drivers/rtc/rtc-armada38x.c

   1 /*
   2  * RTC driver for the Armada 38x Marvell SoCs
   3  *
   4  * Copyright (C) 2015 Marvell
   5  *
   6  * Gregory Clement <gregory.clement@free-electrons.com>
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License as
  10  * published by the Free Software Foundation; either version 2 of the
  11  * License, or (at your option) any later version.
  12  *
  13  */
  14
  15 #include <linux/delay.h>
  16 #include <linux/io.h>
  17 #include <linux/module.h>
  18 #include <linux/of.h>
  19 #include <linux/of_device.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/rtc.h>
  22
  23 #define RTC_STATUS          0x0
  24 #define RTC_STATUS_ALARM1           BIT(0)
  25 #define RTC_STATUS_ALARM2           BIT(1)
  26 #define RTC_IRQ1_CONF       0x4
  27 #define RTC_IRQ2_CONF       0x8
  28 #define RTC_IRQ_AL_EN               BIT(0)
  29 #define RTC_IRQ_FREQ_EN             BIT(1)
  30 #define RTC_IRQ_FREQ_1HZ            BIT(2)
  31
  32 #define RTC_TIME            0xC
  33 #define RTC_ALARM1          0x10
  34 #define RTC_ALARM2          0x14
  35
  36 /* Armada38x SoC registers  */
  37 #define RTC_38X_BRIDGE_TIMING_CTL   0x0
  38 #define RTC_38X_PERIOD_OFFS             0
  39 #define RTC_38X_PERIOD_MASK             (0x3FF << RTC_38X_PERIOD_OFFS)
  40 #define RTC_38X_READ_DELAY_OFFS         26
  41 #define RTC_38X_READ_DELAY_MASK         (0x1F << RTC_38X_READ_DELAY_OFFS)
  42
  43 /* Armada 7K/8K registers  */
  44 #define RTC_8K_BRIDGE_TIMING_CTL0    0x0
  45 #define RTC_8K_WRCLK_PERIOD_OFFS        0
  46 #define RTC_8K_WRCLK_PERIOD_MASK        (0xFFFF << RTC_8K_WRCLK_PERIOD_OFFS)
  47 #define RTC_8K_WRCLK_SETUP_OFFS         16
  48 #define RTC_8K_WRCLK_SETUP_MASK         (0xFFFF << RTC_8K_WRCLK_SETUP_OFFS)
  49 #define RTC_8K_BRIDGE_TIMING_CTL1   0x4
  50 #define RTC_8K_READ_DELAY_OFFS          0
  51 #define RTC_8K_READ_DELAY_MASK          (0xFFFF << RTC_8K_READ_DELAY_OFFS)
  52
  53 #define RTC_8K_ISR                  0x10
  54 #define RTC_8K_IMR                  0x14
  55 #define RTC_8K_ALARM2                   BIT(0)
  56
  57 #define SOC_RTC_INTERRUPT           0x8
  58 #define SOC_RTC_ALARM1                  BIT(0)
  59 #define SOC_RTC_ALARM2                  BIT(1)
  60 #define SOC_RTC_ALARM1_MASK             BIT(2)
  61 #define SOC_RTC_ALARM2_MASK             BIT(3)
  62
  63 #define SAMPLE_NR 100
  64
  65 struct value_to_freq {
  66         u32 value;
  67         u8 freq;
  68 };
  69
  70 struct armada38x_rtc {
  71         struct rtc_device   *rtc_dev;
  72         void __iomem        *regs;
  73         void __iomem        *regs_soc;
  74         spinlock_t          lock;
  75         int                 irq;
  76         struct value_to_freq *val_to_freq;
  77         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_time_to_tm(time, tm);
 223
 224         return 0;
 225 }
 226
 227 static int armada38x_rtc_set_time(struct device *dev, struct rtc_time *tm)
 228 {
 229         struct armada38x_rtc *rtc = dev_get_drvdata(dev);
 230         int ret = 0;
 231         unsigned long time, flags;
 232
 233         ret = rtc_tm_to_time(tm, &time);
 234
 235         if (ret)
 236                 goto out;
 237
 238         spin_lock_irqsave(&rtc->lock, flags);
 239         rtc_delayed_write(time, rtc, RTC_TIME);
 240         spin_unlock_irqrestore(&rtc->lock, flags);
 241
 242 out:
 243         return ret;
 244 }
 245
 246 static int armada38x_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 247 {
 248         struct armada38x_rtc *rtc = dev_get_drvdata(dev);
 249         unsigned long time, flags;
 250         u32 reg = ALARM_REG(RTC_ALARM1, rtc->data->alarm);
 251         u32 reg_irq = ALARM_REG(RTC_IRQ1_CONF, rtc->data->alarm);
 252         u32 val;
 253
 254         spin_lock_irqsave(&rtc->lock, flags);
 255
 256         time = rtc->data->read_rtc_reg(rtc, reg);
 257         val = rtc->data->read_rtc_reg(rtc, reg_irq) & RTC_IRQ_AL_EN;
 258
 259         spin_unlock_irqrestore(&rtc->lock, flags);
 260
 261         alrm->enabled = val ? 1 : 0;
 262         rtc_time_to_tm(time,  &alrm->time);
 263
 264         return 0;
 265 }
 266
 267 static int armada38x_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 268 {
 269         struct armada38x_rtc *rtc = dev_get_drvdata(dev);
 270         u32 reg = ALARM_REG(RTC_ALARM1, rtc->data->alarm);
 271         u32 reg_irq = ALARM_REG(RTC_IRQ1_CONF, rtc->data->alarm);
 272         unsigned long time, flags;
 273         int ret = 0;
 274
 275         ret = rtc_tm_to_time(&alrm->time, &time);
 276
 277         if (ret)
 278                 goto out;
 279
 280         spin_lock_irqsave(&rtc->lock, flags);
 281
 282         rtc_delayed_write(time, rtc, reg);
 283
 284         if (alrm->enabled) {
 285                 rtc_delayed_write(RTC_IRQ_AL_EN, rtc, reg_irq);
 286                 rtc->data->unmask_interrupt(rtc);
 287         }
 288
 289         spin_unlock_irqrestore(&rtc->lock, flags);
 290
 291 out:
 292         return ret;
 293 }
 294
 295 static int armada38x_rtc_alarm_irq_enable(struct device *dev,
 296                                          unsigned int enabled)
 297 {
 298         struct armada38x_rtc *rtc = dev_get_drvdata(dev);
 299         u32 reg_irq = ALARM_REG(RTC_IRQ1_CONF, rtc->data->alarm);
 300         unsigned long flags;
 301
 302         spin_lock_irqsave(&rtc->lock, flags);
 303
 304         if (enabled)
 305                 rtc_delayed_write(RTC_IRQ_AL_EN, rtc, reg_irq);
 306         else
 307                 rtc_delayed_write(0, rtc, reg_irq);
 308
 309         spin_unlock_irqrestore(&rtc->lock, flags);
 310
 311         return 0;
 312 }
 313
 314 static irqreturn_t armada38x_rtc_alarm_irq(int irq, void *data)
 315 {
 316         struct armada38x_rtc *rtc = data;
 317         u32 val;
 318         int event = RTC_IRQF | RTC_AF;
 319         u32 reg_irq = ALARM_REG(RTC_IRQ1_CONF, rtc->data->alarm);
 320
 321         dev_dbg(&rtc->rtc_dev->dev, "%s:irq(%d)\n", __func__, irq);
 322
 323         spin_lock(&rtc->lock);
 324
 325         rtc->data->clear_isr(rtc);
 326         val = rtc->data->read_rtc_reg(rtc, reg_irq);
 327         /* disable all the interrupts for alarm*/
 328         rtc_delayed_write(0, rtc, reg_irq);
 329         /* Ack the event */
 330         rtc_delayed_write(1 << rtc->data->alarm, rtc, RTC_STATUS);
 331
 332         spin_unlock(&rtc->lock);
 333
 334         if (val & RTC_IRQ_FREQ_EN) {
 335                 if (val & RTC_IRQ_FREQ_1HZ)
 336                         event |= RTC_UF;
 337                 else
 338                         event |= RTC_PF;
 339         }
 340
 341         rtc_update_irq(rtc->rtc_dev, 1, event);
 342
 343         return IRQ_HANDLED;
 344 }
 345
 346 static const struct rtc_class_ops armada38x_rtc_ops = {
 347         .read_time = armada38x_rtc_read_time,
 348         .set_time = armada38x_rtc_set_time,
 349         .read_alarm = armada38x_rtc_read_alarm,
 350         .set_alarm = armada38x_rtc_set_alarm,
 351         .alarm_irq_enable = armada38x_rtc_alarm_irq_enable,
 352 };
 353
 354 static const struct rtc_class_ops armada38x_rtc_ops_noirq = {
 355         .read_time = armada38x_rtc_read_time,
 356         .set_time = armada38x_rtc_set_time,
 357         .read_alarm = armada38x_rtc_read_alarm,
 358 };
 359
 360 static const struct armada38x_rtc_data armada38x_data = {
 361         .update_mbus_timing = rtc_update_38x_mbus_timing_params,
 362         .read_rtc_reg = read_rtc_register_38x_wa,
 363         .clear_isr = armada38x_clear_isr,
 364         .unmask_interrupt = armada38x_unmask_interrupt,
 365         .alarm = ALARM1,
 366 };
 367
 368 static const struct armada38x_rtc_data armada8k_data = {
 369         .update_mbus_timing = rtc_update_8k_mbus_timing_params,
 370         .read_rtc_reg = read_rtc_register,
 371         .clear_isr = armada8k_clear_isr,
 372         .unmask_interrupt = armada8k_unmask_interrupt,
 373         .alarm = ALARM2,
 374 };
 375
 376 #ifdef CONFIG_OF
 377 static const struct of_device_id armada38x_rtc_of_match_table[] = {
 378         {
 379                 .compatible = "marvell,armada-380-rtc",
 380                 .data = &armada38x_data,
 381         },
 382         {
 383                 .compatible = "marvell,armada-8k-rtc",
 384                 .data = &armada8k_data,
 385         },
 386         {}
 387 };
 388 MODULE_DEVICE_TABLE(of, armada38x_rtc_of_match_table);
 389 #endif
 390
 391 static __init int armada38x_rtc_probe(struct platform_device *pdev)
 392 {
 393         const struct rtc_class_ops *ops;
 394         struct resource *res;
 395         struct armada38x_rtc *rtc;
 396         const struct of_device_id *match;
 397         int ret;
 398
 399         match = of_match_device(armada38x_rtc_of_match_table, &pdev->dev);
 400         if (!match)
 401                 return -ENODEV;
 402
 403         rtc = devm_kzalloc(&pdev->dev, sizeof(struct armada38x_rtc),
 404                             GFP_KERNEL);
 405         if (!rtc)
 406                 return -ENOMEM;
 407
 408         rtc->val_to_freq = devm_kcalloc(&pdev->dev, SAMPLE_NR,
 409                                 sizeof(struct value_to_freq), GFP_KERNEL);
 410         if (!rtc->val_to_freq)
 411                 return -ENOMEM;
 412
 413         spin_lock_init(&rtc->lock);
 414
 415         res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "rtc");
 416         rtc->regs = devm_ioremap_resource(&pdev->dev, res);
 417         if (IS_ERR(rtc->regs))
 418                 return PTR_ERR(rtc->regs);
 419         res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "rtc-soc");
 420         rtc->regs_soc = devm_ioremap_resource(&pdev->dev, res);
 421         if (IS_ERR(rtc->regs_soc))
 422                 return PTR_ERR(rtc->regs_soc);
 423
 424         rtc->irq = platform_get_irq(pdev, 0);
 425
 426         if (rtc->irq < 0) {
 427                 dev_err(&pdev->dev, "no irq\n");
 428                 return rtc->irq;
 429         }
 430         if (devm_request_irq(&pdev->dev, rtc->irq, armada38x_rtc_alarm_irq,
 431                                 0, pdev->name, rtc) < 0) {
 432                 dev_warn(&pdev->dev, "Interrupt not available.\n");
 433                 rtc->irq = -1;
 434         }
 435         platform_set_drvdata(pdev, rtc);
 436
 437         if (rtc->irq != -1) {
 438                 device_init_wakeup(&pdev->dev, 1);
 439                 ops = &armada38x_rtc_ops;
 440         } else {
 441                 /*
 442                  * If there is no interrupt available then we can't
 443                  * use the alarm
 444                  */
 445                 ops = &armada38x_rtc_ops_noirq;
 446         }
 447         rtc->data = (struct armada38x_rtc_data *)match->data;
 448
 449
 450         /* Update RTC-MBUS bridge timing parameters */
 451         rtc->data->update_mbus_timing(rtc);
 452
 453         rtc->rtc_dev = devm_rtc_device_register(&pdev->dev, pdev->name,
 454                                                 ops, THIS_MODULE);
 455         if (IS_ERR(rtc->rtc_dev)) {
 456                 ret = PTR_ERR(rtc->rtc_dev);
 457                 dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
 458                 return ret;
 459         }
 460         return 0;
 461 }
 462
 463 #ifdef CONFIG_PM_SLEEP
 464 static int armada38x_rtc_suspend(struct device *dev)
 465 {
 466         if (device_may_wakeup(dev)) {
 467                 struct armada38x_rtc *rtc = dev_get_drvdata(dev);
 468
 469                 return enable_irq_wake(rtc->irq);
 470         }
 471
 472         return 0;
 473 }
 474
 475 static int armada38x_rtc_resume(struct device *dev)
 476 {
 477         if (device_may_wakeup(dev)) {
 478                 struct armada38x_rtc *rtc = dev_get_drvdata(dev);
 479
 480                 /* Update RTC-MBUS bridge timing parameters */
 481                 rtc->data->update_mbus_timing(rtc);
 482
 483                 return disable_irq_wake(rtc->irq);
 484         }
 485
 486         return 0;
 487 }
 488 #endif
 489
 490 static SIMPLE_DEV_PM_OPS(armada38x_rtc_pm_ops,
 491                          armada38x_rtc_suspend, armada38x_rtc_resume);
 492
 493 static struct platform_driver armada38x_rtc_driver = {
 494         .driver         = {
 495                 .name   = "armada38x-rtc",
 496                 .pm     = &armada38x_rtc_pm_ops,
 497                 .of_match_table = of_match_ptr(armada38x_rtc_of_match_table),
 498         },
 499 };
 500
 501 module_platform_driver_probe(armada38x_rtc_driver, armada38x_rtc_probe);
 502
 503 MODULE_DESCRIPTION("Marvell Armada 38x RTC driver");
 504 MODULE_AUTHOR("Gregory CLEMENT <gregory.clement@free-electrons.com>");
 505 MODULE_LICENSE("GPL");