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         } else {
  91                 /*
  92                  * if this function was called with enabled=0
  93                  * then it could mean that the application is
  94                  * trying to cancel an ongoing alarm
  95                  */
  96                 rtc_status_reg = readl(base + TIMER_ALARM_STATUS);
  97                 if (rtc_status_reg)
  98                         writel(1, base + TIMER_CLEAR_ALARM);
  99         }
 100
 101         return ret;
 102 }
 103
 104 static int goldfish_rtc_alarm_irq_enable(struct device *dev,
 105                                          unsigned int enabled)
 106 {
 107         void __iomem *base;
 108         struct goldfish_rtc *rtcdrv;
 109
 110         rtcdrv = dev_get_drvdata(dev);
 111         base = rtcdrv->base;
 112
 113         if (enabled)
 114                 writel(1, base + TIMER_IRQ_ENABLED);
 115         else
 116                 writel(0, base + TIMER_IRQ_ENABLED);
 117
 118         return 0;
 119 }
 120
 121 static irqreturn_t goldfish_rtc_interrupt(int irq, void *dev_id)
 122 {
 123         struct goldfish_rtc *rtcdrv = dev_id;
 124         void __iomem *base = rtcdrv->base;
 125
 126         writel(1, base + TIMER_CLEAR_INTERRUPT);
 127
 128         rtc_update_irq(rtcdrv->rtc, 1, RTC_IRQF | RTC_AF);
 129
 130         return IRQ_HANDLED;
 131 }
 132
 133 static int goldfish_rtc_read_time(struct device *dev, struct rtc_time *tm)
 134 {
 135         struct goldfish_rtc *rtcdrv;
 136         void __iomem *base;
 137         u64 time_high;
 138         u64 time_low;
 139         u64 time;
 140
 141         rtcdrv = dev_get_drvdata(dev);
 142         base = rtcdrv->base;
 143
 144         time_low = readl(base + TIMER_TIME_LOW);
 145         time_high = readl(base + TIMER_TIME_HIGH);
 146         time = (time_high << 32) | time_low;
 147
 148         do_div(time, NSEC_PER_SEC);
 149
 150         rtc_time_to_tm(time, tm);
 151
 152         return 0;
 153 }
 154
 155 static int goldfish_rtc_set_time(struct device *dev, struct rtc_time *tm)
 156 {
 157         struct goldfish_rtc *rtcdrv;
 158         void __iomem *base;
 159         unsigned long now;
 160         u64 now64;
 161         int ret;
 162
 163         rtcdrv = dev_get_drvdata(dev);
 164         base = rtcdrv->base;
 165
 166         ret = rtc_tm_to_time(tm, &now);
 167         if (ret == 0) {
 168                 now64 = now * NSEC_PER_SEC;
 169                 writel((now64 >> 32), base + TIMER_TIME_HIGH);
 170                 writel(now64, base + TIMER_TIME_LOW);
 171         }
 172
 173         return ret;
 174 }
 175
 176 static const struct rtc_class_ops goldfish_rtc_ops = {
 177         .read_time      = goldfish_rtc_read_time,
 178         .set_time       = goldfish_rtc_set_time,
 179         .read_alarm     = goldfish_rtc_read_alarm,
 180         .set_alarm      = goldfish_rtc_set_alarm,
 181         .alarm_irq_enable = goldfish_rtc_alarm_irq_enable
 182 };
 183
 184 static int goldfish_rtc_probe(struct platform_device *pdev)
 185 {
 186         struct goldfish_rtc *rtcdrv;
 187         struct resource *r;
 188         int err;
 189
 190         rtcdrv = devm_kzalloc(&pdev->dev, sizeof(*rtcdrv), GFP_KERNEL);
 191         if (!rtcdrv)
 192                 return -ENOMEM;
 193
 194         platform_set_drvdata(pdev, rtcdrv);
 195
 196         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 197         if (!r)
 198                 return -ENODEV;
 199
 200         rtcdrv->base = devm_ioremap_resource(&pdev->dev, r);
 201         if (IS_ERR(rtcdrv->base))
 202                 return -ENODEV;
 203
 204         rtcdrv->irq = platform_get_irq(pdev, 0);
 205         if (rtcdrv->irq < 0)
 206                 return -ENODEV;
 207
 208         rtcdrv->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
 209                                                &goldfish_rtc_ops,
 210                                                THIS_MODULE);
 211         if (IS_ERR(rtcdrv->rtc))
 212                 return PTR_ERR(rtcdrv->rtc);
 213
 214         err = devm_request_irq(&pdev->dev, rtcdrv->irq,
 215                                goldfish_rtc_interrupt,
 216                                0, pdev->name, rtcdrv);
 217         if (err)
 218                 return err;
 219
 220         return 0;
 221 }
 222
 223 static const struct of_device_id goldfish_rtc_of_match[] = {
 224         { .compatible = "google,goldfish-rtc", },
 225         {},
 226 };
 227 MODULE_DEVICE_TABLE(of, goldfish_rtc_of_match);
 228
 229 static struct platform_driver goldfish_rtc = {
 230         .probe = goldfish_rtc_probe,
 231         .driver = {
 232                 .name = "goldfish_rtc",
 233                 .of_match_table = goldfish_rtc_of_match,
 234         }
 235 };
 236
 237 module_platform_driver(goldfish_rtc);
 238
 239 MODULE_LICENSE("GPL v2");