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/clk.h> 27 #include <linux/rtc.h> 28 #include <linux/init.h> 29 #include <linux/fs.h> 30 #include <linux/interrupt.h> 31 #include <linux/slab.h> 32 #include <linux/string.h> 33 #include <linux/of.h> 34 #include <linux/pm.h> 35 #include <linux/bitops.h> 36 #include <linux/io.h> 37 38 #include <mach/hardware.h> 39 #include <mach/irqs.h> 40 41 #if defined(CONFIG_ARCH_PXA) || defined(CONFIG_ARCH_MMP) 42 #include <mach/regs-rtc.h> 43 #endif 44 45 #define RTC_DEF_DIVIDER (32768 - 1) 46 #define RTC_DEF_TRIM 0 47 #define RTC_FREQ 1024 48 49 struct sa1100_rtc { 50 spinlock_t lock; 51 int irq_1hz; 52 int irq_alarm; 53 struct rtc_device *rtc; 54 struct clk *clk; 55 }; 56 57 static irqreturn_t sa1100_rtc_interrupt(int irq, void *dev_id) 58 { 59 struct sa1100_rtc *info = dev_get_drvdata(dev_id); 60 struct rtc_device *rtc = info->rtc; 61 unsigned int rtsr; 62 unsigned long events = 0; 63 64 spin_lock(&info->lock); 65 66 rtsr = RTSR; 67 /* clear interrupt sources */ 68 RTSR = 0; 69 /* Fix for a nasty initialization problem the in SA11xx RTSR register. 70 * See also the comments in sa1100_rtc_probe(). */ 71 if (rtsr & (RTSR_ALE | RTSR_HZE)) { 72 /* This is the original code, before there was the if test 73 * above. This code does not clear interrupts that were not 74 * enabled. */ 75 RTSR = (RTSR_AL | RTSR_HZ) & (rtsr >> 2); 76 } else { 77 /* For some reason, it is possible to enter this routine 78 * without interruptions enabled, it has been tested with 79 * several units (Bug in SA11xx chip?). 80 * 81 * This situation leads to an infinite "loop" of interrupt 82 * routine calling and as a result the processor seems to 83 * lock on its first call to open(). */ 84 RTSR = RTSR_AL | RTSR_HZ; 85 } 86 87 /* clear alarm interrupt if it has occurred */ 88 if (rtsr & RTSR_AL) 89 rtsr &= ~RTSR_ALE; 90 RTSR = rtsr & (RTSR_ALE | RTSR_HZE); 91 92 /* update irq data & counter */ 93 if (rtsr & RTSR_AL) 94 events |= RTC_AF | RTC_IRQF; 95 if (rtsr & RTSR_HZ) 96 events |= RTC_UF | RTC_IRQF; 97 98 rtc_update_irq(rtc, 1, events); 99 100 spin_unlock(&info->lock); 101 102 return IRQ_HANDLED; 103 } 104 105 static int sa1100_rtc_open(struct device *dev) 106 { 107 struct sa1100_rtc *info = dev_get_drvdata(dev); 108 struct rtc_device *rtc = info->rtc; 109 int ret; 110 111 ret = request_irq(info->irq_1hz, sa1100_rtc_interrupt, 0, "rtc 1Hz", dev); 112 if (ret) { 113 dev_err(dev, "IRQ %d already in use.\n", info->irq_1hz); 114 goto fail_ui; 115 } 116 ret = request_irq(info->irq_alarm, sa1100_rtc_interrupt, 0, "rtc Alrm", dev); 117 if (ret) { 118 dev_err(dev, "IRQ %d already in use.\n", info->irq_alarm); 119 goto fail_ai; 120 } 121 rtc->max_user_freq = RTC_FREQ; 122 rtc_irq_set_freq(rtc, NULL, RTC_FREQ); 123 124 return 0; 125 126 fail_ai: 127 free_irq(info->irq_1hz, dev); 128 fail_ui: 129 clk_disable_unprepare(info->clk); 130 return ret; 131 } 132 133 static void sa1100_rtc_release(struct device *dev) 134 { 135 struct sa1100_rtc *info = dev_get_drvdata(dev); 136 137 spin_lock_irq(&info->lock); 138 RTSR = 0; 139 spin_unlock_irq(&info->lock); 140 141 free_irq(info->irq_alarm, dev); 142 free_irq(info->irq_1hz, dev); 143 } 144 145 static int sa1100_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) 146 { 147 struct sa1100_rtc *info = dev_get_drvdata(dev); 148 149 spin_lock_irq(&info->lock); 150 if (enabled) 151 RTSR |= RTSR_ALE; 152 else 153 RTSR &= ~RTSR_ALE; 154 spin_unlock_irq(&info->lock); 155 return 0; 156 } 157 158 static int sa1100_rtc_read_time(struct device *dev, struct rtc_time *tm) 159 { 160 rtc_time_to_tm(RCNR, tm); 161 return 0; 162 } 163 164 static int sa1100_rtc_set_time(struct device *dev, struct rtc_time *tm) 165 { 166 unsigned long time; 167 int ret; 168 169 ret = rtc_tm_to_time(tm, &time); 170 if (ret == 0) 171 RCNR = time; 172 return ret; 173 } 174 175 static int sa1100_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) 176 { 177 u32 rtsr; 178 179 rtsr = RTSR; 180 alrm->enabled = (rtsr & RTSR_ALE) ? 1 : 0; 181 alrm->pending = (rtsr & RTSR_AL) ? 1 : 0; 182 return 0; 183 } 184 185 static int sa1100_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) 186 { 187 struct sa1100_rtc *info = dev_get_drvdata(dev); 188 unsigned long time; 189 int ret; 190 191 spin_lock_irq(&info->lock); 192 ret = rtc_tm_to_time(&alrm->time, &time); 193 if (ret != 0) 194 goto out; 195 RTSR = RTSR & (RTSR_HZE|RTSR_ALE|RTSR_AL); 196 RTAR = time; 197 if (alrm->enabled) 198 RTSR |= RTSR_ALE; 199 else 200 RTSR &= ~RTSR_ALE; 201 out: 202 spin_unlock_irq(&info->lock); 203 204 return ret; 205 } 206 207 static int sa1100_rtc_proc(struct device *dev, struct seq_file *seq) 208 { 209 seq_printf(seq, "trim/divider\t\t: 0x%08x\n", (u32) RTTR); 210 seq_printf(seq, "RTSR\t\t\t: 0x%08x\n", (u32)RTSR); 211 212 return 0; 213 } 214 215 static const struct rtc_class_ops sa1100_rtc_ops = { 216 .open = sa1100_rtc_open, 217 .release = sa1100_rtc_release, 218 .read_time = sa1100_rtc_read_time, 219 .set_time = sa1100_rtc_set_time, 220 .read_alarm = sa1100_rtc_read_alarm, 221 .set_alarm = sa1100_rtc_set_alarm, 222 .proc = sa1100_rtc_proc, 223 .alarm_irq_enable = sa1100_rtc_alarm_irq_enable, 224 }; 225 226 static int sa1100_rtc_probe(struct platform_device *pdev) 227 { 228 struct rtc_device *rtc; 229 struct sa1100_rtc *info; 230 int irq_1hz, irq_alarm, ret = 0; 231 232 irq_1hz = platform_get_irq_byname(pdev, "rtc 1Hz"); 233 irq_alarm = platform_get_irq_byname(pdev, "rtc alarm"); 234 if (irq_1hz < 0 || irq_alarm < 0) 235 return -ENODEV; 236 237 info = kzalloc(sizeof(struct sa1100_rtc), GFP_KERNEL); 238 if (!info) 239 return -ENOMEM; 240 info->clk = clk_get(&pdev->dev, NULL); 241 if (IS_ERR(info->clk)) { 242 dev_err(&pdev->dev, "failed to find rtc clock source\n"); 243 ret = PTR_ERR(info->clk); 244 goto err_clk; 245 } 246 info->irq_1hz = irq_1hz; 247 info->irq_alarm = irq_alarm; 248 spin_lock_init(&info->lock); 249 platform_set_drvdata(pdev, info); 250 251 ret = clk_prepare_enable(info->clk); 252 if (ret) 253 goto err_enable_clk; 254 /* 255 * According to the manual we should be able to let RTTR be zero 256 * and then a default diviser for a 32.768KHz clock is used. 257 * Apparently this doesn't work, at least for my SA1110 rev 5. 258 * If the clock divider is uninitialized then reset it to the 259 * default value to get the 1Hz clock. 260 */ 261 if (RTTR == 0) { 262 RTTR = RTC_DEF_DIVIDER + (RTC_DEF_TRIM << 16); 263 dev_warn(&pdev->dev, "warning: " 264 "initializing default clock divider/trim value\n"); 265 /* The current RTC value probably doesn't make sense either */ 266 RCNR = 0; 267 } 268 269 device_init_wakeup(&pdev->dev, 1); 270 271 rtc = rtc_device_register(pdev->name, &pdev->dev, &sa1100_rtc_ops, 272 THIS_MODULE); 273 274 if (IS_ERR(rtc)) { 275 ret = PTR_ERR(rtc); 276 goto err_dev; 277 } 278 info->rtc = rtc; 279 280 /* Fix for a nasty initialization problem the in SA11xx RTSR register. 281 * See also the comments in sa1100_rtc_interrupt(). 282 * 283 * Sometimes bit 1 of the RTSR (RTSR_HZ) will wake up 1, which means an 284 * interrupt pending, even though interrupts were never enabled. 285 * In this case, this bit it must be reset before enabling 286 * interruptions to avoid a nonexistent interrupt to occur. 287 * 288 * In principle, the same problem would apply to bit 0, although it has 289 * never been observed to happen. 290 * 291 * This issue is addressed both here and in sa1100_rtc_interrupt(). 292 * If the issue is not addressed here, in the times when the processor 293 * wakes up with the bit set there will be one spurious interrupt. 294 * 295 * The issue is also dealt with in sa1100_rtc_interrupt() to be on the 296 * safe side, once the condition that lead to this strange 297 * initialization is unknown and could in principle happen during 298 * normal processing. 299 * 300 * Notice that clearing bit 1 and 0 is accomplished by writting ONES to 301 * the corresponding bits in RTSR. */ 302 RTSR = RTSR_AL | RTSR_HZ; 303 304 return 0; 305 err_dev: 306 clk_disable_unprepare(info->clk); 307 err_enable_clk: 308 platform_set_drvdata(pdev, NULL); 309 clk_put(info->clk); 310 err_clk: 311 kfree(info); 312 return ret; 313 } 314 315 static int sa1100_rtc_remove(struct platform_device *pdev) 316 { 317 struct sa1100_rtc *info = platform_get_drvdata(pdev); 318 319 if (info) { 320 rtc_device_unregister(info->rtc); 321 clk_disable_unprepare(info->clk); 322 clk_put(info->clk); 323 platform_set_drvdata(pdev, NULL); 324 kfree(info); 325 } 326 327 return 0; 328 } 329 330 #ifdef CONFIG_PM 331 static int sa1100_rtc_suspend(struct device *dev) 332 { 333 struct sa1100_rtc *info = dev_get_drvdata(dev); 334 if (device_may_wakeup(dev)) 335 enable_irq_wake(info->irq_alarm); 336 return 0; 337 } 338 339 static int sa1100_rtc_resume(struct device *dev) 340 { 341 struct sa1100_rtc *info = dev_get_drvdata(dev); 342 if (device_may_wakeup(dev)) 343 disable_irq_wake(info->irq_alarm); 344 return 0; 345 } 346 347 static const struct dev_pm_ops sa1100_rtc_pm_ops = { 348 .suspend = sa1100_rtc_suspend, 349 .resume = sa1100_rtc_resume, 350 }; 351 #endif 352 353 #ifdef CONFIG_OF 354 static struct of_device_id sa1100_rtc_dt_ids[] = { 355 { .compatible = "mrvl,sa1100-rtc", }, 356 { .compatible = "mrvl,mmp-rtc", }, 357 {} 358 }; 359 MODULE_DEVICE_TABLE(of, sa1100_rtc_dt_ids); 360 #endif 361 362 static struct platform_driver sa1100_rtc_driver = { 363 .probe = sa1100_rtc_probe, 364 .remove = sa1100_rtc_remove, 365 .driver = { 366 .name = "sa1100-rtc", 367 #ifdef CONFIG_PM 368 .pm = &sa1100_rtc_pm_ops, 369 #endif 370 .of_match_table = of_match_ptr(sa1100_rtc_dt_ids), 371 }, 372 }; 373 374 module_platform_driver(sa1100_rtc_driver); 375 376 MODULE_AUTHOR("Richard Purdie <rpurdie@rpsys.net>"); 377 MODULE_DESCRIPTION("SA11x0/PXA2xx Realtime Clock Driver (RTC)"); 378 MODULE_LICENSE("GPL"); 379 MODULE_ALIAS("platform:sa1100-rtc"); 380