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

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Message-ID: <20250905142206.4105351-2-akuchynski@chromium.org>
Date: Fri,  5 Sep 2025 14:22:02 +0000
From: Andrei Kuchynski <akuchynski@...omium.org>
To: 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
Cc: Guenter Roeck <groeck@...omium.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>,
	"Christian A. Ehrhardt" <lk@...e.de>,
	Venkat Jayaraman <venkat.jayaraman@...el.com>,
	linux-kernel@...r.kernel.org,
	Andrei Kuchynski <akuchynski@...omium.org>
Subject: [PATCH v3 1/5] usb: typec: Add mode_control field to port property

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;
 };
 
 #define to_typec_port(_dev_) container_of(_dev_, struct typec_port, dev)
diff --git a/include/linux/usb/typec.h b/include/linux/usb/typec.h
index 252af3f77039..8f51665d44ec 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;
-- 
2.51.0.355.g5224444f11-goog