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 <asm/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_set_time(struct device *dev, struct rtc_time *tm)
  53 {
  54         int err;
  55         unsigned long secs;
  56
  57         err = rtc_tm_to_time(tm, &secs);
  58         if (err != 0)
  59                 return err;
  60
  61         return ep93xx_rtc_set_mmss(dev, secs);
  62 }
  63
  64 static int ep93xx_rtc_proc(struct device *dev, struct seq_file *seq)
  65 {
  66         unsigned short preload, delete;
  67
  68         ep93xx_get_swcomp(dev, &preload, &delete);
  69
  70         seq_printf(seq, "preload\t\t: %d\n", preload);
  71         seq_printf(seq, "delete\t\t: %d\n", delete);
  72
  73         return 0;
  74 }
  75
  76 static const struct rtc_class_ops ep93xx_rtc_ops = {
  77         .read_time      = ep93xx_rtc_read_time,
  78         .set_time       = ep93xx_rtc_set_time,
  79         .set_mmss       = ep93xx_rtc_set_mmss,
  80         .proc           = ep93xx_rtc_proc,
  81 };
  82
  83 static ssize_t ep93xx_sysfs_show_comp_preload(struct device *dev,
  84                         struct device_attribute *attr, char *buf)
  85 {
  86         unsigned short preload;
  87
  88         ep93xx_get_swcomp(dev, &preload, NULL);
  89
  90         return sprintf(buf, "%d\n", preload);
  91 }
  92 static DEVICE_ATTR(comp_preload, S_IRUGO, ep93xx_sysfs_show_comp_preload, NULL);
  93
  94 static ssize_t ep93xx_sysfs_show_comp_delete(struct device *dev,
  95                         struct device_attribute *attr, char *buf)
  96 {
  97         unsigned short delete;
  98
  99         ep93xx_get_swcomp(dev, NULL, &delete);
 100
 101         return sprintf(buf, "%d\n", delete);
 102 }
 103 static DEVICE_ATTR(comp_delete, S_IRUGO, ep93xx_sysfs_show_comp_delete, NULL);
 104
 105
 106 static int __devinit ep93xx_rtc_probe(struct platform_device *dev)
 107 {
 108         struct rtc_device *rtc = rtc_device_register("ep93xx",
 109                                 &dev->dev, &ep93xx_rtc_ops, THIS_MODULE);
 110
 111         if (IS_ERR(rtc)) {
 112                 return PTR_ERR(rtc);
 113         }
 114
 115         platform_set_drvdata(dev, rtc);
 116
 117         device_create_file(&dev->dev, &dev_attr_comp_preload);
 118         device_create_file(&dev->dev, &dev_attr_comp_delete);
 119
 120         return 0;
 121 }
 122
 123 static int __devexit ep93xx_rtc_remove(struct platform_device *dev)
 124 {
 125         struct rtc_device *rtc = platform_get_drvdata(dev);
 126
 127         if (rtc)
 128                 rtc_device_unregister(rtc);
 129
 130         platform_set_drvdata(dev, NULL);
 131
 132         return 0;
 133 }
 134
 135 /* work with hotplug and coldplug */
 136 MODULE_ALIAS("platform:ep93xx-rtc");
 137
 138 static struct platform_driver ep93xx_rtc_platform_driver = {
 139         .driver         = {
 140                 .name   = "ep93xx-rtc",
 141                 .owner  = THIS_MODULE,
 142         },
 143         .probe          = ep93xx_rtc_probe,
 144         .remove         = __devexit_p(ep93xx_rtc_remove),
 145 };
 146
 147 static int __init ep93xx_rtc_init(void)
 148 {
 149         return platform_driver_register(&ep93xx_rtc_platform_driver);
 150 }
 151
 152 static void __exit ep93xx_rtc_exit(void)
 153 {
 154         platform_driver_unregister(&ep93xx_rtc_platform_driver);
 155 }
 156
 157 MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
 158 MODULE_DESCRIPTION("EP93XX RTC driver");
 159 MODULE_LICENSE("GPL");
 160 MODULE_VERSION(DRV_VERSION);
 161
 162 module_init(ep93xx_rtc_init);
 163 module_exit(ep93xx_rtc_exit);