[alsa-devel] [RFC-PATCH 0/2] ASoC: simple_card: support for hw-params rules

[Lars-Peter Clausen]

On 05/20/2016 02:30 PM, kernel at martin.sperl.org wrote:
> From: Martin Sperl <kernel at martin.sperl.org>
> 
> Simple_card does require under some circumstances the ability
> to configure certain hw_parameters based on clocks, bits, channels.
> 
> This patchset adds a generic way to configure these kind of things
> via the device tree easily. This patchset implements this
> for simple_card, but other drivers can just as easily make use of
> this.
> 
> For now we have the following matchers and actions:
> * matchers:
>   * match_sample_bits
>   * match_rate
>   * match_channels
> * actions:
>   * set_fixed_bclk_size
> 
> As a note: the available matching rules and action rules right now
> are hard-coded, but this could in principle get extended to be more
> dynamic via kallsyms_lookup_name that would lookup the requested
> symbol and assume it is a struct asoc_generic_hw_params_method,
> on which it could apply several sanity-checks before using
> the pointers for real.

How about allowing to embed eBPF bytecode in the DT that can be installed as
a constraint set? This would allow maximum for flexibility and also make the
implementation a lot easier.