drivers/rtc/rtc-mv.c

   1 /*
   2  * Driver for the RTC in Marvell SoCs.
   3  *
   4  * This file is licensed under the terms of the GNU General Public
   5  * License version 2.  This program is licensed "as is" without any
   6  * warranty of any kind, whether express or implied.
   7  */
   8
   9 #include <linux/init.h>
  10 #include <linux/kernel.h>
  11 #include <linux/rtc.h>
  12 #include <linux/bcd.h>
  13 #include <linux/io.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/delay.h>
  16
  17
  18 #define RTC_TIME_REG_OFFS       0
  19 #define RTC_SECONDS_OFFS        0
  20 #define RTC_MINUTES_OFFS        8
  21 #define RTC_HOURS_OFFS          16
  22 #define RTC_WDAY_OFFS           24
  23 #define RTC_HOURS_12H_MODE              (1 << 22) /* 12 hours mode */
  24
  25 #define RTC_DATE_REG_OFFS       4
  26 #define RTC_MDAY_OFFS           0
  27 #define RTC_MONTH_OFFS          8
  28 #define RTC_YEAR_OFFS           16
  29
  30
  31 struct rtc_plat_data {
  32         struct rtc_device *rtc;
  33         void __iomem *ioaddr;
  34 };
  35
  36 static int mv_rtc_set_time(struct device *dev, struct rtc_time *tm)
  37 {
  38         struct rtc_plat_data *pdata = dev_get_drvdata(dev);
  39         void __iomem *ioaddr = pdata->ioaddr;
  40         u32     rtc_reg;
  41
  42         rtc_reg = (bin2bcd(tm->tm_sec) << RTC_SECONDS_OFFS) |
  43                 (bin2bcd(tm->tm_min) << RTC_MINUTES_OFFS) |
  44                 (bin2bcd(tm->tm_hour) << RTC_HOURS_OFFS) |
  45                 (bin2bcd(tm->tm_wday) << RTC_WDAY_OFFS);
  46         writel(rtc_reg, ioaddr + RTC_TIME_REG_OFFS);
  47
  48         rtc_reg = (bin2bcd(tm->tm_mday) << RTC_MDAY_OFFS) |
  49                 (bin2bcd(tm->tm_mon + 1) << RTC_MONTH_OFFS) |
  50                 (bin2bcd(tm->tm_year % 100) << RTC_YEAR_OFFS);
  51         writel(rtc_reg, ioaddr + RTC_DATE_REG_OFFS);
  52
  53         return 0;
  54 }
  55
  56 static int mv_rtc_read_time(struct device *dev, struct rtc_time *tm)
  57 {
  58         struct rtc_plat_data *pdata = dev_get_drvdata(dev);
  59         void __iomem *ioaddr = pdata->ioaddr;
  60         u32     rtc_time, rtc_date;
  61         unsigned int year, month, day, hour, minute, second, wday;
  62
  63         rtc_time = readl(ioaddr + RTC_TIME_REG_OFFS);
  64         rtc_date = readl(ioaddr + RTC_DATE_REG_OFFS);
  65
  66         second = rtc_time & 0x7f;
  67         minute = (rtc_time >> RTC_MINUTES_OFFS) & 0x7f;
  68         hour = (rtc_time >> RTC_HOURS_OFFS) & 0x3f; /* assume 24 hours mode */
  69         wday = (rtc_time >> RTC_WDAY_OFFS) & 0x7;
  70
  71         day = rtc_date & 0x3f;
  72         month = (rtc_date >> RTC_MONTH_OFFS) & 0x3f;
  73         year = (rtc_date >> RTC_YEAR_OFFS) & 0xff;
  74
  75         tm->tm_sec = bcd2bin(second);
  76         tm->tm_min = bcd2bin(minute);
  77         tm->tm_hour = bcd2bin(hour);
  78         tm->tm_mday = bcd2bin(day);
  79         tm->tm_wday = bcd2bin(wday);
  80         tm->tm_mon = bcd2bin(month) - 1;
  81         /* hw counts from year 2000, but tm_year is relative to 1900 */
  82         tm->tm_year = bcd2bin(year) + 100;
  83
  84         return rtc_valid_tm(tm);
  85 }
  86
  87 static const struct rtc_class_ops mv_rtc_ops = {
  88         .read_time      = mv_rtc_read_time,
  89         .set_time       = mv_rtc_set_time,
  90 };
  91
  92 static int __init mv_rtc_probe(struct platform_device *pdev)
  93 {
  94         struct resource *res;
  95         struct rtc_plat_data *pdata;
  96         resource_size_t size;
  97         u32 rtc_time;
  98
  99         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 100         if (!res)
 101                 return -ENODEV;
 102
 103         pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
 104         if (!pdata)
 105                 return -ENOMEM;
 106
 107         size = resource_size(res);
 108         if (!devm_request_mem_region(&pdev->dev, res->start, size,
 109                                      pdev->name))
 110                 return -EBUSY;
 111
 112         pdata->ioaddr = devm_ioremap(&pdev->dev, res->start, size);
 113         if (!pdata->ioaddr)
 114                 return -ENOMEM;
 115
 116         /* make sure the 24 hours mode is enabled */
 117         rtc_time = readl(pdata->ioaddr + RTC_TIME_REG_OFFS);
 118         if (rtc_time & RTC_HOURS_12H_MODE) {
 119                 dev_err(&pdev->dev, "24 Hours mode not supported.\n");
 120                 return -EINVAL;
 121         }
 122
 123         /* make sure it is actually functional */
 124         if (rtc_time == 0x01000000) {
 125                 ssleep(1);
 126                 rtc_time = readl(pdata->ioaddr + RTC_TIME_REG_OFFS);
 127                 if (rtc_time == 0x01000000) {
 128                         dev_err(&pdev->dev, "internal RTC not ticking\n");
 129                         return -ENODEV;
 130                 }
 131         }
 132
 133         platform_set_drvdata(pdev, pdata);
 134         pdata->rtc = rtc_device_register(pdev->name, &pdev->dev,
 135                                          &mv_rtc_ops, THIS_MODULE);
 136         if (IS_ERR(pdata->rtc))
 137                 return PTR_ERR(pdata->rtc);
 138
 139         return 0;
 140 }
 141
 142 static int __exit mv_rtc_remove(struct platform_device *pdev)
 143 {
 144         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 145
 146         rtc_device_unregister(pdata->rtc);
 147         return 0;
 148 }
 149
 150 static struct platform_driver mv_rtc_driver = {
 151         .remove         = __exit_p(mv_rtc_remove),
 152         .driver         = {
 153                 .name   = "rtc-mv",
 154                 .owner  = THIS_MODULE,
 155         },
 156 };
 157
 158 static __init int mv_init(void)
 159 {
 160         return platform_driver_probe(&mv_rtc_driver, mv_rtc_probe);
 161 }
 162
 163 static __exit void mv_exit(void)
 164 {
 165         platform_driver_unregister(&mv_rtc_driver);
 166 }
 167
 168 module_init(mv_init);
 169 module_exit(mv_exit);
 170
 171 MODULE_AUTHOR("Saeed Bishara <saeed@marvell.com>");
 172 MODULE_DESCRIPTION("Marvell RTC driver");
 173 MODULE_LICENSE("GPL");
 174 MODULE_ALIAS("platform:rtc-mv");