ASoC: doc: ReSTize overview.txt

A simple conversion from a plain text file.
Created a new subdirectory, Documentation/sound/soc, for this and
other ASoC documents.

Since the index page contains the TOC, so "Documentation" section got
removed from overview.

Acked-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 0 insertions, 95 deletions

diff --git a/Documentation/sound/alsa/soc/overview.txt b/Documentation/sound/alsa/soc/overview.txt
deleted file mode 100644
index f3f28b7ae242..000000000000
--- a/Documentation/sound/alsa/soc/overview.txt
+++ /dev/null
@@ -1,95 +0,0 @@
-ALSA SoC Layer
-==============
-
-The overall project goal of the ALSA System on Chip (ASoC) layer is to
-provide better ALSA support for embedded system-on-chip processors (e.g.
-pxa2xx, au1x00, iMX, etc) and portable audio codecs.  Prior to the ASoC
-subsystem there was some support in the kernel for SoC audio, however it
-had some limitations:-
-
-  * Codec drivers were often tightly coupled to the underlying SoC
-    CPU. This is not ideal and leads to code duplication - for example,
-    Linux had different wm8731 drivers for 4 different SoC platforms.
-
-  * There was no standard method to signal user initiated audio events (e.g.
-    Headphone/Mic insertion, Headphone/Mic detection after an insertion
-    event). These are quite common events on portable devices and often require
-    machine specific code to re-route audio, enable amps, etc., after such an
-    event.
-
-  * Drivers tended to power up the entire codec when playing (or
-    recording) audio. This is fine for a PC, but tends to waste a lot of
-    power on portable devices. There was also no support for saving
-    power via changing codec oversampling rates, bias currents, etc.
-
-
-ASoC Design
-===========
-
-The ASoC layer is designed to address these issues and provide the following
-features :-
-
-  * Codec independence. Allows reuse of codec drivers on other platforms
-    and machines.
-
-  * Easy I2S/PCM audio interface setup between codec and SoC. Each SoC
-    interface and codec registers its audio interface capabilities with the
-    core and are subsequently matched and configured when the application
-    hardware parameters are known.
-
-  * Dynamic Audio Power Management (DAPM). DAPM automatically sets the codec to
-    its minimum power state at all times. This includes powering up/down
-    internal power blocks depending on the internal codec audio routing and any
-    active streams.
-
-  * Pop and click reduction. Pops and clicks can be reduced by powering the
-    codec up/down in the correct sequence (including using digital mute). ASoC
-    signals the codec when to change power states.
-
-  * 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
-multiple re-usable component drivers :-
-
-  * 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 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 class driver: The machine driver class acts as the glue that
-    describes 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
-=============
-
-The documentation is spilt into the following sections:-
-
-overview.txt: This file.
-
-codec.txt: Codec driver internals.
-
-DAI.txt: Description of Digital Audio Interface standards and how to configure
-a DAI within your codec and CPU DAI drivers.
-
-dapm.txt: Dynamic Audio Power Management
-
-platform.txt: Platform audio DMA and DAI.
-
-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.