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

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Message-ID: <20251124124639.1101335-2-akuchynski@chromium.org>
Date: Mon, 24 Nov 2025 12:46:36 +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>,
	Abel Vesa <abel.vesa@...aro.org>,
	Pooja Katiyar <pooja.katiyar@...el.com>,
	Venkat Jayaraman <venkat.jayaraman@...el.com>,
	linux-kernel@...r.kernel.org,
	Andrei Kuchynski <akuchynski@...omium.org>
Subject: [PATCH v5 1/4] 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>
Reviewed-by: Heikki Krogerus <heikki.krogerus@...ux.intel.com>
---
 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