Please update the boot loader as dscribed in this documentation.
I used the release from here.
http://builds.96boards.org/releases/hikey/linaro/debian/15.11/
Getting the kernel sources.
$ git clone https://github.com/96boards/linux.git
$ cd linux/
$ git checkout -b working-hikey 96boards-hikey-15.11
Please save this as file name “usb-audio.patch”
--- a/.config 2016-02-12 16:47:15.204957120 +0900
+++ b/.config 2016-02-12 16:49:15.336954840 +0900
@@ -2582,6 +2582,10 @@ CONFIG_LOGO_LINUX_CLUT224=y
CONFIG_SOUND=y
# CONFIG_SOUND_OSS_CORE is not set
CONFIG_SND=y
+CONFIG_SND_TIMER=y
+CONFIG_SND_PCM=y
+CONFIG_SND_HWDEP=y
+CONFIG_SND_RAWMIDI=y
# CONFIG_SND_SEQUENCER is not set
# CONFIG_SND_MIXER_OSS is not set
# CONFIG_SND_PCM_OSS is not set
@@ -2591,6 +2595,7 @@ CONFIG_SND_SUPPORT_OLD_API=y
CONFIG_SND_VERBOSE_PROCFS=y
# CONFIG_SND_VERBOSE_PRINTK is not set
# CONFIG_SND_DEBUG is not set
+CONFIG_SND_VMASTER=y
# CONFIG_SND_RAWMIDI_SEQ is not set
# CONFIG_SND_OPL3_LIB_SEQ is not set
# CONFIG_SND_OPL4_LIB_SEQ is not set
@@ -2672,11 +2677,12 @@ CONFIG_SND_PCI=y
# CONFIG_SND_HDA_INTEL is not set
CONFIG_SND_SPI=y
CONFIG_SND_USB=y
-# CONFIG_SND_USB_AUDIO is not set
-# CONFIG_SND_USB_UA101 is not set
-# CONFIG_SND_USB_CAIAQ is not set
-# CONFIG_SND_USB_6FIRE is not set
-# CONFIG_SND_USB_HIFACE is not set
+CONFIG_SND_USB_AUDIO=y
+CONFIG_SND_USB_UA101=y
+CONFIG_SND_USB_CAIAQ=y
+CONFIG_SND_USB_CAIAQ_INPUT=y
+CONFIG_SND_USB_6FIRE=y
+CONFIG_SND_USB_HIFACE=y
# CONFIG_SND_BCD2000 is not set
# CONFIG_SND_SOC is not set
# CONFIG_SOUND_PRIME is not set
Building the kernel.
$ export ARCH=arm64
$ export CROSS_COMPILE=aarch64-linux-gnu-
$ export LOCALVERSION="-linaro-hikey"
$ make distclean
$ make defconfig
$ patch -p1 < usb-audio.patch
$ make -j8 Image modules hi6220-hikey.dtb 2>&1 | tee build-log.txt
$ export INSTALL_MOD_PATH=<code>pwd</code>/installed_modules
$ mkdir $INSTALL_MOD_PATH
$ make modules_install
$ cd ..
Make boot image on SD.
Insert your SD card to the Linux PC.
$ export USER=your-user-name
$ sudo dd if=hikey-jessie_alip_20151130-387.img of=/dev/mmcblk0 bs=4M oflag=sync status=noxfer
$ cd linux/
$ cp -a arch/arm64/boot/Image /media/$USER/boot/ <- where your SD card is mounted
$ cp -a arch/arm64/boot/dts/hi6220-hikey.dtb /media/$USER/boot/
$ sudo cp -ar install_modulesed/lib/modules/3.18.0-linaro-hikey/ /media/$USER/rootfs/lib/modules/
I do not have the USB-sound device, so I am not perfectly sure this will works for you.
I tried on my USB-ethernet device and this is the output.
[ 33.749894] usb 1-1.2: new full-speed USB device number 3 using dwc2
[ 33.883031] usb 1-1.2: not running at top speed; connect to a high speed hub
[ 34.292478] ax88179_178a 1-1.2:1.0 eth0: register ‘ax88179_178a’ at usb-f72c0000.usb-1.24
[ 38.389585] ax88179_178a 1-1.2:1.0 eth0: ax88179 - Link status is: 1
I hope your sound card works.