While LT9611UXC is a DSI-to-HDMI bridge, it implements all HDMI-related
functions internally, in the firmware, thus it doesn't make sense to
implement DRM_BRIDGE_OP_HDMI. However it is possible to implement
DRM_BRIDGE_OP_HDMI_AUDIO, streamlining HDMI audio plumbing (which
includes plugged notifications and ELD handling).

Implement corresponding callbacks and trigger EDID read /
drm_connector_hdmi_audio_plugged_notify() from the hpd_notify callback.

Signed-off-by: Dmitry Baryshkov <redacted>
---
  drivers/gpu/drm/bridge/lontium-lt9611uxc.c | 125 +++++++++++------------------
  1 file changed, 49 insertions(+), 76 deletions(-)

diff --git a/drivers/gpu/drm/bridge/lontium-lt9611uxc.c b/drivers/gpu/drm/bridge/lontium-lt9611uxc.c
index 38fb8776c0f441ae433c60a7680aaa6501a8956e..11aab07d88df646a54fea287030a183eb823b26d 100644
--- a/drivers/gpu/drm/bridge/lontium-lt9611uxc.c
+++ b/drivers/gpu/drm/bridge/lontium-lt9611uxc.c

@@ -17,8 +17,6 @@
  #include <linux/wait.h>
  #include <linux/workqueue.h>
  
-#include <sound/hdmi-codec.h>
-
  #include <drm/drm_atomic_helper.h>
  #include <drm/drm_bridge.h>
  #include <drm/drm_edid.h>

@@ -27,6 +25,8 @@
  #include <drm/drm_print.h>
  #include <drm/drm_probe_helper.h>
  
+#include <drm/display/drm_hdmi_audio_helper.h>
+
  #define EDID_BLOCK_SIZE	128
  #define EDID_NUM_BLOCKS	2
  

@@ -48,7 +48,6 @@ struct lt9611uxc {
  	struct device_node *dsi1_node;
  	struct mipi_dsi_device *dsi0;
  	struct mipi_dsi_device *dsi1;
-	struct platform_device *audio_pdev;
  
  	struct gpio_desc *reset_gpio;
  	struct gpio_desc *enable_gpio;

@@ -429,12 +428,52 @@ static const struct drm_edid *lt9611uxc_bridge_edid_read(struct drm_bridge *brid
  	return drm_edid_read_custom(connector, lt9611uxc_get_edid_block, lt9611uxc);
  }
  
+static void lt9611uxc_bridge_hpd_notify(struct drm_bridge *bridge,
+					struct drm_connector *connector,
+					enum drm_connector_status status)
+{
+	const struct drm_edid *drm_edid;
+
+	if (status == connector_status_disconnected) {
+		drm_connector_hdmi_audio_plugged_notify(connector, false);
+		drm_edid_connector_update(connector, NULL);
+		return;
+	}
+
+	drm_edid = lt9611uxc_bridge_edid_read(bridge, connector);
+	drm_edid_connector_update(connector, drm_edid);
+	drm_edid_free(drm_edid);
+
+	if (status == connector_status_connected)
+		drm_connector_hdmi_audio_plugged_notify(connector, true);
+}
+
+static int lt9611uxc_hdmi_audio_prepare(struct drm_bridge *bridge,
+					struct drm_connector *connector,
+					struct hdmi_codec_daifmt *fmt,
+					struct hdmi_codec_params *hparms)
+{
+	/*
+	 * LT9611UXC will automatically detect rate and sample size, so no need
+	 * to setup anything here.
+	 */
+	return 0;
+}
+
+static void lt9611uxc_hdmi_audio_shutdown(struct drm_bridge *bridge,
+					  struct drm_connector *connector)
+{
+}
+
  static const struct drm_bridge_funcs lt9611uxc_bridge_funcs = {
  	.attach = lt9611uxc_bridge_attach,
  	.mode_valid = lt9611uxc_bridge_mode_valid,
  	.mode_set = lt9611uxc_bridge_mode_set,
  	.detect = lt9611uxc_bridge_detect,
  	.edid_read = lt9611uxc_bridge_edid_read,
+	.hpd_notify = lt9611uxc_bridge_hpd_notify,
+	.hdmi_audio_prepare = lt9611uxc_hdmi_audio_prepare,
+	.hdmi_audio_shutdown = lt9611uxc_hdmi_audio_shutdown,
  };
  
  static int lt9611uxc_parse_dt(struct device *dev,

@@ -508,73 +547,6 @@ static int lt9611uxc_read_version(struct lt9611uxc *lt9611uxc)
  	return ret < 0 ? ret : rev;
  }
  
-static int lt9611uxc_hdmi_hw_params(struct device *dev, void *data,
-				    struct hdmi_codec_daifmt *fmt,
-				    struct hdmi_codec_params *hparms)
-{
-	/*
-	 * LT9611UXC will automatically detect rate and sample size, so no need
-	 * to setup anything here.
-	 */
-	return 0;
-}
-
-static void lt9611uxc_audio_shutdown(struct device *dev, void *data)
-{
-}
-
-static int lt9611uxc_hdmi_i2s_get_dai_id(struct snd_soc_component *component,
-					 struct device_node *endpoint,
-					 void *data)
-{
-	struct of_endpoint of_ep;
-	int ret;
-
-	ret = of_graph_parse_endpoint(endpoint, &of_ep);
-	if (ret < 0)
-		return ret;
-
-	/*
-	 * HDMI sound should be located as reg = <2>
-	 * Then, it is sound port 0
-	 */
-	if (of_ep.port == 2)
-		return 0;
-
-	return -EINVAL;
-}
-
-static const struct hdmi_codec_ops lt9611uxc_codec_ops = {
-	.hw_params	= lt9611uxc_hdmi_hw_params,
-	.audio_shutdown = lt9611uxc_audio_shutdown,
-	.get_dai_id	= lt9611uxc_hdmi_i2s_get_dai_id,
-};
-
-static int lt9611uxc_audio_init(struct device *dev, struct lt9611uxc *lt9611uxc)
-{
-	struct hdmi_codec_pdata codec_data = {
-		.ops = &lt9611uxc_codec_ops,
-		.max_i2s_channels = 2,
-		.i2s = 1,
-		.data = lt9611uxc,
-	};
-
-	lt9611uxc->audio_pdev =
-		platform_device_register_data(dev, HDMI_CODEC_DRV_NAME,
-					      PLATFORM_DEVID_AUTO,
-					      &codec_data, sizeof(codec_data));
-
-	return PTR_ERR_OR_ZERO(lt9611uxc->audio_pdev);
-}
-
-static void lt9611uxc_audio_exit(struct lt9611uxc *lt9611uxc)
-{
-	if (lt9611uxc->audio_pdev) {
-		platform_device_unregister(lt9611uxc->audio_pdev);
-		lt9611uxc->audio_pdev = NULL;
-	}
-}
-
  #define LT9611UXC_FW_PAGE_SIZE 32
  static void lt9611uxc_firmware_write_page(struct lt9611uxc *lt9611uxc, u16 addr, const u8 *buf)
  {

@@ -858,11 +830,17 @@ static int lt9611uxc_probe(struct i2c_client *client)
  	i2c_set_clientdata(client, lt9611uxc);
  
  	lt9611uxc->bridge.of_node = client->dev.of_node;
-	lt9611uxc->bridge.ops = DRM_BRIDGE_OP_DETECT | DRM_BRIDGE_OP_EDID;
+	lt9611uxc->bridge.ops = DRM_BRIDGE_OP_DETECT |
+		DRM_BRIDGE_OP_EDID |
+		DRM_BRIDGE_OP_HDMI_AUDIO;
  	if (lt9611uxc->hpd_supported)
  		lt9611uxc->bridge.ops |= DRM_BRIDGE_OP_HPD;
  	lt9611uxc->bridge.type = DRM_MODE_CONNECTOR_HDMIA;
  
+	lt9611uxc->bridge.hdmi_audio_dev = dev;
+	lt9611uxc->bridge.hdmi_audio_max_i2s_playback_channels = 2;
+	lt9611uxc->bridge.hdmi_audio_dai_port = 2;
+
  	drm_bridge_add(&lt9611uxc->bridge);
  
  	/* Attach primary DSI */

@@ -881,10 +859,6 @@ static int lt9611uxc_probe(struct i2c_client *client)
  		}
  	}
  
-	ret = lt9611uxc_audio_init(dev, lt9611uxc);
-	if (ret)
-		goto err_remove_bridge;
-
  	return 0;
  
  err_remove_bridge:

@@ -908,7 +882,6 @@ static void lt9611uxc_remove(struct i2c_client *client)
  
  	free_irq(client->irq, lt9611uxc);
  	cancel_work_sync(&lt9611uxc->work);
-	lt9611uxc_audio_exit(lt9611uxc);
  	drm_bridge_remove(&lt9611uxc->bridge);
  
  	mutex_destroy(&lt9611uxc->ocm_lock);