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[34.32.225.240]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-b07b3128a1esm295465366b.29.2025.09.11.23.48.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 11 Sep 2025 23:48:06 -0700 (PDT) From: Andrei Kuchynski To: Heikki Krogerus , Abhishek Pandit-Subedi , Benson Leung , Jameson Thies , Tzung-Bi Shih , linux-usb@vger.kernel.org, chrome-platform@lists.linux.dev Cc: Guenter Roeck , Greg Kroah-Hartman , linux-kernel@vger.kernel.org, Andrei Kuchynski Subject: [PATCH v4 4/4] usb: typec: Expose alternate mode priority via sysfs Date: Fri, 12 Sep 2025 06:47:51 +0000 Message-ID: <20250912064751.1987850-5-akuchynski@chromium.org> X-Mailer: git-send-email 2.51.0.384.g4c02a37b29-goog In-Reply-To: <20250912064751.1987850-1-akuchynski@chromium.org> References: <20250912064751.1987850-1-akuchynski@chromium.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" This patch introduces a priority sysfs attribute to the USB Type-C alternate mode port interface. This new attribute allows user-space to configure the numeric priority of alternate modes managing their preferred order of operation. Signed-off-by: Andrei Kuchynski --- Documentation/ABI/testing/sysfs-class-typec | 11 ++++++ drivers/usb/typec/class.c | 37 ++++++++++++++++++++- 2 files changed, 47 insertions(+), 1 deletion(-) diff --git a/Documentation/ABI/testing/sysfs-class-typec b/Documentation/AB= I/testing/sysfs-class-typec index 38e101c17a00..0f6e6adb71c4 100644 --- a/Documentation/ABI/testing/sysfs-class-typec +++ b/Documentation/ABI/testing/sysfs-class-typec @@ -162,6 +162,17 @@ Description: Lists the supported USB Modes. The defaul= t USB mode that is used - usb3 (USB 3.2) - usb4 (USB4) =20 + What: /sys/class/typec///priority +Date: July 2025 +Contact: Andrei Kuchynski +Description: + Displays and allows setting the priority for a specific alternate mode. + The priority is an integer in the range 0-255. A lower numerical value + indicates a higher priority (0 is the highest). + If the new value is already in use by another mode, the priority of the + conflicting mode and any subsequent modes will be incremented until they + are all unique. + USB Type-C partner devices (eg. /sys/class/typec/port0-partner/) =20 What: /sys/class/typec/-partner/accessory_mode diff --git a/drivers/usb/typec/class.c b/drivers/usb/typec/class.c index 9f86605ce125..6191f7def91c 100644 --- a/drivers/usb/typec/class.c +++ b/drivers/usb/typec/class.c @@ -19,6 +19,7 @@ #include "bus.h" #include "class.h" #include "pd.h" +#include "mode_selection.h" =20 static DEFINE_IDA(typec_index_ida); =20 @@ -445,11 +446,34 @@ svid_show(struct device *dev, struct device_attribute= *attr, char *buf) } static DEVICE_ATTR_RO(svid); =20 +static ssize_t priority_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t size) +{ + u8 val; + int err =3D kstrtou8(buf, 10, &val); + + if (!err) + err =3D typec_mode_set_priority(to_typec_altmode(dev), val); + + if (!err) + return size; + return err; +} + +static ssize_t priority_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sysfs_emit(buf, "%u\n", to_typec_altmode(dev)->priority); +} +static DEVICE_ATTR_RW(priority); + static struct attribute *typec_altmode_attrs[] =3D { &dev_attr_active.attr, &dev_attr_mode.attr, &dev_attr_svid.attr, &dev_attr_vdo.attr, + &dev_attr_priority.attr, NULL }; =20 @@ -459,11 +483,15 @@ static umode_t typec_altmode_attr_is_visible(struct k= object *kobj, struct typec_altmode *adev =3D to_typec_altmode(kobj_to_dev(kobj)); struct typec_port *port =3D typec_altmode2port(adev); =20 - if (attr =3D=3D &dev_attr_active.attr) + if (attr =3D=3D &dev_attr_active.attr) { if (!is_typec_port(adev->dev.parent)) { if (!port->mode_control || !adev->ops || !adev->ops->activate) return 0444; } + } else if (attr =3D=3D &dev_attr_priority.attr) { + if (!is_typec_port(adev->dev.parent) || !port->mode_control) + return 0; + } =20 return attr->mode; } @@ -2471,6 +2499,7 @@ typec_port_register_altmode(struct typec_port *port, struct typec_altmode *adev; struct typec_mux *mux; struct typec_retimer *retimer; + int ret; =20 mux =3D typec_mux_get(&port->dev); if (IS_ERR(mux)) @@ -2489,6 +2518,12 @@ typec_port_register_altmode(struct typec_port *port, } else { to_altmode(adev)->mux =3D mux; to_altmode(adev)->retimer =3D retimer; + + ret =3D typec_mode_set_priority(adev, 0); + if (ret) { + typec_unregister_altmode(adev); + return ERR_PTR(ret); + } } =20 return adev; --=20 2.51.0.384.g4c02a37b29-goog