In some cases we need to probe additional audio components that do not appear as part of the DAI links specified in the device tree. Examples for this are auxiliary devices such as analog amplifiers or codecs.
The ASoC core provides a way to probe these components by adding them to snd_soc_card->aux_dev. We can use the snd_soc_of_parse_aux_devs() function to parse them from the device tree.
As an example for this, some MSM8916 smartphones have an analog speaker amplifier connected to the HPHR output. With the new property this can be modelled as follows:
speaker-amp: audio-amplifier { compatible = "simple-audio-amplifier"; enable-gpios = <&msmgpio 114 GPIO_ACTIVE_HIGH>; sound-name-prefix = "Speaker Amp"; };
&sound { aux-devs = <&speaker_amp>; audio-routing = "Speaker Amp IN", "HPHR"; };
Cc: Srinivas Kandagatla srinivas.kandagatla@linaro.org Signed-off-by: Stephan Gerhold stephan@gerhold.net --- sound/soc/qcom/common.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/sound/soc/qcom/common.c b/sound/soc/qcom/common.c index 5194d90ddb96..fe6e778c31c0 100644 --- a/sound/soc/qcom/common.c +++ b/sound/soc/qcom/common.c @@ -39,6 +39,10 @@ int qcom_snd_parse_of(struct snd_soc_card *card) return ret; }
+ ret = snd_soc_of_parse_aux_devs(card, "aux-devs"); + if (ret) + return ret; + /* Populate links */ num_links = of_get_child_count(dev->of_node);