[alsa-devel] [PATCH V2] ASoC: hdac_hdmi: add device PM dependency

[Pierre-Louis Bossart]

On 4/1/19 12:50 AM, libin.yang at intel.com wrote:
> From: Libin Yang <libin.yang at intel.com>
> 
> HDMI audio codec register operation depends on the display audio power
> domain. The hdmi audio codec dapm event callback must be called after
> display audio power is turned on.
> 
> Add hdac_hdmi_device_link_add() in HDMI audio codec driver. The customer
> audio driver, such as cAVS/SST and SOF audio driver, can call the function
> to set the audio power dependency.
> 
> Signed-off-by: Libin Yang <libin.yang at intel.com>
> ---
>   sound/soc/codecs/hdac_hdmi.c | 12 ++++++++++++
>   sound/soc/codecs/hdac_hdmi.h |  6 ++++++
>   2 files changed, 18 insertions(+)
> 
> diff --git a/sound/soc/codecs/hdac_hdmi.c b/sound/soc/codecs/hdac_hdmi.c
> index 5eeb0fe..c991407 100644
> --- a/sound/soc/codecs/hdac_hdmi.c
> +++ b/sound/soc/codecs/hdac_hdmi.c
> @@ -1792,6 +1792,18 @@ int hdac_hdmi_jack_init(struct snd_soc_dai *dai, int device,
>   }
>   EXPORT_SYMBOL_GPL(hdac_hdmi_jack_init);
>   
> +struct device_link *
> +hdac_hdmi_device_link_add(struct device *consumer,
> +			  struct snd_soc_component *component,
> +			  u32 flags)
> +{
> +	struct hdac_hdmi_priv *hdmi = snd_soc_component_get_drvdata(component);
> +	struct hdac_device *hdev = hdmi->hdev;
> +
> +	return device_link_add(consumer, &hdev->dev, flags);

Don't you need a matching device_link_free() to avoid a memory leak?

Also what would be the expectations for the flags and do you really want 
the consumer to set them?

And last, without a patch of the cAVS driver it's hard to see how this 
might be used.

> +}
> +EXPORT_SYMBOL_GPL(hdac_hdmi_device_link_add);
> +
>   static void hdac_hdmi_present_sense_all_pins(struct hdac_device *hdev,
>   			struct hdac_hdmi_priv *hdmi, bool detect_pin_caps)
>   {
> diff --git a/sound/soc/codecs/hdac_hdmi.h b/sound/soc/codecs/hdac_hdmi.h
> index 4fa2fc9..9239c6b 100644
> --- a/sound/soc/codecs/hdac_hdmi.h
> +++ b/sound/soc/codecs/hdac_hdmi.h
> @@ -7,4 +7,10 @@ int hdac_hdmi_jack_init(struct snd_soc_dai *dai, int pcm,
>   
>   int hdac_hdmi_jack_port_init(struct snd_soc_component *component,
>   			struct snd_soc_dapm_context *dapm);
> +
> +struct device_link *
> +hdac_hdmi_device_link_add(struct device *consumer,
> +			  struct snd_soc_component *component,
> +			  u32 flags);
> +
>   #endif /* __HDAC_HDMI_H__ */
>