ASoC: docs: Update the Overview document

Update the ASoC overview to bring it up to date with the current code base
and include multi-component.

Signed-off-by: Liam Girdwood <liam.r.girdwood@linux.intel.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

Documentation/sound/alsa/soc/overview.txt

@@ -49,18 +49,23 @@ features :-
   * Machine specific controls: Allow machines to add controls to the sound card
     (e.g. volume control for speaker amplifier).
 
-To achieve all this, ASoC basically splits an embedded audio system into 3
-components :-
+To achieve all this, ASoC basically splits an embedded audio system into
+multiple re-usable component drivers :-
 
-  * Codec driver: The codec driver is platform independent and contains audio
-    controls, audio interface capabilities, codec DAPM definition and codec IO
-    functions.
+  * Codec class drivers: The codec class driver is platform independent and
+    contains audio controls, audio interface capabilities, codec DAPM
+    definition and codec IO functions. This class extends to BT, FM and MODEM
+    ICs if required. Codec class drivers should be generic code that can run
+    on any architecture and machine.
 
-  * Platform driver: The platform driver contains the audio DMA engine and audio
-    interface drivers (e.g. I2S, AC97, PCM) for that platform.
+  * Platform class drivers: The platform class driver includes the audio DMA
+    engine driver, digital audio interface (DAI) drivers (e.g. I2S, AC97, PCM)
+    and any audio DSP drivers for that platform.
 
-  * Machine driver: The machine driver handles any machine specific controls and
-    audio events (e.g. turning on an amp at start of playback).
+  * Machine class driver: The machine driver class acts as the glue that
+    decribes and binds the other component drivers together to form an ALSA
+    "sound card device". It handles any machine specific controls and
+    machine level audio events (e.g. turning on an amp at start of playback).
 
 
 Documentation
@@ -84,3 +89,7 @@ machine.txt: Machine driver internals.
 pop_clicks.txt: How to minimise audio artifacts.
 
 clocking.txt: ASoC clocking for best power performance.
+
+jack.txt: ASoC jack detection.
+
+DPCM.txt: Dynamic PCM - Describes DPCM with DSP examples.