[alsa-devel] ASoC: DMA and SSI drivers for i.MX27

javier Martin javier.martin at vista-silicon.com
Mon Aug 3 11:05:11 CEST 2009

As I described in one of my previous mails, I have been trying to port
an old ASoC driver for kernel 2.6.22 to latest stable 2.6.30 kernel.
I am currently facing a big problem which make some repeated samples
appear with a regular pattern:
- frequency of bad samples = 2 * period_size
- bad samples in audio stream are taken from "buffer_size" samples
back in the original file.

You can reproduce this with:
aplay -t raw -f S16_LE -r8000 8k16bitpcm.wav

(http://en.wikipedia.org/wiki/WAV to get this file)

Here I submit two patches:
- One which adds ssi and dma drivers plus a custom machine driver
- Another patch which adds wm8974 codec support taken from ASoC
wm8974-upstream branch (wm8974_list.patch).

Note that the machine driver attached uses wm8974 codec, thus second
patch is needed. Please, note also that patches are currently quite
dirty, and in an early development state. The purpose of this mail is
not to even consider to include them in any branch right now, but to
gather some help to solve the problem. As soon as I have it solved I
will clean all the stuff and try to prepare it for mainline.

Javier Martin
Vista Silicon S.L.
Universidad de Cantabria
CDTUC - FASE C - Oficina S-345
Avda de los Castros s/n
39005- Santander. Cantabria. Spain
+34 942 25 32 60
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