Commit Graph

3 Commits

Author SHA1 Message Date
Heinrich Schuchardt
fb71c3f490 rtc: initialize emulated RTC from environment variable
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>
2020-10-30 14:20:27 +01:00
Heinrich Schuchardt
0ca4b558b5 rtc: use probe() to initialize emulated RTC
Currently the emulated RTC is initialized in the emul_rtc_get() get
function. This does not match the design of the driver model.

Move the initialization of the emulated RTC to the probe() function.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
2020-10-30 14:20:26 +01:00
Heinrich Schuchardt
87e9963d5a rtc: provide an emulated RTC
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>
2020-10-27 21:13:15 +01:00