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[34.91.23.168]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-afe8d03f981sm117294166b.60.2025.08.25.07.58.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 25 Aug 2025 07:58:14 -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 , Dmitry Baryshkov , "Christian A. Ehrhardt" , Venkat Jayaraman , linux-kernel@vger.kernel.org, Andrei Kuchynski Subject: [PATCH v2 5/5] usb: typec: Expose alternate mode priority via sysfs Date: Mon, 25 Aug 2025 14:57:50 +0000 Message-ID: <20250825145750.58820-6-akuchynski@chromium.org> X-Mailer: git-send-email 2.51.0.rc2.233.g662b1ed5c5-goog In-Reply-To: <20250825145750.58820-1-akuchynski@chromium.org> References: <20250825145750.58820-1-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 Reviewed-by: Heikki Krogerus --- Documentation/ABI/testing/sysfs-class-typec | 11 +++++++ drivers/usb/typec/class.c | 32 ++++++++++++++++++++- 2 files changed, 42 insertions(+), 1 deletion(-) diff --git a/Documentation/ABI/testing/sysfs-class-typec b/Documentation/AB= I/testing/sysfs-class-typec index 38e101c17a00..dab3e4e727b6 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 alt-mode. + When read, it shows the current integer priority value. Lower numerical + values indicate higher priority (0 is the highest priority). + 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..aaab2e1e98b4 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) +{ + unsigned int val; + int err =3D kstrtouint(buf, 10, &val); + + if (!err) { + typec_mode_set_priority(to_typec_altmode(dev), val); + return size; + } + + return err; +} + +static ssize_t priority_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sprintf(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; } @@ -2491,6 +2519,8 @@ typec_port_register_altmode(struct typec_port *port, to_altmode(adev)->retimer =3D retimer; } =20 + typec_mode_set_priority(adev, 0); + return adev; } EXPORT_SYMBOL_GPL(typec_port_register_altmode); --=20 2.51.0.rc2.233.g662b1ed5c5-goog