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   1 // SPDX-License-Identifier: GPL-2.0
   2 /* drivers/rtc/rtc-goldfish.c
   3  *
   4  * Copyright (C) 2007 Google, Inc.
   5  * Copyright (C) 2017 Imagination Technologies Ltd.
   6  */
   7
   8 #include <linux/io.h>
   9 #include <linux/module.h>
  10 #include <linux/of.h>
  11 #include <linux/platform_device.h>
  12 #include <linux/rtc.h>
  13
  14 #define TIMER_TIME_LOW          0x00    /* get low bits of current time  */
  15                                         /*   and update TIMER_TIME_HIGH  */
  16 #define TIMER_TIME_HIGH 0x04    /* get high bits of time at last */
  17                                         /*   TIMER_TIME_LOW read         */
  18 #define TIMER_ALARM_LOW 0x08    /* set low bits of alarm and     */
  19                                         /*   activate it                 */
  20 #define TIMER_ALARM_HIGH        0x0c    /* set high bits of next alarm   */
  21 #define TIMER_IRQ_ENABLED       0x10
  22 #define TIMER_CLEAR_ALARM       0x14
  23 #define TIMER_ALARM_STATUS      0x18
  24 #define TIMER_CLEAR_INTERRUPT   0x1c
  25
  26 struct goldfish_rtc {
  27         void __iomem *base;
  28         int irq;
  29         struct rtc_device *rtc;
  30 };
  31
  32 static int goldfish_rtc_read_alarm(struct device *dev,
  33                                    struct rtc_wkalrm *alrm)
  34 {
  35         u64 rtc_alarm;
  36         u64 rtc_alarm_low;
  37         u64 rtc_alarm_high;
  38         void __iomem *base;
  39         struct goldfish_rtc *rtcdrv;
  40
  41         rtcdrv = dev_get_drvdata(dev);
  42         base = rtcdrv->base;
  43
  44         rtc_alarm_low = readl(base + TIMER_ALARM_LOW);
  45         rtc_alarm_high = readl(base + TIMER_ALARM_HIGH);
  46         rtc_alarm = (rtc_alarm_high << 32) | rtc_alarm_low;
  47
  48         do_div(rtc_alarm, NSEC_PER_SEC);
  49         memset(alrm, 0, sizeof(struct rtc_wkalrm));
  50
  51         rtc_time64_to_tm(rtc_alarm, &alrm->time);
  52
  53         if (readl(base + TIMER_ALARM_STATUS))
  54                 alrm->enabled = 1;
  55         else
  56                 alrm->enabled = 0;
  57
  58         return 0;
  59 }
  60
  61 static int goldfish_rtc_set_alarm(struct device *dev,
  62                                   struct rtc_wkalrm *alrm)
  63 {
  64         struct goldfish_rtc *rtcdrv;
  65         u64 rtc_alarm64;
  66         u64 rtc_status_reg;
  67         void __iomem *base;
  68
  69         rtcdrv = dev_get_drvdata(dev);
  70         base = rtcdrv->base;
  71
  72         if (alrm->enabled) {
  73                 rtc_alarm64 = rtc_tm_to_time64(&alrm->time) * NSEC_PER_SEC;
  74                 writel((rtc_alarm64 >> 32), base + TIMER_ALARM_HIGH);
  75                 writel(rtc_alarm64, base + TIMER_ALARM_LOW);
  76         } else {
  77                 /*
  78                  * if this function was called with enabled=0
  79                  * then it could mean that the application is
  80                  * trying to cancel an ongoing alarm
  81                  */
  82                 rtc_status_reg = readl(base + TIMER_ALARM_STATUS);
  83                 if (rtc_status_reg)
  84                         writel(1, base + TIMER_CLEAR_ALARM);
  85         }
  86
  87         return 0;
  88 }
  89
  90 static int goldfish_rtc_alarm_irq_enable(struct device *dev,
  91                                          unsigned int enabled)
  92 {
  93         void __iomem *base;
  94         struct goldfish_rtc *rtcdrv;
  95
  96         rtcdrv = dev_get_drvdata(dev);
  97         base = rtcdrv->base;
  98
  99         if (enabled)
 100                 writel(1, base + TIMER_IRQ_ENABLED);
 101         else
 102                 writel(0, base + TIMER_IRQ_ENABLED);
 103
 104         return 0;
 105 }
 106
 107 static irqreturn_t goldfish_rtc_interrupt(int irq, void *dev_id)
 108 {
 109         struct goldfish_rtc *rtcdrv = dev_id;
 110         void __iomem *base = rtcdrv->base;
 111
 112         writel(1, base + TIMER_CLEAR_INTERRUPT);
 113
 114         rtc_update_irq(rtcdrv->rtc, 1, RTC_IRQF | RTC_AF);
 115
 116         return IRQ_HANDLED;
 117 }
 118
 119 static int goldfish_rtc_read_time(struct device *dev, struct rtc_time *tm)
 120 {
 121         struct goldfish_rtc *rtcdrv;
 122         void __iomem *base;
 123         u64 time_high;
 124         u64 time_low;
 125         u64 time;
 126
 127         rtcdrv = dev_get_drvdata(dev);
 128         base = rtcdrv->base;
 129
 130         time_low = readl(base + TIMER_TIME_LOW);
 131         time_high = readl(base + TIMER_TIME_HIGH);
 132         time = (time_high << 32) | time_low;
 133
 134         do_div(time, NSEC_PER_SEC);
 135
 136         rtc_time64_to_tm(time, tm);
 137
 138         return 0;
 139 }
 140
 141 static int goldfish_rtc_set_time(struct device *dev, struct rtc_time *tm)
 142 {
 143         struct goldfish_rtc *rtcdrv;
 144         void __iomem *base;
 145         u64 now64;
 146
 147         rtcdrv = dev_get_drvdata(dev);
 148         base = rtcdrv->base;
 149
 150         now64 = rtc_tm_to_time64(tm) * NSEC_PER_SEC;
 151         writel((now64 >> 32), base + TIMER_TIME_HIGH);
 152         writel(now64, base + TIMER_TIME_LOW);
 153
 154         return 0;
 155 }
 156
 157 static const struct rtc_class_ops goldfish_rtc_ops = {
 158         .read_time      = goldfish_rtc_read_time,
 159         .set_time       = goldfish_rtc_set_time,
 160         .read_alarm     = goldfish_rtc_read_alarm,
 161         .set_alarm      = goldfish_rtc_set_alarm,
 162         .alarm_irq_enable = goldfish_rtc_alarm_irq_enable
 163 };
 164
 165 static int goldfish_rtc_probe(struct platform_device *pdev)
 166 {
 167         struct goldfish_rtc *rtcdrv;
 168         int err;
 169
 170         rtcdrv = devm_kzalloc(&pdev->dev, sizeof(*rtcdrv), GFP_KERNEL);
 171         if (!rtcdrv)
 172                 return -ENOMEM;
 173
 174         platform_set_drvdata(pdev, rtcdrv);
 175         rtcdrv->base = devm_platform_ioremap_resource(pdev, 0);
 176         if (IS_ERR(rtcdrv->base))
 177                 return PTR_ERR(rtcdrv->base);
 178
 179         rtcdrv->irq = platform_get_irq(pdev, 0);
 180         if (rtcdrv->irq < 0)
 181                 return -ENODEV;
 182
 183         rtcdrv->rtc = devm_rtc_allocate_device(&pdev->dev);
 184         if (IS_ERR(rtcdrv->rtc))
 185                 return PTR_ERR(rtcdrv->rtc);
 186
 187         rtcdrv->rtc->ops = &goldfish_rtc_ops;
 188         rtcdrv->rtc->range_max = U64_MAX / NSEC_PER_SEC;
 189
 190         err = devm_request_irq(&pdev->dev, rtcdrv->irq,
 191                                goldfish_rtc_interrupt,
 192                                0, pdev->name, rtcdrv);
 193         if (err)
 194                 return err;
 195
 196         return rtc_register_device(rtcdrv->rtc);
 197 }
 198
 199 static const struct of_device_id goldfish_rtc_of_match[] = {
 200         { .compatible = "google,goldfish-rtc", },
 201         {},
 202 };
 203 MODULE_DEVICE_TABLE(of, goldfish_rtc_of_match);
 204
 205 static struct platform_driver goldfish_rtc = {
 206         .probe = goldfish_rtc_probe,
 207         .driver = {
 208                 .name = "goldfish_rtc",
 209                 .of_match_table = goldfish_rtc_of_match,
 210         }
 211 };
 212
 213 module_platform_driver(goldfish_rtc);
 214
 215 MODULE_LICENSE("GPL v2");