[PATCH 1/4] riscv: dts: spacemit: k3: add clock tree

[Samuel Holland]

Hi Yixun,

On 2026-03-14 3:52 AM, Yixun Lan wrote:
> On 20:44 Fri 13 Mar     , Samuel Holland wrote:
>> On 2026-03-04 1:36 AM, Yixun Lan wrote:
>>> Add clock support to SpacemiT K3 SoC, the clock tree consist of several
>>> blocks which are APBC, APMU, DCIU, MPUM.
>>>
>>> Signed-off-by: Yixun Lan <dlan at kernel.org>
>>> ---
>>>  arch/riscv/boot/dts/spacemit/k3.dtsi | 75 ++++++++++++++++++++++++++++++++++++
>>>  1 file changed, 75 insertions(+)
>>>
>>> diff --git a/arch/riscv/boot/dts/spacemit/k3.dtsi b/arch/riscv/boot/dts/spacemit/k3.dtsi
>>> index b69cf81b5d55..e3d7f3102fd5 100644
>>> --- a/arch/riscv/boot/dts/spacemit/k3.dtsi
>>> +++ b/arch/riscv/boot/dts/spacemit/k3.dtsi
>>> @@ -4,6 +4,7 @@
>>>   * Copyright (c) 2026 Guodong Xu <guodong at riscstar.com>
>>>   */
>>>  
>>> +#include <dt-bindings/clock/spacemit,k3-clocks.h>
>>>  #include <dt-bindings/interrupt-controller/irq.h>
>>>  
>>>  /dts-v1/;
>>> @@ -398,6 +399,36 @@ core3 {
>>>  		};
>>>  	};
>>>  
>>> +	clocks {
>>> +		vctcxo_1m: clock-1m {
>>> +			compatible = "fixed-clock";
>>> +			clock-frequency = <1000000>;
>>> +			clock-output-names = "vctcxo_1m";
>>> +			#clock-cells = <0>;
>>> +		};
>>> +
>>> +		vctcxo_24m: clock-24m {
>>> +			compatible = "fixed-clock";
>>> +			clock-frequency = <24000000>;
>>> +			clock-output-names = "vctcxo_24m";
>>> +			#clock-cells = <0>;
>>> +		};
>>> +
>>> +		vctcxo_3m: clock-3m {
>>> +			compatible = "fixed-clock";
>>> +			clock-frequency = <3000000>;
>>> +			clock-output-names = "vctcxo_3m";
>>> +			#clock-cells = <0>;
>>> +		};
>>> +
>>> +		osc_32k: clock-32k {
>>> +			compatible = "fixed-clock";
>>> +			clock-frequency = <32000>;
>>> +			clock-output-names = "osc_32k";
>>> +			#clock-cells = <0>;
>>> +		};
>>
>> Are these clocks provided by SoC or by the board? Usually there's a crystal
>> external to the SoC that provides the root of the clock tree. If these clocks
>> are provided by the board, they (or at least the clock-frequency property)
>> should be in the board DT, not the SoC dtsi.
>>
> It's true, as a quick check, osc_32k provided by P1 PMU, while vctcxo_24m is
> a crystal, vctcxo_1m and vctcxo_3m are also marked as external in the clock
> tree, but I would confirm them later..

In that case, osc_32k should ideally be a reference to the P1 PMU clock
provider, not a fixed-clock. But this may be infeasible if it creates dependency
loops (PMU depends on I2C, I2C depends on clocks, clocks depend on PMU).

> I agree to move them out of SoC dtsi file - k3.dtsi, while due to all boards share
> the same clock topology, what if I creating a k3-clock.dtsi and making it shared 
> between all board dts file? to avoid massive DTS duplication

Yes, it is common practice to create a .dtsi file for things shared among
several boards for a SoC (for example if they are all based on a reference
platform). You may want to name it something more generic if more than just
clocks can be shared (like k3-common.dtsi, compare jh7110-common.dtsi).

>> Also, the /clocks node is out of order.
>>
> I will move osc_32k before vtccxo_1m, assuming it's the problem you
> refered to?

I mean that /clocks sorts alphabetically before /cpus. Your ordering of the
fixed-clocks nodes themselves is fine.

Regards,
Samuel