summaryrefslogtreecommitdiff
path: root/Documentation/sound/soc
diff options
context:
space:
mode:
authorTakashi Iwai <tiwai@suse.de>2016-11-11 00:23:02 +0300
committerTakashi Iwai <tiwai@suse.de>2016-11-11 19:33:46 +0300
commitd9641c9d63909ab452405f0a6a3fd6177a4a6b6d (patch)
tree5c242da30fcb0eceb32a59c7aaaaaca6d9a3408a /Documentation/sound/soc
parentd8a5d624cc39c416f008e52b940f47cf619dbd9e (diff)
downloadlinux-d9641c9d63909ab452405f0a6a3fd6177a4a6b6d.tar.xz
ASoC: doc: ReSTize machine.txt
A simple conversion from a plain text file. Acked-by: Mark Brown <broonie@kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'Documentation/sound/soc')
-rw-r--r--Documentation/sound/soc/index.rst1
-rw-r--r--Documentation/sound/soc/machine.rst97
2 files changed, 98 insertions, 0 deletions
diff --git a/Documentation/sound/soc/index.rst b/Documentation/sound/soc/index.rst
index c5a55195bf4d..4ac3585e7dd1 100644
--- a/Documentation/sound/soc/index.rst
+++ b/Documentation/sound/soc/index.rst
@@ -12,3 +12,4 @@ The documentation is spilt into the following sections:-
dai
dapm
platform
+ machine
diff --git a/Documentation/sound/soc/machine.rst b/Documentation/sound/soc/machine.rst
new file mode 100644
index 000000000000..515c9444deaf
--- /dev/null
+++ b/Documentation/sound/soc/machine.rst
@@ -0,0 +1,97 @@
+===================
+ASoC Machine Driver
+===================
+
+The ASoC machine (or board) driver is the code that glues together all the
+component drivers (e.g. codecs, platforms and DAIs). It also describes the
+relationships between each component which include audio paths, GPIOs,
+interrupts, clocking, jacks and voltage regulators.
+
+The machine driver can contain codec and platform specific code. It registers
+the audio subsystem with the kernel as a platform device and is represented by
+the following struct:-
+::
+
+ /* SoC machine */
+ struct snd_soc_card {
+ char *name;
+
+ ...
+
+ int (*probe)(struct platform_device *pdev);
+ int (*remove)(struct platform_device *pdev);
+
+ /* the pre and post PM functions are used to do any PM work before and
+ * after the codec and DAIs do any PM work. */
+ int (*suspend_pre)(struct platform_device *pdev, pm_message_t state);
+ int (*suspend_post)(struct platform_device *pdev, pm_message_t state);
+ int (*resume_pre)(struct platform_device *pdev);
+ int (*resume_post)(struct platform_device *pdev);
+
+ ...
+
+ /* CPU <--> Codec DAI links */
+ struct snd_soc_dai_link *dai_link;
+ int num_links;
+
+ ...
+ };
+
+probe()/remove()
+----------------
+probe/remove are optional. Do any machine specific probe here.
+
+
+suspend()/resume()
+------------------
+The machine driver has pre and post versions of suspend and resume to take care
+of any machine audio tasks that have to be done before or after the codec, DAIs
+and DMA is suspended and resumed. Optional.
+
+
+Machine DAI Configuration
+-------------------------
+The machine DAI configuration glues all the codec and CPU DAIs together. It can
+also be used to set up the DAI system clock and for any machine related DAI
+initialisation e.g. the machine audio map can be connected to the codec audio
+map, unconnected codec pins can be set as such.
+
+struct snd_soc_dai_link is used to set up each DAI in your machine. e.g.
+::
+
+ /* corgi digital audio interface glue - connects codec <--> CPU */
+ static struct snd_soc_dai_link corgi_dai = {
+ .name = "WM8731",
+ .stream_name = "WM8731",
+ .cpu_dai_name = "pxa-is2-dai",
+ .codec_dai_name = "wm8731-hifi",
+ .platform_name = "pxa-pcm-audio",
+ .codec_name = "wm8713-codec.0-001a",
+ .init = corgi_wm8731_init,
+ .ops = &corgi_ops,
+ };
+
+struct snd_soc_card then sets up the machine with its DAIs. e.g.
+::
+
+ /* corgi audio machine driver */
+ static struct snd_soc_card snd_soc_corgi = {
+ .name = "Corgi",
+ .dai_link = &corgi_dai,
+ .num_links = 1,
+ };
+
+
+Machine Power Map
+-----------------
+
+The machine driver can optionally extend the codec power map and to become an
+audio power map of the audio subsystem. This allows for automatic power up/down
+of speaker/HP amplifiers, etc. Codec pins can be connected to the machines jack
+sockets in the machine init function.
+
+
+Machine Controls
+----------------
+
+Machine specific audio mixer controls can be added in the DAI init function.