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 #include <linux/of.h>
  23
  24 /*
  25  * Clock and Power control register offsets
  26  */
  27 #define LPC32XX_RTC_UCOUNT              0x00
  28 #define LPC32XX_RTC_DCOUNT              0x04
  29 #define LPC32XX_RTC_MATCH0              0x08
  30 #define LPC32XX_RTC_MATCH1              0x0C
  31 #define LPC32XX_RTC_CTRL                0x10
  32 #define LPC32XX_RTC_INTSTAT             0x14
  33 #define LPC32XX_RTC_KEY                 0x18
  34 #define LPC32XX_RTC_SRAM                0x80
  35
  36 #define LPC32XX_RTC_CTRL_MATCH0         (1 << 0)
  37 #define LPC32XX_RTC_CTRL_MATCH1         (1 << 1)
  38 #define LPC32XX_RTC_CTRL_ONSW_MATCH0    (1 << 2)
  39 #define LPC32XX_RTC_CTRL_ONSW_MATCH1    (1 << 3)
  40 #define LPC32XX_RTC_CTRL_SW_RESET       (1 << 4)
  41 #define LPC32XX_RTC_CTRL_CNTR_DIS       (1 << 6)
  42 #define LPC32XX_RTC_CTRL_ONSW_FORCE_HI  (1 << 7)
  43
  44 #define LPC32XX_RTC_INTSTAT_MATCH0      (1 << 0)
  45 #define LPC32XX_RTC_INTSTAT_MATCH1      (1 << 1)
  46 #define LPC32XX_RTC_INTSTAT_ONSW        (1 << 2)
  47
  48 #define LPC32XX_RTC_KEY_ONSW_LOADVAL    0xB5C13F27
  49
  50 #define RTC_NAME "rtc-lpc32xx"
  51
  52 #define rtc_readl(dev, reg) \
  53         __raw_readl((dev)->rtc_base + (reg))
  54 #define rtc_writel(dev, reg, val) \
  55         __raw_writel((val), (dev)->rtc_base + (reg))
  56
  57 struct lpc32xx_rtc {
  58         void __iomem *rtc_base;
  59         int irq;
  60         unsigned char alarm_enabled;
  61         struct rtc_device *rtc;
  62         spinlock_t lock;
  63 };
  64
  65 static int lpc32xx_rtc_read_time(struct device *dev, struct rtc_time *time)
  66 {
  67         unsigned long elapsed_sec;
  68         struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
  69
  70         elapsed_sec = rtc_readl(rtc, LPC32XX_RTC_UCOUNT);
  71         rtc_time_to_tm(elapsed_sec, time);
  72
  73         return rtc_valid_tm(time);
  74 }
  75
  76 static int lpc32xx_rtc_set_mmss(struct device *dev, unsigned long secs)
  77 {
  78         struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
  79         u32 tmp;
  80
  81         spin_lock_irq(&rtc->lock);
  82
  83         /* RTC must be disabled during count update */
  84         tmp = rtc_readl(rtc, LPC32XX_RTC_CTRL);
  85         rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp | LPC32XX_RTC_CTRL_CNTR_DIS);
  86         rtc_writel(rtc, LPC32XX_RTC_UCOUNT, secs);
  87         rtc_writel(rtc, LPC32XX_RTC_DCOUNT, 0xFFFFFFFF - secs);
  88         rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp &= ~LPC32XX_RTC_CTRL_CNTR_DIS);
  89
  90         spin_unlock_irq(&rtc->lock);
  91
  92         return 0;
  93 }
  94
  95 static int lpc32xx_rtc_read_alarm(struct device *dev,
  96         struct rtc_wkalrm *wkalrm)
  97 {
  98         struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
  99
 100         rtc_time_to_tm(rtc_readl(rtc, LPC32XX_RTC_MATCH0), &wkalrm->time);
 101         wkalrm->enabled = rtc->alarm_enabled;
 102         wkalrm->pending = !!(rtc_readl(rtc, LPC32XX_RTC_INTSTAT) &
 103                 LPC32XX_RTC_INTSTAT_MATCH0);
 104
 105         return rtc_valid_tm(&wkalrm->time);
 106 }
 107
 108 static int lpc32xx_rtc_set_alarm(struct device *dev,
 109         struct rtc_wkalrm *wkalrm)
 110 {
 111         struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
 112         unsigned long alarmsecs;
 113         u32 tmp;
 114         int ret;
 115
 116         ret = rtc_tm_to_time(&wkalrm->time, &alarmsecs);
 117         if (ret < 0) {
 118                 dev_warn(dev, "Failed to convert time: %d\n", ret);
 119                 return ret;
 120         }
 121
 122         spin_lock_irq(&rtc->lock);
 123
 124         /* Disable alarm during update */
 125         tmp = rtc_readl(rtc, LPC32XX_RTC_CTRL);
 126         rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp & ~LPC32XX_RTC_CTRL_MATCH0);
 127
 128         rtc_writel(rtc, LPC32XX_RTC_MATCH0, alarmsecs);
 129
 130         rtc->alarm_enabled = wkalrm->enabled;
 131         if (wkalrm->enabled) {
 132                 rtc_writel(rtc, LPC32XX_RTC_INTSTAT,
 133                            LPC32XX_RTC_INTSTAT_MATCH0);
 134                 rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp |
 135                            LPC32XX_RTC_CTRL_MATCH0);
 136         }
 137
 138         spin_unlock_irq(&rtc->lock);
 139
 140         return 0;
 141 }
 142
 143 static int lpc32xx_rtc_alarm_irq_enable(struct device *dev,
 144         unsigned int enabled)
 145 {
 146         struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
 147         u32 tmp;
 148
 149         spin_lock_irq(&rtc->lock);
 150         tmp = rtc_readl(rtc, LPC32XX_RTC_CTRL);
 151
 152         if (enabled) {
 153                 rtc->alarm_enabled = 1;
 154                 tmp |= LPC32XX_RTC_CTRL_MATCH0;
 155         } else {
 156                 rtc->alarm_enabled = 0;
 157                 tmp &= ~LPC32XX_RTC_CTRL_MATCH0;
 158         }
 159
 160         rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp);
 161         spin_unlock_irq(&rtc->lock);
 162
 163         return 0;
 164 }
 165
 166 static irqreturn_t lpc32xx_rtc_alarm_interrupt(int irq, void *dev)
 167 {
 168         struct lpc32xx_rtc *rtc = dev;
 169
 170         spin_lock(&rtc->lock);
 171
 172         /* Disable alarm interrupt */
 173         rtc_writel(rtc, LPC32XX_RTC_CTRL,
 174                 rtc_readl(rtc, LPC32XX_RTC_CTRL) &
 175                           ~LPC32XX_RTC_CTRL_MATCH0);
 176         rtc->alarm_enabled = 0;
 177
 178         /*
 179          * Write a large value to the match value so the RTC won't
 180          * keep firing the match status
 181          */
 182         rtc_writel(rtc, LPC32XX_RTC_MATCH0, 0xFFFFFFFF);
 183         rtc_writel(rtc, LPC32XX_RTC_INTSTAT, LPC32XX_RTC_INTSTAT_MATCH0);
 184
 185         spin_unlock(&rtc->lock);
 186
 187         rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_AF);
 188
 189         return IRQ_HANDLED;
 190 }
 191
 192 static const struct rtc_class_ops lpc32xx_rtc_ops = {
 193         .read_time              = lpc32xx_rtc_read_time,
 194         .set_mmss               = lpc32xx_rtc_set_mmss,
 195         .read_alarm             = lpc32xx_rtc_read_alarm,
 196         .set_alarm              = lpc32xx_rtc_set_alarm,
 197         .alarm_irq_enable       = lpc32xx_rtc_alarm_irq_enable,
 198 };
 199
 200 static int lpc32xx_rtc_probe(struct platform_device *pdev)
 201 {
 202         struct resource *res;
 203         struct lpc32xx_rtc *rtc;
 204         resource_size_t size;
 205         int rtcirq;
 206         u32 tmp;
 207
 208         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 209         if (!res) {
 210                 dev_err(&pdev->dev, "Can't get memory resource\n");
 211                 return -ENOENT;
 212         }
 213
 214         rtcirq = platform_get_irq(pdev, 0);
 215         if (rtcirq < 0 || rtcirq >= NR_IRQS) {
 216                 dev_warn(&pdev->dev, "Can't get interrupt resource\n");
 217                 rtcirq = -1;
 218         }
 219
 220         rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
 221         if (unlikely(!rtc)) {
 222                 dev_err(&pdev->dev, "Can't allocate memory\n");
 223                 return -ENOMEM;
 224         }
 225         rtc->irq = rtcirq;
 226
 227         size = resource_size(res);
 228
 229         if (!devm_request_mem_region(&pdev->dev, res->start, size,
 230                                      pdev->name)) {
 231                 dev_err(&pdev->dev, "RTC registers are not free\n");
 232                 return -EBUSY;
 233         }
 234
 235         rtc->rtc_base = devm_ioremap(&pdev->dev, res->start, size);
 236         if (!rtc->rtc_base) {
 237                 dev_err(&pdev->dev, "Can't map memory\n");
 238                 return -ENOMEM;
 239         }
 240
 241         spin_lock_init(&rtc->lock);
 242
 243         /*
 244          * The RTC is on a separate power domain and can keep it's state
 245          * across a chip power cycle. If the RTC has never been previously
 246          * setup, then set it up now for the first time.
 247          */
 248         tmp = rtc_readl(rtc, LPC32XX_RTC_CTRL);
 249         if (rtc_readl(rtc, LPC32XX_RTC_KEY) != LPC32XX_RTC_KEY_ONSW_LOADVAL) {
 250                 tmp &= ~(LPC32XX_RTC_CTRL_SW_RESET |
 251                         LPC32XX_RTC_CTRL_CNTR_DIS |
 252                         LPC32XX_RTC_CTRL_MATCH0 |
 253                         LPC32XX_RTC_CTRL_MATCH1 |
 254                         LPC32XX_RTC_CTRL_ONSW_MATCH0 |
 255                         LPC32XX_RTC_CTRL_ONSW_MATCH1 |
 256                         LPC32XX_RTC_CTRL_ONSW_FORCE_HI);
 257                 rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp);
 258
 259                 /* Clear latched interrupt states */
 260                 rtc_writel(rtc, LPC32XX_RTC_MATCH0, 0xFFFFFFFF);
 261                 rtc_writel(rtc, LPC32XX_RTC_INTSTAT,
 262                            LPC32XX_RTC_INTSTAT_MATCH0 |
 263                            LPC32XX_RTC_INTSTAT_MATCH1 |
 264                            LPC32XX_RTC_INTSTAT_ONSW);
 265
 266                 /* Write key value to RTC so it won't reload on reset */
 267                 rtc_writel(rtc, LPC32XX_RTC_KEY,
 268                            LPC32XX_RTC_KEY_ONSW_LOADVAL);
 269         } else {
 270                 rtc_writel(rtc, LPC32XX_RTC_CTRL,
 271                            tmp & ~LPC32XX_RTC_CTRL_MATCH0);
 272         }
 273
 274         platform_set_drvdata(pdev, rtc);
 275
 276         rtc->rtc = rtc_device_register(RTC_NAME, &pdev->dev, &lpc32xx_rtc_ops,
 277                 THIS_MODULE);
 278         if (IS_ERR(rtc->rtc)) {
 279                 dev_err(&pdev->dev, "Can't get RTC\n");
 280                 platform_set_drvdata(pdev, NULL);
 281                 return PTR_ERR(rtc->rtc);
 282         }
 283
 284         /*
 285          * IRQ is enabled after device registration in case alarm IRQ
 286          * is pending upon suspend exit.
 287          */
 288         if (rtc->irq >= 0) {
 289                 if (devm_request_irq(&pdev->dev, rtc->irq,
 290                                      lpc32xx_rtc_alarm_interrupt,
 291                                      0, pdev->name, rtc) < 0) {
 292                         dev_warn(&pdev->dev, "Can't request interrupt.\n");
 293                         rtc->irq = -1;
 294                 } else {
 295                         device_init_wakeup(&pdev->dev, 1);
 296                 }
 297         }
 298
 299         return 0;
 300 }
 301
 302 static int lpc32xx_rtc_remove(struct platform_device *pdev)
 303 {
 304         struct lpc32xx_rtc *rtc = platform_get_drvdata(pdev);
 305
 306         if (rtc->irq >= 0)
 307                 device_init_wakeup(&pdev->dev, 0);
 308
 309         platform_set_drvdata(pdev, NULL);
 310         rtc_device_unregister(rtc->rtc);
 311
 312         return 0;
 313 }
 314
 315 #ifdef CONFIG_PM
 316 static int lpc32xx_rtc_suspend(struct device *dev)
 317 {
 318         struct platform_device *pdev = to_platform_device(dev);
 319         struct lpc32xx_rtc *rtc = platform_get_drvdata(pdev);
 320
 321         if (rtc->irq >= 0) {
 322                 if (device_may_wakeup(&pdev->dev))
 323                         enable_irq_wake(rtc->irq);
 324                 else
 325                         disable_irq_wake(rtc->irq);
 326         }
 327
 328         return 0;
 329 }
 330
 331 static int lpc32xx_rtc_resume(struct device *dev)
 332 {
 333         struct platform_device *pdev = to_platform_device(dev);
 334         struct lpc32xx_rtc *rtc = platform_get_drvdata(pdev);
 335
 336         if (rtc->irq >= 0 && device_may_wakeup(&pdev->dev))
 337                 disable_irq_wake(rtc->irq);
 338
 339         return 0;
 340 }
 341
 342 /* Unconditionally disable the alarm */
 343 static int lpc32xx_rtc_freeze(struct device *dev)
 344 {
 345         struct platform_device *pdev = to_platform_device(dev);
 346         struct lpc32xx_rtc *rtc = platform_get_drvdata(pdev);
 347
 348         spin_lock_irq(&rtc->lock);
 349
 350         rtc_writel(rtc, LPC32XX_RTC_CTRL,
 351                 rtc_readl(rtc, LPC32XX_RTC_CTRL) &
 352                           ~LPC32XX_RTC_CTRL_MATCH0);
 353
 354         spin_unlock_irq(&rtc->lock);
 355
 356         return 0;
 357 }
 358
 359 static int lpc32xx_rtc_thaw(struct device *dev)
 360 {
 361         struct platform_device *pdev = to_platform_device(dev);
 362         struct lpc32xx_rtc *rtc = platform_get_drvdata(pdev);
 363
 364         if (rtc->alarm_enabled) {
 365                 spin_lock_irq(&rtc->lock);
 366
 367                 rtc_writel(rtc, LPC32XX_RTC_CTRL,
 368                            rtc_readl(rtc, LPC32XX_RTC_CTRL) |
 369                            LPC32XX_RTC_CTRL_MATCH0);
 370
 371                 spin_unlock_irq(&rtc->lock);
 372         }
 373
 374         return 0;
 375 }
 376
 377 static const struct dev_pm_ops lpc32xx_rtc_pm_ops = {
 378         .suspend = lpc32xx_rtc_suspend,
 379         .resume = lpc32xx_rtc_resume,
 380         .freeze = lpc32xx_rtc_freeze,
 381         .thaw = lpc32xx_rtc_thaw,
 382         .restore = lpc32xx_rtc_resume
 383 };
 384
 385 #define LPC32XX_RTC_PM_OPS (&lpc32xx_rtc_pm_ops)
 386 #else
 387 #define LPC32XX_RTC_PM_OPS NULL
 388 #endif
 389
 390 #ifdef CONFIG_OF
 391 static const struct of_device_id lpc32xx_rtc_match[] = {
 392         { .compatible = "nxp,lpc3220-rtc" },
 393         { }
 394 };
 395 MODULE_DEVICE_TABLE(of, lpc32xx_rtc_match);
 396 #endif
 397
 398 static struct platform_driver lpc32xx_rtc_driver = {
 399         .probe          = lpc32xx_rtc_probe,
 400         .remove         = lpc32xx_rtc_remove,
 401         .driver = {
 402                 .name   = RTC_NAME,
 403                 .owner  = THIS_MODULE,
 404                 .pm     = LPC32XX_RTC_PM_OPS,
 405                 .of_match_table = of_match_ptr(lpc32xx_rtc_match),
 406         },
 407 };
 408
 409 module_platform_driver(lpc32xx_rtc_driver);
 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");