When trying to configure an input_datetime with only time I get a configuration error if I try to set an initial value with just a time value. It seems I can get around the issue by including a date in the intial value but it would be nice if it allowed date and time or just a date or just a time. It would be even better if it validated to the appropriate value based on how has_date and has_time are set.
Here is the error I got:
2017-10-08 07:21:13 ERROR (MainThread) [homeassistant.config] Invalid config for [input_datetime]: Invalid datetime specified: 06:30 for dictionary value @ data['input_datetime']['alarm_clock_time']['initial']. Got '06:30'. (See /home/homeassistant/.homeassistant/configuration.yaml, line 169). Please check the docs at https://home-assistant.io/components/input_datetime/ 2017-10-08 07:21:13 ERROR (MainThread) [homeassistant.setup] Setup failed for input_datetime: Invalid config.