drivers/rtc/rtc-armada38x.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * RTC driver for the Armada 38x Marvell SoCs
   4  *
   5  * Copyright (C) 2015 Marvell
   6  *
   7  * Gregory Clement <gregory.clement@free-electrons.com>
   8  */
   9
  10 #include <linux/delay.h>
  11 #include <linux/io.h>
  12 #include <linux/module.h>
  13 #include <linux/of.h>
  14 #include <linux/of_device.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/rtc.h>
  17
  18 #define RTC_STATUS          0x0
  19 #define RTC_STATUS_ALARM1           BIT(0)
  20 #define RTC_STATUS_ALARM2           BIT(1)
  21 #define RTC_IRQ1_CONF       0x4
  22 #define RTC_IRQ2_CONF       0x8
  23 #define RTC_IRQ_AL_EN               BIT(0)
  24 #define RTC_IRQ_FREQ_EN             BIT(1)
  25 #define RTC_IRQ_FREQ_1HZ            BIT(2)
  26 #define RTC_CCR             0x18
  27 #define RTC_CCR_MODE                BIT(15)
  28 #define RTC_CONF_TEST       0x1C
  29 #define RTC_NOMINAL_TIMING          BIT(13)
  30
  31 #define RTC_TIME            0xC
  32 #define RTC_ALARM1          0x10
  33 #define RTC_ALARM2          0x14
  34
  35 /* Armada38x SoC registers  */
  36 #define RTC_38X_BRIDGE_TIMING_CTL   0x0
  37 #define RTC_38X_PERIOD_OFFS             0
  38 #define RTC_38X_PERIOD_MASK             (0x3FF << RTC_38X_PERIOD_OFFS)
  39 #define RTC_38X_READ_DELAY_OFFS         26
  40 #define RTC_38X_READ_DELAY_MASK         (0x1F << RTC_38X_READ_DELAY_OFFS)
  41
  42 /* Armada 7K/8K registers  */
  43 #define RTC_8K_BRIDGE_TIMING_CTL0    0x0
  44 #define RTC_8K_WRCLK_PERIOD_OFFS        0
  45 #define RTC_8K_WRCLK_PERIOD_MASK        (0xFFFF << RTC_8K_WRCLK_PERIOD_OFFS)
  46 #define RTC_8K_WRCLK_SETUP_OFFS         16
  47 #define RTC_8K_WRCLK_SETUP_MASK         (0xFFFF << RTC_8K_WRCLK_SETUP_OFFS)
  48 #define RTC_8K_BRIDGE_TIMING_CTL1   0x4
  49 #define RTC_8K_READ_DELAY_OFFS          0
  50 #define RTC_8K_READ_DELAY_MASK          (0xFFFF << RTC_8K_READ_DELAY_OFFS)
  51
  52 #define RTC_8K_ISR                  0x10
  53 #define RTC_8K_IMR                  0x14
  54 #define RTC_8K_ALARM2                   BIT(0)
  55
  56 #define SOC_RTC_INTERRUPT           0x8
  57 #define SOC_RTC_ALARM1                  BIT(0)
  58 #define SOC_RTC_ALARM2                  BIT(1)
  59 #define SOC_RTC_ALARM1_MASK             BIT(2)
  60 #define SOC_RTC_ALARM2_MASK             BIT(3)
  61
  62 #define SAMPLE_NR 100
  63
  64 struct value_to_freq {
  65         u32 value;
  66         u8 freq;
  67 };
  68
  69 struct armada38x_rtc {
  70         struct rtc_device   *rtc_dev;
  71         void __iomem        *regs;
  72         void __iomem        *regs_soc;
  73         spinlock_t          lock;
  74         int                 irq;
  75         bool                initialized;
  76         struct value_to_freq *val_to_freq;
  77         const struct armada38x_rtc_data *data;
  78 };
  79
  80 #define ALARM1  0
  81 #define ALARM2  1
  82
  83 #define ALARM_REG(base, alarm)   ((base) + (alarm) * sizeof(u32))
  84
  85 struct armada38x_rtc_data {
  86         /* Initialize the RTC-MBUS bridge timing */
  87         void (*update_mbus_timing)(struct armada38x_rtc *rtc);
  88         u32 (*read_rtc_reg)(struct armada38x_rtc *rtc, u8 rtc_reg);
  89         void (*clear_isr)(struct armada38x_rtc *rtc);
  90         void (*unmask_interrupt)(struct armada38x_rtc *rtc);
  91         u32 alarm;
  92 };
  93
  94 /*
  95  * According to the datasheet, the OS should wait 5us after every
  96  * register write to the RTC hard macro so that the required update
  97  * can occur without holding off the system bus
  98  * According to errata RES-3124064, Write to any RTC register
  99  * may fail. As a workaround, before writing to RTC
 100  * register, issue a dummy write of 0x0 twice to RTC Status
 101  * register.
 102  */
 103
 104 static void rtc_delayed_write(u32 val, struct armada38x_rtc *rtc, int offset)
 105 {
 106         writel(0, rtc->regs + RTC_STATUS);
 107         writel(0, rtc->regs + RTC_STATUS);
 108         writel(val, rtc->regs + offset);
 109         udelay(5);
 110 }
 111
 112 /* Update RTC-MBUS bridge timing parameters */
 113 static void rtc_update_38x_mbus_timing_params(struct armada38x_rtc *rtc)
 114 {
 115         u32 reg;
 116
 117         reg = readl(rtc->regs_soc + RTC_38X_BRIDGE_TIMING_CTL);
 118         reg &= ~RTC_38X_PERIOD_MASK;
 119         reg |= 0x3FF << RTC_38X_PERIOD_OFFS; /* Maximum value */
 120         reg &= ~RTC_38X_READ_DELAY_MASK;
 121         reg |= 0x1F << RTC_38X_READ_DELAY_OFFS; /* Maximum value */
 122         writel(reg, rtc->regs_soc + RTC_38X_BRIDGE_TIMING_CTL);
 123 }
 124
 125 static void rtc_update_8k_mbus_timing_params(struct armada38x_rtc *rtc)
 126 {
 127         u32 reg;
 128
 129         reg = readl(rtc->regs_soc + RTC_8K_BRIDGE_TIMING_CTL0);
 130         reg &= ~RTC_8K_WRCLK_PERIOD_MASK;
 131         reg |= 0x3FF << RTC_8K_WRCLK_PERIOD_OFFS;
 132         reg &= ~RTC_8K_WRCLK_SETUP_MASK;
 133         reg |= 0x29 << RTC_8K_WRCLK_SETUP_OFFS;
 134         writel(reg, rtc->regs_soc + RTC_8K_BRIDGE_TIMING_CTL0);
 135
 136         reg = readl(rtc->regs_soc + RTC_8K_BRIDGE_TIMING_CTL1);
 137         reg &= ~RTC_8K_READ_DELAY_MASK;
 138         reg |= 0x3F << RTC_8K_READ_DELAY_OFFS;
 139         writel(reg, rtc->regs_soc + RTC_8K_BRIDGE_TIMING_CTL1);
 140 }
 141
 142 static u32 read_rtc_register(struct armada38x_rtc *rtc, u8 rtc_reg)
 143 {
 144         return readl(rtc->regs + rtc_reg);
 145 }
 146
 147 static u32 read_rtc_register_38x_wa(struct armada38x_rtc *rtc, u8 rtc_reg)
 148 {
 149         int i, index_max = 0, max = 0;
 150
 151         for (i = 0; i < SAMPLE_NR; i++) {
 152                 rtc->val_to_freq[i].value = readl(rtc->regs + rtc_reg);
 153                 rtc->val_to_freq[i].freq = 0;
 154         }
 155
 156         for (i = 0; i < SAMPLE_NR; i++) {
 157                 int j = 0;
 158                 u32 value = rtc->val_to_freq[i].value;
 159
 160                 while (rtc->val_to_freq[j].freq) {
 161                         if (rtc->val_to_freq[j].value == value) {
 162                                 rtc->val_to_freq[j].freq++;
 163                                 break;
 164                         }
 165                         j++;
 166                 }
 167
 168                 if (!rtc->val_to_freq[j].freq) {
 169                         rtc->val_to_freq[j].value = value;
 170                         rtc->val_to_freq[j].freq = 1;
 171                 }
 172
 173                 if (rtc->val_to_freq[j].freq > max) {
 174                         index_max = j;
 175                         max = rtc->val_to_freq[j].freq;
 176                 }
 177
 178                 /*
 179                  * If a value already has half of the sample this is the most
 180                  * frequent one and we can stop the research right now
 181                  */
 182                 if (max > SAMPLE_NR / 2)
 183                         break;
 184         }
 185
 186         return rtc->val_to_freq[index_max].value;
 187 }
 188
 189 static void armada38x_clear_isr(struct armada38x_rtc *rtc)
 190 {
 191         u32 val = readl(rtc->regs_soc + SOC_RTC_INTERRUPT);
 192
 193         writel(val & ~SOC_RTC_ALARM1, rtc->regs_soc + SOC_RTC_INTERRUPT);
 194 }
 195
 196 static void armada38x_unmask_interrupt(struct armada38x_rtc *rtc)
 197 {
 198         u32 val = readl(rtc->regs_soc + SOC_RTC_INTERRUPT);
 199
 200         writel(val | SOC_RTC_ALARM1_MASK, rtc->regs_soc + SOC_RTC_INTERRUPT);
 201 }
 202
 203 static void armada8k_clear_isr(struct armada38x_rtc *rtc)
 204 {
 205         writel(RTC_8K_ALARM2, rtc->regs_soc + RTC_8K_ISR);
 206 }
 207
 208 static void armada8k_unmask_interrupt(struct armada38x_rtc *rtc)
 209 {
 210         writel(RTC_8K_ALARM2, rtc->regs_soc + RTC_8K_IMR);
 211 }
 212
 213 static int armada38x_rtc_read_time(struct device *dev, struct rtc_time *tm)
 214 {
 215         struct armada38x_rtc *rtc = dev_get_drvdata(dev);
 216         unsigned long time, flags;
 217
 218         spin_lock_irqsave(&rtc->lock, flags);
 219         time = rtc->data->read_rtc_reg(rtc, RTC_TIME);
 220         spin_unlock_irqrestore(&rtc->lock, flags);
 221
 222         rtc_time64_to_tm(time, tm);
 223
 224         return 0;
 225 }
 226
 227 static void armada38x_rtc_reset(struct armada38x_rtc *rtc)
 228 {
 229         u32 reg;
 230
 231         reg = rtc->data->read_rtc_reg(rtc, RTC_CONF_TEST);
 232         /* If bits [7:0] are non-zero, assume RTC was uninitialized */
 233         if (reg & 0xff) {
 234                 rtc_delayed_write(0, rtc, RTC_CONF_TEST);
 235                 msleep(500); /* Oscillator startup time */
 236                 rtc_delayed_write(0, rtc, RTC_TIME);
 237                 rtc_delayed_write(SOC_RTC_ALARM1 | SOC_RTC_ALARM2, rtc,
 238                                   RTC_STATUS);
 239                 rtc_delayed_write(RTC_NOMINAL_TIMING, rtc, RTC_CCR);
 240         }
 241         rtc->initialized = true;
 242 }
 243
 244 static int armada38x_rtc_set_time(struct device *dev, struct rtc_time *tm)
 245 {
 246         struct armada38x_rtc *rtc = dev_get_drvdata(dev);
 247         unsigned long time, flags;
 248
 249         time = rtc_tm_to_time64(tm);
 250
 251         if (!rtc->initialized)
 252                 armada38x_rtc_reset(rtc);
 253
 254         spin_lock_irqsave(&rtc->lock, flags);
 255         rtc_delayed_write(time, rtc, RTC_TIME);
 256         spin_unlock_irqrestore(&rtc->lock, flags);
 257
 258         return 0;
 259 }
 260
 261 static int armada38x_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 262 {
 263         struct armada38x_rtc *rtc = dev_get_drvdata(dev);
 264         unsigned long time, flags;
 265         u32 reg = ALARM_REG(RTC_ALARM1, rtc->data->alarm);
 266         u32 reg_irq = ALARM_REG(RTC_IRQ1_CONF, rtc->data->alarm);
 267         u32 val;
 268
 269         spin_lock_irqsave(&rtc->lock, flags);
 270
 271         time = rtc->data->read_rtc_reg(rtc, reg);
 272         val = rtc->data->read_rtc_reg(rtc, reg_irq) & RTC_IRQ_AL_EN;
 273
 274         spin_unlock_irqrestore(&rtc->lock, flags);
 275
 276         alrm->enabled = val ? 1 : 0;
 277         rtc_time64_to_tm(time,  &alrm->time);
 278
 279         return 0;
 280 }
 281
 282 static int armada38x_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 283 {
 284         struct armada38x_rtc *rtc = dev_get_drvdata(dev);
 285         u32 reg = ALARM_REG(RTC_ALARM1, rtc->data->alarm);
 286         u32 reg_irq = ALARM_REG(RTC_IRQ1_CONF, rtc->data->alarm);
 287         unsigned long time, flags;
 288
 289         time = rtc_tm_to_time64(&alrm->time);
 290
 291         spin_lock_irqsave(&rtc->lock, flags);
 292
 293         rtc_delayed_write(time, rtc, reg);
 294
 295         if (alrm->enabled) {
 296                 rtc_delayed_write(RTC_IRQ_AL_EN, rtc, reg_irq);
 297                 rtc->data->unmask_interrupt(rtc);
 298         }
 299
 300         spin_unlock_irqrestore(&rtc->lock, flags);
 301
 302         return 0;
 303 }
 304
 305 static int armada38x_rtc_alarm_irq_enable(struct device *dev,
 306                                          unsigned int enabled)
 307 {
 308         struct armada38x_rtc *rtc = dev_get_drvdata(dev);
 309         u32 reg_irq = ALARM_REG(RTC_IRQ1_CONF, rtc->data->alarm);
 310         unsigned long flags;
 311
 312         spin_lock_irqsave(&rtc->lock, flags);
 313
 314         if (enabled)
 315                 rtc_delayed_write(RTC_IRQ_AL_EN, rtc, reg_irq);
 316         else
 317                 rtc_delayed_write(0, rtc, reg_irq);
 318
 319         spin_unlock_irqrestore(&rtc->lock, flags);
 320
 321         return 0;
 322 }
 323
 324 static irqreturn_t armada38x_rtc_alarm_irq(int irq, void *data)
 325 {
 326         struct armada38x_rtc *rtc = data;
 327         u32 val;
 328         int event = RTC_IRQF | RTC_AF;
 329         u32 reg_irq = ALARM_REG(RTC_IRQ1_CONF, rtc->data->alarm);
 330
 331         dev_dbg(&rtc->rtc_dev->dev, "%s:irq(%d)\n", __func__, irq);
 332
 333         spin_lock(&rtc->lock);
 334
 335         rtc->data->clear_isr(rtc);
 336         val = rtc->data->read_rtc_reg(rtc, reg_irq);
 337         /* disable all the interrupts for alarm*/
 338         rtc_delayed_write(0, rtc, reg_irq);
 339         /* Ack the event */
 340         rtc_delayed_write(1 << rtc->data->alarm, rtc, RTC_STATUS);
 341
 342         spin_unlock(&rtc->lock);
 343
 344         if (val & RTC_IRQ_FREQ_EN) {
 345                 if (val & RTC_IRQ_FREQ_1HZ)
 346                         event |= RTC_UF;
 347                 else
 348                         event |= RTC_PF;
 349         }
 350
 351         rtc_update_irq(rtc->rtc_dev, 1, event);
 352
 353         return IRQ_HANDLED;
 354 }
 355
 356 /*
 357  * The information given in the Armada 388 functional spec is complex.
 358  * They give two different formulas for calculating the offset value,
 359  * but when considering "Offset" as an 8-bit signed integer, they both
 360  * reduce down to (we shall rename "Offset" as "val" here):
 361  *
 362  *   val = (f_ideal / f_measured - 1) / resolution   where f_ideal = 32768
 363  *
 364  * Converting to time, f = 1/t:
 365  *   val = (t_measured / t_ideal - 1) / resolution   where t_ideal = 1/32768
 366  *
 367  *   =>  t_measured / t_ideal = val * resolution + 1
 368  *
 369  * "offset" in the RTC interface is defined as:
 370  *   t = t0 * (1 + offset * 1e-9)
 371  * where t is the desired period, t0 is the measured period with a zero
 372  * offset, which is t_measured above. With t0 = t_measured and t = t_ideal,
 373  *   offset = (t_ideal / t_measured - 1) / 1e-9
 374  *
 375  *   => t_ideal / t_measured = offset * 1e-9 + 1
 376  *
 377  * so:
 378  *
 379  *   offset * 1e-9 + 1 = 1 / (val * resolution + 1)
 380  *
 381  * We want "resolution" to be an integer, so resolution = R * 1e-9, giving
 382  *   offset = 1e18 / (val * R + 1e9) - 1e9
 383  *   val = (1e18 / (offset + 1e9) - 1e9) / R
 384  * with a common transformation:
 385  *   f(x) = 1e18 / (x + 1e9) - 1e9
 386  *   offset = f(val * R)
 387  *   val = f(offset) / R
 388  *
 389  * Armada 38x supports two modes, fine mode (954ppb) and coarse mode (3815ppb).
 390  */
 391 static long armada38x_ppb_convert(long ppb)
 392 {
 393         long div = ppb + 1000000000L;
 394
 395         return div_s64(1000000000000000000LL + div / 2, div) - 1000000000L;
 396 }
 397
 398 static int armada38x_rtc_read_offset(struct device *dev, long *offset)
 399 {
 400         struct armada38x_rtc *rtc = dev_get_drvdata(dev);
 401         unsigned long ccr, flags;
 402         long ppb_cor;
 403
 404         spin_lock_irqsave(&rtc->lock, flags);
 405         ccr = rtc->data->read_rtc_reg(rtc, RTC_CCR);
 406         spin_unlock_irqrestore(&rtc->lock, flags);
 407
 408         ppb_cor = (ccr & RTC_CCR_MODE ? 3815 : 954) * (s8)ccr;
 409         /* ppb_cor + 1000000000L can never be zero */
 410         *offset = armada38x_ppb_convert(ppb_cor);
 411
 412         return 0;
 413 }
 414
 415 static int armada38x_rtc_set_offset(struct device *dev, long offset)
 416 {
 417         struct armada38x_rtc *rtc = dev_get_drvdata(dev);
 418         unsigned long ccr = 0;
 419         long ppb_cor, off;
 420
 421         /*
 422          * The maximum ppb_cor is -128 * 3815 .. 127 * 3815, but we
 423          * need to clamp the input.  This equates to -484270 .. 488558.
 424          * Not only is this to stop out of range "off" but also to
 425          * avoid the division by zero in armada38x_ppb_convert().
 426          */
 427         offset = clamp(offset, -484270L, 488558L);
 428
 429         ppb_cor = armada38x_ppb_convert(offset);
 430
 431         /*
 432          * Use low update mode where possible, which gives a better
 433          * resolution of correction.
 434          */
 435         off = DIV_ROUND_CLOSEST(ppb_cor, 954);
 436         if (off > 127 || off < -128) {
 437                 ccr = RTC_CCR_MODE;
 438                 off = DIV_ROUND_CLOSEST(ppb_cor, 3815);
 439         }
 440
 441         /*
 442          * Armada 388 requires a bit pattern in bits 14..8 depending on
 443          * the sign bit: { 0, ~S, S, S, S, S, S }
 444          */
 445         ccr |= (off & 0x3fff) ^ 0x2000;
 446         rtc_delayed_write(ccr, rtc, RTC_CCR);
 447
 448         return 0;
 449 }
 450
 451 static const struct rtc_class_ops armada38x_rtc_ops = {
 452         .read_time = armada38x_rtc_read_time,
 453         .set_time = armada38x_rtc_set_time,
 454         .read_alarm = armada38x_rtc_read_alarm,
 455         .set_alarm = armada38x_rtc_set_alarm,
 456         .alarm_irq_enable = armada38x_rtc_alarm_irq_enable,
 457         .read_offset = armada38x_rtc_read_offset,
 458         .set_offset = armada38x_rtc_set_offset,
 459 };
 460
 461 static const struct rtc_class_ops armada38x_rtc_ops_noirq = {
 462         .read_time = armada38x_rtc_read_time,
 463         .set_time = armada38x_rtc_set_time,
 464         .read_alarm = armada38x_rtc_read_alarm,
 465         .read_offset = armada38x_rtc_read_offset,
 466         .set_offset = armada38x_rtc_set_offset,
 467 };
 468
 469 static const struct armada38x_rtc_data armada38x_data = {
 470         .update_mbus_timing = rtc_update_38x_mbus_timing_params,
 471         .read_rtc_reg = read_rtc_register_38x_wa,
 472         .clear_isr = armada38x_clear_isr,
 473         .unmask_interrupt = armada38x_unmask_interrupt,
 474         .alarm = ALARM1,
 475 };
 476
 477 static const struct armada38x_rtc_data armada8k_data = {
 478         .update_mbus_timing = rtc_update_8k_mbus_timing_params,
 479         .read_rtc_reg = read_rtc_register,
 480         .clear_isr = armada8k_clear_isr,
 481         .unmask_interrupt = armada8k_unmask_interrupt,
 482         .alarm = ALARM2,
 483 };
 484
 485 #ifdef CONFIG_OF
 486 static const struct of_device_id armada38x_rtc_of_match_table[] = {
 487         {
 488                 .compatible = "marvell,armada-380-rtc",
 489                 .data = &armada38x_data,
 490         },
 491         {
 492                 .compatible = "marvell,armada-8k-rtc",
 493                 .data = &armada8k_data,
 494         },
 495         {}
 496 };
 497 MODULE_DEVICE_TABLE(of, armada38x_rtc_of_match_table);
 498 #endif
 499
 500 static __init int armada38x_rtc_probe(struct platform_device *pdev)
 501 {
 502         struct resource *res;
 503         struct armada38x_rtc *rtc;
 504
 505         rtc = devm_kzalloc(&pdev->dev, sizeof(struct armada38x_rtc),
 506                             GFP_KERNEL);
 507         if (!rtc)
 508                 return -ENOMEM;
 509
 510         rtc->data = of_device_get_match_data(&pdev->dev);
 511
 512         rtc->val_to_freq = devm_kcalloc(&pdev->dev, SAMPLE_NR,
 513                                 sizeof(struct value_to_freq), GFP_KERNEL);
 514         if (!rtc->val_to_freq)
 515                 return -ENOMEM;
 516
 517         spin_lock_init(&rtc->lock);
 518
 519         res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "rtc");
 520         rtc->regs = devm_ioremap_resource(&pdev->dev, res);
 521         if (IS_ERR(rtc->regs))
 522                 return PTR_ERR(rtc->regs);
 523         res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "rtc-soc");
 524         rtc->regs_soc = devm_ioremap_resource(&pdev->dev, res);
 525         if (IS_ERR(rtc->regs_soc))
 526                 return PTR_ERR(rtc->regs_soc);
 527
 528         rtc->irq = platform_get_irq(pdev, 0);
 529         if (rtc->irq < 0)
 530                 return rtc->irq;
 531
 532         rtc->rtc_dev = devm_rtc_allocate_device(&pdev->dev);
 533         if (IS_ERR(rtc->rtc_dev))
 534                 return PTR_ERR(rtc->rtc_dev);
 535
 536         if (devm_request_irq(&pdev->dev, rtc->irq, armada38x_rtc_alarm_irq,
 537                                 0, pdev->name, rtc) < 0) {
 538                 dev_warn(&pdev->dev, "Interrupt not available.\n");
 539                 rtc->irq = -1;
 540         }
 541         platform_set_drvdata(pdev, rtc);
 542
 543         if (rtc->irq != -1) {
 544                 device_init_wakeup(&pdev->dev, 1);
 545                 rtc->rtc_dev->ops = &armada38x_rtc_ops;
 546         } else {
 547                 /*
 548                  * If there is no interrupt available then we can't
 549                  * use the alarm
 550                  */
 551                 rtc->rtc_dev->ops = &armada38x_rtc_ops_noirq;
 552         }
 553
 554         /* Update RTC-MBUS bridge timing parameters */
 555         rtc->data->update_mbus_timing(rtc);
 556
 557         rtc->rtc_dev->range_max = U32_MAX;
 558
 559         return devm_rtc_register_device(rtc->rtc_dev);
 560 }
 561
 562 #ifdef CONFIG_PM_SLEEP
 563 static int armada38x_rtc_suspend(struct device *dev)
 564 {
 565         if (device_may_wakeup(dev)) {
 566                 struct armada38x_rtc *rtc = dev_get_drvdata(dev);
 567
 568                 return enable_irq_wake(rtc->irq);
 569         }
 570
 571         return 0;
 572 }
 573
 574 static int armada38x_rtc_resume(struct device *dev)
 575 {
 576         if (device_may_wakeup(dev)) {
 577                 struct armada38x_rtc *rtc = dev_get_drvdata(dev);
 578
 579                 /* Update RTC-MBUS bridge timing parameters */
 580                 rtc->data->update_mbus_timing(rtc);
 581
 582                 return disable_irq_wake(rtc->irq);
 583         }
 584
 585         return 0;
 586 }
 587 #endif
 588
 589 static SIMPLE_DEV_PM_OPS(armada38x_rtc_pm_ops,
 590                          armada38x_rtc_suspend, armada38x_rtc_resume);
 591
 592 static struct platform_driver armada38x_rtc_driver = {
 593         .driver         = {
 594                 .name   = "armada38x-rtc",
 595                 .pm     = &armada38x_rtc_pm_ops,
 596                 .of_match_table = of_match_ptr(armada38x_rtc_of_match_table),
 597         },
 598 };
 599
 600 module_platform_driver_probe(armada38x_rtc_driver, armada38x_rtc_probe);
 601
 602 MODULE_DESCRIPTION("Marvell Armada 38x RTC driver");
 603 MODULE_AUTHOR("Gregory CLEMENT <gregory.clement@free-electrons.com>");
 604 MODULE_LICENSE("GPL");