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_open(struct device *dev)
  38 {
  39         return 0;
  40 }
  41
  42 static void pl030_release(struct device *dev)
  43 {
  44 }
  45
  46 static int pl030_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
  47 {
  48         return -ENOIOCTLCMD;
  49 }
  50
  51 static int pl030_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
  52 {
  53         struct pl030_rtc *rtc = dev_get_drvdata(dev);
  54
  55         rtc_time_to_tm(readl(rtc->base + RTC_MR), &alrm->time);
  56         return 0;
  57 }
  58
  59 static int pl030_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
  60 {
  61         struct pl030_rtc *rtc = dev_get_drvdata(dev);
  62         unsigned long time;
  63         int ret;
  64
  65         /*
  66          * At the moment, we can only deal with non-wildcarded alarm times.
  67          */
  68         ret = rtc_valid_tm(&alrm->time);
  69         if (ret == 0)
  70                 ret = rtc_tm_to_time(&alrm->time, &time);
  71         if (ret == 0)
  72                 writel(time, rtc->base + RTC_MR);
  73         return ret;
  74 }
  75
  76 static int pl030_read_time(struct device *dev, struct rtc_time *tm)
  77 {
  78         struct pl030_rtc *rtc = dev_get_drvdata(dev);
  79
  80         rtc_time_to_tm(readl(rtc->base + RTC_DR), tm);
  81
  82         return 0;
  83 }
  84
  85 /*
  86  * Set the RTC time.  Unfortunately, we can't accurately set
  87  * the point at which the counter updates.
  88  *
  89  * Also, since RTC_LR is transferred to RTC_CR on next rising
  90  * edge of the 1Hz clock, we must write the time one second
  91  * in advance.
  92  */
  93 static int pl030_set_time(struct device *dev, struct rtc_time *tm)
  94 {
  95         struct pl030_rtc *rtc = dev_get_drvdata(dev);
  96         unsigned long time;
  97         int ret;
  98
  99         ret = rtc_tm_to_time(tm, &time);
 100         if (ret == 0)
 101                 writel(time + 1, rtc->base + RTC_LR);
 102
 103         return ret;
 104 }
 105
 106 static const struct rtc_class_ops pl030_ops = {
 107         .open           = pl030_open,
 108         .release        = pl030_release,
 109         .ioctl          = pl030_ioctl,
 110         .read_time      = pl030_read_time,
 111         .set_time       = pl030_set_time,
 112         .read_alarm     = pl030_read_alarm,
 113         .set_alarm      = pl030_set_alarm,
 114 };
 115
 116 static int pl030_probe(struct amba_device *dev, void *id)
 117 {
 118         struct pl030_rtc *rtc;
 119         int ret;
 120
 121         ret = amba_request_regions(dev, NULL);
 122         if (ret)
 123                 goto err_req;
 124
 125         rtc = kmalloc(sizeof(*rtc), GFP_KERNEL);
 126         if (!rtc) {
 127                 ret = -ENOMEM;
 128                 goto err_rtc;
 129         }
 130
 131         rtc->base = ioremap(dev->res.start, SZ_4K);
 132         if (!rtc->base) {
 133                 ret = -ENOMEM;
 134                 goto err_map;
 135         }
 136
 137         __raw_writel(0, rtc->base + RTC_CR);
 138         __raw_writel(0, rtc->base + RTC_EOI);
 139
 140         amba_set_drvdata(dev, rtc);
 141
 142         ret = request_irq(dev->irq[0], pl030_interrupt, IRQF_DISABLED,
 143                           "rtc-pl030", rtc);
 144         if (ret)
 145                 goto err_irq;
 146
 147         rtc->rtc = rtc_device_register("pl030", &dev->dev, &pl030_ops,
 148                                        THIS_MODULE);
 149         if (IS_ERR(rtc->rtc)) {
 150                 ret = PTR_ERR(rtc->rtc);
 151                 goto err_reg;
 152         }
 153
 154         return 0;
 155
 156  err_reg:
 157         free_irq(dev->irq[0], rtc);
 158  err_irq:
 159         iounmap(rtc->base);
 160  err_map:
 161         kfree(rtc);
 162  err_rtc:
 163         amba_release_regions(dev);
 164  err_req:
 165         return ret;
 166 }
 167
 168 static int pl030_remove(struct amba_device *dev)
 169 {
 170         struct pl030_rtc *rtc = amba_get_drvdata(dev);
 171
 172         amba_set_drvdata(dev, NULL);
 173
 174         writel(0, rtc->base + RTC_CR);
 175
 176         free_irq(dev->irq[0], rtc);
 177         rtc_device_unregister(rtc->rtc);
 178         iounmap(rtc->base);
 179         kfree(rtc);
 180         amba_release_regions(dev);
 181
 182         return 0;
 183 }
 184
 185 static struct amba_id pl030_ids[] = {
 186         {
 187                 .id     = 0x00041030,
 188                 .mask   = 0x000fffff,
 189         },
 190         { 0, 0 },
 191 };
 192
 193 static struct amba_driver pl030_driver = {
 194         .drv            = {
 195                 .name   = "rtc-pl030",
 196         },
 197         .probe          = pl030_probe,
 198         .remove         = pl030_remove,
 199         .id_table       = pl030_ids,
 200 };
 201
 202 static int __init pl030_init(void)
 203 {
 204         return amba_driver_register(&pl030_driver);
 205 }
 206
 207 static void __exit pl030_exit(void)
 208 {
 209         amba_driver_unregister(&pl030_driver);
 210 }
 211
 212 module_init(pl030_init);
 213 module_exit(pl030_exit);
 214
 215 MODULE_AUTHOR("Russell King <rmk@arm.linux.org.uk>");
 216 MODULE_DESCRIPTION("ARM AMBA PL030 RTC Driver");
 217 MODULE_LICENSE("GPL");