linux/drivers/rtc/rtc-vt8500.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * drivers/rtc/rtc-vt8500.c
   4 *
   5 *  Copyright (C) 2010 Alexey Charkov <alchark@gmail.com>
   6 *
   7 * Based on rtc-pxa.c
   8 */
   9
  10#include <linux/module.h>
  11#include <linux/rtc.h>
  12#include <linux/init.h>
  13#include <linux/interrupt.h>
  14#include <linux/io.h>
  15#include <linux/bcd.h>
  16#include <linux/platform_device.h>
  17#include <linux/slab.h>
  18#include <linux/of.h>
  19
  20/*
  21 * Register definitions
  22 */
  23#define VT8500_RTC_TS           0x00    /* Time set */
  24#define VT8500_RTC_DS           0x04    /* Date set */
  25#define VT8500_RTC_AS           0x08    /* Alarm set */
  26#define VT8500_RTC_CR           0x0c    /* Control */
  27#define VT8500_RTC_TR           0x10    /* Time read */
  28#define VT8500_RTC_DR           0x14    /* Date read */
  29#define VT8500_RTC_WS           0x18    /* Write status */
  30#define VT8500_RTC_CL           0x20    /* Calibration */
  31#define VT8500_RTC_IS           0x24    /* Interrupt status */
  32#define VT8500_RTC_ST           0x28    /* Status */
  33
  34#define INVALID_TIME_BIT        (1 << 31)
  35
  36#define DATE_CENTURY_S          19
  37#define DATE_YEAR_S             11
  38#define DATE_YEAR_MASK          (0xff << DATE_YEAR_S)
  39#define DATE_MONTH_S            6
  40#define DATE_MONTH_MASK         (0x1f << DATE_MONTH_S)
  41#define DATE_DAY_MASK           0x3f
  42
  43#define TIME_DOW_S              20
  44#define TIME_DOW_MASK           (0x07 << TIME_DOW_S)
  45#define TIME_HOUR_S             14
  46#define TIME_HOUR_MASK          (0x3f << TIME_HOUR_S)
  47#define TIME_MIN_S              7
  48#define TIME_MIN_MASK           (0x7f << TIME_MIN_S)
  49#define TIME_SEC_MASK           0x7f
  50
  51#define ALARM_DAY_S             20
  52#define ALARM_DAY_MASK          (0x3f << ALARM_DAY_S)
  53
  54#define ALARM_DAY_BIT           (1 << 29)
  55#define ALARM_HOUR_BIT          (1 << 28)
  56#define ALARM_MIN_BIT           (1 << 27)
  57#define ALARM_SEC_BIT           (1 << 26)
  58
  59#define ALARM_ENABLE_MASK       (ALARM_DAY_BIT \
  60                                | ALARM_HOUR_BIT \
  61                                | ALARM_MIN_BIT \
  62                                | ALARM_SEC_BIT)
  63
  64#define VT8500_RTC_CR_ENABLE    (1 << 0)        /* Enable RTC */
  65#define VT8500_RTC_CR_12H       (1 << 1)        /* 12h time format */
  66#define VT8500_RTC_CR_SM_ENABLE (1 << 2)        /* Enable periodic irqs */
  67#define VT8500_RTC_CR_SM_SEC    (1 << 3)        /* 0: 1Hz/60, 1: 1Hz */
  68#define VT8500_RTC_CR_CALIB     (1 << 4)        /* Enable calibration */
  69
  70#define VT8500_RTC_IS_ALARM     (1 << 0)        /* Alarm interrupt status */
  71
  72struct vt8500_rtc {
  73        void __iomem            *regbase;
  74        int                     irq_alarm;
  75        struct rtc_device       *rtc;
  76        spinlock_t              lock;           /* Protects this structure */
  77};
  78
  79static irqreturn_t vt8500_rtc_irq(int irq, void *dev_id)
  80{
  81        struct vt8500_rtc *vt8500_rtc = dev_id;
  82        u32 isr;
  83        unsigned long events = 0;
  84
  85        spin_lock(&vt8500_rtc->lock);
  86
  87        /* clear interrupt sources */
  88        isr = readl(vt8500_rtc->regbase + VT8500_RTC_IS);
  89        writel(isr, vt8500_rtc->regbase + VT8500_RTC_IS);
  90
  91        spin_unlock(&vt8500_rtc->lock);
  92
  93        if (isr & VT8500_RTC_IS_ALARM)
  94                events |= RTC_AF | RTC_IRQF;
  95
  96        rtc_update_irq(vt8500_rtc->rtc, 1, events);
  97
  98        return IRQ_HANDLED;
  99}
 100
 101static int vt8500_rtc_read_time(struct device *dev, struct rtc_time *tm)
 102{
 103        struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
 104        u32 date, time;
 105
 106        date = readl(vt8500_rtc->regbase + VT8500_RTC_DR);
 107        time = readl(vt8500_rtc->regbase + VT8500_RTC_TR);
 108
 109        tm->tm_sec = bcd2bin(time & TIME_SEC_MASK);
 110        tm->tm_min = bcd2bin((time & TIME_MIN_MASK) >> TIME_MIN_S);
 111        tm->tm_hour = bcd2bin((time & TIME_HOUR_MASK) >> TIME_HOUR_S);
 112        tm->tm_mday = bcd2bin(date & DATE_DAY_MASK);
 113        tm->tm_mon = bcd2bin((date & DATE_MONTH_MASK) >> DATE_MONTH_S) - 1;
 114        tm->tm_year = bcd2bin((date & DATE_YEAR_MASK) >> DATE_YEAR_S)
 115                        + ((date >> DATE_CENTURY_S) & 1 ? 200 : 100);
 116        tm->tm_wday = (time & TIME_DOW_MASK) >> TIME_DOW_S;
 117
 118        return 0;
 119}
 120
 121static int vt8500_rtc_set_time(struct device *dev, struct rtc_time *tm)
 122{
 123        struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
 124
 125        if (tm->tm_year < 100) {
 126                dev_warn(dev, "Only years 2000-2199 are supported by the "
 127                              "hardware!\n");
 128                return -EINVAL;
 129        }
 130
 131        writel((bin2bcd(tm->tm_year % 100) << DATE_YEAR_S)
 132                | (bin2bcd(tm->tm_mon + 1) << DATE_MONTH_S)
 133                | (bin2bcd(tm->tm_mday))
 134                | ((tm->tm_year >= 200) << DATE_CENTURY_S),
 135                vt8500_rtc->regbase + VT8500_RTC_DS);
 136        writel((bin2bcd(tm->tm_wday) << TIME_DOW_S)
 137                | (bin2bcd(tm->tm_hour) << TIME_HOUR_S)
 138                | (bin2bcd(tm->tm_min) << TIME_MIN_S)
 139                | (bin2bcd(tm->tm_sec)),
 140                vt8500_rtc->regbase + VT8500_RTC_TS);
 141
 142        return 0;
 143}
 144
 145static int vt8500_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 146{
 147        struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
 148        u32 isr, alarm;
 149
 150        alarm = readl(vt8500_rtc->regbase + VT8500_RTC_AS);
 151        isr = readl(vt8500_rtc->regbase + VT8500_RTC_IS);
 152
 153        alrm->time.tm_mday = bcd2bin((alarm & ALARM_DAY_MASK) >> ALARM_DAY_S);
 154        alrm->time.tm_hour = bcd2bin((alarm & TIME_HOUR_MASK) >> TIME_HOUR_S);
 155        alrm->time.tm_min = bcd2bin((alarm & TIME_MIN_MASK) >> TIME_MIN_S);
 156        alrm->time.tm_sec = bcd2bin((alarm & TIME_SEC_MASK));
 157
 158        alrm->enabled = (alarm & ALARM_ENABLE_MASK) ? 1 : 0;
 159        alrm->pending = (isr & VT8500_RTC_IS_ALARM) ? 1 : 0;
 160
 161        return rtc_valid_tm(&alrm->time);
 162}
 163
 164static int vt8500_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 165{
 166        struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
 167
 168        writel((alrm->enabled ? ALARM_ENABLE_MASK : 0)
 169                | (bin2bcd(alrm->time.tm_mday) << ALARM_DAY_S)
 170                | (bin2bcd(alrm->time.tm_hour) << TIME_HOUR_S)
 171                | (bin2bcd(alrm->time.tm_min) << TIME_MIN_S)
 172                | (bin2bcd(alrm->time.tm_sec)),
 173                vt8500_rtc->regbase + VT8500_RTC_AS);
 174
 175        return 0;
 176}
 177
 178static int vt8500_alarm_irq_enable(struct device *dev, unsigned int enabled)
 179{
 180        struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
 181        unsigned long tmp = readl(vt8500_rtc->regbase + VT8500_RTC_AS);
 182
 183        if (enabled)
 184                tmp |= ALARM_ENABLE_MASK;
 185        else
 186                tmp &= ~ALARM_ENABLE_MASK;
 187
 188        writel(tmp, vt8500_rtc->regbase + VT8500_RTC_AS);
 189        return 0;
 190}
 191
 192static const struct rtc_class_ops vt8500_rtc_ops = {
 193        .read_time = vt8500_rtc_read_time,
 194        .set_time = vt8500_rtc_set_time,
 195        .read_alarm = vt8500_rtc_read_alarm,
 196        .set_alarm = vt8500_rtc_set_alarm,
 197        .alarm_irq_enable = vt8500_alarm_irq_enable,
 198};
 199
 200static int vt8500_rtc_probe(struct platform_device *pdev)
 201{
 202        struct vt8500_rtc *vt8500_rtc;
 203        struct resource *res;
 204        int ret;
 205
 206        vt8500_rtc = devm_kzalloc(&pdev->dev,
 207                           sizeof(struct vt8500_rtc), GFP_KERNEL);
 208        if (!vt8500_rtc)
 209                return -ENOMEM;
 210
 211        spin_lock_init(&vt8500_rtc->lock);
 212        platform_set_drvdata(pdev, vt8500_rtc);
 213
 214        vt8500_rtc->irq_alarm = platform_get_irq(pdev, 0);
 215        if (vt8500_rtc->irq_alarm < 0) {
 216                dev_err(&pdev->dev, "No alarm IRQ resource defined\n");
 217                return vt8500_rtc->irq_alarm;
 218        }
 219
 220        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 221        vt8500_rtc->regbase = devm_ioremap_resource(&pdev->dev, res);
 222        if (IS_ERR(vt8500_rtc->regbase))
 223                return PTR_ERR(vt8500_rtc->regbase);
 224
 225        /* Enable RTC and set it to 24-hour mode */
 226        writel(VT8500_RTC_CR_ENABLE,
 227               vt8500_rtc->regbase + VT8500_RTC_CR);
 228
 229        vt8500_rtc->rtc = devm_rtc_device_register(&pdev->dev, "vt8500-rtc",
 230                                              &vt8500_rtc_ops, THIS_MODULE);
 231        if (IS_ERR(vt8500_rtc->rtc)) {
 232                ret = PTR_ERR(vt8500_rtc->rtc);
 233                dev_err(&pdev->dev,
 234                        "Failed to register RTC device -> %d\n", ret);
 235                goto err_return;
 236        }
 237
 238        ret = devm_request_irq(&pdev->dev, vt8500_rtc->irq_alarm,
 239                                vt8500_rtc_irq, 0, "rtc alarm", vt8500_rtc);
 240        if (ret < 0) {
 241                dev_err(&pdev->dev, "can't get irq %i, err %d\n",
 242                        vt8500_rtc->irq_alarm, ret);
 243                goto err_return;
 244        }
 245
 246        return 0;
 247
 248err_return:
 249        return ret;
 250}
 251
 252static int vt8500_rtc_remove(struct platform_device *pdev)
 253{
 254        struct vt8500_rtc *vt8500_rtc = platform_get_drvdata(pdev);
 255
 256        /* Disable alarm matching */
 257        writel(0, vt8500_rtc->regbase + VT8500_RTC_IS);
 258
 259        return 0;
 260}
 261
 262static const struct of_device_id wmt_dt_ids[] = {
 263        { .compatible = "via,vt8500-rtc", },
 264        {}
 265};
 266MODULE_DEVICE_TABLE(of, wmt_dt_ids);
 267
 268static struct platform_driver vt8500_rtc_driver = {
 269        .probe          = vt8500_rtc_probe,
 270        .remove         = vt8500_rtc_remove,
 271        .driver         = {
 272                .name   = "vt8500-rtc",
 273                .of_match_table = wmt_dt_ids,
 274        },
 275};
 276
 277module_platform_driver(vt8500_rtc_driver);
 278
 279MODULE_AUTHOR("Alexey Charkov <alchark@gmail.com>");
 280MODULE_DESCRIPTION("VIA VT8500 SoC Realtime Clock Driver (RTC)");
 281MODULE_LICENSE("GPL v2");
 282MODULE_ALIAS("platform:vt8500-rtc");
 283