linux-kernel - [PATCH 8/8] usb: typec: ucsi: yoga-c630: register DRM HPD bridge

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Message-Id: <20250621-c630-ucsi-v1-8-a86de5e11361@oss.qualcomm.com>
Date: Sat, 21 Jun 2025 21:13:03 +0300
From: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
To: Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Bryan O'Donoghue <bryan.odonoghue@...aro.org>,
        Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konradybcio@...nel.org>
Cc: linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-msm@...r.kernel.org
Subject: [PATCH 8/8] usb: typec: ucsi: yoga-c630: register DRM HPD bridge

On Qualcomm platforms DisplayPort driver expects to have a drm bridge in
the final device on the USB-C chain. Register the DRM HPD bridge in
order to fulfill this requirement and to send HPD events to the DRM
driver.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
---
 drivers/usb/typec/ucsi/Kconfig          |  1 +
 drivers/usb/typec/ucsi/ucsi_yoga_c630.c | 39 +++++++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+)

diff --git a/drivers/usb/typec/ucsi/Kconfig b/drivers/usb/typec/ucsi/Kconfig
index 8bf8fefb4f07bccc4be90a4b7f771d91294386b0..52b53bb6dfed28c4272f8ccc5e31601aede29911 100644
--- a/drivers/usb/typec/ucsi/Kconfig
+++ b/drivers/usb/typec/ucsi/Kconfig
@@ -85,6 +85,7 @@ config CROS_EC_UCSI
 config UCSI_LENOVO_YOGA_C630
 	tristate "UCSI Interface Driver for Lenovo Yoga C630"
 	depends on EC_LENOVO_YOGA_C630
+	select DRM_AUX_HPD_BRIDGE if DRM_BRIDGE && OF
 	help
 	  This driver enables UCSI support on the Lenovo Yoga C630 laptop.
 
diff --git a/drivers/usb/typec/ucsi/ucsi_yoga_c630.c b/drivers/usb/typec/ucsi/ucsi_yoga_c630.c
index f85170417d19cdc5ae39a15e2f97010259ef12f6..0187c1c4b21abc7b5429526ebb4538c28b2e2e77 100644
--- a/drivers/usb/typec/ucsi/ucsi_yoga_c630.c
+++ b/drivers/usb/typec/ucsi/ucsi_yoga_c630.c
@@ -12,10 +12,14 @@
 #include <linux/container_of.h>
 #include <linux/module.h>
 #include <linux/notifier.h>
+#include <linux/of.h>
+#include <linux/property.h>
 #include <linux/string.h>
 #include <linux/platform_data/lenovo-yoga-c630.h>
 #include <linux/usb/typec_dp.h>
 
+#include <drm/bridge/aux-bridge.h>
+
 #include "ucsi.h"
 
 #define LENOVO_EC_USB_MUX	0x08
@@ -29,6 +33,7 @@
 struct yoga_c630_ucsi {
 	struct yoga_c630_ec *ec;
 	struct ucsi *ucsi;
+	struct auxiliary_device *bridge;
 	struct notifier_block nb;
 	u16 version;
 };
@@ -193,6 +198,13 @@ static void yoga_c630_ucsi_read_port0_status(struct yoga_c630_ucsi *uec)
 				      ccst == 1 ?
 				      TYPEC_ORIENTATION_REVERSE :
 				      TYPEC_ORIENTATION_NORMAL);
+
+	if (uec->bridge)
+		drm_aux_hpd_bridge_notify(&uec->bridge->dev,
+					  dppn != 0 ?
+					  connector_status_connected :
+					  connector_status_disconnected);
+
 }
 
 static int yoga_c630_ucsi_notify(struct notifier_block *nb,
@@ -237,6 +249,24 @@ static int yoga_c630_ucsi_probe(struct auxiliary_device *adev,
 	uec->ec = ec;
 	uec->nb.notifier_call = yoga_c630_ucsi_notify;
 
+	device_for_each_child_node_scoped(&adev->dev, fwnode) {
+		u32 port;
+
+		ret = fwnode_property_read_u32(fwnode, "reg", &port);
+		if (ret < 0) {
+			dev_err(&adev->dev, "missing reg property of %pfwP\n", fwnode);
+			return ret;
+		}
+
+		/* DP is only on port0 */
+		if (port != 0)
+			continue;
+
+		uec->bridge = devm_drm_dp_hpd_bridge_alloc(&adev->dev, to_of_node(fwnode));
+		if (IS_ERR(uec->bridge))
+			return PTR_ERR(uec->bridge);
+	}
+
 	uec->ucsi = ucsi_create(&adev->dev, &yoga_c630_ucsi_ops);
 	if (IS_ERR(uec->ucsi))
 		return PTR_ERR(uec->ucsi);
@@ -255,8 +285,17 @@ static int yoga_c630_ucsi_probe(struct auxiliary_device *adev,
 	if (ret)
 		goto err_unregister;
 
+	if (uec->bridge) {
+		ret = devm_drm_dp_hpd_bridge_add(&adev->dev, uec->bridge);
+		if (ret)
+			goto err_ucsi_unregister;
+	}
+
 	return 0;
 
+err_ucsi_unregister:
+	ucsi_unregister(uec->ucsi);
+
 err_unregister:
 	yoga_c630_ec_unregister_notify(uec->ec, &uec->nb);
 

-- 
2.39.5