Re: [PATCHv2 1/4] ASoC: simple-card: add asoc_simple_card_fmt_master() to simplify the code.

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On 09/03/2014 05:37 AM, Li.Xiubo@xxxxxxxxxxxxx wrote:
Subject: Re: [PATCHv2 1/4] ASoC: simple-card: add asoc_simple_card_fmt_master()
...

This won't work. The logic for cpu node needs to be negated for codec node.


Yes, actually it should be.

As my previous patches about this:
----
Since from the DAI format micro SND_SOC_DAIFMT_CBx_CFx, the 'CBx'
mean Codec's bit clock is as master/slave and the 'CFx' mean Codec's
frame clock is as master/slave.

So these same DAI formats should be informed to CPU and CODE DAIs at
the same time. For the Codec driver will set the bit clock and frame
clock as the DAI formats said, but for the CPU driver, if the the
bit clock or frame clock is as Codec master, so it should be set CPU
DAI device as bit clock or frame clock as slave, and vice versa.

The old code will cause confusion, and we should be clear that the
letter 'C' here mean to Codec.
----

For the master format, no matter for CPU or CODEC, it always means Codec
is master or slave for bit/frame clock, not means the local DAI device's
bit/frame clock as master or slave.

So your CPU DAI device driver should negate this locally as the existed
Ones do.



Yes, but there is double negation in this patch. The switch-case
assignments depend on whether the bitclkmaster and framemaster
DT-node pointers are compared to a cpu-dai-node or
codec-dai-node. When your patch compares the codec-node, it does
the decisions like it was a cpu-node, which produces inverted CBM
and CFM setting.

However, Kurinori-san's patch fixes this problem because it just
uses the daifmt generated by comparing to codec node for both cpu
and codec nodes.

The reason why I did the comparison per node basis, was to make
the code more ready for tdm setups with multiple codecs on a same
wire. But writing code for something that is not really needed
yet is usually a bad idea, like it was this time too.

Kurinori-san's version of the fix should be fine and it cleans up
the code quite nicely.

Best regards,
Jyri

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