drivers/rtc/rtc-goldfish.c

   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                 writel(1, base + TIMER_IRQ_ENABLED);
  77         } else {
  78                 /*
  79                  * if this function was called with enabled=0
  80                  * then it could mean that the application is
  81                  * trying to cancel an ongoing alarm
  82                  */
  83                 rtc_status_reg = readl(base + TIMER_ALARM_STATUS);
  84                 if (rtc_status_reg)
  85                         writel(1, base + TIMER_CLEAR_ALARM);
  86         }
  87
  88         return 0;
  89 }
  90
  91 static int goldfish_rtc_alarm_irq_enable(struct device *dev,
  92                                          unsigned int enabled)
  93 {
  94         void __iomem *base;
  95         struct goldfish_rtc *rtcdrv;
  96
  97         rtcdrv = dev_get_drvdata(dev);
  98         base = rtcdrv->base;
  99
 100         if (enabled)
 101                 writel(1, base + TIMER_IRQ_ENABLED);
 102         else
 103                 writel(0, base + TIMER_IRQ_ENABLED);
 104
 105         return 0;
 106 }
 107
 108 static irqreturn_t goldfish_rtc_interrupt(int irq, void *dev_id)
 109 {
 110         struct goldfish_rtc *rtcdrv = dev_id;
 111         void __iomem *base = rtcdrv->base;
 112
 113         writel(1, base + TIMER_CLEAR_INTERRUPT);
 114
 115         rtc_update_irq(rtcdrv->rtc, 1, RTC_IRQF | RTC_AF);
 116
 117         return IRQ_HANDLED;
 118 }
 119
 120 static int goldfish_rtc_read_time(struct device *dev, struct rtc_time *tm)
 121 {
 122         struct goldfish_rtc *rtcdrv;
 123         void __iomem *base;
 124         u64 time_high;
 125         u64 time_low;
 126         u64 time;
 127
 128         rtcdrv = dev_get_drvdata(dev);
 129         base = rtcdrv->base;
 130
 131         time_low = readl(base + TIMER_TIME_LOW);
 132         time_high = readl(base + TIMER_TIME_HIGH);
 133         time = (time_high << 32) | time_low;
 134
 135         do_div(time, NSEC_PER_SEC);
 136
 137         rtc_time64_to_tm(time, tm);
 138
 139         return 0;
 140 }
 141
 142 static int goldfish_rtc_set_time(struct device *dev, struct rtc_time *tm)
 143 {
 144         struct goldfish_rtc *rtcdrv;
 145         void __iomem *base;
 146         u64 now64;
 147
 148         rtcdrv = dev_get_drvdata(dev);
 149         base = rtcdrv->base;
 150
 151         now64 = rtc_tm_to_time64(tm) * NSEC_PER_SEC;
 152         writel((now64 >> 32), base + TIMER_TIME_HIGH);
 153         writel(now64, base + TIMER_TIME_LOW);
 154
 155         return 0;
 156 }
 157
 158 static const struct rtc_class_ops goldfish_rtc_ops = {
 159         .read_time      = goldfish_rtc_read_time,
 160         .set_time       = goldfish_rtc_set_time,
 161         .read_alarm     = goldfish_rtc_read_alarm,
 162         .set_alarm      = goldfish_rtc_set_alarm,
 163         .alarm_irq_enable = goldfish_rtc_alarm_irq_enable
 164 };
 165
 166 static int goldfish_rtc_probe(struct platform_device *pdev)
 167 {
 168         struct goldfish_rtc *rtcdrv;
 169         int err;
 170
 171         rtcdrv = devm_kzalloc(&pdev->dev, sizeof(*rtcdrv), GFP_KERNEL);
 172         if (!rtcdrv)
 173                 return -ENOMEM;
 174
 175         platform_set_drvdata(pdev, rtcdrv);
 176         rtcdrv->base = devm_platform_ioremap_resource(pdev, 0);
 177         if (IS_ERR(rtcdrv->base))
 178                 return PTR_ERR(rtcdrv->base);
 179
 180         rtcdrv->irq = platform_get_irq(pdev, 0);
 181         if (rtcdrv->irq < 0)
 182                 return -ENODEV;
 183
 184         rtcdrv->rtc = devm_rtc_allocate_device(&pdev->dev);
 185         if (IS_ERR(rtcdrv->rtc))
 186                 return PTR_ERR(rtcdrv->rtc);
 187
 188         rtcdrv->rtc->ops = &goldfish_rtc_ops;
 189         rtcdrv->rtc->range_max = U64_MAX / NSEC_PER_SEC;
 190
 191         err = devm_request_irq(&pdev->dev, rtcdrv->irq,
 192                                goldfish_rtc_interrupt,
 193                                0, pdev->name, rtcdrv);
 194         if (err)
 195                 return err;
 196
 197         return devm_rtc_register_device(rtcdrv->rtc);
 198 }
 199
 200 static const struct of_device_id goldfish_rtc_of_match[] = {
 201         { .compatible = "google,goldfish-rtc", },
 202         {},
 203 };
 204 MODULE_DEVICE_TABLE(of, goldfish_rtc_of_match);
 205
 206 static struct platform_driver goldfish_rtc = {
 207         .probe = goldfish_rtc_probe,
 208         .driver = {
 209                 .name = "goldfish_rtc",
 210                 .of_match_table = goldfish_rtc_of_match,
 211         }
 212 };
 213
 214 module_platform_driver(goldfish_rtc);
 215
 216 MODULE_LICENSE("GPL v2");