linux-kernel - Re: [PATCH v5 1/4] usb: typec: Add mode

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Message-ID: <aST0tXPULUBWSzPU@google.com>
Date: Tue, 25 Nov 2025 00:13:41 +0000
From: Benson Leung <bleung@...gle.com>
To: Andrei Kuchynski <akuchynski@...omium.org>
Cc: Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
	Abhishek Pandit-Subedi <abhishekpandit@...omium.org>,
	Benson Leung <bleung@...omium.org>,
	Jameson Thies <jthies@...gle.com>,
	Tzung-Bi Shih <tzungbi@...nel.org>, linux-usb@...r.kernel.org,
	chrome-platform@...ts.linux.dev,
	Guenter Roeck <groeck@...omium.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>,
	"Christian A. Ehrhardt" <lk@...e.de>,
	Abel Vesa <abel.vesa@...aro.org>,
	Pooja Katiyar <pooja.katiyar@...el.com>,
	Venkat Jayaraman <venkat.jayaraman@...el.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5 1/4] usb: typec: Add mode_control field to port
 property

Hi Andrei,

On Mon, Nov 24, 2025 at 12:46:36PM +0000, Andrei Kuchynski wrote:
> This new field in the port properties dictates whether the Platform Policy
> Manager (PPM) allows the OS Policy Manager (OPM) to change the currently
> active, negotiated alternate mode.
> 
> Signed-off-by: Andrei Kuchynski <akuchynski@...omium.org>
> Reviewed-by: Heikki Krogerus <heikki.krogerus@...ux.intel.com>

Reviewed-by: Benson Leung <bleung@...omium.org>

> ---
>  drivers/usb/typec/class.c | 9 ++++++---
>  drivers/usb/typec/class.h | 1 +
>  include/linux/usb/typec.h | 2 ++
>  3 files changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/usb/typec/class.c b/drivers/usb/typec/class.c
> index 9b2647cb199b..a5327e444265 100644
> --- a/drivers/usb/typec/class.c
> +++ b/drivers/usb/typec/class.c
> @@ -457,11 +457,13 @@ static umode_t typec_altmode_attr_is_visible(struct kobject *kobj,
>  					     struct attribute *attr, int n)
>  {
>  	struct typec_altmode *adev = to_typec_altmode(kobj_to_dev(kobj));
> +	struct typec_port *port = typec_altmode2port(adev);
>  
>  	if (attr == &dev_attr_active.attr)
> -		if (!is_typec_port(adev->dev.parent) &&
> -		    (!adev->ops || !adev->ops->activate))
> -			return 0444;
> +		if (!is_typec_port(adev->dev.parent)) {
> +			if (!port->mode_control || !adev->ops || !adev->ops->activate)
> +				return 0444;
> +		}
>  
>  	return attr->mode;
>  }
> @@ -2694,6 +2696,7 @@ struct typec_port *typec_register_port(struct device *parent,
>  	}
>  
>  	port->pd = cap->pd;
> +	port->mode_control = !cap->no_mode_control;
>  
>  	ret = device_add(&port->dev);
>  	if (ret) {
> diff --git a/drivers/usb/typec/class.h b/drivers/usb/typec/class.h
> index db2fe96c48ff..2e89a83c2eb7 100644
> --- a/drivers/usb/typec/class.h
> +++ b/drivers/usb/typec/class.h
> @@ -62,6 +62,7 @@ struct typec_port {
>  	struct mutex			partner_link_lock;
>  
>  	enum typec_orientation		orientation;
> +	bool				mode_control;
>  	struct typec_switch		*sw;
>  	struct typec_mux		*mux;
>  	struct typec_retimer		*retimer;
> diff --git a/include/linux/usb/typec.h b/include/linux/usb/typec.h
> index 309251572e2e..59d5fd7e4ff4 100644
> --- a/include/linux/usb/typec.h
> +++ b/include/linux/usb/typec.h
> @@ -287,6 +287,7 @@ enum usb_pd_svdm_ver {
>   * @prefer_role: Initial role preference (DRP ports).
>   * @accessory: Supported Accessory Modes
>   * @usb_capability: Supported USB Modes
> + * @no_mode_control: Ability to manage Alternate Modes
>   * @fwnode: Optional fwnode of the port
>   * @driver_data: Private pointer for driver specific info
>   * @pd: Optional USB Power Delivery Support
> @@ -304,6 +305,7 @@ struct typec_capability {
>  	enum typec_accessory	accessory[TYPEC_MAX_ACCESSORY];
>  	unsigned int		orientation_aware:1;
>  	u8			usb_capability;
> +	bool			no_mode_control;
>  
>  	struct fwnode_handle	*fwnode;
>  	void			*driver_data;
> -- 
> 2.52.0.rc2.455.g230fcf2819-goog
> 

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