drivers/rtc/rtc-jz4740.c

   1 /*
   2  *  Copyright (C) 2009-2010, Lars-Peter Clausen <lars@metafoo.de>
   3  *  Copyright (C) 2010, Paul Cercueil <paul@crapouillou.net>
   4  *       JZ4740 SoC RTC driver
   5  *
   6  *  This program is free software; you can redistribute it and/or modify it
   7  *  under  the terms of  the GNU General Public License as published by the
   8  *  Free Software Foundation;  either version 2 of the License, or (at your
   9  *  option) any later version.
  10  *
  11  *  You should have received a copy of the GNU General Public License along
  12  *  with this program; if not, write to the Free Software Foundation, Inc.,
  13  *  675 Mass Ave, Cambridge, MA 02139, USA.
  14  *
  15  */
  16
  17 #include <linux/clk.h>
  18 #include <linux/io.h>
  19 #include <linux/kernel.h>
  20 #include <linux/module.h>
  21 #include <linux/of_device.h>
  22 #include <linux/platform_device.h>
  23 #include <linux/reboot.h>
  24 #include <linux/rtc.h>
  25 #include <linux/slab.h>
  26 #include <linux/spinlock.h>
  27
  28 #define JZ_REG_RTC_CTRL         0x00
  29 #define JZ_REG_RTC_SEC          0x04
  30 #define JZ_REG_RTC_SEC_ALARM    0x08
  31 #define JZ_REG_RTC_REGULATOR    0x0C
  32 #define JZ_REG_RTC_HIBERNATE    0x20
  33 #define JZ_REG_RTC_WAKEUP_FILTER        0x24
  34 #define JZ_REG_RTC_RESET_COUNTER        0x28
  35 #define JZ_REG_RTC_SCRATCHPAD   0x34
  36
  37 /* The following are present on the jz4780 */
  38 #define JZ_REG_RTC_WENR 0x3C
  39 #define JZ_RTC_WENR_WEN BIT(31)
  40
  41 #define JZ_RTC_CTRL_WRDY        BIT(7)
  42 #define JZ_RTC_CTRL_1HZ         BIT(6)
  43 #define JZ_RTC_CTRL_1HZ_IRQ     BIT(5)
  44 #define JZ_RTC_CTRL_AF          BIT(4)
  45 #define JZ_RTC_CTRL_AF_IRQ      BIT(3)
  46 #define JZ_RTC_CTRL_AE          BIT(2)
  47 #define JZ_RTC_CTRL_ENABLE      BIT(0)
  48
  49 /* Magic value to enable writes on jz4780 */
  50 #define JZ_RTC_WENR_MAGIC       0xA55A
  51
  52 #define JZ_RTC_WAKEUP_FILTER_MASK       0x0000FFE0
  53 #define JZ_RTC_RESET_COUNTER_MASK       0x00000FE0
  54
  55 enum jz4740_rtc_type {
  56         ID_JZ4740,
  57         ID_JZ4780,
  58 };
  59
  60 struct jz4740_rtc {
  61         void __iomem *base;
  62         enum jz4740_rtc_type type;
  63
  64         struct rtc_device *rtc;
  65         struct clk *clk;
  66
  67         int irq;
  68
  69         spinlock_t lock;
  70
  71         unsigned int min_wakeup_pin_assert_time;
  72         unsigned int reset_pin_assert_time;
  73 };
  74
  75 static struct device *dev_for_power_off;
  76
  77 static inline uint32_t jz4740_rtc_reg_read(struct jz4740_rtc *rtc, size_t reg)
  78 {
  79         return readl(rtc->base + reg);
  80 }
  81
  82 static int jz4740_rtc_wait_write_ready(struct jz4740_rtc *rtc)
  83 {
  84         uint32_t ctrl;
  85         int timeout = 10000;
  86
  87         do {
  88                 ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL);
  89         } while (!(ctrl & JZ_RTC_CTRL_WRDY) && --timeout);
  90
  91         return timeout ? 0 : -EIO;
  92 }
  93
  94 static inline int jz4780_rtc_enable_write(struct jz4740_rtc *rtc)
  95 {
  96         uint32_t ctrl;
  97         int ret, timeout = 10000;
  98
  99         ret = jz4740_rtc_wait_write_ready(rtc);
 100         if (ret != 0)
 101                 return ret;
 102
 103         writel(JZ_RTC_WENR_MAGIC, rtc->base + JZ_REG_RTC_WENR);
 104
 105         do {
 106                 ctrl = readl(rtc->base + JZ_REG_RTC_WENR);
 107         } while (!(ctrl & JZ_RTC_WENR_WEN) && --timeout);
 108
 109         return timeout ? 0 : -EIO;
 110 }
 111
 112 static inline int jz4740_rtc_reg_write(struct jz4740_rtc *rtc, size_t reg,
 113         uint32_t val)
 114 {
 115         int ret = 0;
 116
 117         if (rtc->type >= ID_JZ4780)
 118                 ret = jz4780_rtc_enable_write(rtc);
 119         if (ret == 0)
 120                 ret = jz4740_rtc_wait_write_ready(rtc);
 121         if (ret == 0)
 122                 writel(val, rtc->base + reg);
 123
 124         return ret;
 125 }
 126
 127 static int jz4740_rtc_ctrl_set_bits(struct jz4740_rtc *rtc, uint32_t mask,
 128         bool set)
 129 {
 130         int ret;
 131         unsigned long flags;
 132         uint32_t ctrl;
 133
 134         spin_lock_irqsave(&rtc->lock, flags);
 135
 136         ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL);
 137
 138         /* Don't clear interrupt flags by accident */
 139         ctrl |= JZ_RTC_CTRL_1HZ | JZ_RTC_CTRL_AF;
 140
 141         if (set)
 142                 ctrl |= mask;
 143         else
 144                 ctrl &= ~mask;
 145
 146         ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_CTRL, ctrl);
 147
 148         spin_unlock_irqrestore(&rtc->lock, flags);
 149
 150         return ret;
 151 }
 152
 153 static int jz4740_rtc_read_time(struct device *dev, struct rtc_time *time)
 154 {
 155         struct jz4740_rtc *rtc = dev_get_drvdata(dev);
 156         uint32_t secs, secs2;
 157         int timeout = 5;
 158
 159         /* If the seconds register is read while it is updated, it can contain a
 160          * bogus value. This can be avoided by making sure that two consecutive
 161          * reads have the same value.
 162          */
 163         secs = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC);
 164         secs2 = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC);
 165
 166         while (secs != secs2 && --timeout) {
 167                 secs = secs2;
 168                 secs2 = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC);
 169         }
 170
 171         if (timeout == 0)
 172                 return -EIO;
 173
 174         rtc_time_to_tm(secs, time);
 175
 176         return 0;
 177 }
 178
 179 static int jz4740_rtc_set_mmss(struct device *dev, unsigned long secs)
 180 {
 181         struct jz4740_rtc *rtc = dev_get_drvdata(dev);
 182
 183         return jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SEC, secs);
 184 }
 185
 186 static int jz4740_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 187 {
 188         struct jz4740_rtc *rtc = dev_get_drvdata(dev);
 189         uint32_t secs;
 190         uint32_t ctrl;
 191
 192         secs = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC_ALARM);
 193
 194         ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL);
 195
 196         alrm->enabled = !!(ctrl & JZ_RTC_CTRL_AE);
 197         alrm->pending = !!(ctrl & JZ_RTC_CTRL_AF);
 198
 199         rtc_time_to_tm(secs, &alrm->time);
 200
 201         return rtc_valid_tm(&alrm->time);
 202 }
 203
 204 static int jz4740_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 205 {
 206         int ret;
 207         struct jz4740_rtc *rtc = dev_get_drvdata(dev);
 208         unsigned long secs;
 209
 210         rtc_tm_to_time(&alrm->time, &secs);
 211
 212         ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SEC_ALARM, secs);
 213         if (!ret)
 214                 ret = jz4740_rtc_ctrl_set_bits(rtc,
 215                         JZ_RTC_CTRL_AE | JZ_RTC_CTRL_AF_IRQ, alrm->enabled);
 216
 217         return ret;
 218 }
 219
 220 static int jz4740_rtc_alarm_irq_enable(struct device *dev, unsigned int enable)
 221 {
 222         struct jz4740_rtc *rtc = dev_get_drvdata(dev);
 223         return jz4740_rtc_ctrl_set_bits(rtc, JZ_RTC_CTRL_AF_IRQ, enable);
 224 }
 225
 226 static const struct rtc_class_ops jz4740_rtc_ops = {
 227         .read_time      = jz4740_rtc_read_time,
 228         .set_mmss       = jz4740_rtc_set_mmss,
 229         .read_alarm     = jz4740_rtc_read_alarm,
 230         .set_alarm      = jz4740_rtc_set_alarm,
 231         .alarm_irq_enable = jz4740_rtc_alarm_irq_enable,
 232 };
 233
 234 static irqreturn_t jz4740_rtc_irq(int irq, void *data)
 235 {
 236         struct jz4740_rtc *rtc = data;
 237         uint32_t ctrl;
 238         unsigned long events = 0;
 239
 240         ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL);
 241
 242         if (ctrl & JZ_RTC_CTRL_1HZ)
 243                 events |= (RTC_UF | RTC_IRQF);
 244
 245         if (ctrl & JZ_RTC_CTRL_AF)
 246                 events |= (RTC_AF | RTC_IRQF);
 247
 248         rtc_update_irq(rtc->rtc, 1, events);
 249
 250         jz4740_rtc_ctrl_set_bits(rtc, JZ_RTC_CTRL_1HZ | JZ_RTC_CTRL_AF, false);
 251
 252         return IRQ_HANDLED;
 253 }
 254
 255 static void jz4740_rtc_poweroff(struct device *dev)
 256 {
 257         struct jz4740_rtc *rtc = dev_get_drvdata(dev);
 258         jz4740_rtc_reg_write(rtc, JZ_REG_RTC_HIBERNATE, 1);
 259 }
 260
 261 static void jz4740_rtc_power_off(void)
 262 {
 263         struct jz4740_rtc *rtc = dev_get_drvdata(dev_for_power_off);
 264         unsigned long rtc_rate;
 265         unsigned long wakeup_filter_ticks;
 266         unsigned long reset_counter_ticks;
 267
 268         clk_prepare_enable(rtc->clk);
 269
 270         rtc_rate = clk_get_rate(rtc->clk);
 271
 272         /*
 273          * Set minimum wakeup pin assertion time: 100 ms.
 274          * Range is 0 to 2 sec if RTC is clocked at 32 kHz.
 275          */
 276         wakeup_filter_ticks =
 277                 (rtc->min_wakeup_pin_assert_time * rtc_rate) / 1000;
 278         if (wakeup_filter_ticks < JZ_RTC_WAKEUP_FILTER_MASK)
 279                 wakeup_filter_ticks &= JZ_RTC_WAKEUP_FILTER_MASK;
 280         else
 281                 wakeup_filter_ticks = JZ_RTC_WAKEUP_FILTER_MASK;
 282         jz4740_rtc_reg_write(rtc,
 283                              JZ_REG_RTC_WAKEUP_FILTER, wakeup_filter_ticks);
 284
 285         /*
 286          * Set reset pin low-level assertion time after wakeup: 60 ms.
 287          * Range is 0 to 125 ms if RTC is clocked at 32 kHz.
 288          */
 289         reset_counter_ticks = (rtc->reset_pin_assert_time * rtc_rate) / 1000;
 290         if (reset_counter_ticks < JZ_RTC_RESET_COUNTER_MASK)
 291                 reset_counter_ticks &= JZ_RTC_RESET_COUNTER_MASK;
 292         else
 293                 reset_counter_ticks = JZ_RTC_RESET_COUNTER_MASK;
 294         jz4740_rtc_reg_write(rtc,
 295                              JZ_REG_RTC_RESET_COUNTER, reset_counter_ticks);
 296
 297         jz4740_rtc_poweroff(dev_for_power_off);
 298         kernel_halt();
 299 }
 300
 301 static const struct of_device_id jz4740_rtc_of_match[] = {
 302         { .compatible = "ingenic,jz4740-rtc", .data = (void *)ID_JZ4740 },
 303         { .compatible = "ingenic,jz4780-rtc", .data = (void *)ID_JZ4780 },
 304         {},
 305 };
 306 MODULE_DEVICE_TABLE(of, jz4740_rtc_of_match);
 307
 308 static int jz4740_rtc_probe(struct platform_device *pdev)
 309 {
 310         int ret;
 311         struct jz4740_rtc *rtc;
 312         uint32_t scratchpad;
 313         struct resource *mem;
 314         const struct platform_device_id *id = platform_get_device_id(pdev);
 315         const struct of_device_id *of_id = of_match_device(
 316                         jz4740_rtc_of_match, &pdev->dev);
 317         struct device_node *np = pdev->dev.of_node;
 318
 319         rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
 320         if (!rtc)
 321                 return -ENOMEM;
 322
 323         if (of_id)
 324                 rtc->type = (enum jz4740_rtc_type)of_id->data;
 325         else
 326                 rtc->type = id->driver_data;
 327
 328         rtc->irq = platform_get_irq(pdev, 0);
 329         if (rtc->irq < 0) {
 330                 dev_err(&pdev->dev, "Failed to get platform irq\n");
 331                 return -ENOENT;
 332         }
 333
 334         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 335         rtc->base = devm_ioremap_resource(&pdev->dev, mem);
 336         if (IS_ERR(rtc->base))
 337                 return PTR_ERR(rtc->base);
 338
 339         rtc->clk = devm_clk_get(&pdev->dev, "rtc");
 340         if (IS_ERR(rtc->clk)) {
 341                 dev_err(&pdev->dev, "Failed to get RTC clock\n");
 342                 return PTR_ERR(rtc->clk);
 343         }
 344
 345         spin_lock_init(&rtc->lock);
 346
 347         platform_set_drvdata(pdev, rtc);
 348
 349         device_init_wakeup(&pdev->dev, 1);
 350
 351         rtc->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
 352                                         &jz4740_rtc_ops, THIS_MODULE);
 353         if (IS_ERR(rtc->rtc)) {
 354                 ret = PTR_ERR(rtc->rtc);
 355                 dev_err(&pdev->dev, "Failed to register rtc device: %d\n", ret);
 356                 return ret;
 357         }
 358
 359         ret = devm_request_irq(&pdev->dev, rtc->irq, jz4740_rtc_irq, 0,
 360                                 pdev->name, rtc);
 361         if (ret) {
 362                 dev_err(&pdev->dev, "Failed to request rtc irq: %d\n", ret);
 363                 return ret;
 364         }
 365
 366         scratchpad = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SCRATCHPAD);
 367         if (scratchpad != 0x12345678) {
 368                 ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SCRATCHPAD, 0x12345678);
 369                 ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SEC, 0);
 370                 if (ret) {
 371                         dev_err(&pdev->dev, "Could not write to RTC registers\n");
 372                         return ret;
 373                 }
 374         }
 375
 376         if (np && of_device_is_system_power_controller(np)) {
 377                 if (!pm_power_off) {
 378                         /* Default: 60ms */
 379                         rtc->reset_pin_assert_time = 60;
 380                         of_property_read_u32(np, "reset-pin-assert-time-ms",
 381                                              &rtc->reset_pin_assert_time);
 382
 383                         /* Default: 100ms */
 384                         rtc->min_wakeup_pin_assert_time = 100;
 385                         of_property_read_u32(np,
 386                                              "min-wakeup-pin-assert-time-ms",
 387                                              &rtc->min_wakeup_pin_assert_time);
 388
 389                         dev_for_power_off = &pdev->dev;
 390                         pm_power_off = jz4740_rtc_power_off;
 391                 } else {
 392                         dev_warn(&pdev->dev,
 393                                  "Poweroff handler already present!\n");
 394                 }
 395         }
 396
 397         return 0;
 398 }
 399
 400 #ifdef CONFIG_PM
 401 static int jz4740_rtc_suspend(struct device *dev)
 402 {
 403         struct jz4740_rtc *rtc = dev_get_drvdata(dev);
 404
 405         if (device_may_wakeup(dev))
 406                 enable_irq_wake(rtc->irq);
 407         return 0;
 408 }
 409
 410 static int jz4740_rtc_resume(struct device *dev)
 411 {
 412         struct jz4740_rtc *rtc = dev_get_drvdata(dev);
 413
 414         if (device_may_wakeup(dev))
 415                 disable_irq_wake(rtc->irq);
 416         return 0;
 417 }
 418
 419 static const struct dev_pm_ops jz4740_pm_ops = {
 420         .suspend = jz4740_rtc_suspend,
 421         .resume  = jz4740_rtc_resume,
 422 };
 423 #define JZ4740_RTC_PM_OPS (&jz4740_pm_ops)
 424
 425 #else
 426 #define JZ4740_RTC_PM_OPS NULL
 427 #endif  /* CONFIG_PM */
 428
 429 static const struct platform_device_id jz4740_rtc_ids[] = {
 430         { "jz4740-rtc", ID_JZ4740 },
 431         { "jz4780-rtc", ID_JZ4780 },
 432         {}
 433 };
 434 MODULE_DEVICE_TABLE(platform, jz4740_rtc_ids);
 435
 436 static struct platform_driver jz4740_rtc_driver = {
 437         .probe   = jz4740_rtc_probe,
 438         .driver  = {
 439                 .name  = "jz4740-rtc",
 440                 .pm    = JZ4740_RTC_PM_OPS,
 441                 .of_match_table = of_match_ptr(jz4740_rtc_of_match),
 442         },
 443         .id_table = jz4740_rtc_ids,
 444 };
 445
 446 module_platform_driver(jz4740_rtc_driver);
 447
 448 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
 449 MODULE_LICENSE("GPL");
 450 MODULE_DESCRIPTION("RTC driver for the JZ4740 SoC\n");
 451 MODULE_ALIAS("platform:jz4740-rtc");