LXR uboot/drivers/rtc/emul

   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * Copyright 2020, Heinrich Schuchardt <xypron.glpk@gmx.de>
   4 *
   5 * This driver emulates a real time clock based on timer ticks.
   6 */
   7
   8#include <common.h>
   9#include <div64.h>
  10#include <dm.h>
  11#include <env.h>
  12#include <rtc.h>
  13#include <timestamp.h>
  14
  15/**
  16 * struct emul_rtc - private data for emulated RTC driver
  17 */
  18struct emul_rtc {
  19        /**
  20         * @offset_us: microseconds from 1970-01-01 to timer_get_us() base
  21         */
  22        u64 offset_us;
  23        /**
  24         * @isdst: daylight saving time
  25         */
  26        int isdst;
  27};
  28
  29static int emul_rtc_get(struct udevice *dev, struct rtc_time *time)
  30{
  31        struct emul_rtc *priv = dev_get_priv(dev);
  32        u64 now;
  33
  34        now = timer_get_us() + priv->offset_us;
  35        do_div(now, 1000000);
  36        rtc_to_tm(now, time);
  37        time->tm_isdst = priv->isdst;
  38
  39        return 0;
  40}
  41
  42static int emul_rtc_set(struct udevice *dev, const struct rtc_time *time)
  43{
  44        struct emul_rtc *priv = dev_get_priv(dev);
  45
  46        if (time->tm_year < 1970)
  47                return -EINVAL;
  48
  49        priv->offset_us = rtc_mktime(time) * 1000000ULL - timer_get_us();
  50
  51        if (time->tm_isdst > 0)
  52                priv->isdst = 1;
  53        else if (time->tm_isdst < 0)
  54                priv->isdst = -1;
  55        else
  56                priv->isdst = 0;
  57
  58        return 0;
  59}
  60
  61int emul_rtc_probe(struct udevice *dev)
  62{
  63        struct emul_rtc *priv = dev_get_priv(dev);
  64        const char *epoch_str;
  65        u64 epoch;
  66
  67        epoch_str = env_get("rtc_emul_epoch");
  68
  69        if (epoch_str) {
  70                epoch = simple_strtoull(epoch_str, NULL, 10);
  71        } else {
  72                /* Use the build date as initial time */
  73                epoch = U_BOOT_EPOCH;
  74        }
  75        priv->offset_us = epoch * 1000000ULL - timer_get_us();
  76        priv->isdst = -1;
  77
  78        return 0;
  79}
  80
  81static const struct rtc_ops emul_rtc_ops = {
  82        .get = emul_rtc_get,
  83        .set = emul_rtc_set,
  84};
  85
  86U_BOOT_DRIVER(rtc_emul) = {
  87        .name   = "rtc_emul",
  88        .id     = UCLASS_RTC,
  89        .ops    = &emul_rtc_ops,
  90        .probe  = emul_rtc_probe,
  91        .priv_auto      = sizeof(struct emul_rtc),
  92};
  93
  94U_BOOT_DRVINFO(rtc_emul) = {
  95        .name   = "rtc_emul",
  96};
  97