On 06/07/2026 14:00, Konrad Dybcio wrote:
On 7/5/26 10:06 PM, David Heidelberg via B4 Relay wrote:
From: David Heidelberg <[email protected]>
Introduce support for sound card and wire two CS35L36 audio codecs for
top and bottom speakers.
Inspired by commit from Joel Selvaraj.
Signed-off-by: David Heidelberg <[email protected]>
---
[...]
+ /* CS35L36, Bottom Speaker */
+ cs35l36_bottom: audio-codec@40 {
+ compatible = "cirrus,cs35l36";
+ reg = <0x40>;
+ reset-gpios = <&tlmm 112 GPIO_ACTIVE_HIGH>;
+ #sound-dai-cells = <0>;
+ sound-name-prefix = "Right"; /* Bottom */
One comment's enough (either above the node or here)
[...]
+ mm1-dai-link {
+ link-name = "MultiMedia1";
+
+ cpu {
+ sound-dai = <&q6asmdai MSM_FRONTEND_DAI_MULTIMEDIA1>;
+ };
+ };
+
+ cs35l36-dai-link {
+ link-name = "Speaker Playback";
+
+ cpu {
+ sound-dai = <&q6afedai QUATERNARY_TDM_RX_0>;
+ };
+
+ platform {
+ sound-dai = <&q6routing>;
+ };
+
+ codec {
+ sound-dai = <&cs35l36_bottom>, <&cs35l36_top>;
+ };
nit: 'co'dec < 'cp'u < 'p'latform
also 'c's35l36-dai-link < `m`m1-dai-link
... aaaand **sorting nodes** broke audio.
Moving `mm1-dai-link` behind `cs35l36-dai-link` broke the audio.
For now I'm keeping m1-dai-link at the begging and added the comment why is it
there, but I guess would be nice to have this solved properly.
---
What actually happens in the core. In soc_probe_component() the ASoC core
creates a component's widgets, probes it, and immediately adds that component's own
routes. Card-level routes, including the DT audio-routing ones, are only
added after every component is probed. So a component whose routes point at another
component's widgets, which is exactly what q6routing does with MM_DL* and
MM_UL*, only works if the other component happens to be probed earlier. Probe
order is
the DT link order, so this becomes a hidden DT contract.
Upstream does not actually sort these nodes. The binding matches .*-dai-link$
and the reference boards rely on the order: db845c lists mm1 to mm4 and then
hdmi-dai-link, sm8250-mtp lists mm1 to mm3 and then wcd-..., wsa-...,
va-dai-link. Neither is alphabetical. So "sorted by name" is not the convention
being
followed for these children, and cs35l36-dai-link sorting before mm1-dai-link
is precisely why an alphabetical rework breaks.
Where a fix would belong. Two options, in order of preference:
- In the ASoC core: defer component routes until after
soc_probe_link_components() finishes, next to where the card routes are added.
That removes the dependency
for every driver with cross-component routes. It is a small change, but it
touches every card, so it needs a wide audience on alsa-devel.
- In qcom_snd_parse_of(): it already knows which links are frontends (no
codec and no platform child, marked dynamic) and which are backends (no_pcm).
Two passes
over the children, frontends first, make the order independent of the DT.
That is local and would be acceptable to the Qualcomm audio maintainers, but it
papers
over a core problem.
otherwise:
Reviewed-by: Konrad Dybcio <[email protected]>
Konrad
