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/mod_devicetable.h>
  11 #include <linux/rtc.h>
  12 #include <linux/platform_device.h>
  13 #include <linux/io.h>
  14 #include <linux/gfp.h>
  15
  16 #define EP93XX_RTC_DATA                 0x000
  17 #define EP93XX_RTC_MATCH                0x004
  18 #define EP93XX_RTC_STATUS               0x008
  19 #define  EP93XX_RTC_STATUS_INTR          BIT(0)
  20 #define EP93XX_RTC_LOAD                 0x00C
  21 #define EP93XX_RTC_CONTROL              0x010
  22 #define  EP93XX_RTC_CONTROL_MIE          BIT(0)
  23 #define EP93XX_RTC_SWCOMP               0x108
  24 #define  EP93XX_RTC_SWCOMP_DEL_MASK      0x001f0000
  25 #define  EP93XX_RTC_SWCOMP_DEL_SHIFT     16
  26 #define  EP93XX_RTC_SWCOMP_INT_MASK      0x0000ffff
  27 #define  EP93XX_RTC_SWCOMP_INT_SHIFT     0
  28
  29 struct ep93xx_rtc {
  30         void __iomem    *mmio_base;
  31         struct rtc_device *rtc;
  32 };
  33
  34 static int ep93xx_rtc_get_swcomp(struct device *dev, unsigned short *preload,
  35                                  unsigned short *delete)
  36 {
  37         struct ep93xx_rtc *ep93xx_rtc = dev_get_drvdata(dev);
  38         unsigned long comp;
  39
  40         comp = readl(ep93xx_rtc->mmio_base + EP93XX_RTC_SWCOMP);
  41
  42         if (preload)
  43                 *preload = (comp & EP93XX_RTC_SWCOMP_INT_MASK)
  44                                 >> EP93XX_RTC_SWCOMP_INT_SHIFT;
  45
  46         if (delete)
  47                 *delete = (comp & EP93XX_RTC_SWCOMP_DEL_MASK)
  48                                 >> EP93XX_RTC_SWCOMP_DEL_SHIFT;
  49
  50         return 0;
  51 }
  52
  53 static int ep93xx_rtc_read_time(struct device *dev, struct rtc_time *tm)
  54 {
  55         struct ep93xx_rtc *ep93xx_rtc = dev_get_drvdata(dev);
  56         unsigned long time;
  57
  58         time = readl(ep93xx_rtc->mmio_base + EP93XX_RTC_DATA);
  59
  60         rtc_time64_to_tm(time, tm);
  61         return 0;
  62 }
  63
  64 static int ep93xx_rtc_set_time(struct device *dev, struct rtc_time *tm)
  65 {
  66         struct ep93xx_rtc *ep93xx_rtc = dev_get_drvdata(dev);
  67         unsigned long secs = rtc_tm_to_time64(tm);
  68
  69         writel(secs + 1, ep93xx_rtc->mmio_base + EP93XX_RTC_LOAD);
  70         return 0;
  71 }
  72
  73 static int ep93xx_rtc_proc(struct device *dev, struct seq_file *seq)
  74 {
  75         unsigned short preload, delete;
  76
  77         ep93xx_rtc_get_swcomp(dev, &preload, &delete);
  78
  79         seq_printf(seq, "preload\t\t: %d\n", preload);
  80         seq_printf(seq, "delete\t\t: %d\n", delete);
  81
  82         return 0;
  83 }
  84
  85 static const struct rtc_class_ops ep93xx_rtc_ops = {
  86         .read_time      = ep93xx_rtc_read_time,
  87         .set_time       = ep93xx_rtc_set_time,
  88         .proc           = ep93xx_rtc_proc,
  89 };
  90
  91 static ssize_t comp_preload_show(struct device *dev,
  92                                  struct device_attribute *attr, char *buf)
  93 {
  94         unsigned short preload;
  95
  96         ep93xx_rtc_get_swcomp(dev->parent, &preload, NULL);
  97
  98         return sprintf(buf, "%d\n", preload);
  99 }
 100 static DEVICE_ATTR_RO(comp_preload);
 101
 102 static ssize_t comp_delete_show(struct device *dev,
 103                                 struct device_attribute *attr, char *buf)
 104 {
 105         unsigned short delete;
 106
 107         ep93xx_rtc_get_swcomp(dev->parent, NULL, &delete);
 108
 109         return sprintf(buf, "%d\n", delete);
 110 }
 111 static DEVICE_ATTR_RO(comp_delete);
 112
 113 static struct attribute *ep93xx_rtc_attrs[] = {
 114         &dev_attr_comp_preload.attr,
 115         &dev_attr_comp_delete.attr,
 116         NULL
 117 };
 118
 119 static const struct attribute_group ep93xx_rtc_sysfs_files = {
 120         .attrs  = ep93xx_rtc_attrs,
 121 };
 122
 123 static int ep93xx_rtc_probe(struct platform_device *pdev)
 124 {
 125         struct ep93xx_rtc *ep93xx_rtc;
 126         int err;
 127
 128         ep93xx_rtc = devm_kzalloc(&pdev->dev, sizeof(*ep93xx_rtc), GFP_KERNEL);
 129         if (!ep93xx_rtc)
 130                 return -ENOMEM;
 131
 132         ep93xx_rtc->mmio_base = devm_platform_ioremap_resource(pdev, 0);
 133         if (IS_ERR(ep93xx_rtc->mmio_base))
 134                 return PTR_ERR(ep93xx_rtc->mmio_base);
 135
 136         platform_set_drvdata(pdev, ep93xx_rtc);
 137
 138         ep93xx_rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
 139         if (IS_ERR(ep93xx_rtc->rtc))
 140                 return PTR_ERR(ep93xx_rtc->rtc);
 141
 142         ep93xx_rtc->rtc->ops = &ep93xx_rtc_ops;
 143         ep93xx_rtc->rtc->range_max = U32_MAX;
 144
 145         err = rtc_add_group(ep93xx_rtc->rtc, &ep93xx_rtc_sysfs_files);
 146         if (err)
 147                 return err;
 148
 149         return devm_rtc_register_device(ep93xx_rtc->rtc);
 150 }
 151
 152 static const struct of_device_id ep93xx_rtc_of_ids[] = {
 153         { .compatible = "cirrus,ep9301-rtc" },
 154         { /* sentinel */ }
 155 };
 156 MODULE_DEVICE_TABLE(of, ep93xx_rtc_of_ids);
 157
 158 static struct platform_driver ep93xx_rtc_driver = {
 159         .driver         = {
 160                 .name   = "ep93xx-rtc",
 161                 .of_match_table = ep93xx_rtc_of_ids,
 162         },
 163         .probe          = ep93xx_rtc_probe,
 164 };
 165
 166 module_platform_driver(ep93xx_rtc_driver);
 167
 168 MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
 169 MODULE_DESCRIPTION("EP93XX RTC driver");
 170 MODULE_LICENSE("GPL");
 171 MODULE_ALIAS("platform:ep93xx-rtc");