STM32L1, STM32L4 RTC: add periodic interrupts, update L1 RTC implementation
* STM32L4 RTC: add support experimental CONFIG_RTC_PERIODIC
* STM32 RTC: separate STM32L1 RTC into a separate file
STM32L1 RTC is very close to F4 or L4 versions, with two alarms
and periodic wakeup support so backported L4 peripheral to L1.
* RTC: add periodic alarms to upper and lower halves
Approved-by: Gregory Nutt <gnutt@nuttx.org>
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
