drivers/rtc/rtc-rtd119x.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Realtek RTD129x RTC
   4  *
   5  * Copyright (c) 2017 Andreas Färber
   6  */
   7
   8 #include <linux/clk.h>
   9 #include <linux/io.h>
  10 #include <linux/module.h>
  11 #include <linux/of.h>
  12 #include <linux/of_address.h>
  13 #include <linux/platform_device.h>
  14 #include <linux/rtc.h>
  15 #include <linux/spinlock.h>
  16
  17 #define RTD_RTCSEC              0x00
  18 #define RTD_RTCMIN              0x04
  19 #define RTD_RTCHR               0x08
  20 #define RTD_RTCDATE1            0x0c
  21 #define RTD_RTCDATE2            0x10
  22 #define RTD_RTCACR              0x28
  23 #define RTD_RTCEN               0x2c
  24 #define RTD_RTCCR               0x30
  25
  26 #define RTD_RTCSEC_RTCSEC_MASK          0x7f
  27
  28 #define RTD_RTCMIN_RTCMIN_MASK          0x3f
  29
  30 #define RTD_RTCHR_RTCHR_MASK            0x1f
  31
  32 #define RTD_RTCDATE1_RTCDATE1_MASK      0xff
  33
  34 #define RTD_RTCDATE2_RTCDATE2_MASK      0x7f
  35
  36 #define RTD_RTCACR_RTCPWR               BIT(7)
  37
  38 #define RTD_RTCEN_RTCEN_MASK            0xff
  39
  40 #define RTD_RTCCR_RTCRST                BIT(6)
  41
  42 struct rtd119x_rtc {
  43         void __iomem *base;
  44         struct clk *clk;
  45         struct rtc_device *rtcdev;
  46         unsigned int base_year;
  47 };
  48
  49 static inline int rtd119x_rtc_days_in_year(int year)
  50 {
  51         return 365 + (is_leap_year(year) ? 1 : 0);
  52 }
  53
  54 static void rtd119x_rtc_reset(struct device *dev)
  55 {
  56         struct rtd119x_rtc *data = dev_get_drvdata(dev);
  57         u32 val;
  58
  59         val = readl_relaxed(data->base + RTD_RTCCR);
  60         val |= RTD_RTCCR_RTCRST;
  61         writel_relaxed(val, data->base + RTD_RTCCR);
  62
  63         val &= ~RTD_RTCCR_RTCRST;
  64         writel(val, data->base + RTD_RTCCR);
  65 }
  66
  67 static void rtd119x_rtc_set_enabled(struct device *dev, bool enable)
  68 {
  69         struct rtd119x_rtc *data = dev_get_drvdata(dev);
  70         u32 val;
  71
  72         val = readl_relaxed(data->base + RTD_RTCEN);
  73         if (enable) {
  74                 if ((val & RTD_RTCEN_RTCEN_MASK) == 0x5a)
  75                         return;
  76                 writel_relaxed(0x5a, data->base + RTD_RTCEN);
  77         } else {
  78                 writel_relaxed(0, data->base + RTD_RTCEN);
  79         }
  80 }
  81
  82 static int rtd119x_rtc_read_time(struct device *dev, struct rtc_time *tm)
  83 {
  84         struct rtd119x_rtc *data = dev_get_drvdata(dev);
  85         s32 day;
  86         u32 sec;
  87         unsigned int year;
  88         int tries = 0;
  89
  90         while (true) {
  91                 tm->tm_sec = (readl_relaxed(data->base + RTD_RTCSEC) & RTD_RTCSEC_RTCSEC_MASK) >> 1;
  92                 tm->tm_min  = readl_relaxed(data->base + RTD_RTCMIN) & RTD_RTCMIN_RTCMIN_MASK;
  93                 tm->tm_hour = readl_relaxed(data->base + RTD_RTCHR) & RTD_RTCHR_RTCHR_MASK;
  94                 day  =  readl_relaxed(data->base + RTD_RTCDATE1) & RTD_RTCDATE1_RTCDATE1_MASK;
  95                 day |= (readl_relaxed(data->base + RTD_RTCDATE2) & RTD_RTCDATE2_RTCDATE2_MASK) << 8;
  96                 sec  = (readl_relaxed(data->base + RTD_RTCSEC) & RTD_RTCSEC_RTCSEC_MASK) >> 1;
  97                 tries++;
  98
  99                 if (sec == tm->tm_sec)
 100                         break;
 101
 102                 if (tries >= 3)
 103                         return -EINVAL;
 104         }
 105         if (tries > 1)
 106                 dev_dbg(dev, "%s: needed %i tries\n", __func__, tries);
 107
 108         year = data->base_year;
 109         while (day >= rtd119x_rtc_days_in_year(year)) {
 110                 day -= rtd119x_rtc_days_in_year(year);
 111                 year++;
 112         }
 113         tm->tm_year = year - 1900;
 114         tm->tm_yday = day;
 115
 116         tm->tm_mon = 0;
 117         while (day >= rtc_month_days(tm->tm_mon, year)) {
 118                 day -= rtc_month_days(tm->tm_mon, year);
 119                 tm->tm_mon++;
 120         }
 121         tm->tm_mday = day + 1;
 122
 123         return 0;
 124 }
 125
 126 static int rtd119x_rtc_set_time(struct device *dev, struct rtc_time *tm)
 127 {
 128         struct rtd119x_rtc *data = dev_get_drvdata(dev);
 129         unsigned int day;
 130         int i;
 131
 132         if (1900 + tm->tm_year < data->base_year)
 133                 return -EINVAL;
 134
 135         day = 0;
 136         for (i = data->base_year; i < 1900 + tm->tm_year; i++)
 137                 day += rtd119x_rtc_days_in_year(i);
 138
 139         day += tm->tm_yday;
 140         if (day > 0x7fff)
 141                 return -EINVAL;
 142
 143         rtd119x_rtc_set_enabled(dev, false);
 144
 145         writel_relaxed((tm->tm_sec << 1) & RTD_RTCSEC_RTCSEC_MASK, data->base + RTD_RTCSEC);
 146         writel_relaxed(tm->tm_min & RTD_RTCMIN_RTCMIN_MASK, data->base + RTD_RTCMIN);
 147         writel_relaxed(tm->tm_hour & RTD_RTCHR_RTCHR_MASK, data->base + RTD_RTCHR);
 148         writel_relaxed(day & RTD_RTCDATE1_RTCDATE1_MASK, data->base + RTD_RTCDATE1);
 149         writel_relaxed((day >> 8) & RTD_RTCDATE2_RTCDATE2_MASK, data->base + RTD_RTCDATE2);
 150
 151         rtd119x_rtc_set_enabled(dev, true);
 152
 153         return 0;
 154 }
 155
 156 static const struct rtc_class_ops rtd119x_rtc_ops = {
 157         .read_time      = rtd119x_rtc_read_time,
 158         .set_time       = rtd119x_rtc_set_time,
 159 };
 160
 161 static const struct of_device_id rtd119x_rtc_dt_ids[] = {
 162          { .compatible = "realtek,rtd1295-rtc" },
 163          { }
 164 };
 165
 166 static int rtd119x_rtc_probe(struct platform_device *pdev)
 167 {
 168         struct rtd119x_rtc *data;
 169         u32 val;
 170         int ret;
 171
 172         data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
 173         if (!data)
 174                 return -ENOMEM;
 175
 176         platform_set_drvdata(pdev, data);
 177         data->base_year = 2014;
 178
 179         data->base = devm_platform_ioremap_resource(pdev, 0);
 180         if (IS_ERR(data->base))
 181                 return PTR_ERR(data->base);
 182
 183         data->clk = of_clk_get(pdev->dev.of_node, 0);
 184         if (IS_ERR(data->clk))
 185                 return PTR_ERR(data->clk);
 186
 187         ret = clk_prepare_enable(data->clk);
 188         if (ret) {
 189                 clk_put(data->clk);
 190                 return ret;
 191         }
 192
 193         val = readl_relaxed(data->base + RTD_RTCACR);
 194         if (!(val & RTD_RTCACR_RTCPWR)) {
 195                 writel_relaxed(RTD_RTCACR_RTCPWR, data->base + RTD_RTCACR);
 196
 197                 rtd119x_rtc_reset(&pdev->dev);
 198
 199                 writel_relaxed(0, data->base + RTD_RTCMIN);
 200                 writel_relaxed(0, data->base + RTD_RTCHR);
 201                 writel_relaxed(0, data->base + RTD_RTCDATE1);
 202                 writel_relaxed(0, data->base + RTD_RTCDATE2);
 203         }
 204
 205         rtd119x_rtc_set_enabled(&pdev->dev, true);
 206
 207         data->rtcdev = devm_rtc_device_register(&pdev->dev, "rtc",
 208                                                 &rtd119x_rtc_ops, THIS_MODULE);
 209         if (IS_ERR(data->rtcdev)) {
 210                 dev_err(&pdev->dev, "failed to register rtc device");
 211                 clk_disable_unprepare(data->clk);
 212                 clk_put(data->clk);
 213                 return PTR_ERR(data->rtcdev);
 214         }
 215
 216         return 0;
 217 }
 218
 219 static void rtd119x_rtc_remove(struct platform_device *pdev)
 220 {
 221         struct rtd119x_rtc *data = platform_get_drvdata(pdev);
 222
 223         rtd119x_rtc_set_enabled(&pdev->dev, false);
 224
 225         clk_disable_unprepare(data->clk);
 226         clk_put(data->clk);
 227 }
 228
 229 static struct platform_driver rtd119x_rtc_driver = {
 230         .probe = rtd119x_rtc_probe,
 231         .remove = rtd119x_rtc_remove,
 232         .driver = {
 233                 .name = "rtd1295-rtc",
 234                 .of_match_table = rtd119x_rtc_dt_ids,
 235         },
 236 };
 237 builtin_platform_driver(rtd119x_rtc_driver);