kernel/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         int rtcirq;
 205         u32 tmp;
 206
 207         rtcirq = platform_get_irq(pdev, 0);
 208         if (rtcirq < 0 || rtcirq >= NR_IRQS) {
 209                 dev_warn(&pdev->dev, "Can't get interrupt resource\n");
 210                 rtcirq = -1;
 211         }
 212
 213         rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
 214         if (unlikely(!rtc))
 215                 return -ENOMEM;
 216
 217         rtc->irq = rtcirq;
 218
 219         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 220         rtc->rtc_base = devm_ioremap_resource(&pdev->dev, res);
 221         if (IS_ERR(rtc->rtc_base))
 222                 return PTR_ERR(rtc->rtc_base);
 223
 224         spin_lock_init(&rtc->lock);
 225
 226         /*
 227          * The RTC is on a separate power domain and can keep it's state
 228          * across a chip power cycle. If the RTC has never been previously
 229          * setup, then set it up now for the first time.
 230          */
 231         tmp = rtc_readl(rtc, LPC32XX_RTC_CTRL);
 232         if (rtc_readl(rtc, LPC32XX_RTC_KEY) != LPC32XX_RTC_KEY_ONSW_LOADVAL) {
 233                 tmp &= ~(LPC32XX_RTC_CTRL_SW_RESET |
 234                         LPC32XX_RTC_CTRL_CNTR_DIS |
 235                         LPC32XX_RTC_CTRL_MATCH0 |
 236                         LPC32XX_RTC_CTRL_MATCH1 |
 237                         LPC32XX_RTC_CTRL_ONSW_MATCH0 |
 238                         LPC32XX_RTC_CTRL_ONSW_MATCH1 |
 239                         LPC32XX_RTC_CTRL_ONSW_FORCE_HI);
 240                 rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp);
 241
 242                 /* Clear latched interrupt states */
 243                 rtc_writel(rtc, LPC32XX_RTC_MATCH0, 0xFFFFFFFF);
 244                 rtc_writel(rtc, LPC32XX_RTC_INTSTAT,
 245                            LPC32XX_RTC_INTSTAT_MATCH0 |
 246                            LPC32XX_RTC_INTSTAT_MATCH1 |
 247                            LPC32XX_RTC_INTSTAT_ONSW);
 248
 249                 /* Write key value to RTC so it won't reload on reset */
 250                 rtc_writel(rtc, LPC32XX_RTC_KEY,
 251                            LPC32XX_RTC_KEY_ONSW_LOADVAL);
 252         } else {
 253                 rtc_writel(rtc, LPC32XX_RTC_CTRL,
 254                            tmp & ~LPC32XX_RTC_CTRL_MATCH0);
 255         }
 256
 257         platform_set_drvdata(pdev, rtc);
 258
 259         rtc->rtc = devm_rtc_device_register(&pdev->dev, RTC_NAME,
 260                                         &lpc32xx_rtc_ops, THIS_MODULE);
 261         if (IS_ERR(rtc->rtc)) {
 262                 dev_err(&pdev->dev, "Can't get RTC\n");
 263                 return PTR_ERR(rtc->rtc);
 264         }
 265
 266         /*
 267          * IRQ is enabled after device registration in case alarm IRQ
 268          * is pending upon suspend exit.
 269          */
 270         if (rtc->irq >= 0) {
 271                 if (devm_request_irq(&pdev->dev, rtc->irq,
 272                                      lpc32xx_rtc_alarm_interrupt,
 273                                      0, pdev->name, rtc) < 0) {
 274                         dev_warn(&pdev->dev, "Can't request interrupt.\n");
 275                         rtc->irq = -1;
 276                 } else {
 277                         device_init_wakeup(&pdev->dev, 1);
 278                 }
 279         }
 280
 281         return 0;
 282 }
 283
 284 static int lpc32xx_rtc_remove(struct platform_device *pdev)
 285 {
 286         struct lpc32xx_rtc *rtc = platform_get_drvdata(pdev);
 287
 288         if (rtc->irq >= 0)
 289                 device_init_wakeup(&pdev->dev, 0);
 290
 291         return 0;
 292 }
 293
 294 #ifdef CONFIG_PM
 295 static int lpc32xx_rtc_suspend(struct device *dev)
 296 {
 297         struct platform_device *pdev = to_platform_device(dev);
 298         struct lpc32xx_rtc *rtc = platform_get_drvdata(pdev);
 299
 300         if (rtc->irq >= 0) {
 301                 if (device_may_wakeup(&pdev->dev))
 302                         enable_irq_wake(rtc->irq);
 303                 else
 304                         disable_irq_wake(rtc->irq);
 305         }
 306
 307         return 0;
 308 }
 309
 310 static int lpc32xx_rtc_resume(struct device *dev)
 311 {
 312         struct platform_device *pdev = to_platform_device(dev);
 313         struct lpc32xx_rtc *rtc = platform_get_drvdata(pdev);
 314
 315         if (rtc->irq >= 0 && device_may_wakeup(&pdev->dev))
 316                 disable_irq_wake(rtc->irq);
 317
 318         return 0;
 319 }
 320
 321 /* Unconditionally disable the alarm */
 322 static int lpc32xx_rtc_freeze(struct device *dev)
 323 {
 324         struct platform_device *pdev = to_platform_device(dev);
 325         struct lpc32xx_rtc *rtc = platform_get_drvdata(pdev);
 326
 327         spin_lock_irq(&rtc->lock);
 328
 329         rtc_writel(rtc, LPC32XX_RTC_CTRL,
 330                 rtc_readl(rtc, LPC32XX_RTC_CTRL) &
 331                           ~LPC32XX_RTC_CTRL_MATCH0);
 332
 333         spin_unlock_irq(&rtc->lock);
 334
 335         return 0;
 336 }
 337
 338 static int lpc32xx_rtc_thaw(struct device *dev)
 339 {
 340         struct platform_device *pdev = to_platform_device(dev);
 341         struct lpc32xx_rtc *rtc = platform_get_drvdata(pdev);
 342
 343         if (rtc->alarm_enabled) {
 344                 spin_lock_irq(&rtc->lock);
 345
 346                 rtc_writel(rtc, LPC32XX_RTC_CTRL,
 347                            rtc_readl(rtc, LPC32XX_RTC_CTRL) |
 348                            LPC32XX_RTC_CTRL_MATCH0);
 349
 350                 spin_unlock_irq(&rtc->lock);
 351         }
 352
 353         return 0;
 354 }
 355
 356 static const struct dev_pm_ops lpc32xx_rtc_pm_ops = {
 357         .suspend = lpc32xx_rtc_suspend,
 358         .resume = lpc32xx_rtc_resume,
 359         .freeze = lpc32xx_rtc_freeze,
 360         .thaw = lpc32xx_rtc_thaw,
 361         .restore = lpc32xx_rtc_resume
 362 };
 363
 364 #define LPC32XX_RTC_PM_OPS (&lpc32xx_rtc_pm_ops)
 365 #else
 366 #define LPC32XX_RTC_PM_OPS NULL
 367 #endif
 368
 369 #ifdef CONFIG_OF
 370 static const struct of_device_id lpc32xx_rtc_match[] = {
 371         { .compatible = "nxp,lpc3220-rtc" },
 372         { }
 373 };
 374 MODULE_DEVICE_TABLE(of, lpc32xx_rtc_match);
 375 #endif
 376
 377 static struct platform_driver lpc32xx_rtc_driver = {
 378         .probe          = lpc32xx_rtc_probe,
 379         .remove         = lpc32xx_rtc_remove,
 380         .driver = {
 381                 .name   = RTC_NAME,
 382                 .pm     = LPC32XX_RTC_PM_OPS,
 383                 .of_match_table = of_match_ptr(lpc32xx_rtc_match),
 384         },
 385 };
 386
 387 module_platform_driver(lpc32xx_rtc_driver);
 388
 389 MODULE_AUTHOR("Kevin Wells <wellsk40@gmail.com");
 390 MODULE_DESCRIPTION("RTC driver for the LPC32xx SoC");
 391 MODULE_LICENSE("GPL");
 392 MODULE_ALIAS("platform:rtc-lpc32xx");