In stm32_rtcc.c the up_rtcinitialize() logic doesn't work with the LSI. The check on RTC_MAGIC on the BK0R register lead to rtc_setup() call that rightfully enables the lsi clock; but the next times, when the rtc is already setup, the rtc_resume() call does NOT start the lsi clock!
The right place to put LSE/LSI initialisation is inside stm32_stdclockconfig() in stm32fxxxxx_rcc.c. Doing this I checked the possible uses of the LSI and the LSE sources: the LSI can be used for RTC and/or the IWDG, while the LSE only for the RTC (and to output the MCO1 pin)..
This change is not verifed for any other platforms.
From Leo Aloe3132
Add a skeleton implementation of the RTC lower half interface at arch/arm/src/stm32/stm32_rtc_lowerhalf.c. This is just the framework for the RTC lower half. None of the interface methods have yet been implemetned.
Some boards do not have the external 32khz oscillator installed, for those boards we must fallback to the crummy to the crummy internal RC clock. Turn on by defining CONFIG_RTC_LSICLOCK.
From Kevin Hester <kevinh@geeksville.com> via Lorenz Meier.
