drivers/rtc/rtc-mt6397.c

   1 /*
   2 * Copyright (c) 2014-2015 MediaTek Inc.
   3 * Author: Tianping.Fang <tianping.fang@mediatek.com>
   4 *
   5 * This program is free software; you can redistribute it and/or modify
   6 * it under the terms of the GNU General Public License version 2 as
   7 * published by the Free Software Foundation.
   8 *
   9 * This program is distributed in the hope that it will be useful,
  10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 * GNU General Public License for more details.
  13 */
  14
  15 #include <linux/delay.h>
  16 #include <linux/init.h>
  17 #include <linux/module.h>
  18 #include <linux/regmap.h>
  19 #include <linux/rtc.h>
  20 #include <linux/irqdomain.h>
  21 #include <linux/platform_device.h>
  22 #include <linux/of_address.h>
  23 #include <linux/of_irq.h>
  24 #include <linux/io.h>
  25 #include <linux/mfd/mt6397/core.h>
  26
  27 #define RTC_BBPU                0x0000
  28 #define RTC_BBPU_CBUSY          BIT(6)
  29
  30 #define RTC_WRTGR               0x003c
  31
  32 #define RTC_IRQ_STA             0x0002
  33 #define RTC_IRQ_STA_AL          BIT(0)
  34 #define RTC_IRQ_STA_LP          BIT(3)
  35
  36 #define RTC_IRQ_EN              0x0004
  37 #define RTC_IRQ_EN_AL           BIT(0)
  38 #define RTC_IRQ_EN_ONESHOT      BIT(2)
  39 #define RTC_IRQ_EN_LP           BIT(3)
  40 #define RTC_IRQ_EN_ONESHOT_AL   (RTC_IRQ_EN_ONESHOT | RTC_IRQ_EN_AL)
  41
  42 #define RTC_AL_MASK             0x0008
  43 #define RTC_AL_MASK_DOW         BIT(4)
  44
  45 #define RTC_TC_SEC              0x000a
  46 /* Min, Hour, Dom... register offset to RTC_TC_SEC */
  47 #define RTC_OFFSET_SEC          0
  48 #define RTC_OFFSET_MIN          1
  49 #define RTC_OFFSET_HOUR         2
  50 #define RTC_OFFSET_DOM          3
  51 #define RTC_OFFSET_DOW          4
  52 #define RTC_OFFSET_MTH          5
  53 #define RTC_OFFSET_YEAR         6
  54 #define RTC_OFFSET_COUNT        7
  55
  56 #define RTC_AL_SEC              0x0018
  57
  58 #define RTC_PDN2                0x002e
  59 #define RTC_PDN2_PWRON_ALARM    BIT(4)
  60
  61 #define RTC_MIN_YEAR            1968
  62 #define RTC_BASE_YEAR           1900
  63 #define RTC_NUM_YEARS           128
  64 #define RTC_MIN_YEAR_OFFSET     (RTC_MIN_YEAR - RTC_BASE_YEAR)
  65
  66 struct mt6397_rtc {
  67         struct device           *dev;
  68         struct rtc_device       *rtc_dev;
  69         struct mutex            lock;
  70         struct regmap           *regmap;
  71         int                     irq;
  72         u32                     addr_base;
  73 };
  74
  75 static int mtk_rtc_write_trigger(struct mt6397_rtc *rtc)
  76 {
  77         unsigned long timeout = jiffies + HZ;
  78         int ret;
  79         u32 data;
  80
  81         ret = regmap_write(rtc->regmap, rtc->addr_base + RTC_WRTGR, 1);
  82         if (ret < 0)
  83                 return ret;
  84
  85         while (1) {
  86                 ret = regmap_read(rtc->regmap, rtc->addr_base + RTC_BBPU,
  87                                   &data);
  88                 if (ret < 0)
  89                         break;
  90                 if (!(data & RTC_BBPU_CBUSY))
  91                         break;
  92                 if (time_after(jiffies, timeout)) {
  93                         ret = -ETIMEDOUT;
  94                         break;
  95                 }
  96                 cpu_relax();
  97         }
  98
  99         return ret;
 100 }
 101
 102 static irqreturn_t mtk_rtc_irq_handler_thread(int irq, void *data)
 103 {
 104         struct mt6397_rtc *rtc = data;
 105         u32 irqsta, irqen;
 106         int ret;
 107
 108         ret = regmap_read(rtc->regmap, rtc->addr_base + RTC_IRQ_STA, &irqsta);
 109         if ((ret >= 0) && (irqsta & RTC_IRQ_STA_AL)) {
 110                 rtc_update_irq(rtc->rtc_dev, 1, RTC_IRQF | RTC_AF);
 111                 irqen = irqsta & ~RTC_IRQ_EN_AL;
 112                 mutex_lock(&rtc->lock);
 113                 if (regmap_write(rtc->regmap, rtc->addr_base + RTC_IRQ_EN,
 114                                  irqen) < 0)
 115                         mtk_rtc_write_trigger(rtc);
 116                 mutex_unlock(&rtc->lock);
 117
 118                 return IRQ_HANDLED;
 119         }
 120
 121         return IRQ_NONE;
 122 }
 123
 124 static int __mtk_rtc_read_time(struct mt6397_rtc *rtc,
 125                                struct rtc_time *tm, int *sec)
 126 {
 127         int ret;
 128         u16 data[RTC_OFFSET_COUNT];
 129
 130         mutex_lock(&rtc->lock);
 131         ret = regmap_bulk_read(rtc->regmap, rtc->addr_base + RTC_TC_SEC,
 132                                data, RTC_OFFSET_COUNT);
 133         if (ret < 0)
 134                 goto exit;
 135
 136         tm->tm_sec = data[RTC_OFFSET_SEC];
 137         tm->tm_min = data[RTC_OFFSET_MIN];
 138         tm->tm_hour = data[RTC_OFFSET_HOUR];
 139         tm->tm_mday = data[RTC_OFFSET_DOM];
 140         tm->tm_mon = data[RTC_OFFSET_MTH];
 141         tm->tm_year = data[RTC_OFFSET_YEAR];
 142
 143         ret = regmap_read(rtc->regmap, rtc->addr_base + RTC_TC_SEC, sec);
 144 exit:
 145         mutex_unlock(&rtc->lock);
 146         return ret;
 147 }
 148
 149 static int mtk_rtc_read_time(struct device *dev, struct rtc_time *tm)
 150 {
 151         time64_t time;
 152         struct mt6397_rtc *rtc = dev_get_drvdata(dev);
 153         int days, sec, ret;
 154
 155         do {
 156                 ret = __mtk_rtc_read_time(rtc, tm, &sec);
 157                 if (ret < 0)
 158                         goto exit;
 159         } while (sec < tm->tm_sec);
 160
 161         /* HW register use 7 bits to store year data, minus
 162          * RTC_MIN_YEAR_OFFSET before write year data to register, and plus
 163          * RTC_MIN_YEAR_OFFSET back after read year from register
 164          */
 165         tm->tm_year += RTC_MIN_YEAR_OFFSET;
 166
 167         /* HW register start mon from one, but tm_mon start from zero. */
 168         tm->tm_mon--;
 169         time = rtc_tm_to_time64(tm);
 170
 171         /* rtc_tm_to_time64 covert Gregorian date to seconds since
 172          * 01-01-1970 00:00:00, and this date is Thursday.
 173          */
 174         days = div_s64(time, 86400);
 175         tm->tm_wday = (days + 4) % 7;
 176
 177 exit:
 178         return ret;
 179 }
 180
 181 static int mtk_rtc_set_time(struct device *dev, struct rtc_time *tm)
 182 {
 183         struct mt6397_rtc *rtc = dev_get_drvdata(dev);
 184         int ret;
 185         u16 data[RTC_OFFSET_COUNT];
 186
 187         tm->tm_year -= RTC_MIN_YEAR_OFFSET;
 188         tm->tm_mon++;
 189
 190         data[RTC_OFFSET_SEC] = tm->tm_sec;
 191         data[RTC_OFFSET_MIN] = tm->tm_min;
 192         data[RTC_OFFSET_HOUR] = tm->tm_hour;
 193         data[RTC_OFFSET_DOM] = tm->tm_mday;
 194         data[RTC_OFFSET_MTH] = tm->tm_mon;
 195         data[RTC_OFFSET_YEAR] = tm->tm_year;
 196
 197         mutex_lock(&rtc->lock);
 198         ret = regmap_bulk_write(rtc->regmap, rtc->addr_base + RTC_TC_SEC,
 199                                 data, RTC_OFFSET_COUNT);
 200         if (ret < 0)
 201                 goto exit;
 202
 203         /* Time register write to hardware after call trigger function */
 204         ret = mtk_rtc_write_trigger(rtc);
 205
 206 exit:
 207         mutex_unlock(&rtc->lock);
 208         return ret;
 209 }
 210
 211 static int mtk_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
 212 {
 213         struct rtc_time *tm = &alm->time;
 214         struct mt6397_rtc *rtc = dev_get_drvdata(dev);
 215         u32 irqen, pdn2;
 216         int ret;
 217         u16 data[RTC_OFFSET_COUNT];
 218
 219         mutex_lock(&rtc->lock);
 220         ret = regmap_read(rtc->regmap, rtc->addr_base + RTC_IRQ_EN, &irqen);
 221         if (ret < 0)
 222                 goto err_exit;
 223         ret = regmap_read(rtc->regmap, rtc->addr_base + RTC_PDN2, &pdn2);
 224         if (ret < 0)
 225                 goto err_exit;
 226
 227         ret = regmap_bulk_read(rtc->regmap, rtc->addr_base + RTC_AL_SEC,
 228                                data, RTC_OFFSET_COUNT);
 229         if (ret < 0)
 230                 goto err_exit;
 231
 232         alm->enabled = !!(irqen & RTC_IRQ_EN_AL);
 233         alm->pending = !!(pdn2 & RTC_PDN2_PWRON_ALARM);
 234         mutex_unlock(&rtc->lock);
 235
 236         tm->tm_sec = data[RTC_OFFSET_SEC];
 237         tm->tm_min = data[RTC_OFFSET_MIN];
 238         tm->tm_hour = data[RTC_OFFSET_HOUR];
 239         tm->tm_mday = data[RTC_OFFSET_DOM];
 240         tm->tm_mon = data[RTC_OFFSET_MTH];
 241         tm->tm_year = data[RTC_OFFSET_YEAR];
 242
 243         tm->tm_year += RTC_MIN_YEAR_OFFSET;
 244         tm->tm_mon--;
 245
 246         return 0;
 247 err_exit:
 248         mutex_unlock(&rtc->lock);
 249         return ret;
 250 }
 251
 252 static int mtk_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
 253 {
 254         struct rtc_time *tm = &alm->time;
 255         struct mt6397_rtc *rtc = dev_get_drvdata(dev);
 256         int ret;
 257         u16 data[RTC_OFFSET_COUNT];
 258
 259         tm->tm_year -= RTC_MIN_YEAR_OFFSET;
 260         tm->tm_mon++;
 261
 262         data[RTC_OFFSET_SEC] = tm->tm_sec;
 263         data[RTC_OFFSET_MIN] = tm->tm_min;
 264         data[RTC_OFFSET_HOUR] = tm->tm_hour;
 265         data[RTC_OFFSET_DOM] = tm->tm_mday;
 266         data[RTC_OFFSET_MTH] = tm->tm_mon;
 267         data[RTC_OFFSET_YEAR] = tm->tm_year;
 268
 269         mutex_lock(&rtc->lock);
 270         if (alm->enabled) {
 271                 ret = regmap_bulk_write(rtc->regmap,
 272                                         rtc->addr_base + RTC_AL_SEC,
 273                                         data, RTC_OFFSET_COUNT);
 274                 if (ret < 0)
 275                         goto exit;
 276                 ret = regmap_write(rtc->regmap, rtc->addr_base + RTC_AL_MASK,
 277                                    RTC_AL_MASK_DOW);
 278                 if (ret < 0)
 279                         goto exit;
 280                 ret = regmap_update_bits(rtc->regmap,
 281                                          rtc->addr_base + RTC_IRQ_EN,
 282                                          RTC_IRQ_EN_ONESHOT_AL,
 283                                          RTC_IRQ_EN_ONESHOT_AL);
 284                 if (ret < 0)
 285                         goto exit;
 286         } else {
 287                 ret = regmap_update_bits(rtc->regmap,
 288                                          rtc->addr_base + RTC_IRQ_EN,
 289                                          RTC_IRQ_EN_ONESHOT_AL, 0);
 290                 if (ret < 0)
 291                         goto exit;
 292         }
 293
 294         /* All alarm time register write to hardware after calling
 295          * mtk_rtc_write_trigger. This can avoid race condition if alarm
 296          * occur happen during writing alarm time register.
 297          */
 298         ret = mtk_rtc_write_trigger(rtc);
 299 exit:
 300         mutex_unlock(&rtc->lock);
 301         return ret;
 302 }
 303
 304 static struct rtc_class_ops mtk_rtc_ops = {
 305         .read_time  = mtk_rtc_read_time,
 306         .set_time   = mtk_rtc_set_time,
 307         .read_alarm = mtk_rtc_read_alarm,
 308         .set_alarm  = mtk_rtc_set_alarm,
 309 };
 310
 311 static int mtk_rtc_probe(struct platform_device *pdev)
 312 {
 313         struct resource *res;
 314         struct mt6397_chip *mt6397_chip = dev_get_drvdata(pdev->dev.parent);
 315         struct mt6397_rtc *rtc;
 316         int ret;
 317
 318         rtc = devm_kzalloc(&pdev->dev, sizeof(struct mt6397_rtc), GFP_KERNEL);
 319         if (!rtc)
 320                 return -ENOMEM;
 321
 322         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 323         rtc->addr_base = res->start;
 324
 325         res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 326         rtc->irq = irq_create_mapping(mt6397_chip->irq_domain, res->start);
 327         if (rtc->irq <= 0)
 328                 return -EINVAL;
 329
 330         rtc->regmap = mt6397_chip->regmap;
 331         rtc->dev = &pdev->dev;
 332         mutex_init(&rtc->lock);
 333
 334         platform_set_drvdata(pdev, rtc);
 335
 336         ret = request_threaded_irq(rtc->irq, NULL,
 337                                    mtk_rtc_irq_handler_thread,
 338                                    IRQF_ONESHOT | IRQF_TRIGGER_HIGH,
 339                                    "mt6397-rtc", rtc);
 340         if (ret) {
 341                 dev_err(&pdev->dev, "Failed to request alarm IRQ: %d: %d\n",
 342                         rtc->irq, ret);
 343                 goto out_dispose_irq;
 344         }
 345
 346         device_init_wakeup(&pdev->dev, 1);
 347
 348         rtc->rtc_dev = rtc_device_register("mt6397-rtc", &pdev->dev,
 349                                            &mtk_rtc_ops, THIS_MODULE);
 350         if (IS_ERR(rtc->rtc_dev)) {
 351                 dev_err(&pdev->dev, "register rtc device failed\n");
 352                 ret = PTR_ERR(rtc->rtc_dev);
 353                 goto out_free_irq;
 354         }
 355
 356         return 0;
 357
 358 out_free_irq:
 359         free_irq(rtc->irq, rtc->rtc_dev);
 360 out_dispose_irq:
 361         irq_dispose_mapping(rtc->irq);
 362         return ret;
 363 }
 364
 365 static int mtk_rtc_remove(struct platform_device *pdev)
 366 {
 367         struct mt6397_rtc *rtc = platform_get_drvdata(pdev);
 368
 369         rtc_device_unregister(rtc->rtc_dev);
 370         free_irq(rtc->irq, rtc->rtc_dev);
 371         irq_dispose_mapping(rtc->irq);
 372
 373         return 0;
 374 }
 375
 376 static const struct of_device_id mt6397_rtc_of_match[] = {
 377         { .compatible = "mediatek,mt6397-rtc", },
 378         { }
 379 };
 380
 381 static struct platform_driver mtk_rtc_driver = {
 382         .driver = {
 383                 .name = "mt6397-rtc",
 384                 .of_match_table = mt6397_rtc_of_match,
 385         },
 386         .probe  = mtk_rtc_probe,
 387         .remove = mtk_rtc_remove,
 388 };
 389
 390 module_platform_driver(mtk_rtc_driver);
 391
 392 MODULE_LICENSE("GPL v2");
 393 MODULE_AUTHOR("Tianping Fang <tianping.fang@mediatek.com>");
 394 MODULE_DESCRIPTION("RTC Driver for MediaTek MT6397 PMIC");
 395 MODULE_ALIAS("platform:mt6397-rtc");