[PATCH RFC] drm/vc4: hdmi: Add jack detection to HDMI audio driver

[Stefan Wahren]

Hi Dmitry,

Am 24.02.25 um 04:15 schrieb Dmitry Baryshkov:
> On Sat, Feb 22, 2025 at 11:29:21AM +0100, Stefan Wahren wrote:
>> From: David Turner <david.turner at raspberrypi.com>
>>
>> Add ALSA jack detection to the vc4-hdmi audio driver so userspace knows
>> when to add/remove HDMI audio devices.
>>
>> Signed-off-by: David Turner <david.turner at raspberrypi.com>
>> Signed-off-by: Stefan Wahren <wahrenst at gmx.net>
>> ---
>>   drivers/gpu/drm/vc4/vc4_hdmi.c | 26 ++++++++++++++++++++++++--
>>   drivers/gpu/drm/vc4/vc4_hdmi.h |  7 +++++++
>>   2 files changed, 31 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
>> index 47d9ada98430..d24ae86d799e 100644
>> --- a/drivers/gpu/drm/vc4/vc4_hdmi.c
>> +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
>> @@ -51,6 +51,7 @@
>>   #include <linux/reset.h>
>>   #include <sound/dmaengine_pcm.h>
>>   #include <sound/hdmi-codec.h>
>> +#include <sound/jack.h>
>>   #include <sound/pcm_drm_eld.h>
>>   #include <sound/pcm_params.h>
>>   #include <sound/soc.h>
>> @@ -386,6 +387,12 @@ static void vc4_hdmi_handle_hotplug(struct vc4_hdmi *vc4_hdmi,
>>   	struct drm_connector *connector = &vc4_hdmi->connector;
>>   	int ret;
>>
>> +	/*
>> +	 * Needs to be called for both connects and disconnects for HDMI
>> +	 * audio hotplug to work correctly.
>> +	 */
>> +	drm_atomic_helper_connector_hdmi_hotplug(connector, status);
>> +
>>   	/*
>>   	 * NOTE: This function should really be called with vc4_hdmi->mutex
>>   	 * held, but doing so results in reentrancy issues since
>> @@ -405,8 +412,6 @@ static void vc4_hdmi_handle_hotplug(struct vc4_hdmi *vc4_hdmi,
>>   		return;
>>   	}
>>
>> -	drm_atomic_helper_connector_hdmi_hotplug(connector, status);
>> -
>>   	cec_s_phys_addr(vc4_hdmi->cec_adap,
>>   			connector->display_info.source_physical_address, false);
>>
>> @@ -2203,6 +2208,22 @@ static const struct drm_connector_hdmi_audio_funcs vc4_hdmi_audio_funcs = {
>>   	.shutdown = vc4_hdmi_audio_shutdown,
>>   };
>>
>> +static int vc4_hdmi_codec_init(struct snd_soc_pcm_runtime *rtd)
>> +{
>> +	struct vc4_hdmi *vc4_hdmi = snd_soc_card_get_drvdata(rtd->card);
>> +	struct snd_soc_component *component = snd_soc_rtd_to_codec(rtd, 0)->component;
>> +	int ret;
>> +
>> +	ret = snd_soc_card_jack_new(rtd->card, "HDMI Jack", SND_JACK_LINEOUT,
>> +				    &vc4_hdmi->hdmi_jack);
>> +	if (ret) {
>> +		dev_err(rtd->dev, "HDMI Jack creation failed: %d\n", ret);
>> +		return ret;
>> +	}
>> +
>> +	return snd_soc_component_set_jack(component, &vc4_hdmi->hdmi_jack, NULL);
> PLease excuse my ignorance, but dows this work. In other words, how is
> the driver exporting the plugged state through this jack?
there is no ignorance just a valid question. Unfortunately my knowledge
here is very limited and I just wanted to minimize the delta between
vendor and mainline tree. That's why I marked it as RFC.

Can someone from Raspberry Pi helps here?

The patch seems to fix an issue? But I don't know the broader context.

Regards