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 #define RTSR_HZE BIT(3) /* HZ interrupt enable */ 39 #define RTSR_ALE BIT(2) /* RTC alarm interrupt enable */ 40 #define RTSR_HZ BIT(1) /* HZ rising-edge detected */ 41 #define RTSR_AL BIT(0) /* RTC alarm detected */ 42 43 #include "rtc-sa1100.h" 44 45 #define RTC_DEF_DIVIDER (32768 - 1) 46 #define RTC_DEF_TRIM 0 47 #define RTC_FREQ 1024 48 49 50 static irqreturn_t sa1100_rtc_interrupt(int irq, void *dev_id) 51 { 52 struct sa1100_rtc *info = dev_get_drvdata(dev_id); 53 struct rtc_device *rtc = info->rtc; 54 unsigned int rtsr; 55 unsigned long events = 0; 56 57 spin_lock(&info->lock); 58 59 rtsr = readl_relaxed(info->rtsr); 60 /* clear interrupt sources */ 61 writel_relaxed(0, info->rtsr); 62 /* Fix for a nasty initialization problem the in SA11xx RTSR register. 63 * See also the comments in sa1100_rtc_probe(). */ 64 if (rtsr & (RTSR_ALE | RTSR_HZE)) { 65 /* This is the original code, before there was the if test 66 * above. This code does not clear interrupts that were not 67 * enabled. */ 68 writel_relaxed((RTSR_AL | RTSR_HZ) & (rtsr >> 2), info->rtsr); 69 } else { 70 /* For some reason, it is possible to enter this routine 71 * without interruptions enabled, it has been tested with 72 * several units (Bug in SA11xx chip?). 73 * 74 * This situation leads to an infinite "loop" of interrupt 75 * routine calling and as a result the processor seems to 76 * lock on its first call to open(). */ 77 writel_relaxed(RTSR_AL | RTSR_HZ, info->rtsr); 78 } 79 80 /* clear alarm interrupt if it has occurred */ 81 if (rtsr & RTSR_AL) 82 rtsr &= ~RTSR_ALE; 83 writel_relaxed(rtsr & (RTSR_ALE | RTSR_HZE), info->rtsr); 84 85 /* update irq data & counter */ 86 if (rtsr & RTSR_AL) 87 events |= RTC_AF | RTC_IRQF; 88 if (rtsr & RTSR_HZ) 89 events |= RTC_UF | RTC_IRQF; 90 91 rtc_update_irq(rtc, 1, events); 92 93 spin_unlock(&info->lock); 94 95 return IRQ_HANDLED; 96 } 97 98 static int sa1100_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) 99 { 100 u32 rtsr; 101 struct sa1100_rtc *info = dev_get_drvdata(dev); 102 103 spin_lock_irq(&info->lock); 104 rtsr = readl_relaxed(info->rtsr); 105 if (enabled) 106 rtsr |= RTSR_ALE; 107 else 108 rtsr &= ~RTSR_ALE; 109 writel_relaxed(rtsr, info->rtsr); 110 spin_unlock_irq(&info->lock); 111 return 0; 112 } 113 114 static int sa1100_rtc_read_time(struct device *dev, struct rtc_time *tm) 115 { 116 struct sa1100_rtc *info = dev_get_drvdata(dev); 117 118 rtc_time_to_tm(readl_relaxed(info->rcnr), tm); 119 return 0; 120 } 121 122 static int sa1100_rtc_set_time(struct device *dev, struct rtc_time *tm) 123 { 124 struct sa1100_rtc *info = dev_get_drvdata(dev); 125 unsigned long time; 126 int ret; 127 128 ret = rtc_tm_to_time(tm, &time); 129 if (ret == 0) 130 writel_relaxed(time, info->rcnr); 131 return ret; 132 } 133 134 static int sa1100_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) 135 { 136 u32 rtsr; 137 struct sa1100_rtc *info = dev_get_drvdata(dev); 138 139 rtsr = readl_relaxed(info->rtsr); 140 alrm->enabled = (rtsr & RTSR_ALE) ? 1 : 0; 141 alrm->pending = (rtsr & RTSR_AL) ? 1 : 0; 142 return 0; 143 } 144 145 static int sa1100_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) 146 { 147 struct sa1100_rtc *info = dev_get_drvdata(dev); 148 unsigned long time; 149 int ret; 150 151 spin_lock_irq(&info->lock); 152 ret = rtc_tm_to_time(&alrm->time, &time); 153 if (ret != 0) 154 goto out; 155 writel_relaxed(readl_relaxed(info->rtsr) & 156 (RTSR_HZE | RTSR_ALE | RTSR_AL), info->rtsr); 157 writel_relaxed(time, info->rtar); 158 if (alrm->enabled) 159 writel_relaxed(readl_relaxed(info->rtsr) | RTSR_ALE, info->rtsr); 160 else 161 writel_relaxed(readl_relaxed(info->rtsr) & ~RTSR_ALE, info->rtsr); 162 out: 163 spin_unlock_irq(&info->lock); 164 165 return ret; 166 } 167 168 static int sa1100_rtc_proc(struct device *dev, struct seq_file *seq) 169 { 170 struct sa1100_rtc *info = dev_get_drvdata(dev); 171 172 seq_printf(seq, "trim/divider\t\t: 0x%08x\n", readl_relaxed(info->rttr)); 173 seq_printf(seq, "RTSR\t\t\t: 0x%08x\n", readl_relaxed(info->rtsr)); 174 175 return 0; 176 } 177 178 static const struct rtc_class_ops sa1100_rtc_ops = { 179 .read_time = sa1100_rtc_read_time, 180 .set_time = sa1100_rtc_set_time, 181 .read_alarm = sa1100_rtc_read_alarm, 182 .set_alarm = sa1100_rtc_set_alarm, 183 .proc = sa1100_rtc_proc, 184 .alarm_irq_enable = sa1100_rtc_alarm_irq_enable, 185 }; 186 187 int sa1100_rtc_init(struct platform_device *pdev, struct sa1100_rtc *info) 188 { 189 struct rtc_device *rtc; 190 int ret; 191 192 spin_lock_init(&info->lock); 193 194 info->clk = devm_clk_get(&pdev->dev, NULL); 195 if (IS_ERR(info->clk)) { 196 dev_err(&pdev->dev, "failed to find rtc clock source\n"); 197 return PTR_ERR(info->clk); 198 } 199 200 ret = clk_prepare_enable(info->clk); 201 if (ret) 202 return ret; 203 /* 204 * According to the manual we should be able to let RTTR be zero 205 * and then a default diviser for a 32.768KHz clock is used. 206 * Apparently this doesn't work, at least for my SA1110 rev 5. 207 * If the clock divider is uninitialized then reset it to the 208 * default value to get the 1Hz clock. 209 */ 210 if (readl_relaxed(info->rttr) == 0) { 211 writel_relaxed(RTC_DEF_DIVIDER + (RTC_DEF_TRIM << 16), info->rttr); 212 dev_warn(&pdev->dev, "warning: " 213 "initializing default clock divider/trim value\n"); 214 /* The current RTC value probably doesn't make sense either */ 215 writel_relaxed(0, info->rcnr); 216 } 217 218 rtc = devm_rtc_device_register(&pdev->dev, pdev->name, &sa1100_rtc_ops, 219 THIS_MODULE); 220 if (IS_ERR(rtc)) { 221 clk_disable_unprepare(info->clk); 222 return PTR_ERR(rtc); 223 } 224 info->rtc = rtc; 225 226 rtc->max_user_freq = RTC_FREQ; 227 rtc_irq_set_freq(rtc, NULL, RTC_FREQ); 228 229 /* Fix for a nasty initialization problem the in SA11xx RTSR register. 230 * See also the comments in sa1100_rtc_interrupt(). 231 * 232 * Sometimes bit 1 of the RTSR (RTSR_HZ) will wake up 1, which means an 233 * interrupt pending, even though interrupts were never enabled. 234 * In this case, this bit it must be reset before enabling 235 * interruptions to avoid a nonexistent interrupt to occur. 236 * 237 * In principle, the same problem would apply to bit 0, although it has 238 * never been observed to happen. 239 * 240 * This issue is addressed both here and in sa1100_rtc_interrupt(). 241 * If the issue is not addressed here, in the times when the processor 242 * wakes up with the bit set there will be one spurious interrupt. 243 * 244 * The issue is also dealt with in sa1100_rtc_interrupt() to be on the 245 * safe side, once the condition that lead to this strange 246 * initialization is unknown and could in principle happen during 247 * normal processing. 248 * 249 * Notice that clearing bit 1 and 0 is accomplished by writting ONES to 250 * the corresponding bits in RTSR. */ 251 writel_relaxed(RTSR_AL | RTSR_HZ, info->rtsr); 252 253 return 0; 254 } 255 EXPORT_SYMBOL_GPL(sa1100_rtc_init); 256 257 static int sa1100_rtc_probe(struct platform_device *pdev) 258 { 259 struct sa1100_rtc *info; 260 struct resource *iores; 261 void __iomem *base; 262 int irq_1hz, irq_alarm; 263 int ret; 264 265 irq_1hz = platform_get_irq_byname(pdev, "rtc 1Hz"); 266 irq_alarm = platform_get_irq_byname(pdev, "rtc alarm"); 267 if (irq_1hz < 0 || irq_alarm < 0) 268 return -ENODEV; 269 270 info = devm_kzalloc(&pdev->dev, sizeof(struct sa1100_rtc), GFP_KERNEL); 271 if (!info) 272 return -ENOMEM; 273 info->irq_1hz = irq_1hz; 274 info->irq_alarm = irq_alarm; 275 276 ret = devm_request_irq(&pdev->dev, irq_1hz, sa1100_rtc_interrupt, 0, 277 "rtc 1Hz", &pdev->dev); 278 if (ret) { 279 dev_err(&pdev->dev, "IRQ %d already in use.\n", irq_1hz); 280 return ret; 281 } 282 ret = devm_request_irq(&pdev->dev, irq_alarm, sa1100_rtc_interrupt, 0, 283 "rtc Alrm", &pdev->dev); 284 if (ret) { 285 dev_err(&pdev->dev, "IRQ %d already in use.\n", irq_alarm); 286 return ret; 287 } 288 289 iores = platform_get_resource(pdev, IORESOURCE_MEM, 0); 290 base = devm_ioremap_resource(&pdev->dev, iores); 291 if (IS_ERR(base)) 292 return PTR_ERR(base); 293 294 if (IS_ENABLED(CONFIG_ARCH_SA1100) || 295 of_device_is_compatible(pdev->dev.of_node, "mrvl,sa1100-rtc")) { 296 info->rcnr = base + 0x04; 297 info->rtsr = base + 0x10; 298 info->rtar = base + 0x00; 299 info->rttr = base + 0x08; 300 } else { 301 info->rcnr = base + 0x0; 302 info->rtsr = base + 0x8; 303 info->rtar = base + 0x4; 304 info->rttr = base + 0xc; 305 } 306 307 platform_set_drvdata(pdev, info); 308 device_init_wakeup(&pdev->dev, 1); 309 310 return sa1100_rtc_init(pdev, info); 311 } 312 313 static int sa1100_rtc_remove(struct platform_device *pdev) 314 { 315 struct sa1100_rtc *info = platform_get_drvdata(pdev); 316 317 if (info) { 318 spin_lock_irq(&info->lock); 319 writel_relaxed(0, info->rtsr); 320 spin_unlock_irq(&info->lock); 321 clk_disable_unprepare(info->clk); 322 } 323 324 return 0; 325 } 326 327 #ifdef CONFIG_PM_SLEEP 328 static int sa1100_rtc_suspend(struct device *dev) 329 { 330 struct sa1100_rtc *info = dev_get_drvdata(dev); 331 if (device_may_wakeup(dev)) 332 enable_irq_wake(info->irq_alarm); 333 return 0; 334 } 335 336 static int sa1100_rtc_resume(struct device *dev) 337 { 338 struct sa1100_rtc *info = dev_get_drvdata(dev); 339 if (device_may_wakeup(dev)) 340 disable_irq_wake(info->irq_alarm); 341 return 0; 342 } 343 #endif 344 345 static SIMPLE_DEV_PM_OPS(sa1100_rtc_pm_ops, sa1100_rtc_suspend, 346 sa1100_rtc_resume); 347 348 #ifdef CONFIG_OF 349 static const struct of_device_id sa1100_rtc_dt_ids[] = { 350 { .compatible = "mrvl,sa1100-rtc", }, 351 { .compatible = "mrvl,mmp-rtc", }, 352 {} 353 }; 354 MODULE_DEVICE_TABLE(of, sa1100_rtc_dt_ids); 355 #endif 356 357 static struct platform_driver sa1100_rtc_driver = { 358 .probe = sa1100_rtc_probe, 359 .remove = sa1100_rtc_remove, 360 .driver = { 361 .name = "sa1100-rtc", 362 .pm = &sa1100_rtc_pm_ops, 363 .of_match_table = of_match_ptr(sa1100_rtc_dt_ids), 364 }, 365 }; 366 367 module_platform_driver(sa1100_rtc_driver); 368 369 MODULE_AUTHOR("Richard Purdie <rpurdie@rpsys.net>"); 370 MODULE_DESCRIPTION("SA11x0/PXA2xx Realtime Clock Driver (RTC)"); 371 MODULE_LICENSE("GPL"); 372 MODULE_ALIAS("platform:sa1100-rtc"); 373