From: Peter Ujfalusi <peter.ujfalusi@ti.com>
To: javier Martin <javier.martin@vista-silicon.com>
Cc: alsa-devel@alsa-project.org,
"Mark Brown" <broonie@opensource.wolfsonmicro.com>,
"Sascha Hauer" <s.hauer@pengutronix.de>,
"Eric Bénard" <eric@eukrea.com>
Subject: Re: [Q] ASoC: What's the real meaning of SND_SOC_DAIFMT_NB_NF?
Date: Fri, 24 Feb 2012 16:09:39 +0200 [thread overview]
Message-ID: <4F479A23.6010307@ti.com> (raw)
In-Reply-To: <CACKLOr14EHqGWcYCfLK0WXiVZsewDVyFPV2tpfYJK4tBZKMUXg@mail.gmail.com>
On 02/24/2012 01:05 PM, javier Martin wrote:
>> I don't think it is going to break. I would guess that the channels are
>> swapped on these machines at the moment. If you correct the CPU dai
>> driver the only thing that will happen is that the channels will jump in
>> their correct place.
>
> That would be true for stereo. However, mono should not be working right now.
The notion of mono in I2S, Left/Right Justified formats is not really
valid. They are stereo protocols by design. DSP_A/B is used with mono
audio (which often referred as PCM).
It is the responsibility of the codec/cpu drivers to interpret the
standards correctly, and configure themselves accordingly. Take a look
at the Wolfson codec documentation they are really good in this matter
(what I2S, DSP/PCM, and other coding means in real life).
You can look at the omap-mcbsp driver for an example, but configuring
the FS/BC polarity in the format selection (without taking a look at the
INV mask) does not seam to be correct.
--
Péter
next prev parent reply other threads:[~2012-02-24 14:10 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-23 12:40 [Q] ASoC: What's the real meaning of SND_SOC_DAIFMT_NB_NF? javier Martin
2012-02-23 15:19 ` Mark Brown
2012-02-23 15:58 ` javier Martin
2012-02-23 16:14 ` Mark Brown
2012-02-24 7:53 ` javier Martin
2012-02-24 8:34 ` Peter Ujfalusi
2012-02-24 11:05 ` javier Martin
2012-02-24 11:53 ` Mark Brown
2012-02-24 14:09 ` Peter Ujfalusi [this message]
2012-02-24 11:20 ` Mark Brown
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