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 <mach/hardware.h>
  16
  17 #define EP93XX_RTC_REG(x)       (EP93XX_RTC_BASE + (x))
  18 #define EP93XX_RTC_DATA         EP93XX_RTC_REG(0x0000)
  19 #define EP93XX_RTC_LOAD         EP93XX_RTC_REG(0x000C)
  20 #define EP93XX_RTC_SWCOMP       EP93XX_RTC_REG(0x0108)
  21
  22 #define DRV_VERSION "0.2"
  23
  24 static int ep93xx_get_swcomp(struct device *dev, unsigned short *preload,
  25                                 unsigned short *delete)
  26 {
  27         unsigned short comp = __raw_readl(EP93XX_RTC_SWCOMP);
  28
  29         if (preload)
  30                 *preload = comp & 0xffff;
  31
  32         if (delete)
  33                 *delete = (comp >> 16) & 0x1f;
  34
  35         return 0;
  36 }
  37
  38 static int ep93xx_rtc_read_time(struct device *dev, struct rtc_time *tm)
  39 {
  40         unsigned long time = __raw_readl(EP93XX_RTC_DATA);
  41
  42         rtc_time_to_tm(time, tm);
  43         return 0;
  44 }
  45
  46 static int ep93xx_rtc_set_mmss(struct device *dev, unsigned long secs)
  47 {
  48         __raw_writel(secs + 1, EP93XX_RTC_LOAD);
  49         return 0;
  50 }
  51
  52 static int ep93xx_rtc_proc(struct device *dev, struct seq_file *seq)
  53 {
  54         unsigned short preload, delete;
  55
  56         ep93xx_get_swcomp(dev, &preload, &delete);
  57
  58         seq_printf(seq, "preload\t\t: %d\n", preload);
  59         seq_printf(seq, "delete\t\t: %d\n", delete);
  60
  61         return 0;
  62 }
  63
  64 static const struct rtc_class_ops ep93xx_rtc_ops = {
  65         .read_time      = ep93xx_rtc_read_time,
  66         .set_mmss       = ep93xx_rtc_set_mmss,
  67         .proc           = ep93xx_rtc_proc,
  68 };
  69
  70 static ssize_t ep93xx_sysfs_show_comp_preload(struct device *dev,
  71                         struct device_attribute *attr, char *buf)
  72 {
  73         unsigned short preload;
  74
  75         ep93xx_get_swcomp(dev, &preload, NULL);
  76
  77         return sprintf(buf, "%d\n", preload);
  78 }
  79 static DEVICE_ATTR(comp_preload, S_IRUGO, ep93xx_sysfs_show_comp_preload, NULL);
  80
  81 static ssize_t ep93xx_sysfs_show_comp_delete(struct device *dev,
  82                         struct device_attribute *attr, char *buf)
  83 {
  84         unsigned short delete;
  85
  86         ep93xx_get_swcomp(dev, NULL, &delete);
  87
  88         return sprintf(buf, "%d\n", delete);
  89 }
  90 static DEVICE_ATTR(comp_delete, S_IRUGO, ep93xx_sysfs_show_comp_delete, NULL);
  91
  92
  93 static int __devinit ep93xx_rtc_probe(struct platform_device *dev)
  94 {
  95         struct rtc_device *rtc = rtc_device_register("ep93xx",
  96                                 &dev->dev, &ep93xx_rtc_ops, THIS_MODULE);
  97
  98         if (IS_ERR(rtc)) {
  99                 return PTR_ERR(rtc);
 100         }
 101
 102         platform_set_drvdata(dev, rtc);
 103
 104         device_create_file(&dev->dev, &dev_attr_comp_preload);
 105         device_create_file(&dev->dev, &dev_attr_comp_delete);
 106
 107         return 0;
 108 }
 109
 110 static int __devexit ep93xx_rtc_remove(struct platform_device *dev)
 111 {
 112         struct rtc_device *rtc = platform_get_drvdata(dev);
 113
 114         if (rtc)
 115                 rtc_device_unregister(rtc);
 116
 117         platform_set_drvdata(dev, NULL);
 118
 119         return 0;
 120 }
 121
 122 /* work with hotplug and coldplug */
 123 MODULE_ALIAS("platform:ep93xx-rtc");
 124
 125 static struct platform_driver ep93xx_rtc_platform_driver = {
 126         .driver         = {
 127                 .name   = "ep93xx-rtc",
 128                 .owner  = THIS_MODULE,
 129         },
 130         .probe          = ep93xx_rtc_probe,
 131         .remove         = __devexit_p(ep93xx_rtc_remove),
 132 };
 133
 134 static int __init ep93xx_rtc_init(void)
 135 {
 136         return platform_driver_register(&ep93xx_rtc_platform_driver);
 137 }
 138
 139 static void __exit ep93xx_rtc_exit(void)
 140 {
 141         platform_driver_unregister(&ep93xx_rtc_platform_driver);
 142 }
 143
 144 MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
 145 MODULE_DESCRIPTION("EP93XX RTC driver");
 146 MODULE_LICENSE("GPL");
 147 MODULE_VERSION(DRV_VERSION);
 148
 149 module_init(ep93xx_rtc_init);
 150 module_exit(ep93xx_rtc_exit);