What is the right way to determine the revision (A01/A02/...) of my CP2615?
In Section 220.127.116.11 "Special Operations", the CP2615 Datasheet depicts (in Table 3.13 "Read CP2615 Firmware Revision") an operation available in Configuration Mode to read the Firmware Version Number.
In Section 3.2 "iop_AccessoryInfo", AN1139: CP2615 I/O Protocol depicts a "PartID" described as "Encoded part number of the chip (0x1400 for CP2615-A01, 0x1500 for CP2615-A02)."
Reading the version via I2C in config mode requires an external I2C Master, e.g. the special-PID CP2112 on the CP2615 EVB. This method is suitable for a prototyping environment (it's how Xpress Configurator determines the attached device), or in a customer's production-line environment (e.g. the external I2C master can verify the proper device version before programming the config). For this method, the CP2615 must be powered up, but doesn't have to be connected to a USB host. See Knowledge Base Article "Parsing the CP2615 Firmware Version Number" for details on how to interpret this value.
Reading the version via the iop protocol is suitable for an end-user situation, e.g. an app running on the phone or USB host would query the version number before issuing any version-dependent commands (e.g. downloading user profiles, which is only supported on the -A02).