1 /* 2 * Real Time Clock interface for Linux on Atmel AT91RM9200 3 * 4 * Copyright (C) 2002 Rick Bronson 5 * 6 * Converted to RTC class model by Andrew Victor 7 * 8 * Ported to Linux 2.6 by Steven Scholz 9 * Based on s3c2410-rtc.c Simtec Electronics 10 * 11 * Based on sa1100-rtc.c by Nils Faerber 12 * Based on rtc.c by Paul Gortmaker 13 * 14 * This program is free software; you can redistribute it and/or 15 * modify it under the terms of the GNU General Public License 16 * as published by the Free Software Foundation; either version 17 * 2 of the License, or (at your option) any later version. 18 * 19 */ 20 21 #include <linux/module.h> 22 #include <linux/kernel.h> 23 #include <linux/platform_device.h> 24 #include <linux/time.h> 25 #include <linux/rtc.h> 26 #include <linux/bcd.h> 27 #include <linux/interrupt.h> 28 #include <linux/spinlock.h> 29 #include <linux/ioctl.h> 30 #include <linux/completion.h> 31 #include <linux/io.h> 32 #include <linux/of.h> 33 #include <linux/of_device.h> 34 35 #include <asm/uaccess.h> 36 37 #include "rtc-at91rm9200.h" 38 39 #define at91_rtc_read(field) \ 40 __raw_readl(at91_rtc_regs + field) 41 #define at91_rtc_write(field, val) \ 42 __raw_writel((val), at91_rtc_regs + field) 43 44 #define AT91_RTC_EPOCH 1900UL /* just like arch/arm/common/rtctime.c */ 45 46 struct at91_rtc_config { 47 bool use_shadow_imr; 48 }; 49 50 static const struct at91_rtc_config *at91_rtc_config; 51 static DECLARE_COMPLETION(at91_rtc_updated); 52 static unsigned int at91_alarm_year = AT91_RTC_EPOCH; 53 static void __iomem *at91_rtc_regs; 54 static int irq; 55 static DEFINE_SPINLOCK(at91_rtc_lock); 56 static u32 at91_rtc_shadow_imr; 57 58 static void at91_rtc_write_ier(u32 mask) 59 { 60 unsigned long flags; 61 62 spin_lock_irqsave(&at91_rtc_lock, flags); 63 at91_rtc_shadow_imr |= mask; 64 at91_rtc_write(AT91_RTC_IER, mask); 65 spin_unlock_irqrestore(&at91_rtc_lock, flags); 66 } 67 68 static void at91_rtc_write_idr(u32 mask) 69 { 70 unsigned long flags; 71 72 spin_lock_irqsave(&at91_rtc_lock, flags); 73 at91_rtc_write(AT91_RTC_IDR, mask); 74 /* 75 * Register read back (of any RTC-register) needed to make sure 76 * IDR-register write has reached the peripheral before updating 77 * shadow mask. 78 * 79 * Note that there is still a possibility that the mask is updated 80 * before interrupts have actually been disabled in hardware. The only 81 * way to be certain would be to poll the IMR-register, which is is 82 * the very register we are trying to emulate. The register read back 83 * is a reasonable heuristic. 84 */ 85 at91_rtc_read(AT91_RTC_SR); 86 at91_rtc_shadow_imr &= ~mask; 87 spin_unlock_irqrestore(&at91_rtc_lock, flags); 88 } 89 90 static u32 at91_rtc_read_imr(void) 91 { 92 unsigned long flags; 93 u32 mask; 94 95 if (at91_rtc_config->use_shadow_imr) { 96 spin_lock_irqsave(&at91_rtc_lock, flags); 97 mask = at91_rtc_shadow_imr; 98 spin_unlock_irqrestore(&at91_rtc_lock, flags); 99 } else { 100 mask = at91_rtc_read(AT91_RTC_IMR); 101 } 102 103 return mask; 104 } 105 106 /* 107 * Decode time/date into rtc_time structure 108 */ 109 static void at91_rtc_decodetime(unsigned int timereg, unsigned int calreg, 110 struct rtc_time *tm) 111 { 112 unsigned int time, date; 113 114 /* must read twice in case it changes */ 115 do { 116 time = at91_rtc_read(timereg); 117 date = at91_rtc_read(calreg); 118 } while ((time != at91_rtc_read(timereg)) || 119 (date != at91_rtc_read(calreg))); 120 121 tm->tm_sec = bcd2bin((time & AT91_RTC_SEC) >> 0); 122 tm->tm_min = bcd2bin((time & AT91_RTC_MIN) >> 8); 123 tm->tm_hour = bcd2bin((time & AT91_RTC_HOUR) >> 16); 124 125 /* 126 * The Calendar Alarm register does not have a field for 127 * the year - so these will return an invalid value. When an 128 * alarm is set, at91_alarm_year will store the current year. 129 */ 130 tm->tm_year = bcd2bin(date & AT91_RTC_CENT) * 100; /* century */ 131 tm->tm_year += bcd2bin((date & AT91_RTC_YEAR) >> 8); /* year */ 132 133 tm->tm_wday = bcd2bin((date & AT91_RTC_DAY) >> 21) - 1; /* day of the week [0-6], Sunday=0 */ 134 tm->tm_mon = bcd2bin((date & AT91_RTC_MONTH) >> 16) - 1; 135 tm->tm_mday = bcd2bin((date & AT91_RTC_DATE) >> 24); 136 } 137 138 /* 139 * Read current time and date in RTC 140 */ 141 static int at91_rtc_readtime(struct device *dev, struct rtc_time *tm) 142 { 143 at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, tm); 144 tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year); 145 tm->tm_year = tm->tm_year - 1900; 146 147 dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__, 148 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday, 149 tm->tm_hour, tm->tm_min, tm->tm_sec); 150 151 return 0; 152 } 153 154 /* 155 * Set current time and date in RTC 156 */ 157 static int at91_rtc_settime(struct device *dev, struct rtc_time *tm) 158 { 159 unsigned long cr; 160 161 dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__, 162 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday, 163 tm->tm_hour, tm->tm_min, tm->tm_sec); 164 165 /* Stop Time/Calendar from counting */ 166 cr = at91_rtc_read(AT91_RTC_CR); 167 at91_rtc_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM); 168 169 at91_rtc_write_ier(AT91_RTC_ACKUPD); 170 wait_for_completion(&at91_rtc_updated); /* wait for ACKUPD interrupt */ 171 at91_rtc_write_idr(AT91_RTC_ACKUPD); 172 173 at91_rtc_write(AT91_RTC_TIMR, 174 bin2bcd(tm->tm_sec) << 0 175 | bin2bcd(tm->tm_min) << 8 176 | bin2bcd(tm->tm_hour) << 16); 177 178 at91_rtc_write(AT91_RTC_CALR, 179 bin2bcd((tm->tm_year + 1900) / 100) /* century */ 180 | bin2bcd(tm->tm_year % 100) << 8 /* year */ 181 | bin2bcd(tm->tm_mon + 1) << 16 /* tm_mon starts at zero */ 182 | bin2bcd(tm->tm_wday + 1) << 21 /* day of the week [0-6], Sunday=0 */ 183 | bin2bcd(tm->tm_mday) << 24); 184 185 /* Restart Time/Calendar */ 186 cr = at91_rtc_read(AT91_RTC_CR); 187 at91_rtc_write(AT91_RTC_CR, cr & ~(AT91_RTC_UPDCAL | AT91_RTC_UPDTIM)); 188 189 return 0; 190 } 191 192 /* 193 * Read alarm time and date in RTC 194 */ 195 static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm) 196 { 197 struct rtc_time *tm = &alrm->time; 198 199 at91_rtc_decodetime(AT91_RTC_TIMALR, AT91_RTC_CALALR, tm); 200 tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year); 201 tm->tm_year = at91_alarm_year - 1900; 202 203 alrm->enabled = (at91_rtc_read_imr() & AT91_RTC_ALARM) 204 ? 1 : 0; 205 206 dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__, 207 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday, 208 tm->tm_hour, tm->tm_min, tm->tm_sec); 209 210 return 0; 211 } 212 213 /* 214 * Set alarm time and date in RTC 215 */ 216 static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm) 217 { 218 struct rtc_time tm; 219 220 at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, &tm); 221 222 at91_alarm_year = tm.tm_year; 223 224 tm.tm_hour = alrm->time.tm_hour; 225 tm.tm_min = alrm->time.tm_min; 226 tm.tm_sec = alrm->time.tm_sec; 227 228 at91_rtc_write_idr(AT91_RTC_ALARM); 229 at91_rtc_write(AT91_RTC_TIMALR, 230 bin2bcd(tm.tm_sec) << 0 231 | bin2bcd(tm.tm_min) << 8 232 | bin2bcd(tm.tm_hour) << 16 233 | AT91_RTC_HOUREN | AT91_RTC_MINEN | AT91_RTC_SECEN); 234 at91_rtc_write(AT91_RTC_CALALR, 235 bin2bcd(tm.tm_mon + 1) << 16 /* tm_mon starts at zero */ 236 | bin2bcd(tm.tm_mday) << 24 237 | AT91_RTC_DATEEN | AT91_RTC_MTHEN); 238 239 if (alrm->enabled) { 240 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM); 241 at91_rtc_write_ier(AT91_RTC_ALARM); 242 } 243 244 dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__, 245 at91_alarm_year, tm.tm_mon, tm.tm_mday, tm.tm_hour, 246 tm.tm_min, tm.tm_sec); 247 248 return 0; 249 } 250 251 static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) 252 { 253 dev_dbg(dev, "%s(): cmd=%08x\n", __func__, enabled); 254 255 if (enabled) { 256 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM); 257 at91_rtc_write_ier(AT91_RTC_ALARM); 258 } else 259 at91_rtc_write_idr(AT91_RTC_ALARM); 260 261 return 0; 262 } 263 /* 264 * Provide additional RTC information in /proc/driver/rtc 265 */ 266 static int at91_rtc_proc(struct device *dev, struct seq_file *seq) 267 { 268 unsigned long imr = at91_rtc_read_imr(); 269 270 seq_printf(seq, "update_IRQ\t: %s\n", 271 (imr & AT91_RTC_ACKUPD) ? "yes" : "no"); 272 seq_printf(seq, "periodic_IRQ\t: %s\n", 273 (imr & AT91_RTC_SECEV) ? "yes" : "no"); 274 275 return 0; 276 } 277 278 /* 279 * IRQ handler for the RTC 280 */ 281 static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id) 282 { 283 struct platform_device *pdev = dev_id; 284 struct rtc_device *rtc = platform_get_drvdata(pdev); 285 unsigned int rtsr; 286 unsigned long events = 0; 287 288 rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_read_imr(); 289 if (rtsr) { /* this interrupt is shared! Is it ours? */ 290 if (rtsr & AT91_RTC_ALARM) 291 events |= (RTC_AF | RTC_IRQF); 292 if (rtsr & AT91_RTC_SECEV) 293 events |= (RTC_UF | RTC_IRQF); 294 if (rtsr & AT91_RTC_ACKUPD) 295 complete(&at91_rtc_updated); 296 297 at91_rtc_write(AT91_RTC_SCCR, rtsr); /* clear status reg */ 298 299 rtc_update_irq(rtc, 1, events); 300 301 dev_dbg(&pdev->dev, "%s(): num=%ld, events=0x%02lx\n", __func__, 302 events >> 8, events & 0x000000FF); 303 304 return IRQ_HANDLED; 305 } 306 return IRQ_NONE; /* not handled */ 307 } 308 309 static const struct at91_rtc_config at91rm9200_config = { 310 }; 311 312 static const struct at91_rtc_config at91sam9x5_config = { 313 .use_shadow_imr = true, 314 }; 315 316 #ifdef CONFIG_OF 317 static const struct of_device_id at91_rtc_dt_ids[] = { 318 { 319 .compatible = "atmel,at91rm9200-rtc", 320 .data = &at91rm9200_config, 321 }, { 322 .compatible = "atmel,at91sam9x5-rtc", 323 .data = &at91sam9x5_config, 324 }, { 325 /* sentinel */ 326 } 327 }; 328 MODULE_DEVICE_TABLE(of, at91_rtc_dt_ids); 329 #endif 330 331 static const struct at91_rtc_config * 332 at91_rtc_get_config(struct platform_device *pdev) 333 { 334 const struct of_device_id *match; 335 336 if (pdev->dev.of_node) { 337 match = of_match_node(at91_rtc_dt_ids, pdev->dev.of_node); 338 if (!match) 339 return NULL; 340 return (const struct at91_rtc_config *)match->data; 341 } 342 343 return &at91rm9200_config; 344 } 345 346 static const struct rtc_class_ops at91_rtc_ops = { 347 .read_time = at91_rtc_readtime, 348 .set_time = at91_rtc_settime, 349 .read_alarm = at91_rtc_readalarm, 350 .set_alarm = at91_rtc_setalarm, 351 .proc = at91_rtc_proc, 352 .alarm_irq_enable = at91_rtc_alarm_irq_enable, 353 }; 354 355 /* 356 * Initialize and install RTC driver 357 */ 358 static int __init at91_rtc_probe(struct platform_device *pdev) 359 { 360 struct rtc_device *rtc; 361 struct resource *regs; 362 int ret = 0; 363 364 at91_rtc_config = at91_rtc_get_config(pdev); 365 if (!at91_rtc_config) 366 return -ENODEV; 367 368 regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); 369 if (!regs) { 370 dev_err(&pdev->dev, "no mmio resource defined\n"); 371 return -ENXIO; 372 } 373 374 irq = platform_get_irq(pdev, 0); 375 if (irq < 0) { 376 dev_err(&pdev->dev, "no irq resource defined\n"); 377 return -ENXIO; 378 } 379 380 at91_rtc_regs = ioremap(regs->start, resource_size(regs)); 381 if (!at91_rtc_regs) { 382 dev_err(&pdev->dev, "failed to map registers, aborting.\n"); 383 return -ENOMEM; 384 } 385 386 at91_rtc_write(AT91_RTC_CR, 0); 387 at91_rtc_write(AT91_RTC_MR, 0); /* 24 hour mode */ 388 389 /* Disable all interrupts */ 390 at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM | 391 AT91_RTC_SECEV | AT91_RTC_TIMEV | 392 AT91_RTC_CALEV); 393 394 ret = request_irq(irq, at91_rtc_interrupt, 395 IRQF_SHARED, 396 "at91_rtc", pdev); 397 if (ret) { 398 dev_err(&pdev->dev, "IRQ %d already in use.\n", irq); 399 goto err_unmap; 400 } 401 402 /* cpu init code should really have flagged this device as 403 * being wake-capable; if it didn't, do that here. 404 */ 405 if (!device_can_wakeup(&pdev->dev)) 406 device_init_wakeup(&pdev->dev, 1); 407 408 rtc = rtc_device_register(pdev->name, &pdev->dev, 409 &at91_rtc_ops, THIS_MODULE); 410 if (IS_ERR(rtc)) { 411 ret = PTR_ERR(rtc); 412 goto err_free_irq; 413 } 414 platform_set_drvdata(pdev, rtc); 415 416 dev_info(&pdev->dev, "AT91 Real Time Clock driver.\n"); 417 return 0; 418 419 err_free_irq: 420 free_irq(irq, pdev); 421 err_unmap: 422 iounmap(at91_rtc_regs); 423 424 return ret; 425 } 426 427 /* 428 * Disable and remove the RTC driver 429 */ 430 static int __exit at91_rtc_remove(struct platform_device *pdev) 431 { 432 struct rtc_device *rtc = platform_get_drvdata(pdev); 433 434 /* Disable all interrupts */ 435 at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM | 436 AT91_RTC_SECEV | AT91_RTC_TIMEV | 437 AT91_RTC_CALEV); 438 free_irq(irq, pdev); 439 440 rtc_device_unregister(rtc); 441 iounmap(at91_rtc_regs); 442 platform_set_drvdata(pdev, NULL); 443 444 return 0; 445 } 446 447 #ifdef CONFIG_PM_SLEEP 448 449 /* AT91RM9200 RTC Power management control */ 450 451 static u32 at91_rtc_imr; 452 453 static int at91_rtc_suspend(struct device *dev) 454 { 455 /* this IRQ is shared with DBGU and other hardware which isn't 456 * necessarily doing PM like we are... 457 */ 458 at91_rtc_imr = at91_rtc_read_imr() 459 & (AT91_RTC_ALARM|AT91_RTC_SECEV); 460 if (at91_rtc_imr) { 461 if (device_may_wakeup(dev)) 462 enable_irq_wake(irq); 463 else 464 at91_rtc_write_idr(at91_rtc_imr); 465 } 466 return 0; 467 } 468 469 static int at91_rtc_resume(struct device *dev) 470 { 471 if (at91_rtc_imr) { 472 if (device_may_wakeup(dev)) 473 disable_irq_wake(irq); 474 else 475 at91_rtc_write_ier(at91_rtc_imr); 476 } 477 return 0; 478 } 479 #endif 480 481 static SIMPLE_DEV_PM_OPS(at91_rtc_pm_ops, at91_rtc_suspend, at91_rtc_resume); 482 483 static struct platform_driver at91_rtc_driver = { 484 .remove = __exit_p(at91_rtc_remove), 485 .driver = { 486 .name = "at91_rtc", 487 .owner = THIS_MODULE, 488 .pm = &at91_rtc_pm_ops, 489 .of_match_table = of_match_ptr(at91_rtc_dt_ids), 490 }, 491 }; 492 493 module_platform_driver_probe(at91_rtc_driver, at91_rtc_probe); 494 495 MODULE_AUTHOR("Rick Bronson"); 496 MODULE_DESCRIPTION("RTC driver for Atmel AT91RM9200"); 497 MODULE_LICENSE("GPL"); 498 MODULE_ALIAS("platform:at91_rtc"); 499