[alsa-devel] Can iMX6SL supports different sampling rate for different SSIs?

[Nicolin Chen]

On Tue, Mar 17, 2015 at 08:24:27AM +0800, Xuebing Wang wrote:

> 2) As pll4_main_clk is global for all 3 SSIs, I think that we can *not* use
> 8k for ssi1 and 44.1k for ssi2, right? Because 8k and 44.1k requires
> different pll4 clock, right?

True.

>     -- However, as 48k, 32k, 16k, 8k can use same pll4, thus different SSI
> can use different sampling rate in this subset (48k, 32k, 16k, 8k).
>     -- Same principle applies for 44.1k, 22.050, 11.025 subset of sampling
> rates.

Correct. You need to choose 48K-group or 44.1K-group if only using PLL4.

If you are so obsessed with full sample rate support in hardware level,
you might need to do a trade-off like sacrificing video function -- you
would then be allowed to use PLL5 to forge a rate for another rate group.

I forgot if PLL3, another possible parent clock of SSI, is suitable for
one of the groups. You may also take a look at it.

Nicolin