linux-kernel - Re: [PATCH v3 1/5] usb: typec: Add mode

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Message-ID: <2025091018-slather-dispose-015d@gregkh>
Date: Wed, 10 Sep 2025 15:30:05 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
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>,
	Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>,
	"Christian A. Ehrhardt" <lk@...e.de>,
	Venkat Jayaraman <venkat.jayaraman@...el.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 1/5] usb: typec: Add mode_control field to port
 property

On Fri, Sep 05, 2025 at 02:22:02PM +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>
> ---
>  drivers/usb/typec/class.c | 9 ++++++---
>  drivers/usb/typec/class.h | 2 ++
>  include/linux/usb/typec.h | 2 ++
>  3 files changed, 10 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/usb/typec/class.c b/drivers/usb/typec/class.c
> index 67a533e35150..9f86605ce125 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;
>  }
> @@ -2681,6 +2683,7 @@ 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..c53a04b9dc75 100644
> --- a/drivers/usb/typec/class.h
> +++ b/drivers/usb/typec/class.h
> @@ -80,6 +80,8 @@ struct typec_port {
>  	 */
>  	struct device			*usb2_dev;
>  	struct device			*usb3_dev;
> +
> +	bool				mode_control;

Shouldn't this go up higher in this structure, to avoid the hole you
created, and to take advantage of the existing hole?  Perhaps after
orientation?

thanks,

greg k-h