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

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Message-ID: <aFpuLuzBXgazxecA@kuha.fi.intel.com>
Date: Tue, 24 Jun 2025 12:21:50 +0300
From: Heikki Krogerus <heikki.krogerus@...ux.intel.com>
To: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
Cc: 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>, linux-usb@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org
Subject: Re: [PATCH 8/8] usb: typec: ucsi: yoga-c630: register DRM HPD bridge

On Sat, Jun 21, 2025 at 09:13:03PM +0300, Dmitry Baryshkov wrote:
> 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>

Reviewed-by: Heikki Krogerus <heikki.krogerus@...ux.intel.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

-- 
heikki