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