drivers/rtc/rtc-lpc32xx.c

   1 /*
   2  * Copyright (C) 2010 NXP Semiconductors
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  *  You should have received a copy of the GNU General Public License along
  10  *  with this program; if not, write to the Free Software Foundation, Inc.,
  11  *  675 Mass Ave, Cambridge, MA 02139, USA.
  12  */
  13
  14 #include <linux/kernel.h>
  15 #include <linux/module.h>
  16 #include <linux/init.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/spinlock.h>
  19 #include <linux/rtc.h>
  20 #include <linux/slab.h>
  21 #include <linux/io.h>
  22
  23 /*
  24  * Clock and Power control register offsets
  25  */
  26 #define LPC32XX_RTC_UCOUNT              0x00
  27 #define LPC32XX_RTC_DCOUNT              0x04
  28 #define LPC32XX_RTC_MATCH0              0x08
  29 #define LPC32XX_RTC_MATCH1              0x0C
  30 #define LPC32XX_RTC_CTRL                0x10
  31 #define LPC32XX_RTC_INTSTAT             0x14
  32 #define LPC32XX_RTC_KEY                 0x18
  33 #define LPC32XX_RTC_SRAM                0x80
  34
  35 #define LPC32XX_RTC_CTRL_MATCH0         (1 << 0)
  36 #define LPC32XX_RTC_CTRL_MATCH1         (1 << 1)
  37 #define LPC32XX_RTC_CTRL_ONSW_MATCH0    (1 << 2)
  38 #define LPC32XX_RTC_CTRL_ONSW_MATCH1    (1 << 3)
  39 #define LPC32XX_RTC_CTRL_SW_RESET       (1 << 4)
  40 #define LPC32XX_RTC_CTRL_CNTR_DIS       (1 << 6)
  41 #define LPC32XX_RTC_CTRL_ONSW_FORCE_HI  (1 << 7)
  42
  43 #define LPC32XX_RTC_INTSTAT_MATCH0      (1 << 0)
  44 #define LPC32XX_RTC_INTSTAT_MATCH1      (1 << 1)
  45 #define LPC32XX_RTC_INTSTAT_ONSW        (1 << 2)
  46
  47 #define LPC32XX_RTC_KEY_ONSW_LOADVAL    0xB5C13F27
  48
  49 #define RTC_NAME "rtc-lpc32xx"
  50
  51 #define rtc_readl(dev, reg) \
  52         __raw_readl((dev)->rtc_base + (reg))
  53 #define rtc_writel(dev, reg, val) \
  54         __raw_writel((val), (dev)->rtc_base + (reg))
  55
  56 struct lpc32xx_rtc {
  57         void __iomem *rtc_base;
  58         int irq;
  59         unsigned char alarm_enabled;
  60         struct rtc_device *rtc;
  61         spinlock_t lock;
  62 };
  63
  64 static int lpc32xx_rtc_read_time(struct device *dev, struct rtc_time *time)
  65 {
  66         unsigned long elapsed_sec;
  67         struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
  68
  69         elapsed_sec = rtc_readl(rtc, LPC32XX_RTC_UCOUNT);
  70         rtc_time_to_tm(elapsed_sec, time);
  71
  72         return rtc_valid_tm(time);
  73 }
  74
  75 static int lpc32xx_rtc_set_mmss(struct device *dev, unsigned long secs)
  76 {
  77         struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
  78         u32 tmp;
  79
  80         spin_lock_irq(&rtc->lock);
  81
  82         /* RTC must be disabled during count update */
  83         tmp = rtc_readl(rtc, LPC32XX_RTC_CTRL);
  84         rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp | LPC32XX_RTC_CTRL_CNTR_DIS);
  85         rtc_writel(rtc, LPC32XX_RTC_UCOUNT, secs);
  86         rtc_writel(rtc, LPC32XX_RTC_DCOUNT, 0xFFFFFFFF - secs);
  87         rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp &= ~LPC32XX_RTC_CTRL_CNTR_DIS);
  88
  89         spin_unlock_irq(&rtc->lock);
  90
  91         return 0;
  92 }
  93
  94 static int lpc32xx_rtc_read_alarm(struct device *dev,
  95         struct rtc_wkalrm *wkalrm)
  96 {
  97         struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
  98
  99         rtc_time_to_tm(rtc_readl(rtc, LPC32XX_RTC_MATCH0), &wkalrm->time);
 100         wkalrm->enabled = rtc->alarm_enabled;
 101         wkalrm->pending = !!(rtc_readl(rtc, LPC32XX_RTC_INTSTAT) &
 102                 LPC32XX_RTC_INTSTAT_MATCH0);
 103
 104         return rtc_valid_tm(&wkalrm->time);
 105 }
 106
 107 static int lpc32xx_rtc_set_alarm(struct device *dev,
 108         struct rtc_wkalrm *wkalrm)
 109 {
 110         struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
 111         unsigned long alarmsecs;
 112         u32 tmp;
 113         int ret;
 114
 115         ret = rtc_tm_to_time(&wkalrm->time, &alarmsecs);
 116         if (ret < 0) {
 117                 dev_warn(dev, "Failed to convert time: %d\n", ret);
 118                 return ret;
 119         }
 120
 121         spin_lock_irq(&rtc->lock);
 122
 123         /* Disable alarm during update */
 124         tmp = rtc_readl(rtc, LPC32XX_RTC_CTRL);
 125         rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp & ~LPC32XX_RTC_CTRL_MATCH0);
 126
 127         rtc_writel(rtc, LPC32XX_RTC_MATCH0, alarmsecs);
 128
 129         rtc->alarm_enabled = wkalrm->enabled;
 130         if (wkalrm->enabled) {
 131                 rtc_writel(rtc, LPC32XX_RTC_INTSTAT,
 132                            LPC32XX_RTC_INTSTAT_MATCH0);
 133                 rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp |
 134                            LPC32XX_RTC_CTRL_MATCH0);
 135         }
 136
 137         spin_unlock_irq(&rtc->lock);
 138
 139         return 0;
 140 }
 141
 142 static int lpc32xx_rtc_alarm_irq_enable(struct device *dev,
 143         unsigned int enabled)
 144 {
 145         struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
 146         u32 tmp;
 147
 148         spin_lock_irq(&rtc->lock);
 149         tmp = rtc_readl(rtc, LPC32XX_RTC_CTRL);
 150
 151         if (enabled) {
 152                 rtc->alarm_enabled = 1;
 153                 tmp |= LPC32XX_RTC_CTRL_MATCH0;
 154         } else {
 155                 rtc->alarm_enabled = 0;
 156                 tmp &= ~LPC32XX_RTC_CTRL_MATCH0;
 157         }
 158
 159         rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp);
 160         spin_unlock_irq(&rtc->lock);
 161
 162         return 0;
 163 }
 164
 165 static irqreturn_t lpc32xx_rtc_alarm_interrupt(int irq, void *dev)
 166 {
 167         struct lpc32xx_rtc *rtc = dev;
 168
 169         spin_lock(&rtc->lock);
 170
 171         /* Disable alarm interrupt */
 172         rtc_writel(rtc, LPC32XX_RTC_CTRL,
 173                 rtc_readl(rtc, LPC32XX_RTC_CTRL) &
 174                           ~LPC32XX_RTC_CTRL_MATCH0);
 175         rtc->alarm_enabled = 0;
 176
 177         /*
 178          * Write a large value to the match value so the RTC won't
 179          * keep firing the match status
 180          */
 181         rtc_writel(rtc, LPC32XX_RTC_MATCH0, 0xFFFFFFFF);
 182         rtc_writel(rtc, LPC32XX_RTC_INTSTAT, LPC32XX_RTC_INTSTAT_MATCH0);
 183
 184         spin_unlock(&rtc->lock);
 185
 186         rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_AF);
 187
 188         return IRQ_HANDLED;
 189 }
 190
 191 static const struct rtc_class_ops lpc32xx_rtc_ops = {
 192         .read_time              = lpc32xx_rtc_read_time,
 193         .set_mmss               = lpc32xx_rtc_set_mmss,
 194         .read_alarm             = lpc32xx_rtc_read_alarm,
 195         .set_alarm              = lpc32xx_rtc_set_alarm,
 196         .alarm_irq_enable       = lpc32xx_rtc_alarm_irq_enable,
 197 };
 198
 199 static int __devinit lpc32xx_rtc_probe(struct platform_device *pdev)
 200 {
 201         struct resource *res;
 202         struct lpc32xx_rtc *rtc;
 203         resource_size_t size;
 204         int rtcirq;
 205         u32 tmp;
 206
 207         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 208         if (!res) {
 209                 dev_err(&pdev->dev, "Can't get memory resource\n");
 210                 return -ENOENT;
 211         }
 212
 213         rtcirq = platform_get_irq(pdev, 0);
 214         if (rtcirq < 0 || rtcirq >= NR_IRQS) {
 215                 dev_warn(&pdev->dev, "Can't get interrupt resource\n");
 216                 rtcirq = -1;
 217         }
 218
 219         rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
 220         if (unlikely(!rtc)) {
 221                 dev_err(&pdev->dev, "Can't allocate memory\n");
 222                 return -ENOMEM;
 223         }
 224         rtc->irq = rtcirq;
 225
 226         size = resource_size(res);
 227
 228         if (!devm_request_mem_region(&pdev->dev, res->start, size,
 229                                      pdev->name)) {
 230                 dev_err(&pdev->dev, "RTC registers are not free\n");
 231                 return -EBUSY;
 232         }
 233
 234         rtc->rtc_base = devm_ioremap(&pdev->dev, res->start, size);
 235         if (!rtc->rtc_base) {
 236                 dev_err(&pdev->dev, "Can't map memory\n");
 237                 return -ENOMEM;
 238         }
 239
 240         spin_lock_init(&rtc->lock);
 241
 242         /*
 243          * The RTC is on a separate power domain and can keep it's state
 244          * across a chip power cycle. If the RTC has never been previously
 245          * setup, then set it up now for the first time.
 246          */
 247         tmp = rtc_readl(rtc, LPC32XX_RTC_CTRL);
 248         if (rtc_readl(rtc, LPC32XX_RTC_KEY) != LPC32XX_RTC_KEY_ONSW_LOADVAL) {
 249                 tmp &= ~(LPC32XX_RTC_CTRL_SW_RESET |
 250                         LPC32XX_RTC_CTRL_CNTR_DIS |
 251                         LPC32XX_RTC_CTRL_MATCH0 |
 252                         LPC32XX_RTC_CTRL_MATCH1 |
 253                         LPC32XX_RTC_CTRL_ONSW_MATCH0 |
 254                         LPC32XX_RTC_CTRL_ONSW_MATCH1 |
 255                         LPC32XX_RTC_CTRL_ONSW_FORCE_HI);
 256                 rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp);
 257
 258                 /* Clear latched interrupt states */
 259                 rtc_writel(rtc, LPC32XX_RTC_MATCH0, 0xFFFFFFFF);
 260                 rtc_writel(rtc, LPC32XX_RTC_INTSTAT,
 261                            LPC32XX_RTC_INTSTAT_MATCH0 |
 262                            LPC32XX_RTC_INTSTAT_MATCH1 |
 263                            LPC32XX_RTC_INTSTAT_ONSW);
 264
 265                 /* Write key value to RTC so it won't reload on reset */
 266                 rtc_writel(rtc, LPC32XX_RTC_KEY,
 267                            LPC32XX_RTC_KEY_ONSW_LOADVAL);
 268         } else {
 269                 rtc_writel(rtc, LPC32XX_RTC_CTRL,
 270                            tmp & ~LPC32XX_RTC_CTRL_MATCH0);
 271         }
 272
 273         platform_set_drvdata(pdev, rtc);
 274
 275         rtc->rtc = rtc_device_register(RTC_NAME, &pdev->dev, &lpc32xx_rtc_ops,
 276                 THIS_MODULE);
 277         if (IS_ERR(rtc->rtc)) {
 278                 dev_err(&pdev->dev, "Can't get RTC\n");
 279                 platform_set_drvdata(pdev, NULL);
 280                 return PTR_ERR(rtc->rtc);
 281         }
 282
 283         /*
 284          * IRQ is enabled after device registration in case alarm IRQ
 285          * is pending upon suspend exit.
 286          */
 287         if (rtc->irq >= 0) {
 288                 if (devm_request_irq(&pdev->dev, rtc->irq,
 289                                      lpc32xx_rtc_alarm_interrupt,
 290                                      IRQF_DISABLED, pdev->name, rtc) < 0) {
 291                         dev_warn(&pdev->dev, "Can't request interrupt.\n");
 292                         rtc->irq = -1;
 293                 } else {
 294                         device_init_wakeup(&pdev->dev, 1);
 295                 }
 296         }
 297
 298         return 0;
 299 }
 300
 301 static int __devexit lpc32xx_rtc_remove(struct platform_device *pdev)
 302 {
 303         struct lpc32xx_rtc *rtc = platform_get_drvdata(pdev);
 304
 305         if (rtc->irq >= 0)
 306                 device_init_wakeup(&pdev->dev, 0);
 307
 308         platform_set_drvdata(pdev, NULL);
 309         rtc_device_unregister(rtc->rtc);
 310
 311         return 0;
 312 }
 313
 314 #ifdef CONFIG_PM
 315 static int lpc32xx_rtc_suspend(struct device *dev)
 316 {
 317         struct platform_device *pdev = to_platform_device(dev);
 318         struct lpc32xx_rtc *rtc = platform_get_drvdata(pdev);
 319
 320         if (rtc->irq >= 0) {
 321                 if (device_may_wakeup(&pdev->dev))
 322                         enable_irq_wake(rtc->irq);
 323                 else
 324                         disable_irq_wake(rtc->irq);
 325         }
 326
 327         return 0;
 328 }
 329
 330 static int lpc32xx_rtc_resume(struct device *dev)
 331 {
 332         struct platform_device *pdev = to_platform_device(dev);
 333         struct lpc32xx_rtc *rtc = platform_get_drvdata(pdev);
 334
 335         if (rtc->irq >= 0 && device_may_wakeup(&pdev->dev))
 336                 disable_irq_wake(rtc->irq);
 337
 338         return 0;
 339 }
 340
 341 /* Unconditionally disable the alarm */
 342 static int lpc32xx_rtc_freeze(struct device *dev)
 343 {
 344         struct platform_device *pdev = to_platform_device(dev);
 345         struct lpc32xx_rtc *rtc = platform_get_drvdata(pdev);
 346
 347         spin_lock_irq(&rtc->lock);
 348
 349         rtc_writel(rtc, LPC32XX_RTC_CTRL,
 350                 rtc_readl(rtc, LPC32XX_RTC_CTRL) &
 351                           ~LPC32XX_RTC_CTRL_MATCH0);
 352
 353         spin_unlock_irq(&rtc->lock);
 354
 355         return 0;
 356 }
 357
 358 static int lpc32xx_rtc_thaw(struct device *dev)
 359 {
 360         struct platform_device *pdev = to_platform_device(dev);
 361         struct lpc32xx_rtc *rtc = platform_get_drvdata(pdev);
 362
 363         if (rtc->alarm_enabled) {
 364                 spin_lock_irq(&rtc->lock);
 365
 366                 rtc_writel(rtc, LPC32XX_RTC_CTRL,
 367                            rtc_readl(rtc, LPC32XX_RTC_CTRL) |
 368                            LPC32XX_RTC_CTRL_MATCH0);
 369
 370                 spin_unlock_irq(&rtc->lock);
 371         }
 372
 373         return 0;
 374 }
 375
 376 static const struct dev_pm_ops lpc32xx_rtc_pm_ops = {
 377         .suspend = lpc32xx_rtc_suspend,
 378         .resume = lpc32xx_rtc_resume,
 379         .freeze = lpc32xx_rtc_freeze,
 380         .thaw = lpc32xx_rtc_thaw,
 381         .restore = lpc32xx_rtc_resume
 382 };
 383
 384 #define LPC32XX_RTC_PM_OPS (&lpc32xx_rtc_pm_ops)
 385 #else
 386 #define LPC32XX_RTC_PM_OPS NULL
 387 #endif
 388
 389 static struct platform_driver lpc32xx_rtc_driver = {
 390         .probe          = lpc32xx_rtc_probe,
 391         .remove         = __devexit_p(lpc32xx_rtc_remove),
 392         .driver = {
 393                 .name   = RTC_NAME,
 394                 .owner  = THIS_MODULE,
 395                 .pm     = LPC32XX_RTC_PM_OPS
 396         },
 397 };
 398
 399 static int __init lpc32xx_rtc_init(void)
 400 {
 401         return platform_driver_register(&lpc32xx_rtc_driver);
 402 }
 403 module_init(lpc32xx_rtc_init);
 404
 405 static void __exit lpc32xx_rtc_exit(void)
 406 {
 407         platform_driver_unregister(&lpc32xx_rtc_driver);
 408 }
 409 module_exit(lpc32xx_rtc_exit);
 410
 411 MODULE_AUTHOR("Kevin Wells <wellsk40@gmail.com");
 412 MODULE_DESCRIPTION("RTC driver for the LPC32xx SoC");
 413 MODULE_LICENSE("GPL");
 414 MODULE_ALIAS("platform:rtc-lpc32xx");