drivers/rtc/rtc-rzn1.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Renesas RZ/N1 Real Time Clock interface for Linux
   4  *
   5  * Copyright:
   6  * - 2014 Renesas Electronics Europe Limited
   7  * - 2022 Schneider Electric
   8  *
   9  * Authors:
  10  * - Michel Pollet <michel.pollet@bp.renesas.com>, <buserror@gmail.com>
  11  * - Miquel Raynal <miquel.raynal@bootlin.com>
  12  */
  13
  14 #include <linux/bcd.h>
  15 #include <linux/init.h>
  16 #include <linux/iopoll.h>
  17 #include <linux/module.h>
  18 #include <linux/of_device.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/pm_runtime.h>
  21 #include <linux/rtc.h>
  22
  23 #define RZN1_RTC_CTL0 0x00
  24 #define   RZN1_RTC_CTL0_SLSB_SUBU 0
  25 #define   RZN1_RTC_CTL0_SLSB_SCMP BIT(4)
  26 #define   RZN1_RTC_CTL0_AMPM BIT(5)
  27 #define   RZN1_RTC_CTL0_CE BIT(7)
  28
  29 #define RZN1_RTC_CTL1 0x04
  30 #define   RZN1_RTC_CTL1_ALME BIT(4)
  31
  32 #define RZN1_RTC_CTL2 0x08
  33 #define   RZN1_RTC_CTL2_WAIT BIT(0)
  34 #define   RZN1_RTC_CTL2_WST BIT(1)
  35 #define   RZN1_RTC_CTL2_WUST BIT(5)
  36 #define   RZN1_RTC_CTL2_STOPPED (RZN1_RTC_CTL2_WAIT | RZN1_RTC_CTL2_WST)
  37
  38 #define RZN1_RTC_SEC 0x14
  39 #define RZN1_RTC_MIN 0x18
  40 #define RZN1_RTC_HOUR 0x1c
  41 #define RZN1_RTC_WEEK 0x20
  42 #define RZN1_RTC_DAY 0x24
  43 #define RZN1_RTC_MONTH 0x28
  44 #define RZN1_RTC_YEAR 0x2c
  45
  46 #define RZN1_RTC_SUBU 0x38
  47 #define   RZN1_RTC_SUBU_DEV BIT(7)
  48 #define   RZN1_RTC_SUBU_DECR BIT(6)
  49
  50 #define RZN1_RTC_ALM 0x40
  51 #define RZN1_RTC_ALH 0x44
  52 #define RZN1_RTC_ALW 0x48
  53
  54 #define RZN1_RTC_SECC 0x4c
  55 #define RZN1_RTC_MINC 0x50
  56 #define RZN1_RTC_HOURC 0x54
  57 #define RZN1_RTC_WEEKC 0x58
  58 #define RZN1_RTC_DAYC 0x5c
  59 #define RZN1_RTC_MONTHC 0x60
  60 #define RZN1_RTC_YEARC 0x64
  61
  62 struct rzn1_rtc {
  63         struct rtc_device *rtcdev;
  64         void __iomem *base;
  65 };
  66
  67 static void rzn1_rtc_get_time_snapshot(struct rzn1_rtc *rtc, struct rtc_time *tm)
  68 {
  69         tm->tm_sec = readl(rtc->base + RZN1_RTC_SECC);
  70         tm->tm_min = readl(rtc->base + RZN1_RTC_MINC);
  71         tm->tm_hour = readl(rtc->base + RZN1_RTC_HOURC);
  72         tm->tm_wday = readl(rtc->base + RZN1_RTC_WEEKC);
  73         tm->tm_mday = readl(rtc->base + RZN1_RTC_DAYC);
  74         tm->tm_mon = readl(rtc->base + RZN1_RTC_MONTHC);
  75         tm->tm_year = readl(rtc->base + RZN1_RTC_YEARC);
  76 }
  77
  78 static unsigned int rzn1_rtc_tm_to_wday(struct rtc_time *tm)
  79 {
  80         time64_t time;
  81         unsigned int days;
  82         u32 secs;
  83
  84         time = rtc_tm_to_time64(tm);
  85         days = div_s64_rem(time, 86400, &secs);
  86
  87         /* day of the week, 1970-01-01 was a Thursday */
  88         return (days + 4) % 7;
  89 }
  90
  91 static int rzn1_rtc_read_time(struct device *dev, struct rtc_time *tm)
  92 {
  93         struct rzn1_rtc *rtc = dev_get_drvdata(dev);
  94         u32 val, secs;
  95
  96         /*
  97          * The RTC was not started or is stopped and thus does not carry the
  98          * proper time/date.
  99          */
 100         val = readl(rtc->base + RZN1_RTC_CTL2);
 101         if (val & RZN1_RTC_CTL2_STOPPED)
 102                 return -EINVAL;
 103
 104         rzn1_rtc_get_time_snapshot(rtc, tm);
 105         secs = readl(rtc->base + RZN1_RTC_SECC);
 106         if (tm->tm_sec != secs)
 107                 rzn1_rtc_get_time_snapshot(rtc, tm);
 108
 109         tm->tm_sec = bcd2bin(tm->tm_sec);
 110         tm->tm_min = bcd2bin(tm->tm_min);
 111         tm->tm_hour = bcd2bin(tm->tm_hour);
 112         tm->tm_wday = bcd2bin(tm->tm_wday);
 113         tm->tm_mday = bcd2bin(tm->tm_mday);
 114         tm->tm_mon = bcd2bin(tm->tm_mon);
 115         tm->tm_year = bcd2bin(tm->tm_year);
 116
 117         return 0;
 118 }
 119
 120 static int rzn1_rtc_set_time(struct device *dev, struct rtc_time *tm)
 121 {
 122         struct rzn1_rtc *rtc = dev_get_drvdata(dev);
 123         u32 val;
 124         int ret;
 125
 126         tm->tm_sec = bin2bcd(tm->tm_sec);
 127         tm->tm_min = bin2bcd(tm->tm_min);
 128         tm->tm_hour = bin2bcd(tm->tm_hour);
 129         tm->tm_wday = bin2bcd(rzn1_rtc_tm_to_wday(tm));
 130         tm->tm_mday = bin2bcd(tm->tm_mday);
 131         tm->tm_mon = bin2bcd(tm->tm_mon);
 132         tm->tm_year = bin2bcd(tm->tm_year);
 133
 134         val = readl(rtc->base + RZN1_RTC_CTL2);
 135         if (!(val & RZN1_RTC_CTL2_STOPPED)) {
 136                 /* Hold the counter if it was counting up */
 137                 writel(RZN1_RTC_CTL2_WAIT, rtc->base + RZN1_RTC_CTL2);
 138
 139                 /* Wait for the counter to stop: two 32k clock cycles */
 140                 usleep_range(61, 100);
 141                 ret = readl_poll_timeout(rtc->base + RZN1_RTC_CTL2, val,
 142                                          val & RZN1_RTC_CTL2_WST, 0, 100);
 143                 if (ret)
 144                         return ret;
 145         }
 146
 147         writel(tm->tm_sec, rtc->base + RZN1_RTC_SEC);
 148         writel(tm->tm_min, rtc->base + RZN1_RTC_MIN);
 149         writel(tm->tm_hour, rtc->base + RZN1_RTC_HOUR);
 150         writel(tm->tm_wday, rtc->base + RZN1_RTC_WEEK);
 151         writel(tm->tm_mday, rtc->base + RZN1_RTC_DAY);
 152         writel(tm->tm_mon, rtc->base + RZN1_RTC_MONTH);
 153         writel(tm->tm_year, rtc->base + RZN1_RTC_YEAR);
 154         writel(0, rtc->base + RZN1_RTC_CTL2);
 155
 156         return 0;
 157 }
 158
 159 static irqreturn_t rzn1_rtc_alarm_irq(int irq, void *dev_id)
 160 {
 161         struct rzn1_rtc *rtc = dev_id;
 162
 163         rtc_update_irq(rtc->rtcdev, 1, RTC_AF | RTC_IRQF);
 164
 165         return IRQ_HANDLED;
 166 }
 167
 168 static int rzn1_rtc_alarm_irq_enable(struct device *dev, unsigned int enable)
 169 {
 170         struct rzn1_rtc *rtc = dev_get_drvdata(dev);
 171         u32 ctl1 = readl(rtc->base + RZN1_RTC_CTL1);
 172
 173         if (enable)
 174                 ctl1 |= RZN1_RTC_CTL1_ALME;
 175         else
 176                 ctl1 &= ~RZN1_RTC_CTL1_ALME;
 177
 178         writel(ctl1, rtc->base + RZN1_RTC_CTL1);
 179
 180         return 0;
 181 }
 182
 183 static int rzn1_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 184 {
 185         struct rzn1_rtc *rtc = dev_get_drvdata(dev);
 186         struct rtc_time *tm = &alrm->time;
 187         unsigned int min, hour, wday, delta_days;
 188         time64_t alarm;
 189         u32 ctl1;
 190         int ret;
 191
 192         ret = rzn1_rtc_read_time(dev, tm);
 193         if (ret)
 194                 return ret;
 195
 196         min = readl(rtc->base + RZN1_RTC_ALM);
 197         hour = readl(rtc->base + RZN1_RTC_ALH);
 198         wday = readl(rtc->base + RZN1_RTC_ALW);
 199
 200         tm->tm_sec = 0;
 201         tm->tm_min = bcd2bin(min);
 202         tm->tm_hour = bcd2bin(hour);
 203         delta_days = ((fls(wday) - 1) - tm->tm_wday + 7) % 7;
 204         tm->tm_wday = fls(wday) - 1;
 205
 206         if (delta_days) {
 207                 alarm = rtc_tm_to_time64(tm) + (delta_days * 86400);
 208                 rtc_time64_to_tm(alarm, tm);
 209         }
 210
 211         ctl1 = readl(rtc->base + RZN1_RTC_CTL1);
 212         alrm->enabled = !!(ctl1 & RZN1_RTC_CTL1_ALME);
 213
 214         return 0;
 215 }
 216
 217 static int rzn1_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 218 {
 219         struct rzn1_rtc *rtc = dev_get_drvdata(dev);
 220         struct rtc_time *tm = &alrm->time, tm_now;
 221         unsigned long alarm, farest;
 222         unsigned int days_ahead, wday;
 223         int ret;
 224
 225         ret = rzn1_rtc_read_time(dev, &tm_now);
 226         if (ret)
 227                 return ret;
 228
 229         /* We cannot set alarms more than one week ahead */
 230         farest = rtc_tm_to_time64(&tm_now) + (7 * 86400);
 231         alarm = rtc_tm_to_time64(tm);
 232         if (time_after(alarm, farest))
 233                 return -ERANGE;
 234
 235         /* Convert alarm day into week day */
 236         days_ahead = tm->tm_mday - tm_now.tm_mday;
 237         wday = (tm_now.tm_wday + days_ahead) % 7;
 238
 239         writel(bin2bcd(tm->tm_min), rtc->base + RZN1_RTC_ALM);
 240         writel(bin2bcd(tm->tm_hour), rtc->base + RZN1_RTC_ALH);
 241         writel(BIT(wday), rtc->base + RZN1_RTC_ALW);
 242
 243         rzn1_rtc_alarm_irq_enable(dev, alrm->enabled);
 244
 245         return 0;
 246 }
 247
 248 static int rzn1_rtc_read_offset(struct device *dev, long *offset)
 249 {
 250         struct rzn1_rtc *rtc = dev_get_drvdata(dev);
 251         unsigned int ppb_per_step;
 252         bool subtract;
 253         u32 val;
 254
 255         val = readl(rtc->base + RZN1_RTC_SUBU);
 256         ppb_per_step = val & RZN1_RTC_SUBU_DEV ? 1017 : 3051;
 257         subtract = val & RZN1_RTC_SUBU_DECR;
 258         val &= 0x3F;
 259
 260         if (!val)
 261                 *offset = 0;
 262         else if (subtract)
 263                 *offset = -(((~val) & 0x3F) + 1) * ppb_per_step;
 264         else
 265                 *offset = (val - 1) * ppb_per_step;
 266
 267         return 0;
 268 }
 269
 270 static int rzn1_rtc_set_offset(struct device *dev, long offset)
 271 {
 272         struct rzn1_rtc *rtc = dev_get_drvdata(dev);
 273         int stepsh, stepsl, steps;
 274         u32 subu = 0, ctl2;
 275         int ret;
 276
 277         /*
 278          * Check which resolution mode (every 20 or 60s) can be used.
 279          * Between 2 and 124 clock pulses can be added or substracted.
 280          *
 281          * In 20s mode, the minimum resolution is 2 / (32768 * 20) which is
 282          * close to 3051 ppb. In 60s mode, the resolution is closer to 1017.
 283          */
 284         stepsh = DIV_ROUND_CLOSEST(offset, 1017);
 285         stepsl = DIV_ROUND_CLOSEST(offset, 3051);
 286
 287         if (stepsh >= -0x3E && stepsh <= 0x3E) {
 288                 /* 1017 ppb per step */
 289                 steps = stepsh;
 290                 subu |= RZN1_RTC_SUBU_DEV;
 291         } else if (stepsl >= -0x3E && stepsl <= 0x3E) {
 292                 /* 3051 ppb per step */
 293                 steps = stepsl;
 294         } else {
 295                 return -ERANGE;
 296         }
 297
 298         if (!steps)
 299                 return 0;
 300
 301         if (steps > 0) {
 302                 subu |= steps + 1;
 303         } else {
 304                 subu |= RZN1_RTC_SUBU_DECR;
 305                 subu |= (~(-steps - 1)) & 0x3F;
 306         }
 307
 308         ret = readl_poll_timeout(rtc->base + RZN1_RTC_CTL2, ctl2,
 309                                  !(ctl2 & RZN1_RTC_CTL2_WUST), 100, 2000000);
 310         if (ret)
 311                 return ret;
 312
 313         writel(subu, rtc->base + RZN1_RTC_SUBU);
 314
 315         return 0;
 316 }
 317
 318 static const struct rtc_class_ops rzn1_rtc_ops = {
 319         .read_time = rzn1_rtc_read_time,
 320         .set_time = rzn1_rtc_set_time,
 321         .read_alarm = rzn1_rtc_read_alarm,
 322         .set_alarm = rzn1_rtc_set_alarm,
 323         .alarm_irq_enable = rzn1_rtc_alarm_irq_enable,
 324         .read_offset = rzn1_rtc_read_offset,
 325         .set_offset = rzn1_rtc_set_offset,
 326 };
 327
 328 static int rzn1_rtc_probe(struct platform_device *pdev)
 329 {
 330         struct rzn1_rtc *rtc;
 331         int alarm_irq;
 332         int ret;
 333
 334         rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
 335         if (!rtc)
 336                 return -ENOMEM;
 337
 338         platform_set_drvdata(pdev, rtc);
 339
 340         rtc->base = devm_platform_ioremap_resource(pdev, 0);
 341         if (IS_ERR(rtc->base))
 342                 return dev_err_probe(&pdev->dev, PTR_ERR(rtc->base), "Missing reg\n");
 343
 344         alarm_irq = platform_get_irq(pdev, 0);
 345         if (alarm_irq < 0)
 346                 return alarm_irq;
 347
 348         rtc->rtcdev = devm_rtc_allocate_device(&pdev->dev);
 349         if (IS_ERR(rtc->rtcdev))
 350                 return PTR_ERR(rtc->rtcdev);
 351
 352         rtc->rtcdev->range_min = RTC_TIMESTAMP_BEGIN_2000;
 353         rtc->rtcdev->range_max = RTC_TIMESTAMP_END_2099;
 354         rtc->rtcdev->ops = &rzn1_rtc_ops;
 355         set_bit(RTC_FEATURE_ALARM_RES_MINUTE, rtc->rtcdev->features);
 356         clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->rtcdev->features);
 357
 358         devm_pm_runtime_enable(&pdev->dev);
 359         ret = pm_runtime_resume_and_get(&pdev->dev);
 360         if (ret < 0)
 361                 return ret;
 362
 363         /*
 364          * Ensure the clock counter is enabled.
 365          * Set 24-hour mode and possible oscillator offset compensation in SUBU mode.
 366          */
 367         writel(RZN1_RTC_CTL0_CE | RZN1_RTC_CTL0_AMPM | RZN1_RTC_CTL0_SLSB_SUBU,
 368                rtc->base + RZN1_RTC_CTL0);
 369
 370         /* Disable all interrupts */
 371         writel(0, rtc->base + RZN1_RTC_CTL1);
 372
 373         ret = devm_request_irq(&pdev->dev, alarm_irq, rzn1_rtc_alarm_irq, 0,
 374                                dev_name(&pdev->dev), rtc);
 375         if (ret) {
 376                 dev_err(&pdev->dev, "RTC timer interrupt not available\n");
 377                 goto dis_runtime_pm;
 378         }
 379
 380         ret = devm_rtc_register_device(rtc->rtcdev);
 381         if (ret)
 382                 goto dis_runtime_pm;
 383
 384         return 0;
 385
 386 dis_runtime_pm:
 387         pm_runtime_put(&pdev->dev);
 388
 389         return ret;
 390 }
 391
 392 static int rzn1_rtc_remove(struct platform_device *pdev)
 393 {
 394         pm_runtime_put(&pdev->dev);
 395
 396         return 0;
 397 }
 398
 399 static const struct of_device_id rzn1_rtc_of_match[] = {
 400         { .compatible   = "renesas,rzn1-rtc" },
 401         {},
 402 };
 403 MODULE_DEVICE_TABLE(of, rzn1_rtc_of_match);
 404
 405 static struct platform_driver rzn1_rtc_driver = {
 406         .probe = rzn1_rtc_probe,
 407         .remove = rzn1_rtc_remove,
 408         .driver = {
 409                 .name   = "rzn1-rtc",
 410                 .of_match_table = rzn1_rtc_of_match,
 411         },
 412 };
 413 module_platform_driver(rzn1_rtc_driver);
 414
 415 MODULE_AUTHOR("Michel Pollet <Michel.Pollet@bp.renesas.com");
 416 MODULE_AUTHOR("Miquel Raynal <miquel.raynal@bootlin.com");
 417 MODULE_DESCRIPTION("RZ/N1 RTC driver");
 418 MODULE_LICENSE("GPL");