linux-kernel - [PATCH v5 09/11] drm/display: bridge-connector: hook in CEC notifier support

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Message-Id: <20250407-drm-hdmi-connector-cec-v5-9-04809b10d206@oss.qualcomm.com>
Date: Mon, 07 Apr 2025 18:11:06 +0300
From: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
To: Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
        Dave Stevenson <dave.stevenson@...pberrypi.com>,
        Maíra Canal <mcanal@...lia.com>,
        Raspberry Pi Kernel Maintenance <kernel-list@...pberrypi.com>,
        Andrzej Hajda <andrzej.hajda@...el.com>,
        Neil Armstrong <neil.armstrong@...aro.org>,
        Robert Foss <rfoss@...nel.org>,
        Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
        Jonas Karlman <jonas@...boo.se>,
        Jernej Skrabec <jernej.skrabec@...il.com>
Cc: dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        Dmitry Baryshkov <lumag@...nel.org>
Subject: [PATCH v5 09/11] drm/display: bridge-connector: hook in CEC
 notifier support

Allow HDMI DRM bridges to create CEC notifier. Physical address is
handled automatically by drm_atomic_helper_connector_hdmi_hotplug()
being called from .detect() path.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
---
 drivers/gpu/drm/display/Kconfig                |  1 +
 drivers/gpu/drm/display/drm_bridge_connector.c | 24 ++++++++++++++++++++++++
 include/drm/drm_bridge.h                       | 11 +++++++++++
 3 files changed, 36 insertions(+)

diff --git a/drivers/gpu/drm/display/Kconfig b/drivers/gpu/drm/display/Kconfig
index 6376ea01ec3093a72de25064e31223d2c9868ed7..df09cf9a8ca19ea894d6f2fad68c0b191e81e3d0 100644
--- a/drivers/gpu/drm/display/Kconfig
+++ b/drivers/gpu/drm/display/Kconfig
@@ -17,6 +17,7 @@ if DRM_DISPLAY_HELPER
 config DRM_BRIDGE_CONNECTOR
 	bool
 	select DRM_DISPLAY_HDMI_AUDIO_HELPER
+	select DRM_DISPLAY_HDMI_CEC_HELPER
 	select DRM_DISPLAY_HDMI_STATE_HELPER
 	help
 	  DRM connector implementation terminating DRM bridge chains.
diff --git a/drivers/gpu/drm/display/drm_bridge_connector.c b/drivers/gpu/drm/display/drm_bridge_connector.c
index 381a0f9d4259bf9f72d3a292b7dcc82e45c61bae..daf6117268d9d3bb0c0c12b5094e79ad13cf72dd 100644
--- a/drivers/gpu/drm/display/drm_bridge_connector.c
+++ b/drivers/gpu/drm/display/drm_bridge_connector.c
@@ -20,6 +20,7 @@
 #include <drm/drm_print.h>
 #include <drm/drm_probe_helper.h>
 #include <drm/display/drm_hdmi_audio_helper.h>
+#include <drm/display/drm_hdmi_cec_helper.h>
 #include <drm/display/drm_hdmi_helper.h>
 #include <drm/display/drm_hdmi_state_helper.h>
 
@@ -113,6 +114,13 @@ struct drm_bridge_connector {
 	 * &DRM_BRIDGE_OP_DP_AUDIO).
 	 */
 	struct drm_bridge *bridge_dp_audio;
+	/**
+	 * @bridge_hdmi_cec:
+	 *
+	 * The bridge in the chain that implements CEC support, if any (see
+	 * DRM_BRIDGE_OP_HDMI_CEC_NOTIFIER).
+	 */
+	struct drm_bridge *bridge_hdmi_cec;
 };
 
 #define to_drm_bridge_connector(x) \
@@ -662,6 +670,13 @@ struct drm_connector *drm_bridge_connector_init(struct drm_device *drm,
 			bridge_connector->bridge_dp_audio = bridge;
 		}
 
+		if (bridge->ops & DRM_BRIDGE_OP_HDMI_CEC_NOTIFIER) {
+			if (bridge_connector->bridge_hdmi_cec)
+				return ERR_PTR(-EBUSY);
+
+			bridge_connector->bridge_hdmi_cec = bridge;
+		}
+
 		if (!drm_bridge_get_next_bridge(bridge))
 			connector_type = bridge->type;
 
@@ -724,6 +739,15 @@ struct drm_connector *drm_bridge_connector_init(struct drm_device *drm,
 			return ERR_PTR(ret);
 	}
 
+	if (bridge_connector->bridge_hdmi_cec &&
+	    bridge_connector->bridge_hdmi_cec->ops & DRM_BRIDGE_OP_HDMI_CEC_NOTIFIER) {
+		ret = drm_connector_hdmi_cec_notifier_register(connector,
+							       NULL,
+							       bridge->hdmi_cec_dev);
+		if (ret)
+			return ERR_PTR(ret);
+	}
+
 	drm_connector_helper_add(connector, &drm_bridge_connector_helper_funcs);
 
 	if (bridge_connector->bridge_hpd)
diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
index db0d374d863b0b1f774d395743f1e29bb84e8937..0e5f6a007d536215bd50e11846433290c2060b9c 100644
--- a/include/drm/drm_bridge.h
+++ b/include/drm/drm_bridge.h
@@ -907,6 +907,11 @@ enum drm_bridge_ops {
 	 * flag.
 	 */
 	DRM_BRIDGE_OP_DP_AUDIO = BIT(6),
+	/**
+	 * @DRM_BRIDGE_OP_HDMI_CEC_NOTIFIER: The bridge requires CEC notifier
+	 * to be present.
+	 */
+	DRM_BRIDGE_OP_HDMI_CEC_NOTIFIER = BIT(7),
 };
 
 /**
@@ -1003,6 +1008,12 @@ struct drm_bridge {
 	 */
 	unsigned int max_bpc;
 
+	/**
+	 * @hdmi_cec_dev: device to be used as a containing device for CEC
+	 * functions.
+	 */
+	struct device *hdmi_cec_dev;
+
 	/**
 	 * @hdmi_audio_dev: device to be used as a parent for the HDMI Codec if
 	 * either of @DRM_BRIDGE_OP_HDMI_AUDIO or @DRM_BRIDGE_OP_DP_AUDIO is set.

-- 
2.39.5