drivers/rtc/rtc-goldfish.c

   1 /* drivers/rtc/rtc-goldfish.c
   2  *
   3  * Copyright (C) 2007 Google, Inc.
   4  * Copyright (C) 2017 Imagination Technologies Ltd.
   5  *
   6  * This software is licensed under the terms of the GNU General Public
   7  * License version 2, as published by the Free Software Foundation, and
   8  * may be copied, distributed, and modified under those terms.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  */
  16
  17 #include <linux/module.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/rtc.h>
  20 #include <linux/io.h>
  21
  22 #define TIMER_TIME_LOW          0x00    /* get low bits of current time  */
  23                                         /*   and update TIMER_TIME_HIGH  */
  24 #define TIMER_TIME_HIGH 0x04    /* get high bits of time at last */
  25                                         /*   TIMER_TIME_LOW read         */
  26 #define TIMER_ALARM_LOW 0x08    /* set low bits of alarm and     */
  27                                         /*   activate it                 */
  28 #define TIMER_ALARM_HIGH        0x0c    /* set high bits of next alarm   */
  29 #define TIMER_IRQ_ENABLED       0x10
  30 #define TIMER_CLEAR_ALARM       0x14
  31 #define TIMER_ALARM_STATUS      0x18
  32 #define TIMER_CLEAR_INTERRUPT   0x1c
  33
  34 struct goldfish_rtc {
  35         void __iomem *base;
  36         int irq;
  37         struct rtc_device *rtc;
  38 };
  39
  40 static int goldfish_rtc_read_alarm(struct device *dev,
  41                                    struct rtc_wkalrm *alrm)
  42 {
  43         u64 rtc_alarm;
  44         u64 rtc_alarm_low;
  45         u64 rtc_alarm_high;
  46         void __iomem *base;
  47         struct goldfish_rtc *rtcdrv;
  48
  49         rtcdrv = dev_get_drvdata(dev);
  50         base = rtcdrv->base;
  51
  52         rtc_alarm_low = readl(base + TIMER_ALARM_LOW);
  53         rtc_alarm_high = readl(base + TIMER_ALARM_HIGH);
  54         rtc_alarm = (rtc_alarm_high << 32) | rtc_alarm_low;
  55
  56         do_div(rtc_alarm, NSEC_PER_SEC);
  57         memset(alrm, 0, sizeof(struct rtc_wkalrm));
  58
  59         rtc_time_to_tm(rtc_alarm, &alrm->time);
  60
  61         if (readl(base + TIMER_ALARM_STATUS))
  62                 alrm->enabled = 1;
  63         else
  64                 alrm->enabled = 0;
  65
  66         return 0;
  67 }
  68
  69 static int goldfish_rtc_set_alarm(struct device *dev,
  70                                   struct rtc_wkalrm *alrm)
  71 {
  72         struct goldfish_rtc *rtcdrv;
  73         unsigned long rtc_alarm;
  74         u64 rtc_alarm64;
  75         u64 rtc_status_reg;
  76         void __iomem *base;
  77         int ret = 0;
  78
  79         rtcdrv = dev_get_drvdata(dev);
  80         base = rtcdrv->base;
  81
  82         if (alrm->enabled) {
  83                 ret = rtc_tm_to_time(&alrm->time, &rtc_alarm);
  84                 if (ret != 0)
  85                         return ret;
  86
  87                 rtc_alarm64 = rtc_alarm * NSEC_PER_SEC;
  88                 writel((rtc_alarm64 >> 32), base + TIMER_ALARM_HIGH);
  89                 writel(rtc_alarm64, base + TIMER_ALARM_LOW);
  90                 writel(1, base + TIMER_IRQ_ENABLED);
  91         } else {
  92                 /*
  93                  * if this function was called with enabled=0
  94                  * then it could mean that the application is
  95                  * trying to cancel an ongoing alarm
  96                  */
  97                 rtc_status_reg = readl(base + TIMER_ALARM_STATUS);
  98                 if (rtc_status_reg)
  99                         writel(1, base + TIMER_CLEAR_ALARM);
 100         }
 101
 102         return ret;
 103 }
 104
 105 static int goldfish_rtc_alarm_irq_enable(struct device *dev,
 106                                          unsigned int enabled)
 107 {
 108         void __iomem *base;
 109         struct goldfish_rtc *rtcdrv;
 110
 111         rtcdrv = dev_get_drvdata(dev);
 112         base = rtcdrv->base;
 113
 114         if (enabled)
 115                 writel(1, base + TIMER_IRQ_ENABLED);
 116         else
 117                 writel(0, base + TIMER_IRQ_ENABLED);
 118
 119         return 0;
 120 }
 121
 122 static irqreturn_t goldfish_rtc_interrupt(int irq, void *dev_id)
 123 {
 124         struct goldfish_rtc *rtcdrv = dev_id;
 125         void __iomem *base = rtcdrv->base;
 126
 127         writel(1, base + TIMER_CLEAR_INTERRUPT);
 128
 129         rtc_update_irq(rtcdrv->rtc, 1, RTC_IRQF | RTC_AF);
 130
 131         return IRQ_HANDLED;
 132 }
 133
 134 static int goldfish_rtc_read_time(struct device *dev, struct rtc_time *tm)
 135 {
 136         struct goldfish_rtc *rtcdrv;
 137         void __iomem *base;
 138         u64 time_high;
 139         u64 time_low;
 140         u64 time;
 141
 142         rtcdrv = dev_get_drvdata(dev);
 143         base = rtcdrv->base;
 144
 145         time_low = readl(base + TIMER_TIME_LOW);
 146         time_high = readl(base + TIMER_TIME_HIGH);
 147         time = (time_high << 32) | time_low;
 148
 149         do_div(time, NSEC_PER_SEC);
 150
 151         rtc_time_to_tm(time, tm);
 152
 153         return 0;
 154 }
 155
 156 static int goldfish_rtc_set_time(struct device *dev, struct rtc_time *tm)
 157 {
 158         struct goldfish_rtc *rtcdrv;
 159         void __iomem *base;
 160         unsigned long now;
 161         u64 now64;
 162         int ret;
 163
 164         rtcdrv = dev_get_drvdata(dev);
 165         base = rtcdrv->base;
 166
 167         ret = rtc_tm_to_time(tm, &now);
 168         if (ret == 0) {
 169                 now64 = now * NSEC_PER_SEC;
 170                 writel((now64 >> 32), base + TIMER_TIME_HIGH);
 171                 writel(now64, base + TIMER_TIME_LOW);
 172         }
 173
 174         return ret;
 175 }
 176
 177 static const struct rtc_class_ops goldfish_rtc_ops = {
 178         .read_time      = goldfish_rtc_read_time,
 179         .set_time       = goldfish_rtc_set_time,
 180         .read_alarm     = goldfish_rtc_read_alarm,
 181         .set_alarm      = goldfish_rtc_set_alarm,
 182         .alarm_irq_enable = goldfish_rtc_alarm_irq_enable
 183 };
 184
 185 static int goldfish_rtc_probe(struct platform_device *pdev)
 186 {
 187         struct goldfish_rtc *rtcdrv;
 188         struct resource *r;
 189         int err;
 190
 191         rtcdrv = devm_kzalloc(&pdev->dev, sizeof(*rtcdrv), GFP_KERNEL);
 192         if (!rtcdrv)
 193                 return -ENOMEM;
 194
 195         platform_set_drvdata(pdev, rtcdrv);
 196
 197         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 198         if (!r)
 199                 return -ENODEV;
 200
 201         rtcdrv->base = devm_ioremap_resource(&pdev->dev, r);
 202         if (IS_ERR(rtcdrv->base))
 203                 return -ENODEV;
 204
 205         rtcdrv->irq = platform_get_irq(pdev, 0);
 206         if (rtcdrv->irq < 0)
 207                 return -ENODEV;
 208
 209         rtcdrv->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
 210                                                &goldfish_rtc_ops,
 211                                                THIS_MODULE);
 212         if (IS_ERR(rtcdrv->rtc))
 213                 return PTR_ERR(rtcdrv->rtc);
 214
 215         err = devm_request_irq(&pdev->dev, rtcdrv->irq,
 216                                goldfish_rtc_interrupt,
 217                                0, pdev->name, rtcdrv);
 218         if (err)
 219                 return err;
 220
 221         return 0;
 222 }
 223
 224 static const struct of_device_id goldfish_rtc_of_match[] = {
 225         { .compatible = "google,goldfish-rtc", },
 226         {},
 227 };
 228 MODULE_DEVICE_TABLE(of, goldfish_rtc_of_match);
 229
 230 static struct platform_driver goldfish_rtc = {
 231         .probe = goldfish_rtc_probe,
 232         .driver = {
 233                 .name = "goldfish_rtc",
 234                 .of_match_table = goldfish_rtc_of_match,
 235         }
 236 };
 237
 238 module_platform_driver(goldfish_rtc);
 239
 240 MODULE_LICENSE("GPL v2");