No root needed, Galaxy S5 SM-G900F records calls perfectly in two directions, just install Boldbeast Recorder and go.
Android 4.x and 5.x please use these settings to record calls:
- Record Mode: 4
- Tune Samsung1: No
- Tune Samsung2: No
- Tune Samsung3: No
- Tune Audio Route: No
Android 6.x please see the post #6 bellow.