drivers/rtc/rtc-vt8500.c

   1 /*
   2  * drivers/rtc/rtc-vt8500.c
   3  *
   4  *  Copyright (C) 2010 Alexey Charkov <alchark@gmail.com>
   5  *
   6  * Based on rtc-pxa.c
   7  *
   8  * This software is licensed under the terms of the GNU General Public
   9  * License version 2, as published by the Free Software Foundation, and
  10  * may be copied, distributed, and modified under those terms.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  */
  17
  18 #include <linux/module.h>
  19 #include <linux/rtc.h>
  20 #include <linux/init.h>
  21 #include <linux/interrupt.h>
  22 #include <linux/io.h>
  23 #include <linux/bcd.h>
  24 #include <linux/platform_device.h>
  25 #include <linux/slab.h>
  26 #include <linux/of.h>
  27
  28 /*
  29  * Register definitions
  30  */
  31 #define VT8500_RTC_TS           0x00    /* Time set */
  32 #define VT8500_RTC_DS           0x04    /* Date set */
  33 #define VT8500_RTC_AS           0x08    /* Alarm set */
  34 #define VT8500_RTC_CR           0x0c    /* Control */
  35 #define VT8500_RTC_TR           0x10    /* Time read */
  36 #define VT8500_RTC_DR           0x14    /* Date read */
  37 #define VT8500_RTC_WS           0x18    /* Write status */
  38 #define VT8500_RTC_CL           0x20    /* Calibration */
  39 #define VT8500_RTC_IS           0x24    /* Interrupt status */
  40 #define VT8500_RTC_ST           0x28    /* Status */
  41
  42 #define INVALID_TIME_BIT        (1 << 31)
  43
  44 #define DATE_CENTURY_S          19
  45 #define DATE_YEAR_S             11
  46 #define DATE_YEAR_MASK          (0xff << DATE_YEAR_S)
  47 #define DATE_MONTH_S            6
  48 #define DATE_MONTH_MASK         (0x1f << DATE_MONTH_S)
  49 #define DATE_DAY_MASK           0x3f
  50
  51 #define TIME_DOW_S              20
  52 #define TIME_DOW_MASK           (0x07 << TIME_DOW_S)
  53 #define TIME_HOUR_S             14
  54 #define TIME_HOUR_MASK          (0x3f << TIME_HOUR_S)
  55 #define TIME_MIN_S              7
  56 #define TIME_MIN_MASK           (0x7f << TIME_MIN_S)
  57 #define TIME_SEC_MASK           0x7f
  58
  59 #define ALARM_DAY_S             20
  60 #define ALARM_DAY_MASK          (0x3f << ALARM_DAY_S)
  61
  62 #define ALARM_DAY_BIT           (1 << 29)
  63 #define ALARM_HOUR_BIT          (1 << 28)
  64 #define ALARM_MIN_BIT           (1 << 27)
  65 #define ALARM_SEC_BIT           (1 << 26)
  66
  67 #define ALARM_ENABLE_MASK       (ALARM_DAY_BIT \
  68                                 | ALARM_HOUR_BIT \
  69                                 | ALARM_MIN_BIT \
  70                                 | ALARM_SEC_BIT)
  71
  72 #define VT8500_RTC_CR_ENABLE    (1 << 0)        /* Enable RTC */
  73 #define VT8500_RTC_CR_12H       (1 << 1)        /* 12h time format */
  74 #define VT8500_RTC_CR_SM_ENABLE (1 << 2)        /* Enable periodic irqs */
  75 #define VT8500_RTC_CR_SM_SEC    (1 << 3)        /* 0: 1Hz/60, 1: 1Hz */
  76 #define VT8500_RTC_CR_CALIB     (1 << 4)        /* Enable calibration */
  77
  78 #define VT8500_RTC_IS_ALARM     (1 << 0)        /* Alarm interrupt status */
  79
  80 struct vt8500_rtc {
  81         void __iomem            *regbase;
  82         int                     irq_alarm;
  83         struct rtc_device       *rtc;
  84         spinlock_t              lock;           /* Protects this structure */
  85 };
  86
  87 static irqreturn_t vt8500_rtc_irq(int irq, void *dev_id)
  88 {
  89         struct vt8500_rtc *vt8500_rtc = dev_id;
  90         u32 isr;
  91         unsigned long events = 0;
  92
  93         spin_lock(&vt8500_rtc->lock);
  94
  95         /* clear interrupt sources */
  96         isr = readl(vt8500_rtc->regbase + VT8500_RTC_IS);
  97         writel(isr, vt8500_rtc->regbase + VT8500_RTC_IS);
  98
  99         spin_unlock(&vt8500_rtc->lock);
 100
 101         if (isr & VT8500_RTC_IS_ALARM)
 102                 events |= RTC_AF | RTC_IRQF;
 103
 104         rtc_update_irq(vt8500_rtc->rtc, 1, events);
 105
 106         return IRQ_HANDLED;
 107 }
 108
 109 static int vt8500_rtc_read_time(struct device *dev, struct rtc_time *tm)
 110 {
 111         struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
 112         u32 date, time;
 113
 114         date = readl(vt8500_rtc->regbase + VT8500_RTC_DR);
 115         time = readl(vt8500_rtc->regbase + VT8500_RTC_TR);
 116
 117         tm->tm_sec = bcd2bin(time & TIME_SEC_MASK);
 118         tm->tm_min = bcd2bin((time & TIME_MIN_MASK) >> TIME_MIN_S);
 119         tm->tm_hour = bcd2bin((time & TIME_HOUR_MASK) >> TIME_HOUR_S);
 120         tm->tm_mday = bcd2bin(date & DATE_DAY_MASK);
 121         tm->tm_mon = bcd2bin((date & DATE_MONTH_MASK) >> DATE_MONTH_S) - 1;
 122         tm->tm_year = bcd2bin((date & DATE_YEAR_MASK) >> DATE_YEAR_S)
 123                         + ((date >> DATE_CENTURY_S) & 1 ? 200 : 100);
 124         tm->tm_wday = (time & TIME_DOW_MASK) >> TIME_DOW_S;
 125
 126         return 0;
 127 }
 128
 129 static int vt8500_rtc_set_time(struct device *dev, struct rtc_time *tm)
 130 {
 131         struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
 132
 133         if (tm->tm_year < 100) {
 134                 dev_warn(dev, "Only years 2000-2199 are supported by the "
 135                               "hardware!\n");
 136                 return -EINVAL;
 137         }
 138
 139         writel((bin2bcd(tm->tm_year % 100) << DATE_YEAR_S)
 140                 | (bin2bcd(tm->tm_mon + 1) << DATE_MONTH_S)
 141                 | (bin2bcd(tm->tm_mday))
 142                 | ((tm->tm_year >= 200) << DATE_CENTURY_S),
 143                 vt8500_rtc->regbase + VT8500_RTC_DS);
 144         writel((bin2bcd(tm->tm_wday) << TIME_DOW_S)
 145                 | (bin2bcd(tm->tm_hour) << TIME_HOUR_S)
 146                 | (bin2bcd(tm->tm_min) << TIME_MIN_S)
 147                 | (bin2bcd(tm->tm_sec)),
 148                 vt8500_rtc->regbase + VT8500_RTC_TS);
 149
 150         return 0;
 151 }
 152
 153 static int vt8500_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 154 {
 155         struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
 156         u32 isr, alarm;
 157
 158         alarm = readl(vt8500_rtc->regbase + VT8500_RTC_AS);
 159         isr = readl(vt8500_rtc->regbase + VT8500_RTC_IS);
 160
 161         alrm->time.tm_mday = bcd2bin((alarm & ALARM_DAY_MASK) >> ALARM_DAY_S);
 162         alrm->time.tm_hour = bcd2bin((alarm & TIME_HOUR_MASK) >> TIME_HOUR_S);
 163         alrm->time.tm_min = bcd2bin((alarm & TIME_MIN_MASK) >> TIME_MIN_S);
 164         alrm->time.tm_sec = bcd2bin((alarm & TIME_SEC_MASK));
 165
 166         alrm->enabled = (alarm & ALARM_ENABLE_MASK) ? 1 : 0;
 167         alrm->pending = (isr & VT8500_RTC_IS_ALARM) ? 1 : 0;
 168
 169         return rtc_valid_tm(&alrm->time);
 170 }
 171
 172 static int vt8500_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 173 {
 174         struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
 175
 176         writel((alrm->enabled ? ALARM_ENABLE_MASK : 0)
 177                 | (bin2bcd(alrm->time.tm_mday) << ALARM_DAY_S)
 178                 | (bin2bcd(alrm->time.tm_hour) << TIME_HOUR_S)
 179                 | (bin2bcd(alrm->time.tm_min) << TIME_MIN_S)
 180                 | (bin2bcd(alrm->time.tm_sec)),
 181                 vt8500_rtc->regbase + VT8500_RTC_AS);
 182
 183         return 0;
 184 }
 185
 186 static int vt8500_alarm_irq_enable(struct device *dev, unsigned int enabled)
 187 {
 188         struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
 189         unsigned long tmp = readl(vt8500_rtc->regbase + VT8500_RTC_AS);
 190
 191         if (enabled)
 192                 tmp |= ALARM_ENABLE_MASK;
 193         else
 194                 tmp &= ~ALARM_ENABLE_MASK;
 195
 196         writel(tmp, vt8500_rtc->regbase + VT8500_RTC_AS);
 197         return 0;
 198 }
 199
 200 static const struct rtc_class_ops vt8500_rtc_ops = {
 201         .read_time = vt8500_rtc_read_time,
 202         .set_time = vt8500_rtc_set_time,
 203         .read_alarm = vt8500_rtc_read_alarm,
 204         .set_alarm = vt8500_rtc_set_alarm,
 205         .alarm_irq_enable = vt8500_alarm_irq_enable,
 206 };
 207
 208 static int vt8500_rtc_probe(struct platform_device *pdev)
 209 {
 210         struct vt8500_rtc *vt8500_rtc;
 211         struct resource *res;
 212         int ret;
 213
 214         vt8500_rtc = devm_kzalloc(&pdev->dev,
 215                            sizeof(struct vt8500_rtc), GFP_KERNEL);
 216         if (!vt8500_rtc)
 217                 return -ENOMEM;
 218
 219         spin_lock_init(&vt8500_rtc->lock);
 220         platform_set_drvdata(pdev, vt8500_rtc);
 221
 222         vt8500_rtc->irq_alarm = platform_get_irq(pdev, 0);
 223         if (vt8500_rtc->irq_alarm < 0) {
 224                 dev_err(&pdev->dev, "No alarm IRQ resource defined\n");
 225                 return vt8500_rtc->irq_alarm;
 226         }
 227
 228         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 229         vt8500_rtc->regbase = devm_ioremap_resource(&pdev->dev, res);
 230         if (IS_ERR(vt8500_rtc->regbase))
 231                 return PTR_ERR(vt8500_rtc->regbase);
 232
 233         /* Enable RTC and set it to 24-hour mode */
 234         writel(VT8500_RTC_CR_ENABLE,
 235                vt8500_rtc->regbase + VT8500_RTC_CR);
 236
 237         vt8500_rtc->rtc = devm_rtc_device_register(&pdev->dev, "vt8500-rtc",
 238                                               &vt8500_rtc_ops, THIS_MODULE);
 239         if (IS_ERR(vt8500_rtc->rtc)) {
 240                 ret = PTR_ERR(vt8500_rtc->rtc);
 241                 dev_err(&pdev->dev,
 242                         "Failed to register RTC device -> %d\n", ret);
 243                 goto err_return;
 244         }
 245
 246         ret = devm_request_irq(&pdev->dev, vt8500_rtc->irq_alarm,
 247                                 vt8500_rtc_irq, 0, "rtc alarm", vt8500_rtc);
 248         if (ret < 0) {
 249                 dev_err(&pdev->dev, "can't get irq %i, err %d\n",
 250                         vt8500_rtc->irq_alarm, ret);
 251                 goto err_return;
 252         }
 253
 254         return 0;
 255
 256 err_return:
 257         return ret;
 258 }
 259
 260 static int vt8500_rtc_remove(struct platform_device *pdev)
 261 {
 262         struct vt8500_rtc *vt8500_rtc = platform_get_drvdata(pdev);
 263
 264         /* Disable alarm matching */
 265         writel(0, vt8500_rtc->regbase + VT8500_RTC_IS);
 266
 267         return 0;
 268 }
 269
 270 static const struct of_device_id wmt_dt_ids[] = {
 271         { .compatible = "via,vt8500-rtc", },
 272         {}
 273 };
 274
 275 static struct platform_driver vt8500_rtc_driver = {
 276         .probe          = vt8500_rtc_probe,
 277         .remove         = vt8500_rtc_remove,
 278         .driver         = {
 279                 .name   = "vt8500-rtc",
 280                 .of_match_table = wmt_dt_ids,
 281         },
 282 };
 283
 284 module_platform_driver(vt8500_rtc_driver);
 285
 286 MODULE_AUTHOR("Alexey Charkov <alchark@gmail.com>");
 287 MODULE_DESCRIPTION("VIA VT8500 SoC Realtime Clock Driver (RTC)");
 288 MODULE_LICENSE("GPL v2");
 289 MODULE_ALIAS("platform:vt8500-rtc");