Up to now the emulated RTC is initialized using the U-Boot build time.

With this patch the environment variable 'rtc_emul_epoch' can be used to
provide a better initial time. The variable is a decimal string with
the number of seconds since 1970-01-01. Here is an example where the RTC
had not been probed yet:

    => setenv rtc_emul_epoch 1610109000
    => date
    Date: 2021-01-08 (Friday)    Time: 12:30:00

If the variable does not exist, the U-Boot build time is used as fallback.

The environment variable may be set when shutting down the operating system
if the U-Boot environment is exposed to the OS (cf. ENV_IS_IN_FAT and
ENV_IS_IN_EXT4).

Suggested-by: Pablo Sebastián Greco <pgreco@centosproject.org>
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

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>

add Kconfig option for pcf8563 driver and
run tools/moveconfig.py

Signed-off-by: Heiko Schocher <hs@denx.de>
Reviewed-by: Stefan Roese <sr@denx.de>

DS3232 is an i2c RTC with 236 bytes of battery-backed SRAM.

Add an RTC driver for DS3232 device, which provides time and
date support. Also read and write functions are provided,
which can be used to access the SRAM memory.

Signed-off-by: Nandor Han <nandor.han@vaisala.com>

In the next commit, rtc_mktime(), for compatibility with linux, will be
implemented using rtc_mktime(), which is no longer drivers/rtc specific.
So move this file under lib/.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>

Add an implementation of the rtc_enable_32khz_output() that uses the
driver model i2c APIs.

Also put code related to rtc_enable_32khz_output
under CONFIG_RTC_ENABLE_32KHZ_OUTPUT.

Signed-off-by: Chuanhua Han <chuanhua.han@nxp.com>
Reviewed-by: Prabhakar Kushwaha <prabhakar.kushwaha@nxp.com>

move RTC_RX8025 to Kconfig and fixup board configs.

Signed-off-by: Heiko Schocher <hs@denx.de>

Add support of STM32MP1 rtc driver.
Enable it for basic and trusted configurations.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>

Signed-off-by: Michael Walle <michael@walle.cc>

This patch moves the RTC M41T62 config define to Kconfig.

Signed-off-by: Lukasz Majewski <lukma@denx.de>
Reviewed-by: Stefan Roese <sr@denx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>