drivers/rtc/rtc-ep93xx.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * A driver for the RTC embedded in the Cirrus Logic EP93XX processors
   4  * Copyright (c) 2006 Tower Technologies
   5  *
   6  * Author: Alessandro Zummo <a.zummo@towertech.it>
   7  */
   8
   9 #include <linux/module.h>
  10 #include <linux/rtc.h>
  11 #include <linux/platform_device.h>
  12 #include <linux/io.h>
  13 #include <linux/gfp.h>
  14
  15 #define EP93XX_RTC_DATA                 0x000
  16 #define EP93XX_RTC_MATCH                0x004
  17 #define EP93XX_RTC_STATUS               0x008
  18 #define  EP93XX_RTC_STATUS_INTR          BIT(0)
  19 #define EP93XX_RTC_LOAD                 0x00C
  20 #define EP93XX_RTC_CONTROL              0x010
  21 #define  EP93XX_RTC_CONTROL_MIE          BIT(0)
  22 #define EP93XX_RTC_SWCOMP               0x108
  23 #define  EP93XX_RTC_SWCOMP_DEL_MASK      0x001f0000
  24 #define  EP93XX_RTC_SWCOMP_DEL_SHIFT     16
  25 #define  EP93XX_RTC_SWCOMP_INT_MASK      0x0000ffff
  26 #define  EP93XX_RTC_SWCOMP_INT_SHIFT     0
  27
  28 struct ep93xx_rtc {
  29         void __iomem    *mmio_base;
  30         struct rtc_device *rtc;
  31 };
  32
  33 static int ep93xx_rtc_get_swcomp(struct device *dev, unsigned short *preload,
  34                                  unsigned short *delete)
  35 {
  36         struct ep93xx_rtc *ep93xx_rtc = dev_get_drvdata(dev);
  37         unsigned long comp;
  38
  39         comp = readl(ep93xx_rtc->mmio_base + EP93XX_RTC_SWCOMP);
  40
  41         if (preload)
  42                 *preload = (comp & EP93XX_RTC_SWCOMP_INT_MASK)
  43                                 >> EP93XX_RTC_SWCOMP_INT_SHIFT;
  44
  45         if (delete)
  46                 *delete = (comp & EP93XX_RTC_SWCOMP_DEL_MASK)
  47                                 >> EP93XX_RTC_SWCOMP_DEL_SHIFT;
  48
  49         return 0;
  50 }
  51
  52 static int ep93xx_rtc_read_time(struct device *dev, struct rtc_time *tm)
  53 {
  54         struct ep93xx_rtc *ep93xx_rtc = dev_get_drvdata(dev);
  55         unsigned long time;
  56
  57         time = readl(ep93xx_rtc->mmio_base + EP93XX_RTC_DATA);
  58
  59         rtc_time64_to_tm(time, tm);
  60         return 0;
  61 }
  62
  63 static int ep93xx_rtc_set_time(struct device *dev, struct rtc_time *tm)
  64 {
  65         struct ep93xx_rtc *ep93xx_rtc = dev_get_drvdata(dev);
  66         unsigned long secs = rtc_tm_to_time64(tm);
  67
  68         writel(secs + 1, ep93xx_rtc->mmio_base + EP93XX_RTC_LOAD);
  69         return 0;
  70 }
  71
  72 static int ep93xx_rtc_proc(struct device *dev, struct seq_file *seq)
  73 {
  74         unsigned short preload, delete;
  75
  76         ep93xx_rtc_get_swcomp(dev, &preload, &delete);
  77
  78         seq_printf(seq, "preload\t\t: %d\n", preload);
  79         seq_printf(seq, "delete\t\t: %d\n", delete);
  80
  81         return 0;
  82 }
  83
  84 static const struct rtc_class_ops ep93xx_rtc_ops = {
  85         .read_time      = ep93xx_rtc_read_time,
  86         .set_time       = ep93xx_rtc_set_time,
  87         .proc           = ep93xx_rtc_proc,
  88 };
  89
  90 static ssize_t comp_preload_show(struct device *dev,
  91                                  struct device_attribute *attr, char *buf)
  92 {
  93         unsigned short preload;
  94
  95         ep93xx_rtc_get_swcomp(dev->parent, &preload, NULL);
  96
  97         return sprintf(buf, "%d\n", preload);
  98 }
  99 static DEVICE_ATTR_RO(comp_preload);
 100
 101 static ssize_t comp_delete_show(struct device *dev,
 102                                 struct device_attribute *attr, char *buf)
 103 {
 104         unsigned short delete;
 105
 106         ep93xx_rtc_get_swcomp(dev->parent, NULL, &delete);
 107
 108         return sprintf(buf, "%d\n", delete);
 109 }
 110 static DEVICE_ATTR_RO(comp_delete);
 111
 112 static struct attribute *ep93xx_rtc_attrs[] = {
 113         &dev_attr_comp_preload.attr,
 114         &dev_attr_comp_delete.attr,
 115         NULL
 116 };
 117
 118 static const struct attribute_group ep93xx_rtc_sysfs_files = {
 119         .attrs  = ep93xx_rtc_attrs,
 120 };
 121
 122 static int ep93xx_rtc_probe(struct platform_device *pdev)
 123 {
 124         struct ep93xx_rtc *ep93xx_rtc;
 125         int err;
 126
 127         ep93xx_rtc = devm_kzalloc(&pdev->dev, sizeof(*ep93xx_rtc), GFP_KERNEL);
 128         if (!ep93xx_rtc)
 129                 return -ENOMEM;
 130
 131         ep93xx_rtc->mmio_base = devm_platform_ioremap_resource(pdev, 0);
 132         if (IS_ERR(ep93xx_rtc->mmio_base))
 133                 return PTR_ERR(ep93xx_rtc->mmio_base);
 134
 135         platform_set_drvdata(pdev, ep93xx_rtc);
 136
 137         ep93xx_rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
 138         if (IS_ERR(ep93xx_rtc->rtc))
 139                 return PTR_ERR(ep93xx_rtc->rtc);
 140
 141         ep93xx_rtc->rtc->ops = &ep93xx_rtc_ops;
 142         ep93xx_rtc->rtc->range_max = U32_MAX;
 143
 144         err = rtc_add_group(ep93xx_rtc->rtc, &ep93xx_rtc_sysfs_files);
 145         if (err)
 146                 return err;
 147
 148         return devm_rtc_register_device(ep93xx_rtc->rtc);
 149 }
 150
 151 static struct platform_driver ep93xx_rtc_driver = {
 152         .driver         = {
 153                 .name   = "ep93xx-rtc",
 154         },
 155         .probe          = ep93xx_rtc_probe,
 156 };
 157
 158 module_platform_driver(ep93xx_rtc_driver);
 159
 160 MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
 161 MODULE_DESCRIPTION("EP93XX RTC driver");
 162 MODULE_LICENSE("GPL");
 163 MODULE_ALIAS("platform:ep93xx-rtc");