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Diffstat (limited to 'Documentation/ABI/testing/sysfs-class-dual-role-usb')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-class-dual-role-usb | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-class-dual-role-usb b/Documentation/ABI/testing/sysfs-class-dual-role-usb new file mode 100644 index 000000000000..a900fd75430c --- /dev/null +++ b/Documentation/ABI/testing/sysfs-class-dual-role-usb @@ -0,0 +1,71 @@ +What: /sys/class/dual_role_usb/.../ +Date: June 2015 +Contact: Badhri Jagan Sridharan<badhri@google.com> +Description: + Provide a generic interface to monitor and change + the state of dual role usb ports. The name here + refers to the name mentioned in the + dual_role_phy_desc that is passed while registering + the dual_role_phy_intstance through + devm_dual_role_instance_register. + +What: /sys/class/dual_role_usb/.../supported_modes +Date: June 2015 +Contact: Badhri Jagan Sridharan<badhri@google.com> +Description: + This is a static node, once initialized this + is not expected to change during runtime. "dfp" + refers to "downstream facing port" i.e. port can + only act as host. "ufp" refers to "upstream + facing port" i.e. port can only act as device. + "dfp ufp" refers to "dual role port" i.e. the port + can either be a host port or a device port. + +What: /sys/class/dual_role_usb/.../mode +Date: June 2015 +Contact: Badhri Jagan Sridharan<badhri@google.com> +Description: + The mode node refers to the current mode in which the + port is operating. "dfp" for host ports. "ufp" for device + ports and "none" when cable is not connected. + + On devices where the USB mode is software-controllable, + userspace can change the mode by writing "dfp" or "ufp". + On devices where the USB mode is fixed in hardware, + this attribute is read-only. + +What: /sys/class/dual_role_usb/.../power_role +Date: June 2015 +Contact: Badhri Jagan Sridharan<badhri@google.com> +Description: + The power_role node mentions whether the port + is "sink"ing or "source"ing power. "none" if + they are not connected. + + On devices implementing USB Power Delivery, + userspace can control the power role by writing "sink" or + "source". On devices without USB-PD, this attribute is + read-only. + +What: /sys/class/dual_role_usb/.../data_role +Date: June 2015 +Contact: Badhri Jagan Sridharan<badhri@google.com> +Description: + The data_role node mentions whether the port + is acting as "host" or "device" for USB data connection. + "none" if there is no active data link. + + On devices implementing USB Power Delivery, userspace + can control the data role by writing "host" or "device". + On devices without USB-PD, this attribute is read-only + +What: /sys/class/dual_role_usb/.../powers_vconn +Date: June 2015 +Contact: Badhri Jagan Sridharan<badhri@google.com> +Description: + The powers_vconn node mentions whether the port + is supplying power for VCONN pin. + + On devices with software control of VCONN, + userspace can disable the power supply to VCONN by writing "n", + or enable the power supply by writing "y". |