Comment 2 for bug 420447

seems in the freescale binary kernel (2.6.28) the board uses the sgtl5000 driver (dmesg excerpt):

Advanced Linux Sound Architecture Driver Version 1.0.18rc3.
ASoC version 0.13.2
sgtl5000-i2c 1-000a: SGTL5000 revision 17
DMA Sound Buffers Allocated:UseIram=1 buf->addr=1ffef000 buf->area=de8a8000 size=24576
DMA Sound Buffers Allocated:UseIram=1 buf->addr=ac068000 buf->area=fbef4000 size=24576
asoc: SGTL5000 <-> imx-ssi-3 mapping ok
ALSA device list:
  #0: imx-3stack (SGTL5000)

with the following options set in the config:

CONFIG_SOUND=y
CONFIG_SOUND_OSS_CORE=y
CONFIG_SND=y
CONFIG_SND_TIMER=y
CONFIG_SND_PCM=y
# CONFIG_SND_SEQUENCER is not set
CONFIG_SND_OSSEMUL=y
CONFIG_SND_MIXER_OSS=y
CONFIG_SND_PCM_OSS=y
CONFIG_SND_PCM_OSS_PLUGINS=y
# CONFIG_SND_DYNAMIC_MINORS is not set
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_DRIVERS=y
# CONFIG_SND_DUMMY is not set
# CONFIG_SND_MTPAV is not set
# CONFIG_SND_SERIAL_U16550 is not set
# CONFIG_SND_MPU401 is not set
CONFIG_SND_ARM=y
CONFIG_SND_MXC_SPDIF=m
CONFIG_SND_SPI=y
CONFIG_SND_USB=y
# CONFIG_SND_USB_AUDIO is not set
# CONFIG_SND_USB_CAIAQ is not set
CONFIG_SND_SOC=y
CONFIG_SND_MXC_SOC=y
CONFIG_SND_MXC_SOC_SSI=y
CONFIG_SND_MXC_SOC_IRAM=y
CONFIG_SND_SOC_IMX_3STACK_SGTL5000=y
# CONFIG_SND_SOC_IMX_3STACK_AK4647 is not set
# CONFIG_SND_SOC_IMX_3STACK_WM8580 is not set
# CONFIG_SND_SOC_ALL_CODECS is not set
CONFIG_SND_SOC_SGTL5000=y
# CONFIG_SOUND_PRIME is not set

trying to build it as builtin or module in the current 2.6.30 kernel for imx51 results in the following error message when trying to compile the codecs for SGTL5000:

  CC [M] sound/soc/codecs/sgtl5000.o
/home/ogra/linux-fsl-imx51-2.6.31/sound/soc/codecs/sgtl5000.c: In function 'sgtl5000_init':
/home/ogra/linux-fsl-imx51-2.6.31/sound/soc/codecs/sgtl5000.c:978: error: implicit declaration of function 'snd_soc_register_card'
make[6]: *** [sound/soc/codecs/sgtl5000.o] Error 1