On 3/2/2021 7:40 AM, Rob Herring wrote:
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On Thu, Feb 25, 2021 at 12:06 PM Sameer Pujar spujar@nvidia.com wrote:
ASoC core provides callbacks snd_soc_dai_set_sysclk() and snd_soc_dai_set_pll() for system clock (sysclk) and pll configurations respectively. Add bindings for flexible sysclk or pll configurations which can be driven from CPU/Codec DAI or endpoint subnode from DT. This in turn helps to avoid hard codings in driver and makes it more generic.
Also add system-clock related bindings, "system-clock-direction-out" and "system-clock-frequency", which are already supported.
This all looks like duplication of what the clock binding can provide. We don't need 2 ways to describe clocks in DT.
This was targetted for external audio codecs. Their internal clock management is not exposed with the clock framework. Instead ASoC provides callbacks to set this up on Codec side. There are many references where this is followed with some hardcoded settings in the drivers.
Are you suggesting to instead expose codec internal clocks and manage via generic clock bindings? Would this mean each codec driver has to implement these clock APIs (for ex: set_rate()) and program registers accordingly? For a platform, different audio cards can be plugged in. In that case, each codec has to be updated to follow this. Wouldn't it be simpler to use available ASoC callbacks?