Re: [PATCH 1/2] ASoC: simple-card-utils: add ignore_zero_sysclk flag

["Sheetal ." <sheetal@nvidia.com>]

On 18-03-2026 04:32, Kuninori Morimoto wrote:
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> 
> 
> Hi
> 
>>> Commit 2458adb8f92a ("SoC: simple-card-utils: set 0Hz to
>>> sysclk when shutdown") updated the simple-card-util driver to
>>> send 0Hz frequency requests during stream shutdown, which can
>>> request frequencies lower than a platform may support.
>>
>>> Add ignore_zero_sysclk flag to struct simple_util_priv to allow drivers
>>> to ignore these 0Hz sysclk requests when they would result in a clock
>>> frequency below the hardware's minimum allowed rate.
>>
>> If the driver simply can't tolerate disabling the sysclk it seems like
>> it would be easier to just have the driver directly ignore attempts to
>> do so rather than adding this flag which the driver has to set only to
>> get it passed in?
> 
> Agree.
> I think this commit can help you ?
> 
>          1e1a2ef95b571825ca9c0113f6bef51e9cec98b0
>          ("ASoC: da7213: Avoid setting PLL when closing audio stream")
> 
> Thank you for your help !!


Thank you for the feedback and the da7213 reference.

The concern with the per-codec approach is that this affects any codec 
with a set_dai_sysclk that forwards the frequency to clk_set_rate(). 
Since any codec can be connected to Tegra platforms, and MCLK is 
provided by the SoC to external codecs, when clk_set_rate(..., 0) 
reaches the BPMP firmware, it raises a fault for rates below the 
hardware minimum. Fixing this per-codec would require individual patches 
for each.


> 
> Best regards
> ---
> Kuninori Morimoto