Merge tag 'docs-4.10' of git://git.lwn.net/linux

Pull documentation update from Jonathan Corbet:
 "These are the documentation changes for 4.10.

  It's another busy cycle for the docs tree, as the sphinx conversion
  continues. Highlights include:

   - Further work on PDF output, which remains a bit of a pain but
     should be more solid now.

   - Five more DocBook template files converted to Sphinx. Only 27 to
     go... Lots of plain-text files have also been converted and
     integrated.

   - Images in binary formats have been replaced with more
     source-friendly versions.

   - Various bits of organizational work, including the renaming of
     various files discussed at the kernel summit.

   - New documentation for the device_link mechanism.

  ... and, of course, lots of typo fixes and small updates"

* tag 'docs-4.10' of git://git.lwn.net/linux: (193 commits)
  dma-buf: Extract dma-buf.rst
  Update Documentation/00-INDEX
  docs: 00-INDEX: document directories/files with no docs
  docs: 00-INDEX: remove non-existing entries
  docs: 00-INDEX: add missing entries for documentation files/dirs
  docs: 00-INDEX: consolidate process/ and admin-guide/ description
  scripts: add a script to check if Documentation/00-INDEX is sane
  Docs: change sh -> awk in REPORTING-BUGS
  Documentation/core-api/device_link: Add initial documentation
  core-api: remove an unexpected unident
  ppc/idle: Add documentation for powersave=off
  Doc: Correct typo, "Introdution" => "Introduction"
  Documentation/atomic_ops.txt: convert to ReST markup
  Documentation/local_ops.txt: convert to ReST markup
  Documentation/assoc_array.txt: convert to ReST markup
  docs-rst: parse-headers.pl: cleanup the documentation
  docs-rst: fix media cleandocs target
  docs-rst: media/Makefile: reorganize the rules
  docs-rst: media: build SVG from graphviz files
  docs-rst: replace bayer.png by a SVG image
  ...

1 files changed, 46 insertions, 0 deletions

diff --git a/Documentation/sound/soc/clocking.rst b/Documentation/sound/soc/clocking.rst
new file mode 100644
index 000000000000..32122d6877a3
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+==============
+Audio Clocking
+==============
+
+This text describes the audio clocking terms in ASoC and digital audio in
+general. Note: Audio clocking can be complex!
+
+
+Master Clock
+------------
+
+Every audio subsystem is driven by a master clock (sometimes referred to as MCLK
+or SYSCLK). This audio master clock can be derived from a number of sources
+(e.g. crystal, PLL, CPU clock) and is responsible for producing the correct
+audio playback and capture sample rates.
+
+Some master clocks (e.g. PLLs and CPU based clocks) are configurable in that
+their speed can be altered by software (depending on the system use and to save
+power). Other master clocks are fixed at a set frequency (i.e. crystals).
+
+
+DAI Clocks
+----------
+The Digital Audio Interface is usually driven by a Bit Clock (often referred to
+as BCLK). This clock is used to drive the digital audio data across the link
+between the codec and CPU.
+
+The DAI also has a frame clock to signal the start of each audio frame. This
+clock is sometimes referred to as LRC (left right clock) or FRAME. This clock
+runs at exactly the sample rate (LRC = Rate).
+
+Bit Clock can be generated as follows:-
+
+- BCLK = MCLK / x, or
+- BCLK = LRC * x, or
+- BCLK = LRC * Channels * Word Size
+
+This relationship depends on the codec or SoC CPU in particular. In general
+it is best to configure BCLK to the lowest possible speed (depending on your
+rate, number of channels and word size) to save on power.
+
+It is also desirable to use the codec (if possible) to drive (or master) the
+audio clocks as it usually gives more accurate sample rates than the CPU.
+
+
+