1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Real Time Clock interface for StrongARM SA1x00 and XScale PXA2xx 4 * 5 * Copyright (c) 2000 Nils Faerber 6 * 7 * Based on rtc.c by Paul Gortmaker 8 * 9 * Original Driver by Nils Faerber <nils@kernelconcepts.de> 10 * 11 * Modifications from: 12 * CIH <cih@coventive.com> 13 * Nicolas Pitre <nico@fluxnic.net> 14 * Andrew Christian <andrew.christian@hp.com> 15 * 16 * Converted to the RTC subsystem and Driver Model 17 * by Richard Purdie <rpurdie@rpsys.net> 18 */ 19 20 #include <linux/platform_device.h> 21 #include <linux/module.h> 22 #include <linux/clk.h> 23 #include <linux/rtc.h> 24 #include <linux/init.h> 25 #include <linux/fs.h> 26 #include <linux/interrupt.h> 27 #include <linux/slab.h> 28 #include <linux/string.h> 29 #include <linux/of.h> 30 #include <linux/pm.h> 31 #include <linux/bitops.h> 32 #include <linux/io.h> 33 34 #define RTSR_HZE BIT(3) /* HZ interrupt enable */ 35 #define RTSR_ALE BIT(2) /* RTC alarm interrupt enable */ 36 #define RTSR_HZ BIT(1) /* HZ rising-edge detected */ 37 #define RTSR_AL BIT(0) /* RTC alarm detected */ 38 39 #include "rtc-sa1100.h" 40 41 #define RTC_DEF_DIVIDER (32768 - 1) 42 #define RTC_DEF_TRIM 0 43 #define RTC_FREQ 1024 44 45 46 static irqreturn_t sa1100_rtc_interrupt(int irq, void *dev_id) 47 { 48 struct sa1100_rtc *info = dev_get_drvdata(dev_id); 49 struct rtc_device *rtc = info->rtc; 50 unsigned int rtsr; 51 unsigned long events = 0; 52 53 spin_lock(&info->lock); 54 55 rtsr = readl_relaxed(info->rtsr); 56 /* clear interrupt sources */ 57 writel_relaxed(0, info->rtsr); 58 /* Fix for a nasty initialization problem the in SA11xx RTSR register. 59 * See also the comments in sa1100_rtc_probe(). */ 60 if (rtsr & (RTSR_ALE | RTSR_HZE)) { 61 /* This is the original code, before there was the if test 62 * above. This code does not clear interrupts that were not 63 * enabled. */ 64 writel_relaxed((RTSR_AL | RTSR_HZ) & (rtsr >> 2), info->rtsr); 65 } else { 66 /* For some reason, it is possible to enter this routine 67 * without interruptions enabled, it has been tested with 68 * several units (Bug in SA11xx chip?). 69 * 70 * This situation leads to an infinite "loop" of interrupt 71 * routine calling and as a result the processor seems to 72 * lock on its first call to open(). */ 73 writel_relaxed(RTSR_AL | RTSR_HZ, info->rtsr); 74 } 75 76 /* clear alarm interrupt if it has occurred */ 77 if (rtsr & RTSR_AL) 78 rtsr &= ~RTSR_ALE; 79 writel_relaxed(rtsr & (RTSR_ALE | RTSR_HZE), info->rtsr); 80 81 /* update irq data & counter */ 82 if (rtsr & RTSR_AL) 83 events |= RTC_AF | RTC_IRQF; 84 if (rtsr & RTSR_HZ) 85 events |= RTC_UF | RTC_IRQF; 86 87 rtc_update_irq(rtc, 1, events); 88 89 spin_unlock(&info->lock); 90 91 return IRQ_HANDLED; 92 } 93 94 static int sa1100_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) 95 { 96 u32 rtsr; 97 struct sa1100_rtc *info = dev_get_drvdata(dev); 98 99 spin_lock_irq(&info->lock); 100 rtsr = readl_relaxed(info->rtsr); 101 if (enabled) 102 rtsr |= RTSR_ALE; 103 else 104 rtsr &= ~RTSR_ALE; 105 writel_relaxed(rtsr, info->rtsr); 106 spin_unlock_irq(&info->lock); 107 return 0; 108 } 109 110 static int sa1100_rtc_read_time(struct device *dev, struct rtc_time *tm) 111 { 112 struct sa1100_rtc *info = dev_get_drvdata(dev); 113 114 rtc_time_to_tm(readl_relaxed(info->rcnr), tm); 115 return 0; 116 } 117 118 static int sa1100_rtc_set_time(struct device *dev, struct rtc_time *tm) 119 { 120 struct sa1100_rtc *info = dev_get_drvdata(dev); 121 unsigned long time; 122 int ret; 123 124 ret = rtc_tm_to_time(tm, &time); 125 if (ret == 0) 126 writel_relaxed(time, info->rcnr); 127 return ret; 128 } 129 130 static int sa1100_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) 131 { 132 u32 rtsr; 133 struct sa1100_rtc *info = dev_get_drvdata(dev); 134 135 rtsr = readl_relaxed(info->rtsr); 136 alrm->enabled = (rtsr & RTSR_ALE) ? 1 : 0; 137 alrm->pending = (rtsr & RTSR_AL) ? 1 : 0; 138 return 0; 139 } 140 141 static int sa1100_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) 142 { 143 struct sa1100_rtc *info = dev_get_drvdata(dev); 144 unsigned long time; 145 int ret; 146 147 spin_lock_irq(&info->lock); 148 ret = rtc_tm_to_time(&alrm->time, &time); 149 if (ret != 0) 150 goto out; 151 writel_relaxed(readl_relaxed(info->rtsr) & 152 (RTSR_HZE | RTSR_ALE | RTSR_AL), info->rtsr); 153 writel_relaxed(time, info->rtar); 154 if (alrm->enabled) 155 writel_relaxed(readl_relaxed(info->rtsr) | RTSR_ALE, info->rtsr); 156 else 157 writel_relaxed(readl_relaxed(info->rtsr) & ~RTSR_ALE, info->rtsr); 158 out: 159 spin_unlock_irq(&info->lock); 160 161 return ret; 162 } 163 164 static int sa1100_rtc_proc(struct device *dev, struct seq_file *seq) 165 { 166 struct sa1100_rtc *info = dev_get_drvdata(dev); 167 168 seq_printf(seq, "trim/divider\t\t: 0x%08x\n", readl_relaxed(info->rttr)); 169 seq_printf(seq, "RTSR\t\t\t: 0x%08x\n", readl_relaxed(info->rtsr)); 170 171 return 0; 172 } 173 174 static const struct rtc_class_ops sa1100_rtc_ops = { 175 .read_time = sa1100_rtc_read_time, 176 .set_time = sa1100_rtc_set_time, 177 .read_alarm = sa1100_rtc_read_alarm, 178 .set_alarm = sa1100_rtc_set_alarm, 179 .proc = sa1100_rtc_proc, 180 .alarm_irq_enable = sa1100_rtc_alarm_irq_enable, 181 }; 182 183 int sa1100_rtc_init(struct platform_device *pdev, struct sa1100_rtc *info) 184 { 185 struct rtc_device *rtc; 186 int ret; 187 188 spin_lock_init(&info->lock); 189 190 info->clk = devm_clk_get(&pdev->dev, NULL); 191 if (IS_ERR(info->clk)) { 192 dev_err(&pdev->dev, "failed to find rtc clock source\n"); 193 return PTR_ERR(info->clk); 194 } 195 196 ret = clk_prepare_enable(info->clk); 197 if (ret) 198 return ret; 199 /* 200 * According to the manual we should be able to let RTTR be zero 201 * and then a default diviser for a 32.768KHz clock is used. 202 * Apparently this doesn't work, at least for my SA1110 rev 5. 203 * If the clock divider is uninitialized then reset it to the 204 * default value to get the 1Hz clock. 205 */ 206 if (readl_relaxed(info->rttr) == 0) { 207 writel_relaxed(RTC_DEF_DIVIDER + (RTC_DEF_TRIM << 16), info->rttr); 208 dev_warn(&pdev->dev, "warning: " 209 "initializing default clock divider/trim value\n"); 210 /* The current RTC value probably doesn't make sense either */ 211 writel_relaxed(0, info->rcnr); 212 } 213 214 rtc = devm_rtc_device_register(&pdev->dev, pdev->name, &sa1100_rtc_ops, 215 THIS_MODULE); 216 if (IS_ERR(rtc)) { 217 clk_disable_unprepare(info->clk); 218 return PTR_ERR(rtc); 219 } 220 info->rtc = rtc; 221 222 rtc->max_user_freq = RTC_FREQ; 223 224 /* Fix for a nasty initialization problem the in SA11xx RTSR register. 225 * See also the comments in sa1100_rtc_interrupt(). 226 * 227 * Sometimes bit 1 of the RTSR (RTSR_HZ) will wake up 1, which means an 228 * interrupt pending, even though interrupts were never enabled. 229 * In this case, this bit it must be reset before enabling 230 * interruptions to avoid a nonexistent interrupt to occur. 231 * 232 * In principle, the same problem would apply to bit 0, although it has 233 * never been observed to happen. 234 * 235 * This issue is addressed both here and in sa1100_rtc_interrupt(). 236 * If the issue is not addressed here, in the times when the processor 237 * wakes up with the bit set there will be one spurious interrupt. 238 * 239 * The issue is also dealt with in sa1100_rtc_interrupt() to be on the 240 * safe side, once the condition that lead to this strange 241 * initialization is unknown and could in principle happen during 242 * normal processing. 243 * 244 * Notice that clearing bit 1 and 0 is accomplished by writting ONES to 245 * the corresponding bits in RTSR. */ 246 writel_relaxed(RTSR_AL | RTSR_HZ, info->rtsr); 247 248 return 0; 249 } 250 EXPORT_SYMBOL_GPL(sa1100_rtc_init); 251 252 static int sa1100_rtc_probe(struct platform_device *pdev) 253 { 254 struct sa1100_rtc *info; 255 void __iomem *base; 256 int irq_1hz, irq_alarm; 257 int ret; 258 259 irq_1hz = platform_get_irq_byname(pdev, "rtc 1Hz"); 260 irq_alarm = platform_get_irq_byname(pdev, "rtc alarm"); 261 if (irq_1hz < 0 || irq_alarm < 0) 262 return -ENODEV; 263 264 info = devm_kzalloc(&pdev->dev, sizeof(struct sa1100_rtc), GFP_KERNEL); 265 if (!info) 266 return -ENOMEM; 267 info->irq_1hz = irq_1hz; 268 info->irq_alarm = irq_alarm; 269 270 ret = devm_request_irq(&pdev->dev, irq_1hz, sa1100_rtc_interrupt, 0, 271 "rtc 1Hz", &pdev->dev); 272 if (ret) { 273 dev_err(&pdev->dev, "IRQ %d already in use.\n", irq_1hz); 274 return ret; 275 } 276 ret = devm_request_irq(&pdev->dev, irq_alarm, sa1100_rtc_interrupt, 0, 277 "rtc Alrm", &pdev->dev); 278 if (ret) { 279 dev_err(&pdev->dev, "IRQ %d already in use.\n", irq_alarm); 280 return ret; 281 } 282 283 base = devm_platform_ioremap_resource(pdev, 0); 284 if (IS_ERR(base)) 285 return PTR_ERR(base); 286 287 if (IS_ENABLED(CONFIG_ARCH_SA1100) || 288 of_device_is_compatible(pdev->dev.of_node, "mrvl,sa1100-rtc")) { 289 info->rcnr = base + 0x04; 290 info->rtsr = base + 0x10; 291 info->rtar = base + 0x00; 292 info->rttr = base + 0x08; 293 } else { 294 info->rcnr = base + 0x0; 295 info->rtsr = base + 0x8; 296 info->rtar = base + 0x4; 297 info->rttr = base + 0xc; 298 } 299 300 platform_set_drvdata(pdev, info); 301 device_init_wakeup(&pdev->dev, 1); 302 303 return sa1100_rtc_init(pdev, info); 304 } 305 306 static int sa1100_rtc_remove(struct platform_device *pdev) 307 { 308 struct sa1100_rtc *info = platform_get_drvdata(pdev); 309 310 if (info) { 311 spin_lock_irq(&info->lock); 312 writel_relaxed(0, info->rtsr); 313 spin_unlock_irq(&info->lock); 314 clk_disable_unprepare(info->clk); 315 } 316 317 return 0; 318 } 319 320 #ifdef CONFIG_PM_SLEEP 321 static int sa1100_rtc_suspend(struct device *dev) 322 { 323 struct sa1100_rtc *info = dev_get_drvdata(dev); 324 if (device_may_wakeup(dev)) 325 enable_irq_wake(info->irq_alarm); 326 return 0; 327 } 328 329 static int sa1100_rtc_resume(struct device *dev) 330 { 331 struct sa1100_rtc *info = dev_get_drvdata(dev); 332 if (device_may_wakeup(dev)) 333 disable_irq_wake(info->irq_alarm); 334 return 0; 335 } 336 #endif 337 338 static SIMPLE_DEV_PM_OPS(sa1100_rtc_pm_ops, sa1100_rtc_suspend, 339 sa1100_rtc_resume); 340 341 #ifdef CONFIG_OF 342 static const struct of_device_id sa1100_rtc_dt_ids[] = { 343 { .compatible = "mrvl,sa1100-rtc", }, 344 { .compatible = "mrvl,mmp-rtc", }, 345 {} 346 }; 347 MODULE_DEVICE_TABLE(of, sa1100_rtc_dt_ids); 348 #endif 349 350 static struct platform_driver sa1100_rtc_driver = { 351 .probe = sa1100_rtc_probe, 352 .remove = sa1100_rtc_remove, 353 .driver = { 354 .name = "sa1100-rtc", 355 .pm = &sa1100_rtc_pm_ops, 356 .of_match_table = of_match_ptr(sa1100_rtc_dt_ids), 357 }, 358 }; 359 360 module_platform_driver(sa1100_rtc_driver); 361 362 MODULE_AUTHOR("Richard Purdie <rpurdie@rpsys.net>"); 363 MODULE_DESCRIPTION("SA11x0/PXA2xx Realtime Clock Driver (RTC)"); 364 MODULE_LICENSE("GPL"); 365 MODULE_ALIAS("platform:sa1100-rtc"); 366