Re: [PATCH RFC v2 05/11] ASoC: dt-bindings: amlogic: add schema for audin-formatter and audin-toddr

From: Krzysztof Kozlowski <krzk@kernel.org>
To: Jerome Brunet <jbrunet@baylibre.com>
Cc: Valerio Setti <vsetti@baylibre.com>, linux-amlogic@lists.infradead.org
Subject: Re: [PATCH RFC v2 05/11] ASoC: dt-bindings: amlogic: add schema for audin-formatter and audin-toddr
Date: Thu, 23 Apr 2026 15:17:18 +0200	[thread overview]
Message-ID: <b556ad94-373d-4a1c-83e6-055cfd3d9557@kernel.org> (raw)
In-Reply-To: <1j8qaerldi.fsf@starbuckisacylon.baylibre.com>

On 23/04/2026 13:01, Jerome Brunet wrote:
> 
>>
>>>
>>> Then the question might be: why not merging this together with 
>>> audin-fifo? Becuase these are 3 indipendent instances from the interface 
>>> and each of which can receive data from the interface. Each of them has 
>>> its own registers range (and optionally also an interrupt - which is not 
>>
>> 4 bytes is not "registers range". It is one register of someone else's
>> range.
> 
> Yes, exactly like the AXG family which had an "audio bus" with reg and
> ranges property of length 0x2000, like you are describing, and a
> collection of smaller devices with very specific and targeted functions,
> using the range in question.
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/arch/arm64/boot/dts/amlogic/meson-axg.dtsi?h=v6.8#n1317
> 
> The registers length of devices in this examples are in then 0x10 to
> 0x40 length. I honestly do not see the fundamental difference between 1
> and 10 regs to define what is a device and what is not.

And that example above is probably also not right if you only looked at
register range, but the difference is that you have distinctive other
resource - clocks.

And just to remind the old antipattern - each clock is also a "separate"
device and there is even old SoC architecture which did it. One clock
per device node. Since some years this is not allowed.

This device has no other distinctive resources. Only 4 bytes wide IO
range. So let me a bit clarify my previous statements:

A device having only one resource - four bytes MMIO range - and nothing
else, and being tightly coupled with other devices, almost certainly is
not separate enough to be called a separate device node.

Just like individual clocks are not separate device nodes.

Best regards,
Krzysztof

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