drivers/rtc/rtc-lpc32xx.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright (C) 2010 NXP Semiconductors
   4  */
   5
   6 #include <linux/kernel.h>
   7 #include <linux/module.h>
   8 #include <linux/init.h>
   9 #include <linux/platform_device.h>
  10 #include <linux/spinlock.h>
  11 #include <linux/rtc.h>
  12 #include <linux/slab.h>
  13 #include <linux/io.h>
  14 #include <linux/of.h>
  15
  16 /*
  17  * Clock and Power control register offsets
  18  */
  19 #define LPC32XX_RTC_UCOUNT              0x00
  20 #define LPC32XX_RTC_DCOUNT              0x04
  21 #define LPC32XX_RTC_MATCH0              0x08
  22 #define LPC32XX_RTC_MATCH1              0x0C
  23 #define LPC32XX_RTC_CTRL                0x10
  24 #define LPC32XX_RTC_INTSTAT             0x14
  25 #define LPC32XX_RTC_KEY                 0x18
  26 #define LPC32XX_RTC_SRAM                0x80
  27
  28 #define LPC32XX_RTC_CTRL_MATCH0         (1 << 0)
  29 #define LPC32XX_RTC_CTRL_MATCH1         (1 << 1)
  30 #define LPC32XX_RTC_CTRL_ONSW_MATCH0    (1 << 2)
  31 #define LPC32XX_RTC_CTRL_ONSW_MATCH1    (1 << 3)
  32 #define LPC32XX_RTC_CTRL_SW_RESET       (1 << 4)
  33 #define LPC32XX_RTC_CTRL_CNTR_DIS       (1 << 6)
  34 #define LPC32XX_RTC_CTRL_ONSW_FORCE_HI  (1 << 7)
  35
  36 #define LPC32XX_RTC_INTSTAT_MATCH0      (1 << 0)
  37 #define LPC32XX_RTC_INTSTAT_MATCH1      (1 << 1)
  38 #define LPC32XX_RTC_INTSTAT_ONSW        (1 << 2)
  39
  40 #define LPC32XX_RTC_KEY_ONSW_LOADVAL    0xB5C13F27
  41
  42 #define rtc_readl(dev, reg) \
  43         __raw_readl((dev)->rtc_base + (reg))
  44 #define rtc_writel(dev, reg, val) \
  45         __raw_writel((val), (dev)->rtc_base + (reg))
  46
  47 struct lpc32xx_rtc {
  48         void __iomem *rtc_base;
  49         int irq;
  50         unsigned char alarm_enabled;
  51         struct rtc_device *rtc;
  52         spinlock_t lock;
  53 };
  54
  55 static int lpc32xx_rtc_read_time(struct device *dev, struct rtc_time *time)
  56 {
  57         unsigned long elapsed_sec;
  58         struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
  59
  60         elapsed_sec = rtc_readl(rtc, LPC32XX_RTC_UCOUNT);
  61         rtc_time64_to_tm(elapsed_sec, time);
  62
  63         return 0;
  64 }
  65
  66 static int lpc32xx_rtc_set_time(struct device *dev, struct rtc_time *time)
  67 {
  68         struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
  69         u32 secs = rtc_tm_to_time64(time);
  70         u32 tmp;
  71
  72         spin_lock_irq(&rtc->lock);
  73
  74         /* RTC must be disabled during count update */
  75         tmp = rtc_readl(rtc, LPC32XX_RTC_CTRL);
  76         rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp | LPC32XX_RTC_CTRL_CNTR_DIS);
  77         rtc_writel(rtc, LPC32XX_RTC_UCOUNT, secs);
  78         rtc_writel(rtc, LPC32XX_RTC_DCOUNT, 0xFFFFFFFF - secs);
  79         rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp &= ~LPC32XX_RTC_CTRL_CNTR_DIS);
  80
  81         spin_unlock_irq(&rtc->lock);
  82
  83         return 0;
  84 }
  85
  86 static int lpc32xx_rtc_read_alarm(struct device *dev,
  87         struct rtc_wkalrm *wkalrm)
  88 {
  89         struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
  90
  91         rtc_time64_to_tm(rtc_readl(rtc, LPC32XX_RTC_MATCH0), &wkalrm->time);
  92         wkalrm->enabled = rtc->alarm_enabled;
  93         wkalrm->pending = !!(rtc_readl(rtc, LPC32XX_RTC_INTSTAT) &
  94                 LPC32XX_RTC_INTSTAT_MATCH0);
  95
  96         return rtc_valid_tm(&wkalrm->time);
  97 }
  98
  99 static int lpc32xx_rtc_set_alarm(struct device *dev,
 100         struct rtc_wkalrm *wkalrm)
 101 {
 102         struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
 103         unsigned long alarmsecs;
 104         u32 tmp;
 105
 106         alarmsecs = rtc_tm_to_time64(&wkalrm->time);
 107
 108         spin_lock_irq(&rtc->lock);
 109
 110         /* Disable alarm during update */
 111         tmp = rtc_readl(rtc, LPC32XX_RTC_CTRL);
 112         rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp & ~LPC32XX_RTC_CTRL_MATCH0);
 113
 114         rtc_writel(rtc, LPC32XX_RTC_MATCH0, alarmsecs);
 115
 116         rtc->alarm_enabled = wkalrm->enabled;
 117         if (wkalrm->enabled) {
 118                 rtc_writel(rtc, LPC32XX_RTC_INTSTAT,
 119                            LPC32XX_RTC_INTSTAT_MATCH0);
 120                 rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp |
 121                            LPC32XX_RTC_CTRL_MATCH0);
 122         }
 123
 124         spin_unlock_irq(&rtc->lock);
 125
 126         return 0;
 127 }
 128
 129 static int lpc32xx_rtc_alarm_irq_enable(struct device *dev,
 130         unsigned int enabled)
 131 {
 132         struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
 133         u32 tmp;
 134
 135         spin_lock_irq(&rtc->lock);
 136         tmp = rtc_readl(rtc, LPC32XX_RTC_CTRL);
 137
 138         if (enabled) {
 139                 rtc->alarm_enabled = 1;
 140                 tmp |= LPC32XX_RTC_CTRL_MATCH0;
 141         } else {
 142                 rtc->alarm_enabled = 0;
 143                 tmp &= ~LPC32XX_RTC_CTRL_MATCH0;
 144         }
 145
 146         rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp);
 147         spin_unlock_irq(&rtc->lock);
 148
 149         return 0;
 150 }
 151
 152 static irqreturn_t lpc32xx_rtc_alarm_interrupt(int irq, void *dev)
 153 {
 154         struct lpc32xx_rtc *rtc = dev;
 155
 156         spin_lock(&rtc->lock);
 157
 158         /* Disable alarm interrupt */
 159         rtc_writel(rtc, LPC32XX_RTC_CTRL,
 160                 rtc_readl(rtc, LPC32XX_RTC_CTRL) &
 161                           ~LPC32XX_RTC_CTRL_MATCH0);
 162         rtc->alarm_enabled = 0;
 163
 164         /*
 165          * Write a large value to the match value so the RTC won't
 166          * keep firing the match status
 167          */
 168         rtc_writel(rtc, LPC32XX_RTC_MATCH0, 0xFFFFFFFF);
 169         rtc_writel(rtc, LPC32XX_RTC_INTSTAT, LPC32XX_RTC_INTSTAT_MATCH0);
 170
 171         spin_unlock(&rtc->lock);
 172
 173         rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_AF);
 174
 175         return IRQ_HANDLED;
 176 }
 177
 178 static const struct rtc_class_ops lpc32xx_rtc_ops = {
 179         .read_time              = lpc32xx_rtc_read_time,
 180         .set_time               = lpc32xx_rtc_set_time,
 181         .read_alarm             = lpc32xx_rtc_read_alarm,
 182         .set_alarm              = lpc32xx_rtc_set_alarm,
 183         .alarm_irq_enable       = lpc32xx_rtc_alarm_irq_enable,
 184 };
 185
 186 static int lpc32xx_rtc_probe(struct platform_device *pdev)
 187 {
 188         struct lpc32xx_rtc *rtc;
 189         int err;
 190         u32 tmp;
 191
 192         rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
 193         if (unlikely(!rtc))
 194                 return -ENOMEM;
 195
 196         rtc->rtc_base = devm_platform_ioremap_resource(pdev, 0);
 197         if (IS_ERR(rtc->rtc_base))
 198                 return PTR_ERR(rtc->rtc_base);
 199
 200         spin_lock_init(&rtc->lock);
 201
 202         /*
 203          * The RTC is on a separate power domain and can keep it's state
 204          * across a chip power cycle. If the RTC has never been previously
 205          * setup, then set it up now for the first time.
 206          */
 207         tmp = rtc_readl(rtc, LPC32XX_RTC_CTRL);
 208         if (rtc_readl(rtc, LPC32XX_RTC_KEY) != LPC32XX_RTC_KEY_ONSW_LOADVAL) {
 209                 tmp &= ~(LPC32XX_RTC_CTRL_SW_RESET |
 210                         LPC32XX_RTC_CTRL_CNTR_DIS |
 211                         LPC32XX_RTC_CTRL_MATCH0 |
 212                         LPC32XX_RTC_CTRL_MATCH1 |
 213                         LPC32XX_RTC_CTRL_ONSW_MATCH0 |
 214                         LPC32XX_RTC_CTRL_ONSW_MATCH1 |
 215                         LPC32XX_RTC_CTRL_ONSW_FORCE_HI);
 216                 rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp);
 217
 218                 /* Clear latched interrupt states */
 219                 rtc_writel(rtc, LPC32XX_RTC_MATCH0, 0xFFFFFFFF);
 220                 rtc_writel(rtc, LPC32XX_RTC_INTSTAT,
 221                            LPC32XX_RTC_INTSTAT_MATCH0 |
 222                            LPC32XX_RTC_INTSTAT_MATCH1 |
 223                            LPC32XX_RTC_INTSTAT_ONSW);
 224
 225                 /* Write key value to RTC so it won't reload on reset */
 226                 rtc_writel(rtc, LPC32XX_RTC_KEY,
 227                            LPC32XX_RTC_KEY_ONSW_LOADVAL);
 228         } else {
 229                 rtc_writel(rtc, LPC32XX_RTC_CTRL,
 230                            tmp & ~LPC32XX_RTC_CTRL_MATCH0);
 231         }
 232
 233         platform_set_drvdata(pdev, rtc);
 234
 235         rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
 236         if (IS_ERR(rtc->rtc))
 237                 return PTR_ERR(rtc->rtc);
 238
 239         rtc->rtc->ops = &lpc32xx_rtc_ops;
 240         rtc->rtc->range_max = U32_MAX;
 241
 242         err = devm_rtc_register_device(rtc->rtc);
 243         if (err)
 244                 return err;
 245
 246         /*
 247          * IRQ is enabled after device registration in case alarm IRQ
 248          * is pending upon suspend exit.
 249          */
 250         rtc->irq = platform_get_irq(pdev, 0);
 251         if (rtc->irq < 0) {
 252                 dev_warn(&pdev->dev, "Can't get interrupt resource\n");
 253         } else {
 254                 if (devm_request_irq(&pdev->dev, rtc->irq,
 255                                      lpc32xx_rtc_alarm_interrupt,
 256                                      0, pdev->name, rtc) < 0) {
 257                         dev_warn(&pdev->dev, "Can't request interrupt.\n");
 258                         rtc->irq = -1;
 259                 } else {
 260                         device_init_wakeup(&pdev->dev, 1);
 261                 }
 262         }
 263
 264         return 0;
 265 }
 266
 267 #ifdef CONFIG_PM
 268 static int lpc32xx_rtc_suspend(struct device *dev)
 269 {
 270         struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
 271
 272         if (rtc->irq >= 0) {
 273                 if (device_may_wakeup(dev))
 274                         enable_irq_wake(rtc->irq);
 275                 else
 276                         disable_irq_wake(rtc->irq);
 277         }
 278
 279         return 0;
 280 }
 281
 282 static int lpc32xx_rtc_resume(struct device *dev)
 283 {
 284         struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
 285
 286         if (rtc->irq >= 0 && device_may_wakeup(dev))
 287                 disable_irq_wake(rtc->irq);
 288
 289         return 0;
 290 }
 291
 292 /* Unconditionally disable the alarm */
 293 static int lpc32xx_rtc_freeze(struct device *dev)
 294 {
 295         struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
 296
 297         spin_lock_irq(&rtc->lock);
 298
 299         rtc_writel(rtc, LPC32XX_RTC_CTRL,
 300                 rtc_readl(rtc, LPC32XX_RTC_CTRL) &
 301                           ~LPC32XX_RTC_CTRL_MATCH0);
 302
 303         spin_unlock_irq(&rtc->lock);
 304
 305         return 0;
 306 }
 307
 308 static int lpc32xx_rtc_thaw(struct device *dev)
 309 {
 310         struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
 311
 312         if (rtc->alarm_enabled) {
 313                 spin_lock_irq(&rtc->lock);
 314
 315                 rtc_writel(rtc, LPC32XX_RTC_CTRL,
 316                            rtc_readl(rtc, LPC32XX_RTC_CTRL) |
 317                            LPC32XX_RTC_CTRL_MATCH0);
 318
 319                 spin_unlock_irq(&rtc->lock);
 320         }
 321
 322         return 0;
 323 }
 324
 325 static const struct dev_pm_ops lpc32xx_rtc_pm_ops = {
 326         .suspend = lpc32xx_rtc_suspend,
 327         .resume = lpc32xx_rtc_resume,
 328         .freeze = lpc32xx_rtc_freeze,
 329         .thaw = lpc32xx_rtc_thaw,
 330         .restore = lpc32xx_rtc_resume
 331 };
 332
 333 #define LPC32XX_RTC_PM_OPS (&lpc32xx_rtc_pm_ops)
 334 #else
 335 #define LPC32XX_RTC_PM_OPS NULL
 336 #endif
 337
 338 #ifdef CONFIG_OF
 339 static const struct of_device_id lpc32xx_rtc_match[] = {
 340         { .compatible = "nxp,lpc3220-rtc" },
 341         { }
 342 };
 343 MODULE_DEVICE_TABLE(of, lpc32xx_rtc_match);
 344 #endif
 345
 346 static struct platform_driver lpc32xx_rtc_driver = {
 347         .probe          = lpc32xx_rtc_probe,
 348         .driver = {
 349                 .name   = "rtc-lpc32xx",
 350                 .pm     = LPC32XX_RTC_PM_OPS,
 351                 .of_match_table = of_match_ptr(lpc32xx_rtc_match),
 352         },
 353 };
 354
 355 module_platform_driver(lpc32xx_rtc_driver);
 356
 357 MODULE_AUTHOR("Kevin Wells <wellsk40@gmail.com");
 358 MODULE_DESCRIPTION("RTC driver for the LPC32xx SoC");
 359 MODULE_LICENSE("GPL");
 360 MODULE_ALIAS("platform:rtc-lpc32xx");