1d76898928
dai_link is used to selecting Component (= CPU/Codec/Platform) and DAI (= CPU/Codec). And selected CPU/Codec/Platform components are *listed* on Card. Many drivers don't need special Platform component, but was mandatory at legacy style ALSA SoC. Thus, there is this kind of settings on many drivers. dai_link->platform_of_node = dai_link->cpu_of_node; In this case, soc_bind_dai_link() will pick-up "CPU component" as "Platform component", and try to add it to snd_soc_pcm_runtime. But it will be ignored, because it is already added when CPU bindings. Historically, this kind of "CPU component" is used/selected as "Platform" on many ALSA SoC drivers. OTOH, Dummy Platform will be selected automatically by ALSA SoC if driver doesn't have Platform settings. These indicates that there are 2 type of Platforms exist at current ALSA SoC if driver doesn't need special Platform. 1) use Dummy Platform as Platform component 2) use CPU component as Platform component ALSA SoC will call Dummy Platform callback function if it is using Dummy Platform, but it is completely pointless. Because it is the sound card which doesn't need special Platform. Thus, the behavior we request to ALSA SoC is selecting 2) automatically instead of 1) if sound card doesn't need special Platform. And, 2) means "do nothing" as above explain. These were needed at legacy style dai_link, but is no longer needed at modern style dai_link anymore. This patch allows "no Platform" settings on dai_link, and will do nothing for it if there was no platform settings. This is same as 2). By this patch, all drivers which is selecting "CPU component" as "Platform" can remove such settings. Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com> Signed-off-by: Mark Brown <broonie@kernel.org> |
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| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
README
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.