[PATCH v3] drm/rockchip: cdn-dp: Convert to drm bridge

Dmitry Baryshkov dmitry.baryshkov at oss.qualcomm.com
Tue May 27 20:25:58 UTC 2025


On Tue, May 27, 2025 at 04:14:47PM +0800, Chaoyi Chen wrote:
> From: Chaoyi Chen <chaoyi.chen at rock-chips.com>
> 
> Convert it to drm bridge driver, it will be convenient for us to
> migrate the connector part to the display driver later.
> Considering that some code depend on the connector, the following
> changes have been made:
> - Only process edid in &drm_bridge_funcs.edid_read(), so no need to
> store additional edid info.
> - Now cdn_dp_get_sink_capability() only focused on reading DPCD_REV.
> - Update bpc info in cdn_dp_bridge_atomic_enable() instead of
> cdn_dp_encoder_mode_set(). Actually, the bpc data will be used in
> cdn_dp_bridge_atomic_enable().
> - Switch to use DRM_BRIDGE_OP_DP_AUDIO helpers.
> 
> This patch also convert to use devm_drm_bridge_alloc() API.
> 
> Tested with RK3399 EVB IND board.
> 
> Signed-off-by: Chaoyi Chen <chaoyi.chen at rock-chips.com>
> ---
> 
> Changes in v3:
> - Link to V2: https://lore.kernel.org/all/20250523011310.120-1-kernel@airkyi.com/
> - Switch to use DRM_BRIDGE_OP_DP_AUDIO helpers
> - Remove the dependency for connector
> - Remove the extra stored edid
> - Code cleanup
> 
> Changes in v2:
> - Link to V1: https://lore.kernel.org/all/20250507035148.415-1-kernel@airkyi.com/
> - Use drm_atomic_get_new_connector_for_encoder() to get connector
> - Convert to use devm_drm_bridge_alloc() API
> - Fix typo: cdn_dp_connector_edid_read -> cdn_dp_bridge_edid_read
> 
>  drivers/gpu/drm/rockchip/cdn-dp-core.c | 279 ++++++++++---------------
>  drivers/gpu/drm/rockchip/cdn-dp-core.h |   9 +-
>  2 files changed, 110 insertions(+), 178 deletions(-)
> 


> @@ -595,16 +546,41 @@ static bool cdn_dp_check_link_status(struct cdn_dp_device *dp)
>  static void cdn_dp_audio_handle_plugged_change(struct cdn_dp_device *dp,
>  					       bool plugged)
>  {
> -	if (dp->codec_dev)
> -		dp->plugged_cb(dp->codec_dev, plugged);
> +	if (dp->sink_has_audio)
> +		drm_connector_hdmi_audio_plugged_notify(dp->connector, plugged);

I'd say, notify always and let userspace figure it out via the ELD. Then
you shouldn't need sink_has_audio. This would match the behaviour of
HDMI drivers.

>  }
>  

[...]

> @@ -705,8 +681,6 @@ static int cdn_dp_encoder_atomic_check(struct drm_encoder *encoder,
>  
>  static const struct drm_encoder_helper_funcs cdn_dp_encoder_helper_funcs = {
>  	.mode_set = cdn_dp_encoder_mode_set,
> -	.enable = cdn_dp_encoder_enable,
> -	.disable = cdn_dp_encoder_disable,
>  	.atomic_check = cdn_dp_encoder_atomic_check,

Nit: for the future cleanup, it should probably be possible to get rid
of these encoder ops too by moving them to the bridge ops.

>  };
>  

[...]

> @@ -1006,7 +947,8 @@ static void cdn_dp_pd_event_work(struct work_struct *work)
>  
>  out:
>  	mutex_unlock(&dp->lock);
> -	drm_connector_helper_hpd_irq_event(&dp->connector);
> +	if (dp->connector)
> +		drm_connector_helper_hpd_irq_event(dp->connector);

drm_bridge_hpd_notify(). I think then you don't need dp->connector.

>  }
>  
>  static int cdn_dp_pd_event(struct notifier_block *nb,
> @@ -1062,26 +1004,35 @@ static int cdn_dp_bind(struct device *dev, struct device *master, void *data)
>  
>  	drm_encoder_helper_add(encoder, &cdn_dp_encoder_helper_funcs);
>  
> -	connector = &dp->connector;
> -	connector->polled = DRM_CONNECTOR_POLL_HPD;
> -	connector->dpms = DRM_MODE_DPMS_OFF;
> -
> -	ret = drm_connector_init(drm_dev, connector,
> -				 &cdn_dp_atomic_connector_funcs,
> -				 DRM_MODE_CONNECTOR_DisplayPort);
> -	if (ret) {
> -		DRM_ERROR("failed to initialize connector with drm\n");
> -		goto err_free_encoder;
> -	}
> +	dp->bridge.ops =
> +			DRM_BRIDGE_OP_DETECT |
> +			DRM_BRIDGE_OP_EDID |
> +			DRM_BRIDGE_OP_HPD |
> +			DRM_BRIDGE_OP_DP_AUDIO;
> +	dp->bridge.of_node = dp->dev->of_node;
> +	dp->bridge.type = DRM_MODE_CONNECTOR_DisplayPort;
> +	dp->bridge.hdmi_audio_dev = dp->dev;
> +	dp->bridge.hdmi_audio_max_i2s_playback_channels = 8;
> +	dp->bridge.hdmi_audio_spdif_playback = 1;
> +	dp->bridge.hdmi_audio_dai_port = -1;
> +
> +	ret = devm_drm_bridge_add(dev, &dp->bridge);
> +	if (ret)
> +		return ret;
>  
> -	drm_connector_helper_add(connector, &cdn_dp_connector_helper_funcs);
> +	ret = drm_bridge_attach(encoder, &dp->bridge, NULL, DRM_BRIDGE_ATTACH_NO_CONNECTOR);
> +	if (ret)
> +		return ret;
>  
> -	ret = drm_connector_attach_encoder(connector, encoder);
> -	if (ret) {
> -		DRM_ERROR("failed to attach connector and encoder\n");
> -		goto err_free_connector;
> +	connector = drm_bridge_connector_init(drm_dev, encoder);
> +	if (IS_ERR(connector)) {
> +		ret = PTR_ERR(connector);
> +		dev_err(dp->dev, "failed to init bridge connector: %d\n", ret);
> +		return ret;
>  	}
>  
> +	drm_connector_attach_encoder(connector, encoder);
> +
>  	for (i = 0; i < dp->ports; i++) {
>  		port = dp->port[i];
>  
> @@ -1101,30 +1052,19 @@ static int cdn_dp_bind(struct device *dev, struct device *master, void *data)
>  	schedule_work(&dp->event_work);
>  
>  	return 0;
> -
> -err_free_connector:
> -	drm_connector_cleanup(connector);
> -err_free_encoder:
> -	drm_encoder_cleanup(encoder);
> -	return ret;
>  }
>  
>  static void cdn_dp_unbind(struct device *dev, struct device *master, void *data)
>  {
>  	struct cdn_dp_device *dp = dev_get_drvdata(dev);
>  	struct drm_encoder *encoder = &dp->encoder.encoder;
> -	struct drm_connector *connector = &dp->connector;
>  
>  	cancel_work_sync(&dp->event_work);
> -	cdn_dp_encoder_disable(encoder);
>  	encoder->funcs->destroy(encoder);
> -	connector->funcs->destroy(connector);
>  
>  	pm_runtime_disable(dev);
>  	if (dp->fw_loaded)
>  		release_firmware(dp->fw);
> -	drm_edid_free(dp->drm_edid);
> -	dp->drm_edid = NULL;
>  }
>  
>  static const struct component_ops cdn_dp_component_ops = {
> @@ -1171,9 +1111,10 @@ static int cdn_dp_probe(struct platform_device *pdev)
>  	int ret;
>  	int i;
>  
> -	dp = devm_kzalloc(dev, sizeof(*dp), GFP_KERNEL);
> -	if (!dp)
> -		return -ENOMEM;
> +	dp = devm_drm_bridge_alloc(dev, struct cdn_dp_device, bridge,
> +				   &cdn_dp_bridge_funcs);
> +	if (IS_ERR(dp))
> +		return PTR_ERR(dp);
>  	dp->dev = dev;
>  
>  	match = of_match_node(cdn_dp_dt_ids, pdev->dev.of_node);
> @@ -1209,19 +1150,11 @@ static int cdn_dp_probe(struct platform_device *pdev)
>  	mutex_init(&dp->lock);
>  	dev_set_drvdata(dev, dp);
>  
> -	ret = cdn_dp_audio_codec_init(dp, dev);
> -	if (ret)
> -		return ret;
> -
>  	ret = component_add(dev, &cdn_dp_component_ops);
>  	if (ret)
> -		goto err_audio_deinit;
> +		return ret;
>  
>  	return 0;
> -
> -err_audio_deinit:
> -	platform_device_unregister(dp->audio_pdev);
> -	return ret;
>  }
>  
>  static void cdn_dp_remove(struct platform_device *pdev)
> diff --git a/drivers/gpu/drm/rockchip/cdn-dp-core.h b/drivers/gpu/drm/rockchip/cdn-dp-core.h
> index 17498f576ce7..6aa3ce489382 100644
> --- a/drivers/gpu/drm/rockchip/cdn-dp-core.h
> +++ b/drivers/gpu/drm/rockchip/cdn-dp-core.h
> @@ -8,6 +8,8 @@
>  #define _CDN_DP_CORE_H
>  
>  #include <drm/display/drm_dp_helper.h>
> +#include <drm/drm_bridge.h>
> +#include <drm/drm_bridge_connector.h>

This include can go to the C file instead of the header.

>  #include <drm/drm_panel.h>
>  #include <drm/drm_probe_helper.h>
>  #include <sound/hdmi-codec.h>
> @@ -65,12 +67,12 @@ struct cdn_dp_port {
>  struct cdn_dp_device {
>  	struct device *dev;
>  	struct drm_device *drm_dev;
> -	struct drm_connector connector;
> +	struct drm_bridge bridge;
> +	struct drm_connector *connector;
>  	struct rockchip_encoder encoder;
>  	struct drm_display_mode mode;
>  	struct platform_device *audio_pdev;
>  	struct work_struct event_work;
> -	const struct drm_edid *drm_edid;
>  
>  	struct mutex lock;
>  	bool connected;
> @@ -102,8 +104,5 @@ struct cdn_dp_device {
>  
>  	u8 dpcd[DP_RECEIVER_CAP_SIZE];
>  	bool sink_has_audio;
> -
> -	hdmi_codec_plugged_cb plugged_cb;
> -	struct device *codec_dev;
>  };
>  #endif  /* _CDN_DP_CORE_H */
> -- 
> 2.49.0
> 

-- 
With best wishes
Dmitry


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