drivers/rtc/rtc-ep93xx.c

   1 /*
   2  * A driver for the RTC embedded in the Cirrus Logic EP93XX processors
   3  * Copyright (c) 2006 Tower Technologies
   4  *
   5  * Author: Alessandro Zummo <a.zummo@towertech.it>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/rtc.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/io.h>
  16 #include <linux/gfp.h>
  17
  18 #define EP93XX_RTC_DATA                 0x000
  19 #define EP93XX_RTC_MATCH                0x004
  20 #define EP93XX_RTC_STATUS               0x008
  21 #define  EP93XX_RTC_STATUS_INTR          (1<<0)
  22 #define EP93XX_RTC_LOAD                 0x00C
  23 #define EP93XX_RTC_CONTROL              0x010
  24 #define  EP93XX_RTC_CONTROL_MIE          (1<<0)
  25 #define EP93XX_RTC_SWCOMP               0x108
  26 #define  EP93XX_RTC_SWCOMP_DEL_MASK      0x001f0000
  27 #define  EP93XX_RTC_SWCOMP_DEL_SHIFT     16
  28 #define  EP93XX_RTC_SWCOMP_INT_MASK      0x0000ffff
  29 #define  EP93XX_RTC_SWCOMP_INT_SHIFT     0
  30
  31 struct ep93xx_rtc {
  32         void __iomem    *mmio_base;
  33         struct rtc_device *rtc;
  34 };
  35
  36 static int ep93xx_rtc_get_swcomp(struct device *dev, unsigned short *preload,
  37                                 unsigned short *delete)
  38 {
  39         struct ep93xx_rtc *ep93xx_rtc = dev_get_platdata(dev);
  40         unsigned long comp;
  41
  42         comp = readl(ep93xx_rtc->mmio_base + EP93XX_RTC_SWCOMP);
  43
  44         if (preload)
  45                 *preload = (comp & EP93XX_RTC_SWCOMP_INT_MASK)
  46                                 >> EP93XX_RTC_SWCOMP_INT_SHIFT;
  47
  48         if (delete)
  49                 *delete = (comp & EP93XX_RTC_SWCOMP_DEL_MASK)
  50                                 >> EP93XX_RTC_SWCOMP_DEL_SHIFT;
  51
  52         return 0;
  53 }
  54
  55 static int ep93xx_rtc_read_time(struct device *dev, struct rtc_time *tm)
  56 {
  57         struct ep93xx_rtc *ep93xx_rtc = dev_get_platdata(dev);
  58         unsigned long time;
  59
  60         time = readl(ep93xx_rtc->mmio_base + EP93XX_RTC_DATA);
  61
  62         rtc_time_to_tm(time, tm);
  63         return 0;
  64 }
  65
  66 static int ep93xx_rtc_set_mmss(struct device *dev, unsigned long secs)
  67 {
  68         struct ep93xx_rtc *ep93xx_rtc = dev_get_platdata(dev);
  69
  70         writel(secs + 1, ep93xx_rtc->mmio_base + EP93XX_RTC_LOAD);
  71         return 0;
  72 }
  73
  74 static int ep93xx_rtc_proc(struct device *dev, struct seq_file *seq)
  75 {
  76         unsigned short preload, delete;
  77
  78         ep93xx_rtc_get_swcomp(dev, &preload, &delete);
  79
  80         seq_printf(seq, "preload\t\t: %d\n", preload);
  81         seq_printf(seq, "delete\t\t: %d\n", delete);
  82
  83         return 0;
  84 }
  85
  86 static const struct rtc_class_ops ep93xx_rtc_ops = {
  87         .read_time      = ep93xx_rtc_read_time,
  88         .set_mmss       = ep93xx_rtc_set_mmss,
  89         .proc           = ep93xx_rtc_proc,
  90 };
  91
  92 static ssize_t ep93xx_rtc_show_comp_preload(struct device *dev,
  93                         struct device_attribute *attr, char *buf)
  94 {
  95         unsigned short preload;
  96
  97         ep93xx_rtc_get_swcomp(dev->parent, &preload, NULL);
  98
  99         return sprintf(buf, "%d\n", preload);
 100 }
 101 static DEVICE_ATTR(comp_preload, S_IRUGO, ep93xx_rtc_show_comp_preload, NULL);
 102
 103 static ssize_t ep93xx_rtc_show_comp_delete(struct device *dev,
 104                         struct device_attribute *attr, char *buf)
 105 {
 106         unsigned short delete;
 107
 108         ep93xx_rtc_get_swcomp(dev->parent, NULL, &delete);
 109
 110         return sprintf(buf, "%d\n", delete);
 111 }
 112 static DEVICE_ATTR(comp_delete, S_IRUGO, ep93xx_rtc_show_comp_delete, NULL);
 113
 114 static struct attribute *ep93xx_rtc_attrs[] = {
 115         &dev_attr_comp_preload.attr,
 116         &dev_attr_comp_delete.attr,
 117         NULL
 118 };
 119
 120 static const struct attribute_group ep93xx_rtc_sysfs_files = {
 121         .attrs  = ep93xx_rtc_attrs,
 122 };
 123
 124 static int ep93xx_rtc_probe(struct platform_device *pdev)
 125 {
 126         struct ep93xx_rtc *ep93xx_rtc;
 127         struct resource *res;
 128         int err;
 129
 130         ep93xx_rtc = devm_kzalloc(&pdev->dev, sizeof(*ep93xx_rtc), GFP_KERNEL);
 131         if (!ep93xx_rtc)
 132                 return -ENOMEM;
 133
 134         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 135         ep93xx_rtc->mmio_base = devm_ioremap_resource(&pdev->dev, res);
 136         if (IS_ERR(ep93xx_rtc->mmio_base))
 137                 return PTR_ERR(ep93xx_rtc->mmio_base);
 138
 139         platform_set_drvdata(pdev, ep93xx_rtc);
 140
 141         ep93xx_rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
 142         if (IS_ERR(ep93xx_rtc->rtc))
 143                 return PTR_ERR(ep93xx_rtc->rtc);
 144
 145         ep93xx_rtc->rtc->ops = &ep93xx_rtc_ops;
 146         ep93xx_rtc->rtc->range_max = U32_MAX;
 147
 148         err = rtc_add_group(ep93xx_rtc->rtc, &ep93xx_rtc_sysfs_files);
 149         if (err)
 150                 return err;
 151
 152         return rtc_register_device(ep93xx_rtc->rtc);
 153 }
 154
 155 static struct platform_driver ep93xx_rtc_driver = {
 156         .driver         = {
 157                 .name   = "ep93xx-rtc",
 158         },
 159         .probe          = ep93xx_rtc_probe,
 160 };
 161
 162 module_platform_driver(ep93xx_rtc_driver);
 163
 164 MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
 165 MODULE_DESCRIPTION("EP93XX RTC driver");
 166 MODULE_LICENSE("GPL");
 167 MODULE_ALIAS("platform:ep93xx-rtc");