Some sound card setups might require extra pin switches to allow
turning off certain audio components. There are two real examples for
this in smartphones/tablets based on MSM8916:
1. Analog speaker amplifiers connected to headphone outputs.
The MSM8916 analog codec does not have a separate "Line Out" port
so some devices have an analog speaker amplifier connected to one
of the headphone outputs. A pin switch is necessary to allow
playback on headphones without also activating the speaker.
2. External speaker codec also used as earpiece.
Some smartphones have two front-facing (stereo) speakers that can
be also configured to act as an earpiece during voice calls. A pin
switch is needed to allow disabling the second speaker during
voice calls.
There are existing bindings that allow setting up such pin switches in
simple-card.yaml. Document the same for Qcom sound cards.
One variant of example 1 above is added to the examples in the DT
schema: There is an analog speaker amplifier connected to the HPH_R
(right headphone channel) output. Adding a "Speaker" pin switch and
widget allows turning off the speaker when audio should be only played
via the connected headphones.
Cc: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
Signed-off-by: Stephan Gerhold <stephan@xxxxxxxxxxx>
---
.../devicetree/bindings/sound/qcom,sm8250.yaml | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/Documentation/devicetree/bindings/sound/qcom,sm8250.yaml b/Documentation/devicetree/bindings/sound/qcom,sm8250.yaml
index e50964c54bb9..4bfda04b4608 100644
--- a/Documentation/devicetree/bindings/sound/qcom,sm8250.yaml
+++ b/Documentation/devicetree/bindings/sound/qcom,sm8250.yaml
@@ -39,6 +39,14 @@ properties:
$ref: /schemas/types.yaml#/definitions/string
description: User visible long sound card name
+ pin-switches:
+ description: List of widget names for which pin switches should be created.
+ $ref: /schemas/types.yaml#/definitions/string-array
+
+ widgets:
+ description: User specified audio sound widgets.
+ $ref: /schemas/types.yaml#/definitions/non-unique-string-array
+
# Only valid for some compatibles (see allOf if below)
reg: true
reg-names: true
@@ -251,7 +259,15 @@ examples:
reg-names = "mic-iomux", "spkr-iomux";
model = "msm8916";
+ widgets =
+ "Speaker", "Speaker",
+ "Headphone", "Headphones";
+ pin-switches = "Speaker";
audio-routing =
+ "Speaker", "Speaker Amp OUT",
+ "Speaker Amp IN", "HPH_R",
+ "Headphones", "HPH_L",
+ "Headphones", "HPH_R",
"AMIC1", "MIC BIAS Internal1",
"AMIC2", "MIC BIAS Internal2",
"AMIC3", "MIC BIAS Internal3";
--
2.34.1
