drivers/rtc/rtc-pl030.c

   1 /*
   2  *  linux/drivers/rtc/rtc-pl030.c
   3  *
   4  *  Copyright (C) 2000-2001 Deep Blue Solutions Ltd.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10 #include <linux/module.h>
  11 #include <linux/rtc.h>
  12 #include <linux/init.h>
  13 #include <linux/interrupt.h>
  14 #include <linux/amba/bus.h>
  15 #include <linux/io.h>
  16
  17 #define RTC_DR          (0)
  18 #define RTC_MR          (4)
  19 #define RTC_STAT        (8)
  20 #define RTC_EOI         (8)
  21 #define RTC_LR          (12)
  22 #define RTC_CR          (16)
  23 #define RTC_CR_MIE      (1 << 0)
  24
  25 struct pl030_rtc {
  26         struct rtc_device       *rtc;
  27         void __iomem            *base;
  28 };
  29
  30 static irqreturn_t pl030_interrupt(int irq, void *dev_id)
  31 {
  32         struct pl030_rtc *rtc = dev_id;
  33         writel(0, rtc->base + RTC_EOI);
  34         return IRQ_HANDLED;
  35 }
  36
  37 static int pl030_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
  38 {
  39         return -ENOIOCTLCMD;
  40 }
  41
  42 static int pl030_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
  43 {
  44         struct pl030_rtc *rtc = dev_get_drvdata(dev);
  45
  46         rtc_time_to_tm(readl(rtc->base + RTC_MR), &alrm->time);
  47         return 0;
  48 }
  49
  50 static int pl030_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
  51 {
  52         struct pl030_rtc *rtc = dev_get_drvdata(dev);
  53         unsigned long time;
  54         int ret;
  55
  56         /*
  57          * At the moment, we can only deal with non-wildcarded alarm times.
  58          */
  59         ret = rtc_valid_tm(&alrm->time);
  60         if (ret == 0)
  61                 ret = rtc_tm_to_time(&alrm->time, &time);
  62         if (ret == 0)
  63                 writel(time, rtc->base + RTC_MR);
  64         return ret;
  65 }
  66
  67 static int pl030_read_time(struct device *dev, struct rtc_time *tm)
  68 {
  69         struct pl030_rtc *rtc = dev_get_drvdata(dev);
  70
  71         rtc_time_to_tm(readl(rtc->base + RTC_DR), tm);
  72
  73         return 0;
  74 }
  75
  76 /*
  77  * Set the RTC time.  Unfortunately, we can't accurately set
  78  * the point at which the counter updates.
  79  *
  80  * Also, since RTC_LR is transferred to RTC_CR on next rising
  81  * edge of the 1Hz clock, we must write the time one second
  82  * in advance.
  83  */
  84 static int pl030_set_time(struct device *dev, struct rtc_time *tm)
  85 {
  86         struct pl030_rtc *rtc = dev_get_drvdata(dev);
  87         unsigned long time;
  88         int ret;
  89
  90         ret = rtc_tm_to_time(tm, &time);
  91         if (ret == 0)
  92                 writel(time + 1, rtc->base + RTC_LR);
  93
  94         return ret;
  95 }
  96
  97 static const struct rtc_class_ops pl030_ops = {
  98         .ioctl          = pl030_ioctl,
  99         .read_time      = pl030_read_time,
 100         .set_time       = pl030_set_time,
 101         .read_alarm     = pl030_read_alarm,
 102         .set_alarm      = pl030_set_alarm,
 103 };
 104
 105 static int pl030_probe(struct amba_device *dev, void *id)
 106 {
 107         struct pl030_rtc *rtc;
 108         int ret;
 109
 110         ret = amba_request_regions(dev, NULL);
 111         if (ret)
 112                 goto err_req;
 113
 114         rtc = kmalloc(sizeof(*rtc), GFP_KERNEL);
 115         if (!rtc) {
 116                 ret = -ENOMEM;
 117                 goto err_rtc;
 118         }
 119
 120         rtc->base = ioremap(dev->res.start, SZ_4K);
 121         if (!rtc->base) {
 122                 ret = -ENOMEM;
 123                 goto err_map;
 124         }
 125
 126         __raw_writel(0, rtc->base + RTC_CR);
 127         __raw_writel(0, rtc->base + RTC_EOI);
 128
 129         amba_set_drvdata(dev, rtc);
 130
 131         ret = request_irq(dev->irq[0], pl030_interrupt, IRQF_DISABLED,
 132                           "rtc-pl030", rtc);
 133         if (ret)
 134                 goto err_irq;
 135
 136         rtc->rtc = rtc_device_register("pl030", &dev->dev, &pl030_ops,
 137                                        THIS_MODULE);
 138         if (IS_ERR(rtc->rtc)) {
 139                 ret = PTR_ERR(rtc->rtc);
 140                 goto err_reg;
 141         }
 142
 143         return 0;
 144
 145  err_reg:
 146         free_irq(dev->irq[0], rtc);
 147  err_irq:
 148         iounmap(rtc->base);
 149  err_map:
 150         kfree(rtc);
 151  err_rtc:
 152         amba_release_regions(dev);
 153  err_req:
 154         return ret;
 155 }
 156
 157 static int pl030_remove(struct amba_device *dev)
 158 {
 159         struct pl030_rtc *rtc = amba_get_drvdata(dev);
 160
 161         amba_set_drvdata(dev, NULL);
 162
 163         writel(0, rtc->base + RTC_CR);
 164
 165         free_irq(dev->irq[0], rtc);
 166         rtc_device_unregister(rtc->rtc);
 167         iounmap(rtc->base);
 168         kfree(rtc);
 169         amba_release_regions(dev);
 170
 171         return 0;
 172 }
 173
 174 static struct amba_id pl030_ids[] = {
 175         {
 176                 .id     = 0x00041030,
 177                 .mask   = 0x000fffff,
 178         },
 179         { 0, 0 },
 180 };
 181
 182 static struct amba_driver pl030_driver = {
 183         .drv            = {
 184                 .name   = "rtc-pl030",
 185         },
 186         .probe          = pl030_probe,
 187         .remove         = pl030_remove,
 188         .id_table       = pl030_ids,
 189 };
 190
 191 static int __init pl030_init(void)
 192 {
 193         return amba_driver_register(&pl030_driver);
 194 }
 195
 196 static void __exit pl030_exit(void)
 197 {
 198         amba_driver_unregister(&pl030_driver);
 199 }
 200
 201 module_init(pl030_init);
 202 module_exit(pl030_exit);
 203
 204 MODULE_AUTHOR("Russell King <rmk@arm.linux.org.uk>");
 205 MODULE_DESCRIPTION("ARM AMBA PL030 RTC Driver");
 206 MODULE_LICENSE("GPL");