leandrof/u-boot
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

rtc: provide an emulated RTC

Browse Source 
On a board without hardware clock this software real time clock can be
used. The build time is used to initialize the RTC. So you will have
to adjust the time either manually using the 'date' command  or use
the 'sntp' to update the RTC with the time from a network time server.
See CONFIG_CMD_SNTP and CONFIG_BOOTP_NTPSERVER. The RTC time is
advanced according to CPU ticks.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
This commit is contained in:
Heinrich Schuchardt 2020-10-22 23:52:14 +02:00
parent cbf0ffea14
commit 87e9963d5a
4 changed files with 93 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
MAINTAINERS
View File

@ -678,6 +678,7 @@ S: Maintained
T: git https://gitlab.denx.de/u-boot/custodians/u-boot-efi.git
F: doc/api/efi.rst
F: doc/uefi/*
F: drivers/rtc/emul_rtc.c
F: include/capitalization.h
F: include/charset.h
F: include/cp1250.h

11
drivers/rtc/Kconfig
View File

@ -63,6 +63,17 @@ config RTC_DS3232
Support for Dallas Semiconductor (now Maxim) DS3232 compatible
Real Time Clock devices.
config RTC_EMULATION
bool "Enable emulated RTC"
depends on DM_RTC
help
On a board without hardware clock this software real time clock can be
used. The build time is used to initialize the RTC. So you will have
to adjust the time either manually using the 'date' command or use
the 'sntp' to update the RTC with the time from a network time server.
See CONFIG_CMD_SNTP and CONFIG_BOOTP_NTPSERVER. The RTC time is
advanced according to CPU ticks.
config RTC_ISL1208
bool "Enable ISL1208 driver"
depends on DM_RTC

1
drivers/rtc/Makefile
View File

@ -22,6 +22,7 @@ obj-$(CONFIG_RTC_DS164x) += ds164x.o
obj-$(CONFIG_RTC_DS174x) += ds174x.o
obj-$(CONFIG_RTC_DS3231) += ds3231.o
obj-$(CONFIG_RTC_DS3232) += ds3232.o
obj-$(CONFIG_RTC_EMULATION) += emul_rtc.o
obj-$(CONFIG_RTC_FTRTC010) += ftrtc010.o
obj-$(CONFIG_SANDBOX) += i2c_rtc_emul.o
obj-$(CONFIG_RTC_IMXDI) += imxdi.o

80
drivers/rtc/emul_rtc.c Normal file
View File

@ -0,0 +1,80 @@
// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright 2020, Heinrich Schuchardt <xypron.glpk@gmx.de>
*
* This driver emulates a real time clock based on timer ticks.
*/
#include <common.h>
#include <div64.h>
#include <dm.h>
#include <generated/timestamp_autogenerated.h>
#include <rtc.h>
/**
* struct emul_rtc - private data for emulated RTC driver
*/
struct emul_rtc {
/**
* @offset_us: microseconds from 1970-01-01 to timer_get_us() base
*/
u64 offset_us;
/**
* @isdst: daylight saving time
*/
int isdst;
};
static int emul_rtc_get(struct udevice *dev, struct rtc_time *time)
{
struct emul_rtc *priv = dev_get_priv(dev);
u64 now;
if (!priv->offset_us) {
/* Use the build date as initial time */
priv->offset_us = U_BOOT_EPOCH * 1000000ULL - timer_get_us();
priv->isdst = -1;
}
now = timer_get_us() + priv->offset_us;
do_div(now, 1000000);
rtc_to_tm(now, time);
time->tm_isdst = priv->isdst;
return 0;
}
static int emul_rtc_set(struct udevice *dev, const struct rtc_time *time)
{
struct emul_rtc *priv = dev_get_priv(dev);
if (time->tm_year < 1970)
return -EINVAL;
priv->offset_us = rtc_mktime(time) * 1000000ULL - timer_get_us();
if (time->tm_isdst > 0)
priv->isdst = 1;
else if (time->tm_isdst < 0)
priv->isdst = -1;
else
priv->isdst = 0;
return 0;
}
static const struct rtc_ops emul_rtc_ops = {
.get = emul_rtc_get,
.set = emul_rtc_set,
};
U_BOOT_DRIVER(rtc_emul) = {
.name = "rtc_emul",
.id = UCLASS_RTC,
.ops = &emul_rtc_ops,
.priv_auto_alloc_size = sizeof(struct emul_rtc),
};
U_BOOT_DEVICE(rtc_emul) = {
.name = "rtc_emul",
};