Toggle location services via adb in Android 5 I see this answer from 2013, but now there are options for High Accuracy, Battery Saving, and Device Only.  Also, there was no command for disabling location.
You may check-out my updated answer dealing with the question in entirety, or consider the following info:


High accuracy: gps,wifi,network or gps,network (if you don't want Wi-Fi enabled)
Battery saving: wifi,network or network only
Device only: gps


E.g:

adb shell settings put secure location_providers_allowed gps,wifi,network


To disable Location mode

adb shell settings put secure location_providers_allowed ' '