我用的是am335x-evm 环境是SDK7.0
因为要实现一个gadget设备驱动
在配置USB驱动时如下配置：
<*> Support for Host-side USB
[ ] USB verbose debug messages
[*] USB announce new devices
*** Miscellaneous USB options ***
[*] Enable USB persist by default
[ ] Dynamic USB minor allocation
[*] OTG support
[ ] Rely on OTG Targeted Peripherals List
[ ] Disable external hubs
<*> USB Monitor
< > Support WUSB Cable Based Association (CBA)
*** USB Host Controller Drivers ***
< > Cypress C67x00 HCD support
< > xHCI HCD (USB 3.0) support
< > EHCI HCD (USB 2.0) support
< > OXU210HP HCD support
< > ISP116X HCD support
< > ISP 1760 HCD support
< > ISP1362 HCD support
< > FUSBH200 HCD support
< > FOTG210 HCD support
< > OHCI HCD (USB 1.1) support
< > UHCI HCD (most Intel and VIA) support
< > SL811HS HCD support
< > R8A66597 HCD support
[ ] HCD test mode support
<*> Inventra Highspeed Dual Role Controller (TI, ADI, ...)
MUSB Mode Selection (Dual Role mode) --->
<*> Platform Glue Layer (TI DSPS platforms) --->
<*> Enable support for AM335x devices
MUSB DMA mode (Disable DMA (always use PIO)) --->
...
<*> USB Mass Storage support
...
<*> USB Gadget Support --->
结果内核打印
Error:Driver 'am335x-usb-childs' is already registered aborting...
这个打印信息是跟上面选的<*> Enable support for AM335x devices有关，一选这个选件就报这个错