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@cam.org> 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 33 #include <asm/bitops.h> 34 #include <asm/hardware.h> 35 #include <asm/irq.h> 36 #include <asm/rtc.h> 37 38 #ifdef CONFIG_ARCH_PXA 39 #include <asm/arch/pxa-regs.h> 40 #endif 41 42 #define TIMER_FREQ CLOCK_TICK_RATE 43 #define RTC_DEF_DIVIDER 32768 - 1 44 #define RTC_DEF_TRIM 0 45 46 static unsigned long rtc_freq = 1024; 47 static struct rtc_time rtc_alarm; 48 static spinlock_t sa1100_rtc_lock = SPIN_LOCK_UNLOCKED; 49 50 static int rtc_update_alarm(struct rtc_time *alrm) 51 { 52 struct rtc_time alarm_tm, now_tm; 53 unsigned long now, time; 54 int ret; 55 56 do { 57 now = RCNR; 58 rtc_time_to_tm(now, &now_tm); 59 rtc_next_alarm_time(&alarm_tm, &now_tm, alrm); 60 ret = rtc_tm_to_time(&alarm_tm, &time); 61 if (ret != 0) 62 break; 63 64 RTSR = RTSR & (RTSR_HZE|RTSR_ALE|RTSR_AL); 65 RTAR = time; 66 } while (now != RCNR); 67 68 return ret; 69 } 70 71 static irqreturn_t sa1100_rtc_interrupt(int irq, void *dev_id, 72 struct pt_regs *regs) 73 { 74 struct platform_device *pdev = to_platform_device(dev_id); 75 struct rtc_device *rtc = platform_get_drvdata(pdev); 76 unsigned int rtsr; 77 unsigned long events = 0; 78 79 spin_lock(&sa1100_rtc_lock); 80 81 rtsr = RTSR; 82 /* clear interrupt sources */ 83 RTSR = 0; 84 RTSR = (RTSR_AL | RTSR_HZ) & (rtsr >> 2); 85 86 /* clear alarm interrupt if it has occurred */ 87 if (rtsr & RTSR_AL) 88 rtsr &= ~RTSR_ALE; 89 RTSR = rtsr & (RTSR_ALE | RTSR_HZE); 90 91 /* update irq data & counter */ 92 if (rtsr & RTSR_AL) 93 events |= RTC_AF | RTC_IRQF; 94 if (rtsr & RTSR_HZ) 95 events |= RTC_UF | RTC_IRQF; 96 97 rtc_update_irq(&rtc->class_dev, 1, events); 98 99 if (rtsr & RTSR_AL && rtc_periodic_alarm(&rtc_alarm)) 100 rtc_update_alarm(&rtc_alarm); 101 102 spin_unlock(&sa1100_rtc_lock); 103 104 return IRQ_HANDLED; 105 } 106 107 static int rtc_timer1_count; 108 109 static irqreturn_t timer1_interrupt(int irq, void *dev_id, 110 struct pt_regs *regs) 111 { 112 struct platform_device *pdev = to_platform_device(dev_id); 113 struct rtc_device *rtc = platform_get_drvdata(pdev); 114 115 /* 116 * If we match for the first time, rtc_timer1_count will be 1. 117 * Otherwise, we wrapped around (very unlikely but 118 * still possible) so compute the amount of missed periods. 119 * The match reg is updated only when the data is actually retrieved 120 * to avoid unnecessary interrupts. 121 */ 122 OSSR = OSSR_M1; /* clear match on timer1 */ 123 124 rtc_update_irq(&rtc->class_dev, rtc_timer1_count, RTC_PF | RTC_IRQF); 125 126 if (rtc_timer1_count == 1) 127 rtc_timer1_count = (rtc_freq * ((1<<30)/(TIMER_FREQ>>2))); 128 129 return IRQ_HANDLED; 130 } 131 132 static int sa1100_rtc_read_callback(struct device *dev, int data) 133 { 134 if (data & RTC_PF) { 135 /* interpolate missed periods and set match for the next */ 136 unsigned long period = TIMER_FREQ/rtc_freq; 137 unsigned long oscr = OSCR; 138 unsigned long osmr1 = OSMR1; 139 unsigned long missed = (oscr - osmr1)/period; 140 data += missed << 8; 141 OSSR = OSSR_M1; /* clear match on timer 1 */ 142 OSMR1 = osmr1 + (missed + 1)*period; 143 /* Ensure we didn't miss another match in the mean time. 144 * Here we compare (match - OSCR) 8 instead of 0 -- 145 * see comment in pxa_timer_interrupt() for explanation. 146 */ 147 while( (signed long)((osmr1 = OSMR1) - OSCR) <= 8 ) { 148 data += 0x100; 149 OSSR = OSSR_M1; /* clear match on timer 1 */ 150 OSMR1 = osmr1 + period; 151 } 152 } 153 return data; 154 } 155 156 static int sa1100_rtc_open(struct device *dev) 157 { 158 int ret; 159 160 ret = request_irq(IRQ_RTC1Hz, sa1100_rtc_interrupt, SA_INTERRUPT, 161 "rtc 1Hz", dev); 162 if (ret) { 163 dev_err(dev, "IRQ %d already in use.\n", IRQ_RTC1Hz); 164 goto fail_ui; 165 } 166 ret = request_irq(IRQ_RTCAlrm, sa1100_rtc_interrupt, SA_INTERRUPT, 167 "rtc Alrm", dev); 168 if (ret) { 169 dev_err(dev, "IRQ %d already in use.\n", IRQ_RTCAlrm); 170 goto fail_ai; 171 } 172 ret = request_irq(IRQ_OST1, timer1_interrupt, SA_INTERRUPT, 173 "rtc timer", dev); 174 if (ret) { 175 dev_err(dev, "IRQ %d already in use.\n", IRQ_OST1); 176 goto fail_pi; 177 } 178 return 0; 179 180 fail_pi: 181 free_irq(IRQ_RTCAlrm, dev); 182 fail_ai: 183 free_irq(IRQ_RTC1Hz, dev); 184 fail_ui: 185 return ret; 186 } 187 188 static void sa1100_rtc_release(struct device *dev) 189 { 190 spin_lock_irq(&sa1100_rtc_lock); 191 RTSR = 0; 192 OIER &= ~OIER_E1; 193 OSSR = OSSR_M1; 194 spin_unlock_irq(&sa1100_rtc_lock); 195 196 free_irq(IRQ_OST1, dev); 197 free_irq(IRQ_RTCAlrm, dev); 198 free_irq(IRQ_RTC1Hz, dev); 199 } 200 201 202 static int sa1100_rtc_ioctl(struct device *dev, unsigned int cmd, 203 unsigned long arg) 204 { 205 switch(cmd) { 206 case RTC_AIE_OFF: 207 spin_lock_irq(&sa1100_rtc_lock); 208 RTSR &= ~RTSR_ALE; 209 spin_unlock_irq(&sa1100_rtc_lock); 210 return 0; 211 case RTC_AIE_ON: 212 spin_lock_irq(&sa1100_rtc_lock); 213 RTSR |= RTSR_ALE; 214 spin_unlock_irq(&sa1100_rtc_lock); 215 return 0; 216 case RTC_UIE_OFF: 217 spin_lock_irq(&sa1100_rtc_lock); 218 RTSR &= ~RTSR_HZE; 219 spin_unlock_irq(&sa1100_rtc_lock); 220 return 0; 221 case RTC_UIE_ON: 222 spin_lock_irq(&sa1100_rtc_lock); 223 RTSR |= RTSR_HZE; 224 spin_unlock_irq(&sa1100_rtc_lock); 225 return 0; 226 case RTC_PIE_OFF: 227 spin_lock_irq(&sa1100_rtc_lock); 228 OIER &= ~OIER_E1; 229 spin_unlock_irq(&sa1100_rtc_lock); 230 return 0; 231 case RTC_PIE_ON: 232 if ((rtc_freq > 64) && !capable(CAP_SYS_RESOURCE)) 233 return -EACCES; 234 spin_lock_irq(&sa1100_rtc_lock); 235 OSMR1 = TIMER_FREQ/rtc_freq + OSCR; 236 OIER |= OIER_E1; 237 rtc_timer1_count = 1; 238 spin_unlock_irq(&sa1100_rtc_lock); 239 return 0; 240 case RTC_IRQP_READ: 241 return put_user(rtc_freq, (unsigned long *)arg); 242 case RTC_IRQP_SET: 243 if (arg < 1 || arg > TIMER_FREQ) 244 return -EINVAL; 245 if ((arg > 64) && (!capable(CAP_SYS_RESOURCE))) 246 return -EACCES; 247 rtc_freq = arg; 248 return 0; 249 } 250 return -ENOIOCTLCMD; 251 } 252 253 static int sa1100_rtc_read_time(struct device *dev, struct rtc_time *tm) 254 { 255 rtc_time_to_tm(RCNR, tm); 256 return 0; 257 } 258 259 static int sa1100_rtc_set_time(struct device *dev, struct rtc_time *tm) 260 { 261 unsigned long time; 262 int ret; 263 264 ret = rtc_tm_to_time(tm, &time); 265 if (ret == 0) 266 RCNR = time; 267 return ret; 268 } 269 270 static int sa1100_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) 271 { 272 memcpy(&alrm->time, &rtc_alarm, sizeof(struct rtc_time)); 273 alrm->pending = RTSR & RTSR_AL ? 1 : 0; 274 return 0; 275 } 276 277 static int sa1100_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) 278 { 279 int ret; 280 281 spin_lock_irq(&sa1100_rtc_lock); 282 ret = rtc_update_alarm(&alrm->time); 283 if (ret == 0) { 284 memcpy(&rtc_alarm, &alrm->time, sizeof(struct rtc_time)); 285 286 if (alrm->enabled) 287 enable_irq_wake(IRQ_RTCAlrm); 288 else 289 disable_irq_wake(IRQ_RTCAlrm); 290 } 291 spin_unlock_irq(&sa1100_rtc_lock); 292 293 return ret; 294 } 295 296 static int sa1100_rtc_proc(struct device *dev, struct seq_file *seq) 297 { 298 seq_printf(seq, "trim/divider\t: 0x%08lx\n", RTTR); 299 seq_printf(seq, "alarm_IRQ\t: %s\n", 300 (RTSR & RTSR_ALE) ? "yes" : "no" ); 301 seq_printf(seq, "update_IRQ\t: %s\n", 302 (RTSR & RTSR_HZE) ? "yes" : "no"); 303 seq_printf(seq, "periodic_IRQ\t: %s\n", 304 (OIER & OIER_E1) ? "yes" : "no"); 305 seq_printf(seq, "periodic_freq\t: %ld\n", rtc_freq); 306 307 return 0; 308 } 309 310 static struct rtc_class_ops sa1100_rtc_ops = { 311 .open = sa1100_rtc_open, 312 .read_callback = sa1100_rtc_read_callback, 313 .release = sa1100_rtc_release, 314 .ioctl = sa1100_rtc_ioctl, 315 .read_time = sa1100_rtc_read_time, 316 .set_time = sa1100_rtc_set_time, 317 .read_alarm = sa1100_rtc_read_alarm, 318 .set_alarm = sa1100_rtc_set_alarm, 319 .proc = sa1100_rtc_proc, 320 }; 321 322 static int sa1100_rtc_probe(struct platform_device *pdev) 323 { 324 struct rtc_device *rtc; 325 326 /* 327 * According to the manual we should be able to let RTTR be zero 328 * and then a default diviser for a 32.768KHz clock is used. 329 * Apparently this doesn't work, at least for my SA1110 rev 5. 330 * If the clock divider is uninitialized then reset it to the 331 * default value to get the 1Hz clock. 332 */ 333 if (RTTR == 0) { 334 RTTR = RTC_DEF_DIVIDER + (RTC_DEF_TRIM << 16); 335 dev_warn(&pdev->dev, "warning: initializing default clock divider/trim value\n"); 336 /* The current RTC value probably doesn't make sense either */ 337 RCNR = 0; 338 } 339 340 rtc = rtc_device_register(pdev->name, &pdev->dev, &sa1100_rtc_ops, 341 THIS_MODULE); 342 343 if (IS_ERR(rtc)) 344 return PTR_ERR(rtc); 345 346 platform_set_drvdata(pdev, rtc); 347 348 return 0; 349 } 350 351 static int sa1100_rtc_remove(struct platform_device *pdev) 352 { 353 struct rtc_device *rtc = platform_get_drvdata(pdev); 354 355 if (rtc) 356 rtc_device_unregister(rtc); 357 358 return 0; 359 } 360 361 static struct platform_driver sa1100_rtc_driver = { 362 .probe = sa1100_rtc_probe, 363 .remove = sa1100_rtc_remove, 364 .driver = { 365 .name = "sa1100-rtc", 366 }, 367 }; 368 369 static int __init sa1100_rtc_init(void) 370 { 371 return platform_driver_register(&sa1100_rtc_driver); 372 } 373 374 static void __exit sa1100_rtc_exit(void) 375 { 376 platform_driver_unregister(&sa1100_rtc_driver); 377 } 378 379 module_init(sa1100_rtc_init); 380 module_exit(sa1100_rtc_exit); 381 382 MODULE_AUTHOR("Richard Purdie <rpurdie@rpsys.net>"); 383 MODULE_DESCRIPTION("SA11x0/PXA2xx Realtime Clock Driver (RTC)"); 384 MODULE_LICENSE("GPL"); 385