USB OTG on the Linux Kernel

Studying

Some background
History
USB 1.0 - 1996, 01.
USB 2.0 - 2000, 04.
OTG 1.0 - 2001, 12. Supplement to the USB 2.0 Specification
OTG 1.3 - 2006, 12. Supplement to the USB 2.0 Specification

On-The-Go Supplement to the USB 2.0 Specification, Revision 1.3
(TOC, 53 pages)
1. Introduction
2. Acronyms and Terms
3. Significant Features
4. Cables and Connectors
5. Electrical Requirements
5.1 A-Device Electrical Requirements
5.2 B-Device Electrical Requirements
5.3 Session Request Protocol
5.4 Electrical Characteristics
5.5 Device Timings
6. Host Negotiation Protocol

Something new in OTG 1.0
Session Request Protocol (SRP)
USB OTG uses the SRP to establish a session (connection) between two USB devices.

Host Negotiation Protocol (HNP)
Once connected, OTG dual-role devices can exchange roles—host and peripheral—by using HNP.

Targeted Peripheral List (TPL)

No Silent Failures

Mini-AB Receptacle

Mini-A Plug and Mini-A Receptacle

USB OTG on the Linux Kernel

Example:
(1) SMC WSKP100 Wi-Fi Phone

Reference:
USB On-The-Go

Related Blog:
USB Mass Storage Device Descriptor