OIER &= ~OIER_E1; 304 OSSR = OSSR_M1; 305 spin_unlock_irq(&sa1100_rtc_lock); 306 307 free_irq(IRQ_OST1, dev); 308 free_irq(IRQ_RTCAlrm, dev); 309 free_irq(IRQ_RTC1Hz, dev); 310 } 311 312 313 static int sa1100_rtc_ioctl(struct device *dev, unsigned int cmd, 314 unsigned long arg) 315 { 316 switch (cmd) { 317 case RTC_AIE_OFF: 318 spin_lock_irq(&sa1100_rtc_lock); 319 RTSR &= ~RTSR_ALE; 320 spin_unlock_irq(&sa1100_rtc_lock); 321 return 0; 322 case RTC_AIE_ON: 323 spin_lock_irq(&sa1100_rtc_lock); 324 RTSR |= RTSR_ALE; 325 spin_unlock_irq(&sa1100_rtc_lock); 326 return 0; 327 case RTC_UIE_OFF: 328 spin_lock_irq(&sa1100_rtc_lock); 329 RTSR &= ~RTSR_HZE; 330 spin_unlock_irq(&sa1100_rtc_lock); 331 return 0; 332 case RTC_UIE_ON: 333 spin_lock_irq(&sa1100_rtc_lock); 334 RTSR |= RTSR_HZE; 335 spin_unlock_irq(&sa1100_rtc_lock); 336 return 0; 337 } 338 return -ENOIOCTLCMD; 339 } 340 341 static int sa1100_rtc_read_time(struct device *dev, struct rtc_time *tm) 342 { 343 rtc_time_to_tm(RCNR, tm); 344 return 0; 345 } 346 347 static int sa1100_rtc_set_time(struct device *dev, struct rtc_time *tm) 348 { 349 unsigned long time; 350 int ret; 351 352 ret = rtc_tm_to_time(tm, &time); 353 if (ret == 0) 354 RCNR = time; 355 return ret; 356 } 357 358 static int sa1100_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) 359 { 360 u32 rtsr; 361 362 memcpy(&alrm->time, &rtc_alarm, sizeof(struct rtc_time)); 363 rtsr = RTSR; 364 alrm->enabled = (rtsr & RTSR_ALE) ? 1 : 0; 365 alrm->pending = (rtsr & RTSR_AL) ? 1 : 0; 366 return 0; 367 } 368 369 static int sa1100_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) 370 { 371 int ret; 372 373 spin_lock_irq(&sa1100_rtc_lock); 374 ret = rtc_update_alarm(&alrm->time); 375 if (ret == 0) { 376 if (alrm->enabled) 377 RTSR |= RTSR_ALE; 378 else 379 RTSR &= ~RTSR_ALE; 380 } 381 spin_unlock_irq(&sa1100_rtc_lock); 382 383 return ret; 384 } 385 386 static int sa1100_rtc_proc(struct device *dev, struct seq_file *seq) 387 { 388 struct rtc_device *rtc = (struct rtc_device *)dev; 389 390 seq_printf(seq, "trim/divider\t: 0x%08x\n", (u32) RTTR); 391 seq_printf(seq, "update_IRQ\t: %s\n", 392 (RTSR & RTSR_HZE) ? "yes" : "no"); 393 seq_printf(seq, "periodic_IRQ\t: %s\n", 394 (OIER & OIER_E1) ? "yes" : "no"); 395 seq_printf(seq, "periodic_freq\t: %d\n", rtc->irq_freq); 396 seq_printf(seq, "RTSR\t\t: 0x%08x\n", (u32)RTSR); 397 398 return 0; 399 } 400 401 static const struct rtc_class_ops sa1100_rtc_ops = { 402 .open = sa1100_rtc_open, 403 .read_callback = sa1100_rtc_read_callback, 404 .release = sa1100_rtc_release, 405 .ioctl = sa1100_rtc_ioctl, 406 .read_time = sa1100_rtc_read_time, 407 .set_time = sa1100_rtc_set_time, 408 .read_alarm = sa1100_rtc_read_alarm, 409 .set_alarm = sa1100_rtc_set_alarm, 410 .proc = sa1100_rtc_proc, 411 .irq_set_freq = sa1100_irq_set_freq, 412 .irq_set_state = sa1100_irq_set_state, 413 }; 414 415 static int sa1100_rtc_probe(struct platform_device *pdev) 416 { 417 struct rtc_device *rtc; 418 419 timer_freq = get_clock_tick_rate(); 420 421 /* 422 * According to the manual we should be able to let RTTR be zero 423 * and then a default diviser for a 32.768KHz clock is used. 424 * Apparently this doesn't work, at least for my SA1110 rev 5. 425 * If the clock divider is uninitialized then reset it to the 426 * default value to get the 1Hz clock. 427 */ 428 if (RTTR == 0) { 429 RTTR = RTC_DEF_DIVIDER + (RTC_DEF_TRIM << 16); 430 dev_warn(&pdev->dev, "warning: " 431 "initializing default clock divider/trim value\n"); 432 /* The current RTC value probably doesn't make sense either */ 433 RCNR = 0; 434 } 435 436 device_init_wakeup(&pdev->dev, 1); 437 438 rtc = rtc_device_register(pdev->name, &pdev->dev, &sa1100_rtc_ops, 439 THIS_MODULE); 440 441 if (IS_ERR(rtc)) 442 return PTR_ERR(rtc); 443 444 platform_set_drvdata(pdev, rtc); 445 446 /* Set the irq_freq */ 447 /*TODO: Find out who is messing with this value after we initialize 448 * it here.*/ 449 rtc->irq_freq = RTC_FREQ; 450 451 /* Fix for a nasty initialization problem the in SA11xx RTSR register. 452 * See also the comments in sa1100_rtc_interrupt(). 453 * 454 * Sometimes bit 1 of the RTSR (RTSR_HZ) will wake up 1, which means an 455 * interrupt pending, even though interrupts were never enabled. 456 * In this case, this bit it must be reset before enabling 457 * interruptions to avoid a nonexistent interrupt to occur. 458 * 459 * In principle, the same problem would apply to bit 0, although it has 460 * never been observed to happen. 461 * 462 * This issue is addressed both here and in sa1100_rtc_interrupt(). 463 * If the issue is not addressed here, in the times when the processor 464 * wakes up with the bit set there will be one spurious interrupt. 465 * 466 * The issue is also dealt with in sa1100_rtc_interrupt() to be on the 467 * safe side, once the condition that lead to this strange 468 * initialization is unknown and could in principle happen during 469 * normal processing. 470 * 471 * Notice that clearing bit 1 and 0 is accomplished by writting ONES to 472 * the corresponding bits in RTSR. */ 473 RTSR = RTSR_AL | RTSR_HZ; 474 475 return 0; 476 } 477 478 static int sa1100_rtc_remove(struct platform_device *pdev) 479 { 480 struct rtc_device *rtc = platform_get_drvdata(pdev); 481 482 if (rtc) 483 rtc_device_unregister(rtc); 484 485 return 0; 486 } 487 488 #ifdef CONFIG_PM 489 static int sa1100_rtc_suspend(struct device *dev) 490 { 491 if (device_may_wakeup(dev)) 492 enable_irq_wake(IRQ_RTCAlrm); 493 return 0; 494 } 495 496 static int sa1100_rtc_resume(struct device *dev) 497 { 498 if (device_may_wakeup(dev)) 499 disable_irq_wake(IRQ_RTCAlrm); 500 return 0; 501 } 502 503 static const struct dev_pm_ops sa1100_rtc_pm_ops = { 504 .suspend = sa1100_rtc_suspend, 505 .resume = sa1100_rtc_resume, 506 }; 507 #endif 508 509 static struct platform_driver sa1100_rtc_driver = { 510 .probe = sa1100_rtc_probe, 511 .remove = sa1100_rtc_remove, 512 .driver = { 513 .name = "sa1100-rtc", 514 #ifdef CONFIG_PM 515 .pm = &sa1100_rtc_pm_ops, 516 #endif 517 }, 518 }; 519 520 static int __init sa1100_rtc_init(void) 521 { 522 return platform_driver_register(&sa1100_rtc_driver); 523 } 524 525 static void __exit sa1100_rtc_exit(void) 526 { 527 platform_driver_unregister(&sa1100_rtc_driver); 528 } 529 530 module_init(sa1100_rtc_init); 531 module_exit(sa1100_rtc_exit); 532 533 MODULE_AUTHOR("Richard Purdie <rpurdie@rpsys.net>"); 534 MODULE_DESCRIPTION("SA11x0/PXA2xx Realtime Clock Driver (RTC)"); 535 MODULE_LICENSE("GPL"); 536 MODULE_ALIAS("platform:sa1100-rtc"); 537