McBSP sidetone is needed in telephony applications. McBSP sidetone is a configurable FIR filter that forms a loopback from McBSP input to output. This patch enables the McBSP2 sidetone ALSA controls so that it can be used on Nokia RX-51/N900.

Sidetone feature can be tested with following commands:

(set up codec input and output paths) # Enable and configure sidetone amixer -D hw:0 set 'McBSP2 Sidetone' on amixer set -D hw:0 'McBSP2 Sidetone Channel 0' 32767 echo 32767 >/sys/devices/platform/omap-mcbsp.2/st_taps # Do not loop audio via CPU arecord -f dat >/dev/null |aplay /dev/zero

Signed-off-by: Jarkko Nikula jhnikula@gmail.com --- sound/soc/omap/rx51.c | 4 ++++ 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/sound/soc/omap/rx51.c b/sound/soc/omap/rx51.c index 055e447..d098622 100644 --- a/sound/soc/omap/rx51.c +++ b/sound/soc/omap/rx51.c @@ -331,6 +331,10 @@ static int rx51_aic34_init(struct snd_soc_pcm_runtime *rtd) return err; snd_soc_limit_volume(codec, "TPA6130A2 Headphone Playback Volume", 42);

+ err = omap_mcbsp_st_add_controls(codec, 1); + if (err < 0) + return err; + snd_soc_dapm_sync(dapm);

/* AV jack detection */