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