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 <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/mod_devicetable.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_TIME 0x30
  39 #define RZN1_RTC_TIME_MIN_SHIFT 8
  40 #define RZN1_RTC_TIME_HOUR_SHIFT 16
  41 #define RZN1_RTC_CAL 0x34
  42 #define RZN1_RTC_CAL_DAY_SHIFT 8
  43 #define RZN1_RTC_CAL_MON_SHIFT 16
  44 #define RZN1_RTC_CAL_YEAR_SHIFT 24
  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_TIMEC 0x68
  56 #define RZN1_RTC_CALC 0x6c
  57
  58 struct rzn1_rtc {
  59         struct rtc_device *rtcdev;
  60         void __iomem *base;
  61 };
  62
  63 static void rzn1_rtc_get_time_snapshot(struct rzn1_rtc *rtc, struct rtc_time *tm)
  64 {
  65         u32 val;
  66
  67         val = readl(rtc->base + RZN1_RTC_TIMEC);
  68         tm->tm_sec = bcd2bin(val);
  69         tm->tm_min = bcd2bin(val >> RZN1_RTC_TIME_MIN_SHIFT);
  70         tm->tm_hour = bcd2bin(val >> RZN1_RTC_TIME_HOUR_SHIFT);
  71
  72         val = readl(rtc->base + RZN1_RTC_CALC);
  73         tm->tm_wday = val & 0x0f;
  74         tm->tm_mday = bcd2bin(val >> RZN1_RTC_CAL_DAY_SHIFT);
  75         tm->tm_mon = bcd2bin(val >> RZN1_RTC_CAL_MON_SHIFT) - 1;
  76         tm->tm_year = bcd2bin(val >> RZN1_RTC_CAL_YEAR_SHIFT) + 100;
  77 }
  78
  79 static int rzn1_rtc_read_time(struct device *dev, struct rtc_time *tm)
  80 {
  81         struct rzn1_rtc *rtc = dev_get_drvdata(dev);
  82         u32 val, secs;
  83
  84         /*
  85          * The RTC was not started or is stopped and thus does not carry the
  86          * proper time/date.
  87          */
  88         val = readl(rtc->base + RZN1_RTC_CTL2);
  89         if (val & RZN1_RTC_CTL2_STOPPED)
  90                 return -EINVAL;
  91
  92         rzn1_rtc_get_time_snapshot(rtc, tm);
  93         secs = readl(rtc->base + RZN1_RTC_SECC);
  94         if (tm->tm_sec != bcd2bin(secs))
  95                 rzn1_rtc_get_time_snapshot(rtc, tm);
  96
  97         return 0;
  98 }
  99
 100 static int rzn1_rtc_set_time(struct device *dev, struct rtc_time *tm)
 101 {
 102         struct rzn1_rtc *rtc = dev_get_drvdata(dev);
 103         u32 val;
 104         int ret;
 105
 106         val = readl(rtc->base + RZN1_RTC_CTL2);
 107         if (!(val & RZN1_RTC_CTL2_STOPPED)) {
 108                 /* Hold the counter if it was counting up */
 109                 writel(RZN1_RTC_CTL2_WAIT, rtc->base + RZN1_RTC_CTL2);
 110
 111                 /* Wait for the counter to stop: two 32k clock cycles */
 112                 usleep_range(61, 100);
 113                 ret = readl_poll_timeout(rtc->base + RZN1_RTC_CTL2, val,
 114                                          val & RZN1_RTC_CTL2_WST, 0, 100);
 115                 if (ret)
 116                         return ret;
 117         }
 118
 119         val = bin2bcd(tm->tm_sec);
 120         val |= bin2bcd(tm->tm_min) << RZN1_RTC_TIME_MIN_SHIFT;
 121         val |= bin2bcd(tm->tm_hour) << RZN1_RTC_TIME_HOUR_SHIFT;
 122         writel(val, rtc->base + RZN1_RTC_TIME);
 123
 124         val = tm->tm_wday;
 125         val |= bin2bcd(tm->tm_mday) << RZN1_RTC_CAL_DAY_SHIFT;
 126         val |= bin2bcd(tm->tm_mon + 1) << RZN1_RTC_CAL_MON_SHIFT;
 127         val |= bin2bcd(tm->tm_year - 100) << RZN1_RTC_CAL_YEAR_SHIFT;
 128         writel(val, rtc->base + RZN1_RTC_CAL);
 129
 130         writel(0, rtc->base + RZN1_RTC_CTL2);
 131
 132         return 0;
 133 }
 134
 135 static irqreturn_t rzn1_rtc_alarm_irq(int irq, void *dev_id)
 136 {
 137         struct rzn1_rtc *rtc = dev_id;
 138
 139         rtc_update_irq(rtc->rtcdev, 1, RTC_AF | RTC_IRQF);
 140
 141         return IRQ_HANDLED;
 142 }
 143
 144 static int rzn1_rtc_alarm_irq_enable(struct device *dev, unsigned int enable)
 145 {
 146         struct rzn1_rtc *rtc = dev_get_drvdata(dev);
 147         u32 ctl1 = readl(rtc->base + RZN1_RTC_CTL1);
 148
 149         if (enable)
 150                 ctl1 |= RZN1_RTC_CTL1_ALME;
 151         else
 152                 ctl1 &= ~RZN1_RTC_CTL1_ALME;
 153
 154         writel(ctl1, rtc->base + RZN1_RTC_CTL1);
 155
 156         return 0;
 157 }
 158
 159 static int rzn1_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 160 {
 161         struct rzn1_rtc *rtc = dev_get_drvdata(dev);
 162         struct rtc_time *tm = &alrm->time;
 163         unsigned int min, hour, wday, delta_days;
 164         time64_t alarm;
 165         u32 ctl1;
 166         int ret;
 167
 168         ret = rzn1_rtc_read_time(dev, tm);
 169         if (ret)
 170                 return ret;
 171
 172         min = readl(rtc->base + RZN1_RTC_ALM);
 173         hour = readl(rtc->base + RZN1_RTC_ALH);
 174         wday = readl(rtc->base + RZN1_RTC_ALW);
 175
 176         tm->tm_sec = 0;
 177         tm->tm_min = bcd2bin(min);
 178         tm->tm_hour = bcd2bin(hour);
 179         delta_days = ((fls(wday) - 1) - tm->tm_wday + 7) % 7;
 180         tm->tm_wday = fls(wday) - 1;
 181
 182         if (delta_days) {
 183                 alarm = rtc_tm_to_time64(tm) + (delta_days * 86400);
 184                 rtc_time64_to_tm(alarm, tm);
 185         }
 186
 187         ctl1 = readl(rtc->base + RZN1_RTC_CTL1);
 188         alrm->enabled = !!(ctl1 & RZN1_RTC_CTL1_ALME);
 189
 190         return 0;
 191 }
 192
 193 static int rzn1_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 194 {
 195         struct rzn1_rtc *rtc = dev_get_drvdata(dev);
 196         struct rtc_time *tm = &alrm->time, tm_now;
 197         unsigned long alarm, farest;
 198         unsigned int days_ahead, wday;
 199         int ret;
 200
 201         ret = rzn1_rtc_read_time(dev, &tm_now);
 202         if (ret)
 203                 return ret;
 204
 205         /* We cannot set alarms more than one week ahead */
 206         farest = rtc_tm_to_time64(&tm_now) + rtc->rtcdev->alarm_offset_max;
 207         alarm = rtc_tm_to_time64(tm);
 208         if (time_after(alarm, farest))
 209                 return -ERANGE;
 210
 211         /* Convert alarm day into week day */
 212         days_ahead = tm->tm_mday - tm_now.tm_mday;
 213         wday = (tm_now.tm_wday + days_ahead) % 7;
 214
 215         writel(bin2bcd(tm->tm_min), rtc->base + RZN1_RTC_ALM);
 216         writel(bin2bcd(tm->tm_hour), rtc->base + RZN1_RTC_ALH);
 217         writel(BIT(wday), rtc->base + RZN1_RTC_ALW);
 218
 219         rzn1_rtc_alarm_irq_enable(dev, alrm->enabled);
 220
 221         return 0;
 222 }
 223
 224 static int rzn1_rtc_read_offset(struct device *dev, long *offset)
 225 {
 226         struct rzn1_rtc *rtc = dev_get_drvdata(dev);
 227         unsigned int ppb_per_step;
 228         bool subtract;
 229         u32 val;
 230
 231         val = readl(rtc->base + RZN1_RTC_SUBU);
 232         ppb_per_step = val & RZN1_RTC_SUBU_DEV ? 1017 : 3051;
 233         subtract = val & RZN1_RTC_SUBU_DECR;
 234         val &= 0x3F;
 235
 236         if (!val)
 237                 *offset = 0;
 238         else if (subtract)
 239                 *offset = -(((~val) & 0x3F) + 1) * ppb_per_step;
 240         else
 241                 *offset = (val - 1) * ppb_per_step;
 242
 243         return 0;
 244 }
 245
 246 static int rzn1_rtc_set_offset(struct device *dev, long offset)
 247 {
 248         struct rzn1_rtc *rtc = dev_get_drvdata(dev);
 249         int stepsh, stepsl, steps;
 250         u32 subu = 0, ctl2;
 251         int ret;
 252
 253         /*
 254          * Check which resolution mode (every 20 or 60s) can be used.
 255          * Between 2 and 124 clock pulses can be added or substracted.
 256          *
 257          * In 20s mode, the minimum resolution is 2 / (32768 * 20) which is
 258          * close to 3051 ppb. In 60s mode, the resolution is closer to 1017.
 259          */
 260         stepsh = DIV_ROUND_CLOSEST(offset, 1017);
 261         stepsl = DIV_ROUND_CLOSEST(offset, 3051);
 262
 263         if (stepsh >= -0x3E && stepsh <= 0x3E) {
 264                 /* 1017 ppb per step */
 265                 steps = stepsh;
 266                 subu |= RZN1_RTC_SUBU_DEV;
 267         } else if (stepsl >= -0x3E && stepsl <= 0x3E) {
 268                 /* 3051 ppb per step */
 269                 steps = stepsl;
 270         } else {
 271                 return -ERANGE;
 272         }
 273
 274         if (!steps)
 275                 return 0;
 276
 277         if (steps > 0) {
 278                 subu |= steps + 1;
 279         } else {
 280                 subu |= RZN1_RTC_SUBU_DECR;
 281                 subu |= (~(-steps - 1)) & 0x3F;
 282         }
 283
 284         ret = readl_poll_timeout(rtc->base + RZN1_RTC_CTL2, ctl2,
 285                                  !(ctl2 & RZN1_RTC_CTL2_WUST), 100, 2000000);
 286         if (ret)
 287                 return ret;
 288
 289         writel(subu, rtc->base + RZN1_RTC_SUBU);
 290
 291         return 0;
 292 }
 293
 294 static const struct rtc_class_ops rzn1_rtc_ops = {
 295         .read_time = rzn1_rtc_read_time,
 296         .set_time = rzn1_rtc_set_time,
 297         .read_alarm = rzn1_rtc_read_alarm,
 298         .set_alarm = rzn1_rtc_set_alarm,
 299         .alarm_irq_enable = rzn1_rtc_alarm_irq_enable,
 300         .read_offset = rzn1_rtc_read_offset,
 301         .set_offset = rzn1_rtc_set_offset,
 302 };
 303
 304 static int rzn1_rtc_probe(struct platform_device *pdev)
 305 {
 306         struct rzn1_rtc *rtc;
 307         int alarm_irq;
 308         int ret;
 309
 310         rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
 311         if (!rtc)
 312                 return -ENOMEM;
 313
 314         platform_set_drvdata(pdev, rtc);
 315
 316         rtc->base = devm_platform_ioremap_resource(pdev, 0);
 317         if (IS_ERR(rtc->base))
 318                 return dev_err_probe(&pdev->dev, PTR_ERR(rtc->base), "Missing reg\n");
 319
 320         alarm_irq = platform_get_irq(pdev, 0);
 321         if (alarm_irq < 0)
 322                 return alarm_irq;
 323
 324         rtc->rtcdev = devm_rtc_allocate_device(&pdev->dev);
 325         if (IS_ERR(rtc->rtcdev))
 326                 return PTR_ERR(rtc->rtcdev);
 327
 328         rtc->rtcdev->range_min = RTC_TIMESTAMP_BEGIN_2000;
 329         rtc->rtcdev->range_max = RTC_TIMESTAMP_END_2099;
 330         rtc->rtcdev->alarm_offset_max = 7 * 86400;
 331         rtc->rtcdev->ops = &rzn1_rtc_ops;
 332         set_bit(RTC_FEATURE_ALARM_RES_MINUTE, rtc->rtcdev->features);
 333         clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->rtcdev->features);
 334
 335         ret = devm_pm_runtime_enable(&pdev->dev);
 336         if (ret < 0)
 337                 return ret;
 338         ret = pm_runtime_resume_and_get(&pdev->dev);
 339         if (ret < 0)
 340                 return ret;
 341
 342         /*
 343          * Ensure the clock counter is enabled.
 344          * Set 24-hour mode and possible oscillator offset compensation in SUBU mode.
 345          */
 346         writel(RZN1_RTC_CTL0_CE | RZN1_RTC_CTL0_AMPM | RZN1_RTC_CTL0_SLSB_SUBU,
 347                rtc->base + RZN1_RTC_CTL0);
 348
 349         /* Disable all interrupts */
 350         writel(0, rtc->base + RZN1_RTC_CTL1);
 351
 352         ret = devm_request_irq(&pdev->dev, alarm_irq, rzn1_rtc_alarm_irq, 0,
 353                                dev_name(&pdev->dev), rtc);
 354         if (ret) {
 355                 dev_err(&pdev->dev, "RTC timer interrupt not available\n");
 356                 goto dis_runtime_pm;
 357         }
 358
 359         ret = devm_rtc_register_device(rtc->rtcdev);
 360         if (ret)
 361                 goto dis_runtime_pm;
 362
 363         return 0;
 364
 365 dis_runtime_pm:
 366         pm_runtime_put(&pdev->dev);
 367
 368         return ret;
 369 }
 370
 371 static void rzn1_rtc_remove(struct platform_device *pdev)
 372 {
 373         pm_runtime_put(&pdev->dev);
 374 }
 375
 376 static const struct of_device_id rzn1_rtc_of_match[] = {
 377         { .compatible   = "renesas,rzn1-rtc" },
 378         {},
 379 };
 380 MODULE_DEVICE_TABLE(of, rzn1_rtc_of_match);
 381
 382 static struct platform_driver rzn1_rtc_driver = {
 383         .probe = rzn1_rtc_probe,
 384         .remove = rzn1_rtc_remove,
 385         .driver = {
 386                 .name   = "rzn1-rtc",
 387                 .of_match_table = rzn1_rtc_of_match,
 388         },
 389 };
 390 module_platform_driver(rzn1_rtc_driver);
 391
 392 MODULE_AUTHOR("Michel Pollet <buserror@gmail.com>");
 393 MODULE_AUTHOR("Miquel Raynal <miquel.raynal@bootlin.com");
 394 MODULE_DESCRIPTION("RZ/N1 RTC driver");
 395 MODULE_LICENSE("GPL");