Message-ID: <tsgfxlkxty653crmzmwsr7p6slf27pxf6n6to5p7zvi6wsl444@525tz5uhbj44>
Date: Fri, 12 Sep 2025 14:03:02 +0300
From: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
To: Damon Ding <damon.ding@...k-chips.com>
Cc: andrzej.hajda@...el.com, neil.armstrong@...aro.org, rfoss@...nel.org,
        Laurent.pinchart@...asonboard.com, jonas@...boo.se,
        jernej.skrabec@...il.com, maarten.lankhorst@...ux.intel.com,
        mripard@...nel.org, tzimmermann@...e.de, airlied@...il.com,
        simona@...ll.ch, jingoohan1@...il.com, inki.dae@...sung.com,
        sw0312.kim@...sung.com, kyungmin.park@...sung.com, krzk@...nel.org,
        alim.akhtar@...sung.com, hjc@...k-chips.com, heiko@...ech.de,
        andy.yan@...k-chips.com, dianders@...omium.org,
        m.szyprowski@...sung.com, luca.ceresoli@...tlin.com,
        dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-samsung-soc@...r.kernel.org, linux-rockchip@...ts.infradead.org
Subject: Re: [PATCH v5 10/17] drm/bridge: analogix_dp: Apply
 drm_bridge_connector helper

On Fri, Sep 12, 2025 at 04:58:39PM +0800, Damon Ding wrote:
> Apply drm_bridge_connector helper for Analogix DP driver.
> 
> The following changes have been made:
> - Apply drm_bridge_connector helper to get rid of &drm_connector_funcs
>   and &drm_connector_helper_funcs.
> - Remove unnecessary parameter struct drm_connector* for callback
>   &analogix_dp_plat_data.attach.
> - Remove &analogix_dp_device.connector.
> - Convert analogix_dp_atomic_check()/analogix_dp_detect() to
>   &drm_bridge_funcs.atomic_check()/&drm_bridge_funcs.detect().
> - Split analogix_dp_get_modes() into &drm_bridge_funcs.get_modes() and
>   &drm_bridge_funcs.edid_read().
> 
> Signed-off-by: Damon Ding <damon.ding@...k-chips.com>
> 
> ------
> 
> Changes in v2:
> - For &drm_bridge.ops, remove DRM_BRIDGE_OP_HPD and add
>   DRM_BRIDGE_OP_EDID.
> - Add analogix_dp_bridge_edid_read().
> - Move &analogix_dp_plat_data.skip_connector deletion to the previous
>   patches.
> 
> Changes in v3:
> - Rebase with the new devm_drm_bridge_alloc() related commit
>   48f05c3b4b70 ("drm/bridge: analogix_dp: Use devm_drm_bridge_alloc()
>   API").
> - Expand the commit message.
> - Call drm_bridge_get_modes() in analogix_dp_bridge_get_modes() if the
>   bridge is available.
> - Remove unnecessary parameter struct drm_connector* for callback
>   &analogix_dp_plat_data.attach.
> - In order to decouple the connector driver and the bridge driver, move
>   the bridge connector initilization to the Rockchip and Exynos sides.
> 
> Changes in v4:
> - Expand analogix_dp_bridge_detect() parameters to &drm_bridge and
>   &drm_connector.
> - Rename the &analogix_dp_plat_data.bridge to
>   &analogix_dp_plat_data.next_bridge.
> 
> Changes in v5:
> - Set the flag fo drm_bridge_attach() to DRM_BRIDGE_ATTACH_NO_CONNECTOR
>   for next bridge attachment of Exynos side.
> - Distinguish the &drm_bridge->ops of Analogix bridge based on whether
>   the downstream device is a panel, a bridge or neither.
> - Remove the calls to &analogix_dp_plat_data.get_modes().
> ---
>  .../drm/bridge/analogix/analogix_dp_core.c    | 151 ++++++++----------
>  .../drm/bridge/analogix/analogix_dp_core.h    |   1 -
>  drivers/gpu/drm/exynos/exynos_dp.c            |  25 +--
>  .../gpu/drm/rockchip/analogix_dp-rockchip.c   |  11 +-
>  include/drm/bridge/analogix_dp.h              |   3 +-
>  5 files changed, 95 insertions(+), 96 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> index 9bf91d7595d6..156114170c4d 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> @@ -856,44 +856,38 @@ static int analogix_dp_disable_psr(struct analogix_dp_device *dp)
>  	return analogix_dp_send_psr_spd(dp, &psr_vsc, true);
>  }
>  
> -static int analogix_dp_get_modes(struct drm_connector *connector)
> +static int analogix_dp_bridge_get_modes(struct drm_bridge *bridge, struct drm_connector *connector)
>  {
> -	struct analogix_dp_device *dp = to_dp(connector);
> -	const struct drm_edid *drm_edid;
> +	struct analogix_dp_device *dp = to_dp(bridge);
>  	int num_modes = 0;
>  
> -	if (dp->plat_data->panel) {
> +	if (dp->plat_data->panel)
>  		num_modes += drm_panel_get_modes(dp->plat_data->panel, connector);
> -	} else {
> -		drm_edid = drm_edid_read_ddc(connector, &dp->aux.ddc);
>  
> -		drm_edid_connector_update(&dp->connector, drm_edid);
> -
> -		if (drm_edid) {
> -			num_modes += drm_edid_connector_add_modes(&dp->connector);
> -			drm_edid_free(drm_edid);
> -		}
> -	}
> +	if (dp->plat_data->next_bridge)
> +		num_modes += drm_bridge_get_modes(dp->plat_data->next_bridge, connector);

This will be already handled by drm_bridge_connector, it will use the
last bridge in chain which implements OP_EDID or OP_MODES (with OP_EDID
having higher priority).

>  
>  	return num_modes;
>  }
>  
> -static struct drm_encoder *
> -analogix_dp_best_encoder(struct drm_connector *connector)
> +static const struct drm_edid *analogix_dp_bridge_edid_read(struct drm_bridge *bridge,
> +							   struct drm_connector *connector)
>  {
> -	struct analogix_dp_device *dp = to_dp(connector);
> +	struct analogix_dp_device *dp = to_dp(bridge);
> +	const struct drm_edid *drm_edid = NULL;
>  
> -	return dp->encoder;
> -}
> +	drm_edid = drm_edid_read_ddc(connector, &dp->aux.ddc);

return drm_edid_read_ddc(...);

>  
> +	return drm_edid;
> +}
>  
> -static int analogix_dp_atomic_check(struct drm_connector *connector,
> -				    struct drm_atomic_state *state)
> +static int analogix_dp_bridge_atomic_check(struct drm_bridge *bridge,
> +					   struct drm_bridge_state *bridge_state,
> +					   struct drm_crtc_state *crtc_state,
> +					   struct drm_connector_state *conn_state)
>  {
> -	struct analogix_dp_device *dp = to_dp(connector);
> -	struct drm_display_info *di = &connector->display_info;
> -	struct drm_connector_state *conn_state;
> -	struct drm_crtc_state *crtc_state;
> +	struct analogix_dp_device *dp = to_dp(bridge);
> +	struct drm_display_info *di = &conn_state->connector->display_info;
>  	u32 mask = DRM_COLOR_FORMAT_YCBCR444 | DRM_COLOR_FORMAT_YCBCR422;
>  
>  	if (is_rockchip(dp->plat_data->dev_type)) {
> @@ -905,35 +899,18 @@ static int analogix_dp_atomic_check(struct drm_connector *connector,
>  		}
>  	}
>  
> -	conn_state = drm_atomic_get_new_connector_state(state, connector);
> -	if (WARN_ON(!conn_state))
> -		return -ENODEV;
> -
>  	conn_state->self_refresh_aware = true;
>  
> -	if (!conn_state->crtc)
> -		return 0;
> -
> -	crtc_state = drm_atomic_get_new_crtc_state(state, conn_state->crtc);
> -	if (!crtc_state)
> -		return 0;
> -
>  	if (crtc_state->self_refresh_active && !dp->psr_supported)
>  		return -EINVAL;
>  
>  	return 0;
>  }
>  
> -static const struct drm_connector_helper_funcs analogix_dp_connector_helper_funcs = {
> -	.get_modes = analogix_dp_get_modes,
> -	.best_encoder = analogix_dp_best_encoder,
> -	.atomic_check = analogix_dp_atomic_check,
> -};
> -
>  static enum drm_connector_status
> -analogix_dp_detect(struct drm_connector *connector, bool force)
> +analogix_dp_bridge_detect(struct drm_bridge *bridge, struct drm_connector *connector)
>  {
> -	struct analogix_dp_device *dp = to_dp(connector);
> +	struct analogix_dp_device *dp = to_dp(bridge);
>  	enum drm_connector_status status = connector_status_disconnected;
>  
>  	if (dp->plat_data->panel)
> @@ -945,21 +922,11 @@ analogix_dp_detect(struct drm_connector *connector, bool force)
>  	return status;
>  }
>  
> -static const struct drm_connector_funcs analogix_dp_connector_funcs = {
> -	.fill_modes = drm_helper_probe_single_connector_modes,
> -	.detect = analogix_dp_detect,
> -	.destroy = drm_connector_cleanup,
> -	.reset = drm_atomic_helper_connector_reset,
> -	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
> -	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
> -};
> -
>  static int analogix_dp_bridge_attach(struct drm_bridge *bridge,
>  				     struct drm_encoder *encoder,
>  				     enum drm_bridge_attach_flags flags)
>  {
>  	struct analogix_dp_device *dp = to_dp(bridge);
> -	struct drm_connector *connector = NULL;
>  	int ret = 0;
>  
>  	if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR) {
> @@ -967,31 +934,8 @@ static int analogix_dp_bridge_attach(struct drm_bridge *bridge,
>  		return -EINVAL;
>  	}
>  
> -	if (!dp->plat_data->next_bridge) {
> -		connector = &dp->connector;
> -		connector->polled = DRM_CONNECTOR_POLL_HPD;
> -
> -		ret = drm_connector_init(dp->drm_dev, connector,
> -					 &analogix_dp_connector_funcs,
> -					 DRM_MODE_CONNECTOR_eDP);
> -		if (ret) {
> -			DRM_ERROR("Failed to initialize connector with drm\n");
> -			return ret;
> -		}
> -
> -		drm_connector_helper_add(connector,
> -					 &analogix_dp_connector_helper_funcs);
> -		drm_connector_attach_encoder(connector, encoder);
> -	}
> -
> -	/*
> -	 * NOTE: the connector registration is implemented in analogix
> -	 * platform driver, that to say connector would be exist after
> -	 * plat_data->attch return, that's why we record the connector
> -	 * point after plat attached.
> -	 */
>  	if (dp->plat_data->attach) {
> -		ret = dp->plat_data->attach(dp->plat_data, bridge, connector);
> +		ret = dp->plat_data->attach(dp->plat_data, bridge);
>  		if (ret) {
>  			DRM_ERROR("Failed at platform attach func\n");
>  			return ret;
> @@ -1095,14 +1039,21 @@ static int analogix_dp_set_bridge(struct analogix_dp_device *dp)
>  }
>  
>  static void analogix_dp_bridge_mode_set(struct drm_bridge *bridge,
> +					struct drm_atomic_state *state,
>  					const struct drm_display_mode *mode)
>  {
>  	struct analogix_dp_device *dp = to_dp(bridge);
> -	struct drm_display_info *display_info = &dp->connector.display_info;
>  	struct video_info *video = &dp->video_info;
>  	struct device_node *dp_node = dp->dev->of_node;
> +	struct drm_connector *connector;
> +	struct drm_display_info *display_info;
>  	int vic;
>  
> +	connector = drm_atomic_get_new_connector_for_encoder(state, bridge->encoder);
> +	if (!connector)
> +		return;
> +	display_info = &connector->display_info;
> +
>  	/* Input video interlaces & hsync pol & vsync pol */
>  	video->interlaced = !!(mode->flags & DRM_MODE_FLAG_INTERLACE);
>  	video->v_sync_polarity = !!(mode->flags & DRM_MODE_FLAG_NVSYNC);
> @@ -1186,7 +1137,7 @@ static void analogix_dp_bridge_atomic_enable(struct drm_bridge *bridge,
>  	new_crtc_state = drm_atomic_get_new_crtc_state(old_state, crtc);
>  	if (!new_crtc_state)
>  		return;
> -	analogix_dp_bridge_mode_set(bridge, &new_crtc_state->adjusted_mode);
> +	analogix_dp_bridge_mode_set(bridge, old_state, &new_crtc_state->adjusted_mode);
>  
>  	old_crtc_state = drm_atomic_get_old_crtc_state(old_state, crtc);
>  	/* Not a full enable, just disable PSR and continue */
> @@ -1302,7 +1253,11 @@ static const struct drm_bridge_funcs analogix_dp_bridge_funcs = {
>  	.atomic_enable = analogix_dp_bridge_atomic_enable,
>  	.atomic_disable = analogix_dp_bridge_atomic_disable,
>  	.atomic_post_disable = analogix_dp_bridge_atomic_post_disable,
> +	.atomic_check = analogix_dp_bridge_atomic_check,
>  	.attach = analogix_dp_bridge_attach,
> +	.get_modes = analogix_dp_bridge_get_modes,
> +	.edid_read = analogix_dp_bridge_edid_read,
> +	.detect = analogix_dp_bridge_detect,
>  };
>  
>  static int analogix_dp_dt_parse_pdata(struct analogix_dp_device *dp)
> @@ -1532,6 +1487,7 @@ EXPORT_SYMBOL_GPL(analogix_dp_resume);
>  
>  int analogix_dp_bind(struct analogix_dp_device *dp, struct drm_device *drm_dev)
>  {
> +	struct drm_bridge *bridge = &dp->bridge;
>  	int ret;
>  
>  	dp->drm_dev = drm_dev;
> @@ -1545,7 +1501,23 @@ int analogix_dp_bind(struct analogix_dp_device *dp, struct drm_device *drm_dev)
>  		return ret;
>  	}
>  
> -	ret = drm_bridge_attach(dp->encoder, &dp->bridge, NULL, 0);
> +	if (dp->plat_data->panel)
> +		/* If the next is a panel, the EDID parsing is checked by the panel driver */
> +		bridge->ops = DRM_BRIDGE_OP_MODES | DRM_BRIDGE_OP_DETECT;
> +	else if (dp->plat_data->next_bridge)
> +		/* If the next is a bridge, the supported operations depend on the next bridge */
> +		bridge->ops = 0;

And what if the next bridge is dp_connector without a separate HPD pin?

> +	else
> +		/* In DP mode, the EDID parsing and HPD detection should be supported */
> +		bridge->ops = DRM_BRIDGE_OP_EDID | DRM_BRIDGE_OP_DETECT;
> +
> +	bridge->of_node = dp->dev->of_node;
> +	bridge->type = DRM_MODE_CONNECTOR_eDP;
> +	ret = devm_drm_bridge_add(dp->dev, &dp->bridge);
> +	if (ret)
> +		goto err_unregister_aux;
> +
> +	ret = drm_bridge_attach(dp->encoder, bridge, NULL, 0);
>  	if (ret) {
>  		DRM_ERROR("failed to create bridge (%d)\n", ret);
>  		goto err_unregister_aux;

-- 
With best wishes
Dmitry

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