Say Y here if you want to connect USB mass storage devices to your
computer's USB port. This is the driver you need for USB
floppy drives, USB hard disks, USB tape drives, USB CD-ROMs,
USB flash devices, and memory sticks, along with
similar devices. This driver may also be used for some cameras
and card readers.

This option depends on 'SCSI' support being enabled, but you
probably also need 'SCSI device support: SCSI disk support'
(BLK_DEV_SD) for most USB storage devices.

To compile this driver as a module, choose M here: the
module will be called usb-storage.

source code:

drivers/usb/storage/