drivers/rtc/rtc-jz4740.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  *  Copyright (C) 2009-2010, Lars-Peter Clausen <lars@metafoo.de>
   4  *  Copyright (C) 2010, Paul Cercueil <paul@crapouillou.net>
   5  *       JZ4740 SoC RTC driver
   6  */
   7
   8 #include <linux/clk.h>
   9 #include <linux/clk-provider.h>
  10 #include <linux/io.h>
  11 #include <linux/iopoll.h>
  12 #include <linux/kernel.h>
  13 #include <linux/module.h>
  14 #include <linux/of_device.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/pm_wakeirq.h>
  17 #include <linux/property.h>
  18 #include <linux/reboot.h>
  19 #include <linux/rtc.h>
  20 #include <linux/slab.h>
  21 #include <linux/spinlock.h>
  22
  23 #define JZ_REG_RTC_CTRL         0x00
  24 #define JZ_REG_RTC_SEC          0x04
  25 #define JZ_REG_RTC_SEC_ALARM    0x08
  26 #define JZ_REG_RTC_REGULATOR    0x0C
  27 #define JZ_REG_RTC_HIBERNATE    0x20
  28 #define JZ_REG_RTC_WAKEUP_FILTER        0x24
  29 #define JZ_REG_RTC_RESET_COUNTER        0x28
  30 #define JZ_REG_RTC_SCRATCHPAD   0x34
  31 #define JZ_REG_RTC_CKPCR        0x40
  32
  33 /* The following are present on the jz4780 */
  34 #define JZ_REG_RTC_WENR 0x3C
  35 #define JZ_RTC_WENR_WEN BIT(31)
  36
  37 #define JZ_RTC_CTRL_WRDY        BIT(7)
  38 #define JZ_RTC_CTRL_1HZ         BIT(6)
  39 #define JZ_RTC_CTRL_1HZ_IRQ     BIT(5)
  40 #define JZ_RTC_CTRL_AF          BIT(4)
  41 #define JZ_RTC_CTRL_AF_IRQ      BIT(3)
  42 #define JZ_RTC_CTRL_AE          BIT(2)
  43 #define JZ_RTC_CTRL_ENABLE      BIT(0)
  44
  45 /* Magic value to enable writes on jz4780 */
  46 #define JZ_RTC_WENR_MAGIC       0xA55A
  47
  48 #define JZ_RTC_WAKEUP_FILTER_MASK       0x0000FFE0
  49 #define JZ_RTC_RESET_COUNTER_MASK       0x00000FE0
  50
  51 #define JZ_RTC_CKPCR_CK32PULL_DIS       BIT(4)
  52 #define JZ_RTC_CKPCR_CK32CTL_EN         (BIT(2) | BIT(1))
  53
  54 enum jz4740_rtc_type {
  55         ID_JZ4740,
  56         ID_JZ4760,
  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
  66         struct clk_hw clk32k;
  67
  68         spinlock_t lock;
  69 };
  70
  71 static struct device *dev_for_power_off;
  72
  73 static inline uint32_t jz4740_rtc_reg_read(struct jz4740_rtc *rtc, size_t reg)
  74 {
  75         return readl(rtc->base + reg);
  76 }
  77
  78 static int jz4740_rtc_wait_write_ready(struct jz4740_rtc *rtc)
  79 {
  80         uint32_t ctrl;
  81
  82         return readl_poll_timeout(rtc->base + JZ_REG_RTC_CTRL, ctrl,
  83                                   ctrl & JZ_RTC_CTRL_WRDY, 0, 1000);
  84 }
  85
  86 static inline int jz4780_rtc_enable_write(struct jz4740_rtc *rtc)
  87 {
  88         uint32_t ctrl;
  89         int ret;
  90
  91         ret = jz4740_rtc_wait_write_ready(rtc);
  92         if (ret != 0)
  93                 return ret;
  94
  95         writel(JZ_RTC_WENR_MAGIC, rtc->base + JZ_REG_RTC_WENR);
  96
  97         return readl_poll_timeout(rtc->base + JZ_REG_RTC_WENR, ctrl,
  98                                   ctrl & JZ_RTC_WENR_WEN, 0, 1000);
  99 }
 100
 101 static inline int jz4740_rtc_reg_write(struct jz4740_rtc *rtc, size_t reg,
 102         uint32_t val)
 103 {
 104         int ret = 0;
 105
 106         if (rtc->type >= ID_JZ4760)
 107                 ret = jz4780_rtc_enable_write(rtc);
 108         if (ret == 0)
 109                 ret = jz4740_rtc_wait_write_ready(rtc);
 110         if (ret == 0)
 111                 writel(val, rtc->base + reg);
 112
 113         return ret;
 114 }
 115
 116 static int jz4740_rtc_ctrl_set_bits(struct jz4740_rtc *rtc, uint32_t mask,
 117         bool set)
 118 {
 119         int ret;
 120         unsigned long flags;
 121         uint32_t ctrl;
 122
 123         spin_lock_irqsave(&rtc->lock, flags);
 124
 125         ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL);
 126
 127         /* Don't clear interrupt flags by accident */
 128         ctrl |= JZ_RTC_CTRL_1HZ | JZ_RTC_CTRL_AF;
 129
 130         if (set)
 131                 ctrl |= mask;
 132         else
 133                 ctrl &= ~mask;
 134
 135         ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_CTRL, ctrl);
 136
 137         spin_unlock_irqrestore(&rtc->lock, flags);
 138
 139         return ret;
 140 }
 141
 142 static int jz4740_rtc_read_time(struct device *dev, struct rtc_time *time)
 143 {
 144         struct jz4740_rtc *rtc = dev_get_drvdata(dev);
 145         uint32_t secs, secs2;
 146         int timeout = 5;
 147
 148         if (jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SCRATCHPAD) != 0x12345678)
 149                 return -EINVAL;
 150
 151         /* If the seconds register is read while it is updated, it can contain a
 152          * bogus value. This can be avoided by making sure that two consecutive
 153          * reads have the same value.
 154          */
 155         secs = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC);
 156         secs2 = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC);
 157
 158         while (secs != secs2 && --timeout) {
 159                 secs = secs2;
 160                 secs2 = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC);
 161         }
 162
 163         if (timeout == 0)
 164                 return -EIO;
 165
 166         rtc_time64_to_tm(secs, time);
 167
 168         return 0;
 169 }
 170
 171 static int jz4740_rtc_set_time(struct device *dev, struct rtc_time *time)
 172 {
 173         struct jz4740_rtc *rtc = dev_get_drvdata(dev);
 174         int ret;
 175
 176         ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SEC, rtc_tm_to_time64(time));
 177         if (ret)
 178                 return ret;
 179
 180         return jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SCRATCHPAD, 0x12345678);
 181 }
 182
 183 static int jz4740_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 184 {
 185         struct jz4740_rtc *rtc = dev_get_drvdata(dev);
 186         uint32_t secs;
 187         uint32_t ctrl;
 188
 189         secs = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC_ALARM);
 190
 191         ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL);
 192
 193         alrm->enabled = !!(ctrl & JZ_RTC_CTRL_AE);
 194         alrm->pending = !!(ctrl & JZ_RTC_CTRL_AF);
 195
 196         rtc_time64_to_tm(secs, &alrm->time);
 197
 198         return 0;
 199 }
 200
 201 static int jz4740_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 202 {
 203         int ret;
 204         struct jz4740_rtc *rtc = dev_get_drvdata(dev);
 205         uint32_t secs = lower_32_bits(rtc_tm_to_time64(&alrm->time));
 206
 207         ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SEC_ALARM, secs);
 208         if (!ret)
 209                 ret = jz4740_rtc_ctrl_set_bits(rtc,
 210                         JZ_RTC_CTRL_AE | JZ_RTC_CTRL_AF_IRQ, alrm->enabled);
 211
 212         return ret;
 213 }
 214
 215 static int jz4740_rtc_alarm_irq_enable(struct device *dev, unsigned int enable)
 216 {
 217         struct jz4740_rtc *rtc = dev_get_drvdata(dev);
 218         return jz4740_rtc_ctrl_set_bits(rtc, JZ_RTC_CTRL_AF_IRQ, enable);
 219 }
 220
 221 static const struct rtc_class_ops jz4740_rtc_ops = {
 222         .read_time      = jz4740_rtc_read_time,
 223         .set_time       = jz4740_rtc_set_time,
 224         .read_alarm     = jz4740_rtc_read_alarm,
 225         .set_alarm      = jz4740_rtc_set_alarm,
 226         .alarm_irq_enable = jz4740_rtc_alarm_irq_enable,
 227 };
 228
 229 static irqreturn_t jz4740_rtc_irq(int irq, void *data)
 230 {
 231         struct jz4740_rtc *rtc = data;
 232         uint32_t ctrl;
 233         unsigned long events = 0;
 234
 235         ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL);
 236
 237         if (ctrl & JZ_RTC_CTRL_1HZ)
 238                 events |= (RTC_UF | RTC_IRQF);
 239
 240         if (ctrl & JZ_RTC_CTRL_AF)
 241                 events |= (RTC_AF | RTC_IRQF);
 242
 243         rtc_update_irq(rtc->rtc, 1, events);
 244
 245         jz4740_rtc_ctrl_set_bits(rtc, JZ_RTC_CTRL_1HZ | JZ_RTC_CTRL_AF, false);
 246
 247         return IRQ_HANDLED;
 248 }
 249
 250 static void jz4740_rtc_poweroff(struct device *dev)
 251 {
 252         struct jz4740_rtc *rtc = dev_get_drvdata(dev);
 253         jz4740_rtc_reg_write(rtc, JZ_REG_RTC_HIBERNATE, 1);
 254 }
 255
 256 static void jz4740_rtc_power_off(void)
 257 {
 258         jz4740_rtc_poweroff(dev_for_power_off);
 259         kernel_halt();
 260 }
 261
 262 static const struct of_device_id jz4740_rtc_of_match[] = {
 263         { .compatible = "ingenic,jz4740-rtc", .data = (void *)ID_JZ4740 },
 264         { .compatible = "ingenic,jz4760-rtc", .data = (void *)ID_JZ4760 },
 265         { .compatible = "ingenic,jz4770-rtc", .data = (void *)ID_JZ4780 },
 266         { .compatible = "ingenic,jz4780-rtc", .data = (void *)ID_JZ4780 },
 267         {},
 268 };
 269 MODULE_DEVICE_TABLE(of, jz4740_rtc_of_match);
 270
 271 static void jz4740_rtc_set_wakeup_params(struct jz4740_rtc *rtc,
 272                                          struct device_node *np,
 273                                          unsigned long rate)
 274 {
 275         unsigned long wakeup_ticks, reset_ticks;
 276         unsigned int min_wakeup_pin_assert_time = 60; /* Default: 60ms */
 277         unsigned int reset_pin_assert_time = 100; /* Default: 100ms */
 278
 279         of_property_read_u32(np, "ingenic,reset-pin-assert-time-ms",
 280                              &reset_pin_assert_time);
 281         of_property_read_u32(np, "ingenic,min-wakeup-pin-assert-time-ms",
 282                              &min_wakeup_pin_assert_time);
 283
 284         /*
 285          * Set minimum wakeup pin assertion time: 100 ms.
 286          * Range is 0 to 2 sec if RTC is clocked at 32 kHz.
 287          */
 288         wakeup_ticks = (min_wakeup_pin_assert_time * rate) / 1000;
 289         if (wakeup_ticks < JZ_RTC_WAKEUP_FILTER_MASK)
 290                 wakeup_ticks &= JZ_RTC_WAKEUP_FILTER_MASK;
 291         else
 292                 wakeup_ticks = JZ_RTC_WAKEUP_FILTER_MASK;
 293         jz4740_rtc_reg_write(rtc, JZ_REG_RTC_WAKEUP_FILTER, wakeup_ticks);
 294
 295         /*
 296          * Set reset pin low-level assertion time after wakeup: 60 ms.
 297          * Range is 0 to 125 ms if RTC is clocked at 32 kHz.
 298          */
 299         reset_ticks = (reset_pin_assert_time * rate) / 1000;
 300         if (reset_ticks < JZ_RTC_RESET_COUNTER_MASK)
 301                 reset_ticks &= JZ_RTC_RESET_COUNTER_MASK;
 302         else
 303                 reset_ticks = JZ_RTC_RESET_COUNTER_MASK;
 304         jz4740_rtc_reg_write(rtc, JZ_REG_RTC_RESET_COUNTER, reset_ticks);
 305 }
 306
 307 static int jz4740_rtc_clk32k_enable(struct clk_hw *hw)
 308 {
 309         struct jz4740_rtc *rtc = container_of(hw, struct jz4740_rtc, clk32k);
 310
 311         return jz4740_rtc_reg_write(rtc, JZ_REG_RTC_CKPCR,
 312                                     JZ_RTC_CKPCR_CK32PULL_DIS |
 313                                     JZ_RTC_CKPCR_CK32CTL_EN);
 314 }
 315
 316 static void jz4740_rtc_clk32k_disable(struct clk_hw *hw)
 317 {
 318         struct jz4740_rtc *rtc = container_of(hw, struct jz4740_rtc, clk32k);
 319
 320         jz4740_rtc_reg_write(rtc, JZ_REG_RTC_CKPCR, 0);
 321 }
 322
 323 static int jz4740_rtc_clk32k_is_enabled(struct clk_hw *hw)
 324 {
 325         struct jz4740_rtc *rtc = container_of(hw, struct jz4740_rtc, clk32k);
 326         u32 ckpcr;
 327
 328         ckpcr = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CKPCR);
 329
 330         return !!(ckpcr & JZ_RTC_CKPCR_CK32CTL_EN);
 331 }
 332
 333 static const struct clk_ops jz4740_rtc_clk32k_ops = {
 334         .enable = jz4740_rtc_clk32k_enable,
 335         .disable = jz4740_rtc_clk32k_disable,
 336         .is_enabled = jz4740_rtc_clk32k_is_enabled,
 337 };
 338
 339 static int jz4740_rtc_probe(struct platform_device *pdev)
 340 {
 341         struct device *dev = &pdev->dev;
 342         struct device_node *np = dev->of_node;
 343         struct jz4740_rtc *rtc;
 344         unsigned long rate;
 345         struct clk *clk;
 346         int ret, irq;
 347
 348         rtc = devm_kzalloc(dev, sizeof(*rtc), GFP_KERNEL);
 349         if (!rtc)
 350                 return -ENOMEM;
 351
 352         rtc->type = (enum jz4740_rtc_type)device_get_match_data(dev);
 353
 354         irq = platform_get_irq(pdev, 0);
 355         if (irq < 0)
 356                 return irq;
 357
 358         rtc->base = devm_platform_ioremap_resource(pdev, 0);
 359         if (IS_ERR(rtc->base))
 360                 return PTR_ERR(rtc->base);
 361
 362         clk = devm_clk_get_enabled(dev, "rtc");
 363         if (IS_ERR(clk))
 364                 return dev_err_probe(dev, PTR_ERR(clk), "Failed to get RTC clock\n");
 365
 366         spin_lock_init(&rtc->lock);
 367
 368         platform_set_drvdata(pdev, rtc);
 369
 370         device_init_wakeup(dev, 1);
 371
 372         ret = dev_pm_set_wake_irq(dev, irq);
 373         if (ret)
 374                 return dev_err_probe(dev, ret, "Failed to set wake irq\n");
 375
 376         rtc->rtc = devm_rtc_allocate_device(dev);
 377         if (IS_ERR(rtc->rtc))
 378                 return dev_err_probe(dev, PTR_ERR(rtc->rtc),
 379                                      "Failed to allocate rtc device\n");
 380
 381         rtc->rtc->ops = &jz4740_rtc_ops;
 382         rtc->rtc->range_max = U32_MAX;
 383
 384         rate = clk_get_rate(clk);
 385         jz4740_rtc_set_wakeup_params(rtc, np, rate);
 386
 387         /* Each 1 Hz pulse should happen after (rate) ticks */
 388         jz4740_rtc_reg_write(rtc, JZ_REG_RTC_REGULATOR, rate - 1);
 389
 390         ret = devm_rtc_register_device(rtc->rtc);
 391         if (ret)
 392                 return ret;
 393
 394         ret = devm_request_irq(dev, irq, jz4740_rtc_irq, 0,
 395                                pdev->name, rtc);
 396         if (ret)
 397                 return dev_err_probe(dev, ret, "Failed to request rtc irq\n");
 398
 399         if (of_device_is_system_power_controller(np)) {
 400                 dev_for_power_off = dev;
 401
 402                 if (!pm_power_off)
 403                         pm_power_off = jz4740_rtc_power_off;
 404                 else
 405                         dev_warn(dev, "Poweroff handler already present!\n");
 406         }
 407
 408         if (device_property_present(dev, "#clock-cells")) {
 409                 rtc->clk32k.init = CLK_HW_INIT_HW("clk32k", __clk_get_hw(clk),
 410                                                   &jz4740_rtc_clk32k_ops, 0);
 411
 412                 ret = devm_clk_hw_register(dev, &rtc->clk32k);
 413                 if (ret)
 414                         return dev_err_probe(dev, ret,
 415                                              "Unable to register clk32k clock\n");
 416
 417                 ret = devm_of_clk_add_hw_provider(dev, of_clk_hw_simple_get,
 418                                                   &rtc->clk32k);
 419                 if (ret)
 420                         return dev_err_probe(dev, ret,
 421                                              "Unable to register clk32k clock provider\n");
 422         }
 423
 424         return 0;
 425 }
 426
 427 static struct platform_driver jz4740_rtc_driver = {
 428         .probe   = jz4740_rtc_probe,
 429         .driver  = {
 430                 .name  = "jz4740-rtc",
 431                 .of_match_table = jz4740_rtc_of_match,
 432         },
 433 };
 434
 435 module_platform_driver(jz4740_rtc_driver);
 436
 437 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
 438 MODULE_LICENSE("GPL");
 439 MODULE_DESCRIPTION("RTC driver for the JZ4740 SoC\n");
 440 MODULE_ALIAS("platform:jz4740-rtc");