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