Hi Cezary,
On Wed, 11 May 2022, Cezary Rojewski wrote:
Add generic ASoC equivalent of ALSA HD-Audio codec. This codec is designed to follow HDA_DEV_LEGACY convention. Driver wrapps existing hda_codec.c handlers to prevent code duplication within the newly added code. Number of DAIs created is dependent on capabilities exposed by the codec itself. Because of this, single solution can be applied to support every single HD-Audio codec type.
At the same time, through the ASoC topology, platform drivers may limit the number of endpoints available to the userspace as codec driver exposes BE DAIs only.
Both hda_codec_probe() and hda_codec_remove() declare their expectations on device's usage_count and suspended-status. This is to catch any unexpected behavior as PM-related code for HD-Audio has been changing quite a bit throughout the years.
In order for codec DAI list to reflect its actual PCM capabilities, PCMs need to be built and that can only happen once codec device is constructed. To do that, a valid component->card->snd_card pointer is needed. Said pointer will be provided by the framework once all card components are accounted for and their probing can begin. Usage of "binder" BE DAI solves the problem - codec can be listed as one of HD-Audio card components without declaring any actual BE DAIs statically.
Relation with hdac_hda:
Addition of parallel solution is motivated by behavioral differences between hdac_hda.c and its legacy equivalent found in sound/pci/hda e.g.: lack of dynamic, based on codec capabilities, resource allocation and high cost of removing such differences on actively used targets. Major goal of codec driver presented here is to follow HD-Audio legacy behavior in 1:1 fashion by becoming a wrapper. Doing so increases code coverage of the legacy code and reduces the maintenance cost for both solutions.
Signed-off-by: Cezary Rojewski cezary.rojewski@intel.com
Thanks for your patch, which is now commit b5df2a7dca1cc6c6 ("ASoC: codecs: Add HD-Audio codec driver") in sound-asoc/for-next.
--- a/sound/soc/codecs/Kconfig +++ b/sound/soc/codecs/Kconfig @@ -937,6 +937,16 @@ config SND_SOC_HDAC_HDA tristate select SND_HDA
+config SND_SOC_HDA
- tristate "HD-Audio codec driver"
- select SND_HDA_EXT_CORE
- select SND_HDA
I am wondering if this needs a platform dependency? Or perhaps this symbol should be made invisible, as it is selected by SND_SOC_INTEL_AVS_MACH_HDAUDIO? Are there any other users?
Thanks!
- help
This enables HD-Audio codec support in ASoC subsystem. Comparedto SND_SOC_HDAC_HDA, driver's behavior is identical to HD-Audiolegacy solution - including the dynamic resource allocationbased on actual codec capabilities.config SND_SOC_ICS43432 tristate "ICS43423 and compatible i2s microphones"
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds