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

[Heikki Krogerus <heikki.krogerus@linux.intel.com>]

Tue, Mar 10, 2026 at 06:17:34PM +0100, Sebastian Reichel kirjoitti:
> 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@collabora.com>

Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>

> ---
> 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@collabora.com>

-- 
heikki