usb: device: gs_usb: convert dummy endpoint to fully functional OUT ep #61
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Convert the dummy endpoint to a fully functional bulk OUT endpoint in order to be compatible with gs_usb drivers selecting the first available IN/OUT endpoints for use. Signed-off-by: Henrik Brix Andersen <[email protected]>
Introduce a Kconfig option for turning off gs_usb driver compatibility mode. The Linux kernel gs_usb driver prior to kernel v6.12.5 uses hardcoded USB endpoint addresses 0x81 (bulk IN) and 0x02 (bulk OUT). The same assumption on USB endpoint addresses may be present in other drivers as well (e.g. python-can). Depending on the capabilities of the USB device controller, the requested USB endpoint addresses may be rewritten by the Zephyr USB device stack at runtime. Enabling compatibility mode will include a second bulk OUT endpoint to ensure correct operation with gs_usb drivers using the hardcoded USB endpoint addresses described above. It is safe to enable compatibility mode regardless of the driver being used, but the resulting firmware will require slightly more RAM and flash resources. Signed-off-by: Henrik Brix Andersen <[email protected]>
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Convert the dummy endpoint to a fully functional bulk OUT endpoint in order to be compatible with gs_usb drivers selecting the first available IN/OUT endpoints for use, and introduce a Kconfig option for turning off gs_usb driver compatibility mode.
The Linux kernel gs_usb driver prior to kernel v6.12.5 uses hardcoded USB endpoint addresses 0x81 (bulk IN) and 0x02 (bulk OUT). The same assumption on USB endpoint addresses may be present in other drivers as well (e.g. python-can).
Depending on the capabilities of the USB device controller, the requested USB endpoint addresses may be rewritten by the Zephyr USB device stack at runtime. Enabling compatibility mode will include a second bulk OUT endpoint to ensure correct operation with gs_usb drivers using the hardcoded USB endpoint addresses described above.
It is safe to enable compatibility mode regardless of the driver being used, but the resulting firmware will require slightly more RAM and flash resources.