ts3a227e datasheet says typical key resistance is
  key1 50 Ohm
  key2 135 Ohm
  key3 240 Ohm
  key4 470 Ohm

The android headset specification expect buttons impedance:
  A (MEDIA) 0-70 Ohm
  D (VOICECOMMAND) 110-180 Ohm
  B (VOLUMEUP) 210-290 Ohm
  C (VOLUMEDOWN) 360-680 Ohm

Thus key mapping should be
  key1 - MEDIA
  key2 - VOICECOMMAND
  key3 - VOLUMEUP
  key3 - VOLUMEDOWN
Signed-off-by: Anatol Pomozov <anatol.pomozov@gmail.com>
Acked-by: Dylan Reid <dgreid@chromium.org>
Signed-off-by: Mark Brown <broonie@kernel.org>