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 #endif 40 41 #define RTC_DEF_DIVIDER (32768 - 1) 42 #define RTC_DEF_TRIM 0 43 44 static const unsigned long RTC_FREQ = 1024; 45 static struct rtc_time rtc_alarm; 46 static DEFINE_SPINLOCK(sa1100_rtc_lock); 47 48 static inline int rtc_periodic_alarm(struct rtc_time *tm) 49 { 50 return (tm->tm_year == -1) || 51 ((unsigned)tm->tm_mon >= 12) || 52 ((unsigned)(tm->tm_mday - 1) >= 31) || 53 ((unsigned)tm->tm_hour > 23) || 54 ((unsigned)tm->tm_min > 59) || 55 ((unsigned)tm->tm_sec > 59); 56 } 57 58 /* 59 * Calculate the next alarm time given the requested alarm time mask 60 * and the current time. 61 */ 62 static void rtc_next_alarm_time(struct rtc_time *next, struct rtc_time *now, 63 struct rtc_time *alrm) 64 { 65 unsigned long next_time; 66 unsigned long now_time; 67 68 next->tm_year = now->tm_year; 69 next->tm_mon = now->tm_mon; 70 next->tm_mday = now->tm_mday; 71 next->tm_hour = alrm->tm_hour; 72 next->tm_min = alrm->tm_min; 73 next->tm_sec = alrm->tm_sec; 74 75 rtc_tm_to_time(now, &now_time); 76 rtc_tm_to_time(next, &next_time); 77 78 if (next_time < now_time) { 79 /* Advance one day */ 80 next_time += 60 * 60 * 24; 81 rtc_time_to_tm(next_time, next); 82 } 83 } 84 85 static int rtc_update_alarm(struct rtc_time *alrm) 86 { 87 struct rtc_time alarm_tm, now_tm; 88 unsigned long now, time; 89 int ret; 90 91 do { 92 now = RCNR; 93 rtc_time_to_tm(now, &now_tm); 94 rtc_next_alarm_time(&alarm_tm, &now_tm, alrm); 95 ret = rtc_tm_to_time(&alarm_tm, &time); 96 if (ret != 0) 97 break; 98 99 RTSR = RTSR & (RTSR_HZE|RTSR_ALE|RTSR_AL); 100 RTAR = time; 101 } while (now != RCNR); 102 103 return ret; 104 } 105 106 static irqreturn_t sa1100_rtc_interrupt(int irq, void *dev_id) 107 { 108 struct platform_device *pdev = to_platform_device(dev_id); 109 struct rtc_device *rtc = platform_get_drvdata(pdev); 110 unsigned int rtsr; 111 unsigned long events = 0; 112 113 spin_lock(&sa1100_rtc_lock); 114 115 rtsr = RTSR; 116 /* clear interrupt sources */ 117 RTSR = 0; 118 /* Fix for a nasty initialization problem the in SA11xx RTSR register. 119 * See also the comments in sa1100_rtc_probe(). */ 120 if (rtsr & (RTSR_ALE | RTSR_HZE)) { 121 /* This is the original code, before there was the if test 122 * above. This code does not clear interrupts that were not 123 * enabled. */ 124 RTSR = (RTSR_AL | RTSR_HZ) & (rtsr >> 2); 125 } else { 126 /* For some reason, it is possible to enter this routine 127 * without interruptions enabled, it has been tested with 128 * several units (Bug in SA11xx chip?). 129 * 130 * This situation leads to an infinite "loop" of interrupt 131 * routine calling and as a result the processor seems to 132 * lock on its first call to open(). */ 133 RTSR = RTSR_AL | RTSR_HZ; 134 } 135 136 /* clear alarm interrupt if it has occurred */ 137 if (rtsr & RTSR_AL) 138 rtsr &= ~RTSR_ALE; 139 RTSR = rtsr & (RTSR_ALE | RTSR_HZE); 140 141 /* update irq data & counter */ 142 if (rtsr & RTSR_AL) 143 events |= RTC_AF | RTC_IRQF; 144 if (rtsr & RTSR_HZ) 145 events |= RTC_UF | RTC_IRQF; 146 147 rtc_update_irq(rtc, 1, events); 148 149 if (rtsr & RTSR_AL && rtc_periodic_alarm(&rtc_alarm)) 150 rtc_update_alarm(&rtc_alarm); 151 152 spin_unlock(&sa1100_rtc_lock); 153 154 return IRQ_HANDLED; 155 } 156 157 static int sa1100_rtc_open(struct device *dev) 158 { 159 int ret; 160 struct platform_device *plat_dev = to_platform_device(dev); 161 struct rtc_device *rtc = platform_get_drvdata(plat_dev); 162 163 ret = request_irq(IRQ_RTC1Hz, sa1100_rtc_interrupt, IRQF_DISABLED, 164 "rtc 1Hz", dev); 165 if (ret) { 166 dev_err(dev, "IRQ %d already in use.\n", IRQ_RTC1Hz); 167 goto fail_ui; 168 } 169 ret = request_irq(IRQ_RTCAlrm, sa1100_rtc_interrupt, IRQF_DISABLED, 170 "rtc Alrm", dev); 171 if (ret) { 172 dev_err(dev, "IRQ %d already in use.\n", IRQ_RTCAlrm); 173 goto fail_ai; 174 } 175 rtc->max_user_freq = RTC_FREQ; 176 rtc_irq_set_freq(rtc, NULL, RTC_FREQ); 177 178 return 0; 179 180 fail_ai: 181 free_irq(IRQ_RTC1Hz, dev); 182 fail_ui: 183 return ret; 184 } 185 186 static void sa1100_rtc_release(struct device *dev) 187 { 188 spin_lock_irq(&sa1100_rtc_lock); 189 RTSR = 0; 190 spin_unlock_irq(&sa1100_rtc_lock); 191 192 free_irq(IRQ_RTCAlrm, dev); 193 free_irq(IRQ_RTC1Hz, dev); 194 } 195 196 static int sa1100_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) 197 { 198 spin_lock_irq(&sa1100_rtc_lock); 199 if (enabled) 200 RTSR |= RTSR_ALE; 201 else 202 RTSR &= ~RTSR_ALE; 203 spin_unlock_irq(&sa1100_rtc_lock); 204 return 0; 205 } 206 207 static int sa1100_rtc_read_time(struct device *dev, struct rtc_time *tm) 208 { 209 rtc_time_to_tm(RCNR, tm); 210 return 0; 211 } 212 213 static int sa1100_rtc_set_time(struct device *dev, struct rtc_time *tm) 214 { 215 unsigned long time; 216 int ret; 217 218 ret = rtc_tm_to_time(tm, &time); 219 if (ret == 0) 220 RCNR = time; 221 return ret; 222 } 223 224 static int sa1100_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) 225 { 226 u32 rtsr; 227 228 memcpy(&alrm->time, &rtc_alarm, sizeof(struct rtc_time)); 229 rtsr = RTSR; 230 alrm->enabled = (rtsr & RTSR_ALE) ? 1 : 0; 231 alrm->pending = (rtsr & RTSR_AL) ? 1 : 0; 232 return 0; 233 } 234 235 static int sa1100_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) 236 { 237 int ret; 238 239 spin_lock_irq(&sa1100_rtc_lock); 240 ret = rtc_update_alarm(&alrm->time); 241 if (ret == 0) { 242 if (alrm->enabled) 243 RTSR |= RTSR_ALE; 244 else 245 RTSR &= ~RTSR_ALE; 246 } 247 spin_unlock_irq(&sa1100_rtc_lock); 248 249 return ret; 250 } 251 252 static int sa1100_rtc_proc(struct device *dev, struct seq_file *seq) 253 { 254 seq_printf(seq, "trim/divider\t\t: 0x%08x\n", (u32) RTTR); 255 seq_printf(seq, "RTSR\t\t\t: 0x%08x\n", (u32)RTSR); 256 257 return 0; 258 } 259 260 static const struct rtc_class_ops sa1100_rtc_ops = { 261 .open = sa1100_rtc_open, 262 .release = sa1100_rtc_release, 263 .read_time = sa1100_rtc_read_time, 264 .set_time = sa1100_rtc_set_time, 265 .read_alarm = sa1100_rtc_read_alarm, 266 .set_alarm = sa1100_rtc_set_alarm, 267 .proc = sa1100_rtc_proc, 268 .alarm_irq_enable = sa1100_rtc_alarm_irq_enable, 269 }; 270 271 static int sa1100_rtc_probe(struct platform_device *pdev) 272 { 273 struct rtc_device *rtc; 274 275 /* 276 * According to the manual we should be able to let RTTR be zero 277 * and then a default diviser for a 32.768KHz clock is used. 278 * Apparently this doesn't work, at least for my SA1110 rev 5. 279 * If the clock divider is uninitialized then reset it to the 280 * default value to get the 1Hz clock. 281 */ 282 if (RTTR == 0) { 283 RTTR = RTC_DEF_DIVIDER + (RTC_DEF_TRIM << 16); 284 dev_warn(&pdev->dev, "warning: " 285 "initializing default clock divider/trim value\n"); 286 /* The current RTC value probably doesn't make sense either */ 287 RCNR = 0; 288 } 289 290 device_init_wakeup(&pdev->dev, 1); 291 292 rtc = rtc_device_register(pdev->name, &pdev->dev, &sa1100_rtc_ops, 293 THIS_MODULE); 294 295 if (IS_ERR(rtc)) 296 return PTR_ERR(rtc); 297 298 platform_set_drvdata(pdev, rtc); 299 300 /* Fix for a nasty initialization problem the in SA11xx RTSR register. 301 * See also the comments in sa1100_rtc_interrupt(). 302 * 303 * Sometimes bit 1 of the RTSR (RTSR_HZ) will wake up 1, which means an 304 * interrupt pending, even though interrupts were never enabled. 305 * In this case, this bit it must be reset before enabling 306 * interruptions to avoid a nonexistent interrupt to occur. 307 * 308 * In principle, the same problem would apply to bit 0, although it has 309 * never been observed to happen. 310 * 311 * This issue is addressed both here and in sa1100_rtc_interrupt(). 312 * If the issue is not addressed here, in the times when the processor 313 * wakes up with the bit set there will be one spurious interrupt. 314 * 315 * The issue is also dealt with in sa1100_rtc_interrupt() to be on the 316 * safe side, once the condition that lead to this strange 317 * initialization is unknown and could in principle happen during 318 * normal processing. 319 * 320 * Notice that clearing bit 1 and 0 is accomplished by writting ONES to 321 * the corresponding bits in RTSR. */ 322 RTSR = RTSR_AL | RTSR_HZ; 323 324 return 0; 325 } 326 327 static int sa1100_rtc_remove(struct platform_device *pdev) 328 { 329 struct rtc_device *rtc = platform_get_drvdata(pdev); 330 331 if (rtc) 332 rtc_device_unregister(rtc); 333 334 return 0; 335 } 336 337 #ifdef CONFIG_PM 338 static int sa1100_rtc_suspend(struct device *dev) 339 { 340 if (device_may_wakeup(dev)) 341 enable_irq_wake(IRQ_RTCAlrm); 342 return 0; 343 } 344 345 static int sa1100_rtc_resume(struct device *dev) 346 { 347 if (device_may_wakeup(dev)) 348 disable_irq_wake(IRQ_RTCAlrm); 349 return 0; 350 } 351 352 static const struct dev_pm_ops sa1100_rtc_pm_ops = { 353 .suspend = sa1100_rtc_suspend, 354 .resume = sa1100_rtc_resume, 355 }; 356 #endif 357 358 static struct platform_driver sa1100_rtc_driver = { 359 .probe = sa1100_rtc_probe, 360 .remove = sa1100_rtc_remove, 361 .driver = { 362 .name = "sa1100-rtc", 363 #ifdef CONFIG_PM 364 .pm = &sa1100_rtc_pm_ops, 365 #endif 366 }, 367 }; 368 369 module_platform_driver(sa1100_rtc_driver); 370 371 MODULE_AUTHOR("Richard Purdie <rpurdie@rpsys.net>"); 372 MODULE_DESCRIPTION("SA11x0/PXA2xx Realtime Clock Driver (RTC)"); 373 MODULE_LICENSE("GPL"); 374 MODULE_ALIAS("platform:sa1100-rtc"); 375