[U-Boot-Users] What the right procedure should be when write a new driver for U-boot?

[Lyoo]

Hi maintainer

There is some confusion about what the right procedure should be, when
someone want to add some drivers to U-boot.

When I read U-boot's code, I found the devices initialize function
devices_init() (called in /u-boot-x.x.x/lib_xxx/board.c), It creates a
device list, then dev_xxx_init() register the devices such as LCD, USB,
Serial, Keyboard in the list. 

But, some SOC have their own drivers, for example s3c24x0 have their own
driver of USB, Serial,(/cpu/arm920t/s3c24x0/usb_ohci.c) they don't care
about the device list, they do it their way.

Is there any 'official' policy on it?