kernel/drivers/rtc/rtc-sirfsoc.c

   1 /*
   2  * SiRFSoC Real Time Clock interface for Linux
   3  *
   4  * Copyright (c) 2013 Cambridge Silicon Radio Limited, a CSR plc group company.
   5  *
   6  * Licensed under GPLv2 or later.
   7  */
   8
   9 #include <linux/module.h>
  10 #include <linux/err.h>
  11 #include <linux/rtc.h>
  12 #include <linux/platform_device.h>
  13 #include <linux/slab.h>
  14 #include <linux/io.h>
  15 #include <linux/of.h>
  16 #include <linux/rtc/sirfsoc_rtciobrg.h>
  17
  18
  19 #define RTC_CN                  0x00
  20 #define RTC_ALARM0              0x04
  21 #define RTC_ALARM1              0x18
  22 #define RTC_STATUS              0x08
  23 #define RTC_SW_VALUE            0x40
  24 #define SIRFSOC_RTC_AL1E        (1<<6)
  25 #define SIRFSOC_RTC_AL1         (1<<4)
  26 #define SIRFSOC_RTC_HZE         (1<<3)
  27 #define SIRFSOC_RTC_AL0E        (1<<2)
  28 #define SIRFSOC_RTC_HZ          (1<<1)
  29 #define SIRFSOC_RTC_AL0         (1<<0)
  30 #define RTC_DIV                 0x0c
  31 #define RTC_DEEP_CTRL           0x14
  32 #define RTC_CLOCK_SWITCH        0x1c
  33 #define SIRFSOC_RTC_CLK         0x03    /* others are reserved */
  34
  35 /* Refer to RTC DIV switch */
  36 #define RTC_HZ                  16
  37
  38 /* This macro is also defined in arch/arm/plat-sirfsoc/cpu.c */
  39 #define RTC_SHIFT               4
  40
  41 #define INTR_SYSRTC_CN          0x48
  42
  43 struct sirfsoc_rtc_drv {
  44         struct rtc_device       *rtc;
  45         u32                     rtc_base;
  46         u32                     irq;
  47         unsigned                irq_wake;
  48         /* Overflow for every 8 years extra time */
  49         u32                     overflow_rtc;
  50         spinlock_t              lock;
  51 #ifdef CONFIG_PM
  52         u32             saved_counter;
  53         u32             saved_overflow_rtc;
  54 #endif
  55 };
  56
  57 static int sirfsoc_rtc_read_alarm(struct device *dev,
  58                 struct rtc_wkalrm *alrm)
  59 {
  60         unsigned long rtc_alarm, rtc_count;
  61         struct sirfsoc_rtc_drv *rtcdrv;
  62
  63         rtcdrv = dev_get_drvdata(dev);
  64
  65         spin_lock_irq(&rtcdrv->lock);
  66
  67         rtc_count = sirfsoc_rtc_iobrg_readl(rtcdrv->rtc_base + RTC_CN);
  68
  69         rtc_alarm = sirfsoc_rtc_iobrg_readl(rtcdrv->rtc_base + RTC_ALARM0);
  70         memset(alrm, 0, sizeof(struct rtc_wkalrm));
  71
  72         /*
  73          * assume alarm interval not beyond one round counter overflow_rtc:
  74          * 0->0xffffffff
  75          */
  76         /* if alarm is in next overflow cycle */
  77         if (rtc_count > rtc_alarm)
  78                 rtc_time_to_tm((rtcdrv->overflow_rtc + 1)
  79                                 << (BITS_PER_LONG - RTC_SHIFT)
  80                                 | rtc_alarm >> RTC_SHIFT, &(alrm->time));
  81         else
  82                 rtc_time_to_tm(rtcdrv->overflow_rtc
  83                                 << (BITS_PER_LONG - RTC_SHIFT)
  84                                 | rtc_alarm >> RTC_SHIFT, &(alrm->time));
  85         if (sirfsoc_rtc_iobrg_readl(
  86                         rtcdrv->rtc_base + RTC_STATUS) & SIRFSOC_RTC_AL0E)
  87                 alrm->enabled = 1;
  88
  89         spin_unlock_irq(&rtcdrv->lock);
  90
  91         return 0;
  92 }
  93
  94 static int sirfsoc_rtc_set_alarm(struct device *dev,
  95                 struct rtc_wkalrm *alrm)
  96 {
  97         unsigned long rtc_status_reg, rtc_alarm;
  98         struct sirfsoc_rtc_drv *rtcdrv;
  99         rtcdrv = dev_get_drvdata(dev);
 100
 101         if (alrm->enabled) {
 102                 rtc_tm_to_time(&(alrm->time), &rtc_alarm);
 103
 104                 spin_lock_irq(&rtcdrv->lock);
 105
 106                 rtc_status_reg = sirfsoc_rtc_iobrg_readl(
 107                                 rtcdrv->rtc_base + RTC_STATUS);
 108                 if (rtc_status_reg & SIRFSOC_RTC_AL0E) {
 109                         /*
 110                          * An ongoing alarm in progress - ingore it and not
 111                          * to return EBUSY
 112                          */
 113                         dev_info(dev, "An old alarm was set, will be replaced by a new one\n");
 114                 }
 115
 116                 sirfsoc_rtc_iobrg_writel(
 117                         rtc_alarm << RTC_SHIFT, rtcdrv->rtc_base + RTC_ALARM0);
 118                 rtc_status_reg &= ~0x07; /* mask out the lower status bits */
 119                 /*
 120                  * This bit RTC_AL sets it as a wake-up source for Sleep Mode
 121                  * Writing 1 into this bit will clear it
 122                  */
 123                 rtc_status_reg |= SIRFSOC_RTC_AL0;
 124                 /* enable the RTC alarm interrupt */
 125                 rtc_status_reg |= SIRFSOC_RTC_AL0E;
 126                 sirfsoc_rtc_iobrg_writel(
 127                         rtc_status_reg, rtcdrv->rtc_base + RTC_STATUS);
 128
 129                 spin_unlock_irq(&rtcdrv->lock);
 130         } else {
 131                 /*
 132                  * if this function was called with enabled=0
 133                  * then it could mean that the application is
 134                  * trying to cancel an ongoing alarm
 135                  */
 136                 spin_lock_irq(&rtcdrv->lock);
 137
 138                 rtc_status_reg = sirfsoc_rtc_iobrg_readl(
 139                                 rtcdrv->rtc_base + RTC_STATUS);
 140                 if (rtc_status_reg & SIRFSOC_RTC_AL0E) {
 141                         /* clear the RTC status register's alarm bit */
 142                         rtc_status_reg &= ~0x07;
 143                         /* write 1 into SIRFSOC_RTC_AL0 to force a clear */
 144                         rtc_status_reg |= (SIRFSOC_RTC_AL0);
 145                         /* Clear the Alarm enable bit */
 146                         rtc_status_reg &= ~(SIRFSOC_RTC_AL0E);
 147
 148                         sirfsoc_rtc_iobrg_writel(rtc_status_reg,
 149                                         rtcdrv->rtc_base + RTC_STATUS);
 150                 }
 151
 152                 spin_unlock_irq(&rtcdrv->lock);
 153         }
 154
 155         return 0;
 156 }
 157
 158 static int sirfsoc_rtc_read_time(struct device *dev,
 159                 struct rtc_time *tm)
 160 {
 161         unsigned long tmp_rtc = 0;
 162         struct sirfsoc_rtc_drv *rtcdrv;
 163         rtcdrv = dev_get_drvdata(dev);
 164         /*
 165          * This patch is taken from WinCE - Need to validate this for
 166          * correctness. To work around sirfsoc RTC counter double sync logic
 167          * fail, read several times to make sure get stable value.
 168          */
 169         do {
 170                 tmp_rtc = sirfsoc_rtc_iobrg_readl(rtcdrv->rtc_base + RTC_CN);
 171                 cpu_relax();
 172         } while (tmp_rtc != sirfsoc_rtc_iobrg_readl(rtcdrv->rtc_base + RTC_CN));
 173
 174         rtc_time_to_tm(rtcdrv->overflow_rtc << (BITS_PER_LONG - RTC_SHIFT) |
 175                                         tmp_rtc >> RTC_SHIFT, tm);
 176         return 0;
 177 }
 178
 179 static int sirfsoc_rtc_set_time(struct device *dev,
 180                 struct rtc_time *tm)
 181 {
 182         unsigned long rtc_time;
 183         struct sirfsoc_rtc_drv *rtcdrv;
 184         rtcdrv = dev_get_drvdata(dev);
 185
 186         rtc_tm_to_time(tm, &rtc_time);
 187
 188         rtcdrv->overflow_rtc = rtc_time >> (BITS_PER_LONG - RTC_SHIFT);
 189
 190         sirfsoc_rtc_iobrg_writel(rtcdrv->overflow_rtc,
 191                         rtcdrv->rtc_base + RTC_SW_VALUE);
 192         sirfsoc_rtc_iobrg_writel(
 193                         rtc_time << RTC_SHIFT, rtcdrv->rtc_base + RTC_CN);
 194
 195         return 0;
 196 }
 197
 198 static int sirfsoc_rtc_ioctl(struct device *dev, unsigned int cmd,
 199                 unsigned long arg)
 200 {
 201         switch (cmd) {
 202         case RTC_PIE_ON:
 203         case RTC_PIE_OFF:
 204         case RTC_UIE_ON:
 205         case RTC_UIE_OFF:
 206         case RTC_AIE_ON:
 207         case RTC_AIE_OFF:
 208                 return 0;
 209
 210         default:
 211                 return -ENOIOCTLCMD;
 212         }
 213 }
 214
 215 static int sirfsoc_rtc_alarm_irq_enable(struct device *dev,
 216                 unsigned int enabled)
 217 {
 218         unsigned long rtc_status_reg = 0x0;
 219         struct sirfsoc_rtc_drv *rtcdrv;
 220
 221         rtcdrv = dev_get_drvdata(dev);
 222
 223         spin_lock_irq(&rtcdrv->lock);
 224
 225         rtc_status_reg = sirfsoc_rtc_iobrg_readl(
 226                                 rtcdrv->rtc_base + RTC_STATUS);
 227         if (enabled)
 228                 rtc_status_reg |= SIRFSOC_RTC_AL0E;
 229         else
 230                 rtc_status_reg &= ~SIRFSOC_RTC_AL0E;
 231
 232         sirfsoc_rtc_iobrg_writel(rtc_status_reg, rtcdrv->rtc_base + RTC_STATUS);
 233
 234         spin_unlock_irq(&rtcdrv->lock);
 235
 236         return 0;
 237
 238 }
 239
 240 static const struct rtc_class_ops sirfsoc_rtc_ops = {
 241         .read_time = sirfsoc_rtc_read_time,
 242         .set_time = sirfsoc_rtc_set_time,
 243         .read_alarm = sirfsoc_rtc_read_alarm,
 244         .set_alarm = sirfsoc_rtc_set_alarm,
 245         .ioctl = sirfsoc_rtc_ioctl,
 246         .alarm_irq_enable = sirfsoc_rtc_alarm_irq_enable
 247 };
 248
 249 static irqreturn_t sirfsoc_rtc_irq_handler(int irq, void *pdata)
 250 {
 251         struct sirfsoc_rtc_drv *rtcdrv = pdata;
 252         unsigned long rtc_status_reg = 0x0;
 253         unsigned long events = 0x0;
 254
 255         spin_lock(&rtcdrv->lock);
 256
 257         rtc_status_reg = sirfsoc_rtc_iobrg_readl(rtcdrv->rtc_base + RTC_STATUS);
 258         /* this bit will be set ONLY if an alarm was active
 259          * and it expired NOW
 260          * So this is being used as an ASSERT
 261          */
 262         if (rtc_status_reg & SIRFSOC_RTC_AL0) {
 263                 /*
 264                  * clear the RTC status register's alarm bit
 265                  * mask out the lower status bits
 266                  */
 267                 rtc_status_reg &= ~0x07;
 268                 /* write 1 into SIRFSOC_RTC_AL0 to ACK the alarm interrupt */
 269                 rtc_status_reg |= (SIRFSOC_RTC_AL0);
 270                 /* Clear the Alarm enable bit */
 271                 rtc_status_reg &= ~(SIRFSOC_RTC_AL0E);
 272         }
 273         sirfsoc_rtc_iobrg_writel(rtc_status_reg, rtcdrv->rtc_base + RTC_STATUS);
 274
 275         spin_unlock(&rtcdrv->lock);
 276
 277         /* this should wake up any apps polling/waiting on the read
 278          * after setting the alarm
 279          */
 280         events |= RTC_IRQF | RTC_AF;
 281         rtc_update_irq(rtcdrv->rtc, 1, events);
 282
 283         return IRQ_HANDLED;
 284 }
 285
 286 static const struct of_device_id sirfsoc_rtc_of_match[] = {
 287         { .compatible = "sirf,prima2-sysrtc"},
 288         {},
 289 };
 290 MODULE_DEVICE_TABLE(of, sirfsoc_rtc_of_match);
 291
 292 static int sirfsoc_rtc_probe(struct platform_device *pdev)
 293 {
 294         int err;
 295         unsigned long rtc_div;
 296         struct sirfsoc_rtc_drv *rtcdrv;
 297         struct device_node *np = pdev->dev.of_node;
 298
 299         rtcdrv = devm_kzalloc(&pdev->dev,
 300                 sizeof(struct sirfsoc_rtc_drv), GFP_KERNEL);
 301         if (rtcdrv == NULL)
 302                 return -ENOMEM;
 303
 304         spin_lock_init(&rtcdrv->lock);
 305
 306         err = of_property_read_u32(np, "reg", &rtcdrv->rtc_base);
 307         if (err) {
 308                 dev_err(&pdev->dev, "unable to find base address of rtc node in dtb\n");
 309                 return err;
 310         }
 311
 312         platform_set_drvdata(pdev, rtcdrv);
 313
 314         /* Register rtc alarm as a wakeup source */
 315         device_init_wakeup(&pdev->dev, 1);
 316
 317         /*
 318          * Set SYS_RTC counter in RTC_HZ HZ Units
 319          * We are using 32K RTC crystal (32768 / RTC_HZ / 2) -1
 320          * If 16HZ, therefore RTC_DIV = 1023;
 321          */
 322         rtc_div = ((32768 / RTC_HZ) / 2) - 1;
 323         sirfsoc_rtc_iobrg_writel(rtc_div, rtcdrv->rtc_base + RTC_DIV);
 324
 325         /* 0x3 -> RTC_CLK */
 326         sirfsoc_rtc_iobrg_writel(SIRFSOC_RTC_CLK,
 327                         rtcdrv->rtc_base + RTC_CLOCK_SWITCH);
 328
 329         /* reset SYS RTC ALARM0 */
 330         sirfsoc_rtc_iobrg_writel(0x0, rtcdrv->rtc_base + RTC_ALARM0);
 331
 332         /* reset SYS RTC ALARM1 */
 333         sirfsoc_rtc_iobrg_writel(0x0, rtcdrv->rtc_base + RTC_ALARM1);
 334
 335         /* Restore RTC Overflow From Register After Command Reboot */
 336         rtcdrv->overflow_rtc =
 337                 sirfsoc_rtc_iobrg_readl(rtcdrv->rtc_base + RTC_SW_VALUE);
 338
 339         rtcdrv->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
 340                         &sirfsoc_rtc_ops, THIS_MODULE);
 341         if (IS_ERR(rtcdrv->rtc)) {
 342                 err = PTR_ERR(rtcdrv->rtc);
 343                 dev_err(&pdev->dev, "can't register RTC device\n");
 344                 return err;
 345         }
 346
 347         rtcdrv->irq = platform_get_irq(pdev, 0);
 348         err = devm_request_irq(
 349                         &pdev->dev,
 350                         rtcdrv->irq,
 351                         sirfsoc_rtc_irq_handler,
 352                         IRQF_SHARED,
 353                         pdev->name,
 354                         rtcdrv);
 355         if (err) {
 356                 dev_err(&pdev->dev, "Unable to register for the SiRF SOC RTC IRQ\n");
 357                 return err;
 358         }
 359
 360         return 0;
 361 }
 362
 363 static int sirfsoc_rtc_remove(struct platform_device *pdev)
 364 {
 365         device_init_wakeup(&pdev->dev, 0);
 366
 367         return 0;
 368 }
 369
 370 #ifdef CONFIG_PM_SLEEP
 371 static int sirfsoc_rtc_suspend(struct device *dev)
 372 {
 373         struct sirfsoc_rtc_drv *rtcdrv = dev_get_drvdata(dev);
 374         rtcdrv->overflow_rtc =
 375                 sirfsoc_rtc_iobrg_readl(rtcdrv->rtc_base + RTC_SW_VALUE);
 376
 377         rtcdrv->saved_counter =
 378                 sirfsoc_rtc_iobrg_readl(rtcdrv->rtc_base + RTC_CN);
 379         rtcdrv->saved_overflow_rtc = rtcdrv->overflow_rtc;
 380         if (device_may_wakeup(dev) && !enable_irq_wake(rtcdrv->irq))
 381                 rtcdrv->irq_wake = 1;
 382
 383         return 0;
 384 }
 385
 386 static int sirfsoc_rtc_resume(struct device *dev)
 387 {
 388         u32 tmp;
 389         struct sirfsoc_rtc_drv *rtcdrv = dev_get_drvdata(dev);
 390
 391         /*
 392          * if resume from snapshot and the rtc power is lost,
 393          * restroe the rtc settings
 394          */
 395         if (SIRFSOC_RTC_CLK != sirfsoc_rtc_iobrg_readl(
 396                         rtcdrv->rtc_base + RTC_CLOCK_SWITCH)) {
 397                 u32 rtc_div;
 398                 /* 0x3 -> RTC_CLK */
 399                 sirfsoc_rtc_iobrg_writel(SIRFSOC_RTC_CLK,
 400                         rtcdrv->rtc_base + RTC_CLOCK_SWITCH);
 401                 /*
 402                  * Set SYS_RTC counter in RTC_HZ HZ Units
 403                  * We are using 32K RTC crystal (32768 / RTC_HZ / 2) -1
 404                  * If 16HZ, therefore RTC_DIV = 1023;
 405                  */
 406                 rtc_div = ((32768 / RTC_HZ) / 2) - 1;
 407
 408                 sirfsoc_rtc_iobrg_writel(rtc_div, rtcdrv->rtc_base + RTC_DIV);
 409
 410                 /* reset SYS RTC ALARM0 */
 411                 sirfsoc_rtc_iobrg_writel(0x0, rtcdrv->rtc_base + RTC_ALARM0);
 412
 413                 /* reset SYS RTC ALARM1 */
 414                 sirfsoc_rtc_iobrg_writel(0x0, rtcdrv->rtc_base + RTC_ALARM1);
 415         }
 416         rtcdrv->overflow_rtc = rtcdrv->saved_overflow_rtc;
 417
 418         /*
 419          * if current counter is small than previous,
 420          * it means overflow in sleep
 421          */
 422         tmp = sirfsoc_rtc_iobrg_readl(rtcdrv->rtc_base + RTC_CN);
 423         if (tmp <= rtcdrv->saved_counter)
 424                 rtcdrv->overflow_rtc++;
 425         /*
 426          *PWRC Value Be Changed When Suspend, Restore Overflow
 427          * In Memory To Register
 428          */
 429         sirfsoc_rtc_iobrg_writel(rtcdrv->overflow_rtc,
 430                         rtcdrv->rtc_base + RTC_SW_VALUE);
 431
 432         if (device_may_wakeup(dev) && rtcdrv->irq_wake) {
 433                 disable_irq_wake(rtcdrv->irq);
 434                 rtcdrv->irq_wake = 0;
 435         }
 436
 437         return 0;
 438 }
 439 #endif
 440
 441 static SIMPLE_DEV_PM_OPS(sirfsoc_rtc_pm_ops,
 442                 sirfsoc_rtc_suspend, sirfsoc_rtc_resume);
 443
 444 static struct platform_driver sirfsoc_rtc_driver = {
 445         .driver = {
 446                 .name = "sirfsoc-rtc",
 447                 .pm = &sirfsoc_rtc_pm_ops,
 448                 .of_match_table = sirfsoc_rtc_of_match,
 449         },
 450         .probe = sirfsoc_rtc_probe,
 451         .remove = sirfsoc_rtc_remove,
 452 };
 453 module_platform_driver(sirfsoc_rtc_driver);
 454
 455 MODULE_DESCRIPTION("SiRF SoC rtc driver");
 456 MODULE_AUTHOR("Xianglong Du <Xianglong.Du@csr.com>");
 457 MODULE_LICENSE("GPL v2");
 458 MODULE_ALIAS("platform:sirfsoc-rtc");