[PATCH] usb: typec: fusb302: add DRM DP HPD bridge support

[Sebastian Reichel]

Add support to use fusb302 based USB-C connectors with the DP altmode
helper code on devicetree based platforms. To get this working there
must be a DRM bridge chain from the DisplayPort controller to the USB-C
connector. E.g. on Rockchip RK3576:

root@rk3576 # cat /sys/kernel/debug/dri/0/encoder-0/bridges
bridge[0]: dw_dp_bridge_funcs
	refcount: 7
	type: [10] DP
	OF: /soc/dp@27e40000:rockchip,rk3576-dp
	ops: [0x47] detect edid hpd
bridge[1]: drm_aux_bridge_funcs
	refcount: 4
	type: [0] Unknown
	OF: /soc/phy@2b010000:rockchip,rk3576-usbdp-phy
	ops: [0x0]
bridge[2]: drm_aux_hpd_bridge_funcs
	refcount: 5
	type: [10] DP
	OF: /soc/i2c@2ac50000/typec-portc@22/connector:usb-c-connector
	ops: [0x4] hpd

Signed-off-by: Sebastian Reichel <sebastian.reichel@xxxxxxxxxxxxx>
---
To make this usable on Rockchip RK3588 and RK3576 platforms as shown in
the commit message, the Designware DP driver and the USBDP PHY driver
also need changes. Those are being send separately as the fusb302 patch
can be merged completley independently.
---
 drivers/usb/typec/tcpm/Kconfig   |  2 ++
 drivers/usb/typec/tcpm/fusb302.c | 13 +++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/drivers/usb/typec/tcpm/Kconfig b/drivers/usb/typec/tcpm/Kconfig
index 8cdd84ca5d6f..00baa7503d45 100644
--- a/drivers/usb/typec/tcpm/Kconfig
+++ b/drivers/usb/typec/tcpm/Kconfig
@@ -58,6 +58,8 @@ config TYPEC_FUSB302
 	tristate "Fairchild FUSB302 Type-C chip driver"
 	depends on I2C
 	depends on EXTCON || !EXTCON
+	depends on DRM || DRM=n
+	select DRM_AUX_HPD_BRIDGE if DRM_BRIDGE && OF
 	help
 	  The Fairchild FUSB302 Type-C chip driver that works with
 	  Type-C Port Controller Manager to provide USB PD and USB
diff --git a/drivers/usb/typec/tcpm/fusb302.c b/drivers/usb/typec/tcpm/fusb302.c
index 19ff8217818e..ce7069fb4be6 100644
--- a/drivers/usb/typec/tcpm/fusb302.c
+++ b/drivers/usb/typec/tcpm/fusb302.c
@@ -5,6 +5,7 @@
  * Fairchild FUSB302 Type-C Chip Driver
  */
 
+#include <drm/bridge/aux-bridge.h>
 #include <linux/debugfs.h>
 #include <linux/delay.h>
 #include <linux/errno.h>
@@ -1689,6 +1690,7 @@ static int fusb302_probe(struct i2c_client *client)
 {
 	struct fusb302_chip *chip;
 	struct i2c_adapter *adapter = client->adapter;
+	struct auxiliary_device *bridge_dev;
 	struct device *dev = &client->dev;
 	const char *name;
 	int ret = 0;
@@ -1747,6 +1749,13 @@ static int fusb302_probe(struct i2c_client *client)
 		goto destroy_workqueue;
 	}
 
+	bridge_dev = devm_drm_dp_hpd_bridge_alloc(chip->dev, to_of_node(chip->tcpc_dev.fwnode));
+	if (IS_ERR(bridge_dev)) {
+		ret = PTR_ERR(bridge_dev);
+		dev_err_probe(chip->dev, ret, "failed to alloc bridge\n");
+		goto destroy_workqueue;
+	}
+
 	chip->tcpm_port = tcpm_register_port(&client->dev, &chip->tcpc_dev);
 	if (IS_ERR(chip->tcpm_port)) {
 		fwnode_handle_put(chip->tcpc_dev.fwnode);
@@ -1764,6 +1773,10 @@ static int fusb302_probe(struct i2c_client *client)
 	enable_irq_wake(chip->gpio_int_n_irq);
 	i2c_set_clientdata(client, chip);
 
+	ret = devm_drm_dp_hpd_bridge_add(chip->dev, bridge_dev);
+	if (ret)
+		return ret;
+
 	return ret;
 
 tcpm_unregister_port:

---
base-commit: 6de23f81a5e08be8fbf5e8d7e9febc72a5b5f27f
change-id: 20260310-fusb302-drm-dp-hpd-bridge-00f6c9aec3ab

Best regards,
-- 
Sebastian Reichel <sebastian.reichel@xxxxxxxxxxxxx>