linux/drivers/gpu/drm/display/drm_hdmi_audio_helper.c

// SPDX-License-Identifier: MIT
/*
 * Copyright (c) 2024 Linaro Ltd
 */

#include <linux/mutex.h>
#include <linux/of_graph.h>
#include <linux/platform_device.h>

#include <drm/drm_connector.h>
#include <drm/drm_device.h>
#include <drm/display/drm_hdmi_audio_helper.h>

#include <sound/hdmi-codec.h>

static int drm_connector_hdmi_audio_startup(struct device *dev, void *data)
{
	struct drm_connector *connector = data;
	const struct drm_connector_hdmi_audio_funcs *funcs =
		connector->hdmi_audio.funcs;

	if (funcs->startup)
		return funcs->startup(connector);

	return 0;
}

static int drm_connector_hdmi_audio_prepare(struct device *dev, void *data,
					    struct hdmi_codec_daifmt *fmt,
					    struct hdmi_codec_params *hparms)
{
	struct drm_connector *connector = data;
	const struct drm_connector_hdmi_audio_funcs *funcs =
		connector->hdmi_audio.funcs;

	return funcs->prepare(connector, fmt, hparms);
}

static void drm_connector_hdmi_audio_shutdown(struct device *dev, void *data)
{
	struct drm_connector *connector = data;
	const struct drm_connector_hdmi_audio_funcs *funcs =
		connector->hdmi_audio.funcs;

	return funcs->shutdown(connector);
}

static int drm_connector_hdmi_audio_mute_stream(struct device *dev, void *data,
						bool enable, int direction)
{
	struct drm_connector *connector = data;
	const struct drm_connector_hdmi_audio_funcs *funcs =
		connector->hdmi_audio.funcs;

	if (funcs->mute_stream)
		return funcs->mute_stream(connector, enable, direction);

	return -ENOTSUPP;
}

static int drm_connector_hdmi_audio_get_dai_id(struct snd_soc_component *comment,
					       struct device_node *endpoint,
					       void *data)
{
	struct drm_connector *connector = data;
	struct of_endpoint of_ep;
	int ret;

	if (connector->hdmi_audio.dai_port < 0)
		return -ENOTSUPP;

	ret = of_graph_parse_endpoint(endpoint, &of_ep);
	if (ret < 0)
		return ret;

	if (of_ep.port == connector->hdmi_audio.dai_port)
		return 0;

	return -EINVAL;
}

static int drm_connector_hdmi_audio_get_eld(struct device *dev, void *data,
					    uint8_t *buf, size_t len)
{
	struct drm_connector *connector = data;

	mutex_lock(&connector->eld_mutex);
	memcpy(buf, connector->eld, min(sizeof(connector->eld), len));
	mutex_unlock(&connector->eld_mutex);

	return 0;
}

static int drm_connector_hdmi_audio_hook_plugged_cb(struct device *dev,
						    void *data,
						    hdmi_codec_plugged_cb fn,
						    struct device *codec_dev)
{
	struct drm_connector *connector = data;

	mutex_lock(&connector->hdmi_audio.lock);

	connector->hdmi_audio.plugged_cb = fn;
	connector->hdmi_audio.plugged_cb_dev = codec_dev;

	fn(codec_dev, connector->hdmi_audio.last_state);

	mutex_unlock(&connector->hdmi_audio.lock);

	return 0;
}

void drm_connector_hdmi_audio_plugged_notify(struct drm_connector *connector,
					     bool plugged)
{
	mutex_lock(&connector->hdmi_audio.lock);

	connector->hdmi_audio.last_state = plugged;

	if (connector->hdmi_audio.plugged_cb &&
	    connector->hdmi_audio.plugged_cb_dev)
		connector->hdmi_audio.plugged_cb(connector->hdmi_audio.plugged_cb_dev,
						 connector->hdmi_audio.last_state);

	mutex_unlock(&connector->hdmi_audio.lock);
}
EXPORT_SYMBOL(drm_connector_hdmi_audio_plugged_notify);

static const struct hdmi_codec_ops drm_connector_hdmi_audio_ops = {
	.audio_startup = drm_connector_hdmi_audio_startup,
	.prepare = drm_connector_hdmi_audio_prepare,
	.audio_shutdown = drm_connector_hdmi_audio_shutdown,
	.mute_stream = drm_connector_hdmi_audio_mute_stream,
	.get_eld = drm_connector_hdmi_audio_get_eld,
	.get_dai_id = drm_connector_hdmi_audio_get_dai_id,
	.hook_plugged_cb = drm_connector_hdmi_audio_hook_plugged_cb,
};

/**
 * drm_connector_hdmi_audio_init - Initialize HDMI Codec device for the DRM connector
 * @connector: A pointer to the connector to allocate codec for
 * @hdmi_codec_dev: device to be used as a parent for the HDMI Codec
 * @funcs: callbacks for this HDMI Codec
 * @max_i2s_playback_channels: maximum number of playback I2S channels
 * @spdif_playback: set if HDMI codec has S/PDIF playback port
 * @dai_port: sound DAI port, -1 if it is not enabled
 *
 * Create a HDMI codec device to be used with the specified connector.
 *
 * Returns:
 * Zero on success, error code on failure.
 */
int drm_connector_hdmi_audio_init(struct drm_connector *connector,
				  struct device *hdmi_codec_dev,
				  const struct drm_connector_hdmi_audio_funcs *funcs,
				  unsigned int max_i2s_playback_channels,
				  bool spdif_playback,
				  int dai_port)
{
	struct hdmi_codec_pdata codec_pdata = {
		.ops = &drm_connector_hdmi_audio_ops,
		.max_i2s_channels = max_i2s_playback_channels,
		.i2s = !!max_i2s_playback_channels,
		.spdif = spdif_playback,
		.no_i2s_capture = true,
		.no_spdif_capture = true,
		.data = connector,
	};
	struct platform_device *pdev;

	if (!funcs ||
	    !funcs->prepare ||
	    !funcs->shutdown)
		return -EINVAL;

	connector->hdmi_audio.funcs = funcs;
	connector->hdmi_audio.dai_port = dai_port;

	pdev = platform_device_register_data(hdmi_codec_dev,
					     HDMI_CODEC_DRV_NAME,
					     PLATFORM_DEVID_AUTO,
					     &codec_pdata, sizeof(codec_pdata));
	if (IS_ERR(pdev))
		return PTR_ERR(pdev);

	connector->hdmi_audio.codec_pdev = pdev;

	return 0;
}
EXPORT_SYMBOL(drm_connector_hdmi_audio_init);