linux/drivers/rtc/rtc-vt8500.c
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   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
  80struct vt8500_rtc {
  81        void __iomem            *regbase;
  82        struct resource         *res;
  83        int                     irq_alarm;
  84        struct rtc_device       *rtc;
  85        spinlock_t              lock;           /* Protects this structure */
  86};
  87
  88static irqreturn_t vt8500_rtc_irq(int irq, void *dev_id)
  89{
  90        struct vt8500_rtc *vt8500_rtc = dev_id;
  91        u32 isr;
  92        unsigned long events = 0;
  93
  94        spin_lock(&vt8500_rtc->lock);
  95
  96        /* clear interrupt sources */
  97        isr = readl(vt8500_rtc->regbase + VT8500_RTC_IS);
  98        writel(isr, vt8500_rtc->regbase + VT8500_RTC_IS);
  99
 100        spin_unlock(&vt8500_rtc->lock);
 101
 102        if (isr & VT8500_RTC_IS_ALARM)
 103                events |= RTC_AF | RTC_IRQF;
 104
 105        rtc_update_irq(vt8500_rtc->rtc, 1, events);
 106
 107        return IRQ_HANDLED;
 108}
 109
 110static int vt8500_rtc_read_time(struct device *dev, struct rtc_time *tm)
 111{
 112        struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
 113        u32 date, time;
 114
 115        date = readl(vt8500_rtc->regbase + VT8500_RTC_DR);
 116        time = readl(vt8500_rtc->regbase + VT8500_RTC_TR);
 117
 118        tm->tm_sec = bcd2bin(time & TIME_SEC_MASK);
 119        tm->tm_min = bcd2bin((time & TIME_MIN_MASK) >> TIME_MIN_S);
 120        tm->tm_hour = bcd2bin((time & TIME_HOUR_MASK) >> TIME_HOUR_S);
 121        tm->tm_mday = bcd2bin(date & DATE_DAY_MASK);
 122        tm->tm_mon = bcd2bin((date & DATE_MONTH_MASK) >> DATE_MONTH_S) - 1;
 123        tm->tm_year = bcd2bin((date & DATE_YEAR_MASK) >> DATE_YEAR_S)
 124                        + ((date >> DATE_CENTURY_S) & 1 ? 200 : 100);
 125        tm->tm_wday = (time & TIME_DOW_MASK) >> TIME_DOW_S;
 126
 127        return 0;
 128}
 129
 130static int vt8500_rtc_set_time(struct device *dev, struct rtc_time *tm)
 131{
 132        struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
 133
 134        if (tm->tm_year < 100) {
 135                dev_warn(dev, "Only years 2000-2199 are supported by the "
 136                              "hardware!\n");
 137                return -EINVAL;
 138        }
 139
 140        writel((bin2bcd(tm->tm_year % 100) << DATE_YEAR_S)
 141                | (bin2bcd(tm->tm_mon + 1) << DATE_MONTH_S)
 142                | (bin2bcd(tm->tm_mday))
 143                | ((tm->tm_year >= 200) << DATE_CENTURY_S),
 144                vt8500_rtc->regbase + VT8500_RTC_DS);
 145        writel((bin2bcd(tm->tm_wday) << TIME_DOW_S)
 146                | (bin2bcd(tm->tm_hour) << TIME_HOUR_S)
 147                | (bin2bcd(tm->tm_min) << TIME_MIN_S)
 148                | (bin2bcd(tm->tm_sec)),
 149                vt8500_rtc->regbase + VT8500_RTC_TS);
 150
 151        return 0;
 152}
 153
 154static int vt8500_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 155{
 156        struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
 157        u32 isr, alarm;
 158
 159        alarm = readl(vt8500_rtc->regbase + VT8500_RTC_AS);
 160        isr = readl(vt8500_rtc->regbase + VT8500_RTC_IS);
 161
 162        alrm->time.tm_mday = bcd2bin((alarm & ALARM_DAY_MASK) >> ALARM_DAY_S);
 163        alrm->time.tm_hour = bcd2bin((alarm & TIME_HOUR_MASK) >> TIME_HOUR_S);
 164        alrm->time.tm_min = bcd2bin((alarm & TIME_MIN_MASK) >> TIME_MIN_S);
 165        alrm->time.tm_sec = bcd2bin((alarm & TIME_SEC_MASK));
 166
 167        alrm->enabled = (alarm & ALARM_ENABLE_MASK) ? 1 : 0;
 168        alrm->pending = (isr & VT8500_RTC_IS_ALARM) ? 1 : 0;
 169
 170        return rtc_valid_tm(&alrm->time);
 171}
 172
 173static int vt8500_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 174{
 175        struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
 176
 177        writel((alrm->enabled ? ALARM_ENABLE_MASK : 0)
 178                | (bin2bcd(alrm->time.tm_mday) << ALARM_DAY_S)
 179                | (bin2bcd(alrm->time.tm_hour) << TIME_HOUR_S)
 180                | (bin2bcd(alrm->time.tm_min) << TIME_MIN_S)
 181                | (bin2bcd(alrm->time.tm_sec)),
 182                vt8500_rtc->regbase + VT8500_RTC_AS);
 183
 184        return 0;
 185}
 186
 187static int vt8500_alarm_irq_enable(struct device *dev, unsigned int enabled)
 188{
 189        struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
 190        unsigned long tmp = readl(vt8500_rtc->regbase + VT8500_RTC_AS);
 191
 192        if (enabled)
 193                tmp |= ALARM_ENABLE_MASK;
 194        else
 195                tmp &= ~ALARM_ENABLE_MASK;
 196
 197        writel(tmp, vt8500_rtc->regbase + VT8500_RTC_AS);
 198        return 0;
 199}
 200
 201static const struct rtc_class_ops vt8500_rtc_ops = {
 202        .read_time = vt8500_rtc_read_time,
 203        .set_time = vt8500_rtc_set_time,
 204        .read_alarm = vt8500_rtc_read_alarm,
 205        .set_alarm = vt8500_rtc_set_alarm,
 206        .alarm_irq_enable = vt8500_alarm_irq_enable,
 207};
 208
 209static int vt8500_rtc_probe(struct platform_device *pdev)
 210{
 211        struct vt8500_rtc *vt8500_rtc;
 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->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 223        if (!vt8500_rtc->res) {
 224                dev_err(&pdev->dev, "No I/O memory resource defined\n");
 225                return -ENXIO;
 226        }
 227
 228        vt8500_rtc->irq_alarm = platform_get_irq(pdev, 0);
 229        if (vt8500_rtc->irq_alarm < 0) {
 230                dev_err(&pdev->dev, "No alarm IRQ resource defined\n");
 231                return -ENXIO;
 232        }
 233
 234        vt8500_rtc->res = devm_request_mem_region(&pdev->dev,
 235                                        vt8500_rtc->res->start,
 236                                        resource_size(vt8500_rtc->res),
 237                                        "vt8500-rtc");
 238        if (vt8500_rtc->res == NULL) {
 239                dev_err(&pdev->dev, "failed to request I/O memory\n");
 240                return -EBUSY;
 241        }
 242
 243        vt8500_rtc->regbase = devm_ioremap(&pdev->dev, vt8500_rtc->res->start,
 244                                      resource_size(vt8500_rtc->res));
 245        if (!vt8500_rtc->regbase) {
 246                dev_err(&pdev->dev, "Unable to map RTC I/O memory\n");
 247                ret = -EBUSY;
 248                goto err_return;
 249        }
 250
 251        /* Enable RTC and set it to 24-hour mode */
 252        writel(VT8500_RTC_CR_ENABLE,
 253               vt8500_rtc->regbase + VT8500_RTC_CR);
 254
 255        vt8500_rtc->rtc = devm_rtc_device_register(&pdev->dev, "vt8500-rtc",
 256                                              &vt8500_rtc_ops, THIS_MODULE);
 257        if (IS_ERR(vt8500_rtc->rtc)) {
 258                ret = PTR_ERR(vt8500_rtc->rtc);
 259                dev_err(&pdev->dev,
 260                        "Failed to register RTC device -> %d\n", ret);
 261                goto err_return;
 262        }
 263
 264        ret = devm_request_irq(&pdev->dev, vt8500_rtc->irq_alarm,
 265                                vt8500_rtc_irq, 0, "rtc alarm", vt8500_rtc);
 266        if (ret < 0) {
 267                dev_err(&pdev->dev, "can't get irq %i, err %d\n",
 268                        vt8500_rtc->irq_alarm, ret);
 269                goto err_return;
 270        }
 271
 272        return 0;
 273
 274err_return:
 275        return ret;
 276}
 277
 278static int vt8500_rtc_remove(struct platform_device *pdev)
 279{
 280        struct vt8500_rtc *vt8500_rtc = platform_get_drvdata(pdev);
 281
 282        /* Disable alarm matching */
 283        writel(0, vt8500_rtc->regbase + VT8500_RTC_IS);
 284
 285        platform_set_drvdata(pdev, NULL);
 286
 287        return 0;
 288}
 289
 290static const struct of_device_id wmt_dt_ids[] = {
 291        { .compatible = "via,vt8500-rtc", },
 292        {}
 293};
 294
 295static struct platform_driver vt8500_rtc_driver = {
 296        .probe          = vt8500_rtc_probe,
 297        .remove         = vt8500_rtc_remove,
 298        .driver         = {
 299                .name   = "vt8500-rtc",
 300                .owner  = THIS_MODULE,
 301                .of_match_table = of_match_ptr(wmt_dt_ids),
 302        },
 303};
 304
 305module_platform_driver(vt8500_rtc_driver);
 306
 307MODULE_AUTHOR("Alexey Charkov <alchark@gmail.com>");
 308MODULE_DESCRIPTION("VIA VT8500 SoC Realtime Clock Driver (RTC)");
 309MODULE_LICENSE("GPL v2");
 310MODULE_ALIAS("platform:vt8500-rtc");
 311
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