drivers/rtc/rtc-vt8500.c

   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
  72 struct vt8500_rtc {
  73         void __iomem            *regbase;
  74         int                     irq_alarm;
  75         struct rtc_device       *rtc;
  76         spinlock_t              lock;           /* Protects this structure */
  77 };
  78
  79 static 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
 101 static 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
 121 static 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
 145 static 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
 164 static 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
 178 static 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
 192 static 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
 200 static 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
 248 err_return:
 249         return ret;
 250 }
 251
 252 static 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
 262 static const struct of_device_id wmt_dt_ids[] = {
 263         { .compatible = "via,vt8500-rtc", },
 264         {}
 265 };
 266 MODULE_DEVICE_TABLE(of, wmt_dt_ids);
 267
 268 static 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
 277 module_platform_driver(vt8500_rtc_driver);
 278
 279 MODULE_AUTHOR("Alexey Charkov <alchark@gmail.com>");
 280 MODULE_DESCRIPTION("VIA VT8500 SoC Realtime Clock Driver (RTC)");
 281 MODULE_LICENSE("GPL v2");
 282 MODULE_ALIAS("platform:vt8500-rtc");