Unverified Commit d40e8219 authored by Luca Ceresoli's avatar Luca Ceresoli Committed by Mark Brown
Browse files

ASoC: doc: dapm: fix and improve section "Registering DAPM controls" 



Extend the first paragraph to mention the {,num_}dapm_routes fields just
like the widget conterparts. Mention the route fields also in the code
example. Fix "at build time", this really means "at probe time".

Reviewed-by: default avatarAlexandre Belloni <alexandre.belloni@bootlin.com>
Reviewed-by: default avatarBagas Sanjaya <bagasdotme@gmail.com>
Signed-off-by: default avatarLuca Ceresoli <luca.ceresoli@bootlin.com>
Link: https://lore.kernel.org/r/20240426-dapm-docs-v2-9-87b07547eb5b@bootlin.com


Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent 36de8c0e

Documentation/sound/soc/dapm.rst

+14 −7
Original line number Diff line number Diff line
@@ -253,12 +253,17 @@ This can be used to merge two signal paths together in software. 
Registering DAPM controls

=========================



In many cases the DAPM widgets implemented statically in a ``static const

struct snd_soc_dapm_widget`` array and the routes connecting them in a

``static const struct snd_soc_dapm_route`` array in a codec driver, and

simply declared via the ``dapm_widgets`` and ``num_dapm_widgets`` fields of

the ``struct snd_soc_component_driver`` so the driver registration will

take care of populating them::

In many cases the DAPM widgets are implemented statically in a ``static

const struct snd_soc_dapm_widget`` array in a codec driver, and simply

declared via the ``dapm_widgets`` and ``num_dapm_widgets`` fields of the

``struct snd_soc_component_driver``.



Similarly, routes connecting them are implemented statically in a ``static

const struct snd_soc_dapm_route`` array and declared via the

``dapm_routes`` and ``num_dapm_routes`` fields of the same struct.



With the above declared, the driver registration will take care of

populating them::



  static const struct snd_soc_dapm_widget wm2000_dapm_widgets[] = {

  	SND_SOC_DAPM_OUTPUT("SPKN"),
@@ -277,11 +282,13 @@ take care of populating them:: 
	...

  	.dapm_widgets		= wm2000_dapm_widgets,

  	.num_dapm_widgets	= ARRAY_SIZE(wm2000_dapm_widgets),

  	.dapm_routes            = wm2000_audio_map,

  	.num_dapm_routes        = ARRAY_SIZE(wm2000_audio_map),

	...

  };



In more complex cases the list of DAPM widgets and/or routes can be only

known at build time. This happens for example when a driver supports

known at probe time. This happens for example when a driver supports

different models having a different set of features. In those cases

separate widgets and routes arrays implementing the case-specific features

can be registered programmatically by calling snd_soc_dapm_new_controls()