| Badhri Jagan Sridharan | 7dfee9c | 2015-08-31 21:36:07 -0700 | [diff] [blame] | 1 | What: /sys/class/dual_role_usb/.../ |
| 2 | Date: June 2015 |
| 3 | Contact: Badhri Jagan Sridharan<badhri@google.com> |
| 4 | Description: |
| 5 | Provide a generic interface to monitor and change |
| 6 | the state of dual role usb ports. The name here |
| 7 | refers to the name mentioned in the |
| 8 | dual_role_phy_desc that is passed while registering |
| 9 | the dual_role_phy_intstance through |
| 10 | devm_dual_role_instance_register. |
| 11 | |
| 12 | What: /sys/class/dual_role_usb/.../supported_modes |
| 13 | Date: June 2015 |
| 14 | Contact: Badhri Jagan Sridharan<badhri@google.com> |
| 15 | Description: |
| 16 | This is a static node, once initialized this |
| 17 | is not expected to change during runtime. "dfp" |
| 18 | refers to "downstream facing port" i.e. port can |
| 19 | only act as host. "ufp" refers to "upstream |
| 20 | facing port" i.e. port can only act as device. |
| 21 | "dfp ufp" refers to "dual role port" i.e. the port |
| 22 | can either be a host port or a device port. |
| 23 | |
| 24 | What: /sys/class/dual_role_usb/.../mode |
| 25 | Date: June 2015 |
| 26 | Contact: Badhri Jagan Sridharan<badhri@google.com> |
| 27 | Description: |
| 28 | The mode node refers to the current mode in which the |
| 29 | port is operating. "dfp" for host ports. "ufp" for device |
| 30 | ports and "none" when cable is not connected. |
| 31 | |
| 32 | On devices where the USB mode is software-controllable, |
| 33 | userspace can change the mode by writing "dfp" or "ufp". |
| 34 | On devices where the USB mode is fixed in hardware, |
| 35 | this attribute is read-only. |
| 36 | |
| 37 | What: /sys/class/dual_role_usb/.../power_role |
| 38 | Date: June 2015 |
| 39 | Contact: Badhri Jagan Sridharan<badhri@google.com> |
| 40 | Description: |
| 41 | The power_role node mentions whether the port |
| 42 | is "sink"ing or "source"ing power. "none" if |
| 43 | they are not connected. |
| 44 | |
| 45 | On devices implementing USB Power Delivery, |
| 46 | userspace can control the power role by writing "sink" or |
| 47 | "source". On devices without USB-PD, this attribute is |
| 48 | read-only. |
| 49 | |
| 50 | What: /sys/class/dual_role_usb/.../data_role |
| 51 | Date: June 2015 |
| 52 | Contact: Badhri Jagan Sridharan<badhri@google.com> |
| 53 | Description: |
| 54 | The data_role node mentions whether the port |
| 55 | is acting as "host" or "device" for USB data connection. |
| 56 | "none" if there is no active data link. |
| 57 | |
| 58 | On devices implementing USB Power Delivery, userspace |
| 59 | can control the data role by writing "host" or "device". |
| 60 | On devices without USB-PD, this attribute is read-only |
| 61 | |
| 62 | What: /sys/class/dual_role_usb/.../powers_vconn |
| 63 | Date: June 2015 |
| 64 | Contact: Badhri Jagan Sridharan<badhri@google.com> |
| 65 | Description: |
| 66 | The powers_vconn node mentions whether the port |
| 67 | is supplying power for VCONN pin. |
| 68 | |
| 69 | On devices with software control of VCONN, |
| 70 | userspace can disable the power supply to VCONN by writing "n", |
| 71 | or enable the power supply by writing "y". |