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Message-ID: <1jcyqhc05u.fsf@starbuckisacylon.baylibre.com>
Date: Mon, 22 Apr 2024 09:43:08 +0200
From: Jerome Brunet <jbrunet@...libre.com>
To: Jan Dakinevich <jan.dakinevich@...utedevices.com>
Cc: Krzysztof Kozlowski <krzk@...nel.org>, Neil Armstrong
<neil.armstrong@...aro.org>, Jerome Brunet <jbrunet@...libre.com>, Michael
Turquette <mturquette@...libre.com>, Stephen Boyd <sboyd@...nel.org>, Rob
Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>,
Conor Dooley <conor+dt@...nel.org>, Kevin Hilman <khilman@...libre.com>,
Martin Blumenstingl <martin.blumenstingl@...glemail.com>, Philipp Zabel
<p.zabel@...gutronix.de>, Jiucheng Xu <jiucheng.xu@...ogic.com>,
linux-amlogic@...ts.infradead.org, linux-clk@...r.kernel.org,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org
Subject: Re: [RFC PATCH v3 4/6] dt-bindings: clock: meson: document A1 SoC
audio clock controller driver
On Sat 20 Apr 2024 at 17:48, Jan Dakinevich <jan.dakinevich@...utedevices.com> wrote:
> On 4/19/24 17:06, Krzysztof Kozlowski wrote:
>> On 19/04/2024 14:58, Jan Dakinevich wrote:
>>> Add device tree bindings for A1 SoC audio clock and reset controllers.
>>>
>>> Signed-off-by: Jan Dakinevich <jan.dakinevich@...utedevices.com>
>>
>> This is still RFC, so not ready.
>>
>> Limited, incomplete review follows. Full review will be provided when
>> the work is ready.
>>
>> Drop "driver" references, e.g. from subject. Bindings are about hardware.
>>
>>
>> ....
>>
>>> +
>>> + clocks:
>>> + maxItems: 26
>>> + items:
>>> + - description: input main peripheral bus clock
>>> + - description: input dds_in
>>> + - description: input fixed pll div2
>>> + - description: input fixed pll div3
>>> + - description: input hifi_pll
>>> + - description: input oscillator (usually at 24MHz)
>>> + additionalItems:
>>> + oneOf:
>>> + - description: slv_sclk[0-9] - slave bit clocks provided by external components
>>> + - description: slv_lrclk[0-9]- slave sample clocks provided by external components
>>
>> What does it mean the clocks are optional? Pins could be not routed?
>
> Yes exactly. Pins could be routed in any combination or could be not
> routed at all. It is determined by schematics and that how external
> codecs are configured.
>
>> It's really rare case that clocks within the SoC are optional, so every
>> such case is questionable.
>>
>>
>>> +
>>> + clock-names:
>>> + maxItems: 26
>>> + items:
>>> + - const: pclk
>>> + - const: dds_in
>>> + - const: fclk_div2
>>> + - const: fclk_div3
>>> + - const: hifi_pll
>>> + - const: xtal
>>> + additionalItems:
>>> + oneOf:
>>> + - pattern: "^slv_sclk[0-9]$"
>>> + - pattern: "^slv_lrclk[0-9]$"
>>> +
>>> +required:
>>> + - compatible
>>> + - '#clock-cells'
>>> + - reg
>>> + - clocks
>>> + - clock-names
>>> +
>>> +allOf:
>>> + - if:
>>> + properties:
>>> + compatible:
>>> + contains:
>>> + const: amlogic,a1-audio-clkc
>>> + then:
>>> + required:
>>> + - '#reset-cells'
>>> + else:
>>> + properties:
>>> + '#reset-cells': false
>>> +
>>> +additionalProperties: false
>>> +
>>> +examples:
>>> + - |
>>> + #include <dt-bindings/clock/amlogic,a1-pll-clkc.h>
>>> + #include <dt-bindings/clock/amlogic,a1-peripherals-clkc.h>
>>> + #include <dt-bindings/clock/amlogic,a1-audio-clkc.h>
>>> + audio {
>>> + #address-cells = <2>;
>>> + #size-cells = <2>;
>>> +
>>> + clkc_audio: clock-controller@...50000 {
>>> + compatible = "amlogic,a1-audio-clkc";
>>> + reg = <0x0 0xfe050000 0x0 0xb0>;
>>> + #clock-cells = <1>;
>>> + #reset-cells = <1>;
>>> + clocks = <&clkc_audio_vad AUD_CLKID_VAD_AUDIOTOP>,
>>> + <&clkc_periphs CLKID_DDS_IN>,
>>> + <&clkc_pll CLKID_FCLK_DIV2>,
>>> + <&clkc_pll CLKID_FCLK_DIV3>,
>>> + <&clkc_pll CLKID_HIFI_PLL>,
>>> + <&xtal>;
>>> + clock-names = "pclk",
>>> + "dds_in",
>>> + "fclk_div2",
>>> + "fclk_div3",
>>> + "hifi_pll",
>>> + "xtal";
>>
>> Make it complete - list all clocks.
>>
>
> You mean, all optional clocks should be mentioned here. Right?
>
>>> + };
>>> +
>>> + clkc_audio_vad: clock-controller@...54800 {
>>
>> Just keep one example. It's basically almost the same.
>>
>
> The worth of this duplication is to show how a clock from second
> controller (<&clkc_audio_vad AUD_CLKID_VAD_AUDIOTOP>) is used by first
> one. May be it would be better to keep it... What do you think?
If you think that is worth mentioning, make it part of the
documentation, not the example.
>
>>
>>
>> Best regards,
>> Krzysztof
>>
--
Jerome
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