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