From: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
To: "Martin Povišer" <povik+lin@cutebit.org>
Cc: devicetree@vger.kernel.org, alsa-devel@alsa-project.org,
Philipp Zabel <p.zabel@pengutronix.de>,
Sven Peter <sven@svenpeter.dev>, Hector Martin <marcan@marcan.st>,
Liam Girdwood <lgirdwood@gmail.com>,
Rob Herring <robh+dt@kernel.org>,
linux-kernel@vger.kernel.org, Mark Brown <broonie@kernel.org>,
asahi@lists.linux.dev,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
Alyssa Rosenzweig <alyssa@rosenzweig.io>
Subject: Re: [PATCH v2 2/4] arm64: dts: apple: t8103: Add MCA and its support
Date: Tue, 23 Aug 2022 14:02:43 +0300 [thread overview]
Message-ID: <ae5a10b8-a459-11c9-3fac-4f5de0ba2218@linaro.org> (raw)
In-Reply-To: <A9E366E2-EA4D-4F35-BE28-63745296D222@cutebit.org>
On 19/08/2022 17:24, Martin Povišer wrote:
>
>
>> On 19. 8. 2022, at 15:12, Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> wrote:
>>
>> On 19/08/2022 15:54, Martin Povišer wrote:
>>> Add the MCA I2S transceiver node and its supporting NCO, ADMAC nodes.
>>>
>>> Signed-off-by: Martin Povišer <povik+lin@cutebit.org>
>>> ---
>>> arch/arm64/boot/dts/apple/t8103.dtsi | 70 ++++++++++++++++++++++++++++
>>> 1 file changed, 70 insertions(+)
>>>
>>> diff --git a/arch/arm64/boot/dts/apple/t8103.dtsi b/arch/arm64/boot/dts/apple/t8103.dtsi
>>> index 51a63b29d404..2dc3125aca5b 100644
>>> --- a/arch/arm64/boot/dts/apple/t8103.dtsi
>>> +++ b/arch/arm64/boot/dts/apple/t8103.dtsi
>>> @@ -532,6 +532,76 @@ port02: pci@2,0 {
>>> <0 0 0 4 &port02 0 0 0 3>;
>>> };
>>> };
>>> +
>>> + dart_sio: iommu@235004000 {
>>> + compatible = "apple,t8103-dart", "apple,dart";
>>> + reg = <0x2 0x35004000 0x0 0x4000>;
>>> + interrupt-parent = <&aic>;
>>> + interrupts = <AIC_IRQ 635 IRQ_TYPE_LEVEL_HIGH>;
>>> + #iommu-cells = <1>;
>>> + power-domains = <&ps_sio_cpu>;
>>> + };
>>> +
>>> + nco_clkref: clock-ref {
>>> + compatible = "fixed-clock";
>>> + #clock-cells = <0>;
>>> + clock-frequency = <900000000>;
>>> + clock-output-names = "nco_ref";
>>> + };
>>
>> Reference clocks are usually physically outside of SoC (e.g. on the
>> board), so:
>> 1. Not part of "soc" node.
>> 2. It should be defined by board. At least clock-frequency should be there.
>
> Ah, right, this deserves commentary: Since this is a reverse-engineered
> driver/platform support, we give up on knowing the clock tree exactly. Instead
> we model the clock input to the Numerically Controlled Oscillator (‘nco’ node
> below) with this fabulated fixed clock reference.
>
> I guess eventually the clock tree is rooted off the SoC, and there’s
> nothing guaranteeing the same reference clock to the NCO across machines (being
> function of the board wiring and the proprietary firmware). In the end I would
> argue for keeping the ‘clock-ref’ here in ’soc' but have the clock-frequency
> defined by board. Sounds reasonable?
Yes.
Best regards,
Krzysztof
WARNING: multiple messages have this Message-ID (diff)
From: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
To: "Martin Povišer" <povik+lin@cutebit.org>
Cc: Liam Girdwood <lgirdwood@gmail.com>,
Mark Brown <broonie@kernel.org>, Rob Herring <robh+dt@kernel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
Hector Martin <marcan@marcan.st>, Sven Peter <sven@svenpeter.dev>,
Philipp Zabel <p.zabel@pengutronix.de>,
Alyssa Rosenzweig <alyssa@rosenzweig.io>,
asahi@lists.linux.dev, alsa-devel@alsa-project.org,
devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 2/4] arm64: dts: apple: t8103: Add MCA and its support
Date: Tue, 23 Aug 2022 14:02:43 +0300 [thread overview]
Message-ID: <ae5a10b8-a459-11c9-3fac-4f5de0ba2218@linaro.org> (raw)
In-Reply-To: <A9E366E2-EA4D-4F35-BE28-63745296D222@cutebit.org>
On 19/08/2022 17:24, Martin Povišer wrote:
>
>
>> On 19. 8. 2022, at 15:12, Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> wrote:
>>
>> On 19/08/2022 15:54, Martin Povišer wrote:
>>> Add the MCA I2S transceiver node and its supporting NCO, ADMAC nodes.
>>>
>>> Signed-off-by: Martin Povišer <povik+lin@cutebit.org>
>>> ---
>>> arch/arm64/boot/dts/apple/t8103.dtsi | 70 ++++++++++++++++++++++++++++
>>> 1 file changed, 70 insertions(+)
>>>
>>> diff --git a/arch/arm64/boot/dts/apple/t8103.dtsi b/arch/arm64/boot/dts/apple/t8103.dtsi
>>> index 51a63b29d404..2dc3125aca5b 100644
>>> --- a/arch/arm64/boot/dts/apple/t8103.dtsi
>>> +++ b/arch/arm64/boot/dts/apple/t8103.dtsi
>>> @@ -532,6 +532,76 @@ port02: pci@2,0 {
>>> <0 0 0 4 &port02 0 0 0 3>;
>>> };
>>> };
>>> +
>>> + dart_sio: iommu@235004000 {
>>> + compatible = "apple,t8103-dart", "apple,dart";
>>> + reg = <0x2 0x35004000 0x0 0x4000>;
>>> + interrupt-parent = <&aic>;
>>> + interrupts = <AIC_IRQ 635 IRQ_TYPE_LEVEL_HIGH>;
>>> + #iommu-cells = <1>;
>>> + power-domains = <&ps_sio_cpu>;
>>> + };
>>> +
>>> + nco_clkref: clock-ref {
>>> + compatible = "fixed-clock";
>>> + #clock-cells = <0>;
>>> + clock-frequency = <900000000>;
>>> + clock-output-names = "nco_ref";
>>> + };
>>
>> Reference clocks are usually physically outside of SoC (e.g. on the
>> board), so:
>> 1. Not part of "soc" node.
>> 2. It should be defined by board. At least clock-frequency should be there.
>
> Ah, right, this deserves commentary: Since this is a reverse-engineered
> driver/platform support, we give up on knowing the clock tree exactly. Instead
> we model the clock input to the Numerically Controlled Oscillator (‘nco’ node
> below) with this fabulated fixed clock reference.
>
> I guess eventually the clock tree is rooted off the SoC, and there’s
> nothing guaranteeing the same reference clock to the NCO across machines (being
> function of the board wiring and the proprietary firmware). In the end I would
> argue for keeping the ‘clock-ref’ here in ’soc' but have the clock-frequency
> defined by board. Sounds reasonable?
Yes.
Best regards,
Krzysztof
next prev parent reply other threads:[~2022-08-23 11:03 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-19 12:54 [PATCH v2 0/4] ASoC platform driver for Apple MCA Martin Povišer
2022-08-19 12:54 ` Martin Povišer
2022-08-19 12:54 ` [PATCH v2 1/4] dt-bindings: sound: Add Apple MCA I2S transceiver Martin Povišer
2022-08-19 12:54 ` Martin Povišer
2022-08-19 12:58 ` Martin Povišer
2022-08-19 12:58 ` Martin Povišer
2022-08-19 13:08 ` Krzysztof Kozlowski
2022-08-19 13:08 ` Krzysztof Kozlowski
2022-08-19 13:09 ` Krzysztof Kozlowski
2022-08-19 13:09 ` Krzysztof Kozlowski
2022-08-19 14:14 ` Martin Povišer
2022-08-19 14:14 ` Martin Povišer
2022-08-19 14:17 ` Krzysztof Kozlowski
2022-08-19 14:17 ` Krzysztof Kozlowski
2022-08-22 18:59 ` Rob Herring
2022-08-22 18:59 ` Rob Herring
2022-08-19 12:54 ` [PATCH v2 2/4] arm64: dts: apple: t8103: Add MCA and its support Martin Povišer
2022-08-19 12:54 ` Martin Povišer
2022-08-19 13:12 ` Krzysztof Kozlowski
2022-08-19 13:12 ` Krzysztof Kozlowski
2022-08-19 14:24 ` Martin Povišer
2022-08-19 14:24 ` Martin Povišer
2022-08-23 11:02 ` Krzysztof Kozlowski [this message]
2022-08-23 11:02 ` Krzysztof Kozlowski
2022-08-19 12:54 ` [PATCH v2 3/4] ASoC: apple: mca: Start new platform driver Martin Povišer
2022-08-19 12:54 ` Martin Povišer
2022-08-22 17:39 ` Mark Brown
2022-08-22 17:39 ` Mark Brown
2022-08-23 7:33 ` Martin Povišer
2022-08-23 7:33 ` Martin Povišer
2022-08-23 11:31 ` Mark Brown
2022-08-23 11:31 ` Mark Brown
2022-08-23 11:51 ` Martin Povišer
2022-08-23 11:51 ` Martin Povišer
2022-08-23 11:53 ` Martin Povišer
2022-08-23 11:53 ` Martin Povišer
2022-08-19 12:54 ` [PATCH v2 4/4] ASoC: apple: mca: Add locks on foreign cluster access Martin Povišer
2022-08-19 12:54 ` Martin Povišer
2022-08-22 17:45 ` Mark Brown
2022-08-22 17:45 ` Mark Brown
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