Re: [PATCH v4 11/16] phy: rockchip: usbdp: Register DP aux bridge

[Neil Armstrong <neil.armstrong@linaro.org>]

On 4/28/26 18:13, Sebastian Reichel wrote:
> Add support to use 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>
> ---
>   drivers/phy/rockchip/Kconfig              |  2 ++
>   drivers/phy/rockchip/phy-rockchip-usbdp.c | 14 ++++++++++++++
>   2 files changed, 16 insertions(+)
> 
> diff --git a/drivers/phy/rockchip/Kconfig b/drivers/phy/rockchip/Kconfig
> index 14698571b607..39759bb2fa1d 100644
> --- a/drivers/phy/rockchip/Kconfig
> +++ b/drivers/phy/rockchip/Kconfig
> @@ -136,8 +136,10 @@ config PHY_ROCKCHIP_USBDP
>   	tristate "Rockchip USBDP COMBO PHY Driver"
>   	depends on ARCH_ROCKCHIP && OF
>   	depends on TYPEC
> +	depends on DRM || DRM=n
>   	select GENERIC_PHY
>   	select USB_COMMON
> +	select DRM_AUX_BRIDGE if DRM_BRIDGE
>   	help
>   	  Enable this to support the Rockchip USB3.0/DP combo PHY with
>   	  Samsung IP block. This is required for USB3 support on RK3588.
> diff --git a/drivers/phy/rockchip/phy-rockchip-usbdp.c b/drivers/phy/rockchip/phy-rockchip-usbdp.c
> index beab20e4c512..77ad2a89d4f2 100644
> --- a/drivers/phy/rockchip/phy-rockchip-usbdp.c
> +++ b/drivers/phy/rockchip/phy-rockchip-usbdp.c
> @@ -6,6 +6,7 @@
>    * Copyright (C) 2024 Collabora Ltd
>    */
>   
> +#include <drm/bridge/aux-bridge.h>
>   #include <dt-bindings/phy/phy.h>
>   #include <linux/bitfield.h>
>   #include <linux/bits.h>
> @@ -1434,6 +1435,7 @@ static int rk_udphy_probe(struct platform_device *pdev)
>   {
>   	struct device *dev = &pdev->dev;
>   	struct phy_provider *phy_provider;
> +	struct fwnode_handle *dp_aux_ep;
>   	struct resource *res;
>   	struct rk_udphy *udphy;
>   	void __iomem *base;
> @@ -1492,6 +1494,18 @@ static int rk_udphy_probe(struct platform_device *pdev)
>   			return ret;
>   	}
>   
> +	/*
> +	 * Only register the DRM bridge, if the DP aux channel is connected.
> +	 * Some boards use the USBDP PHY only for its USB3 capabilities.
> +	 */
> +	dp_aux_ep = fwnode_graph_get_endpoint_by_id(dev_fwnode(dev), 3, 0, 0);
> +	if (dp_aux_ep) {
> +		ret = drm_aux_bridge_register(dev);
> +		fwnode_handle_put(dp_aux_ep);
> +		if (ret)
> +			return ret;
> +	}
> +
>   	udphy->phy_u3 = devm_phy_create(dev, dev->of_node, &rk_udphy_usb3_phy_ops);
>   	if (IS_ERR(udphy->phy_u3)) {
>   		ret = PTR_ERR(udphy->phy_u3);
> 

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>

Thanks,
Neil