Re: [PATCH 3/4] arm64: dts: rockchip: Add base DT for rk3528 SoC

[Krzysztof Kozlowski <krzk@kernel.org>]

On 04/08/2024 17:51, Heiko Stübner wrote:
> Am Sonntag, 4. August 2024, 15:59:19 CEST schrieb Dragan Simic:
>> On 2024-08-04 15:44, Heiko Stübner wrote:
>>> Am Sonntag, 4. August 2024, 15:25:47 CEST schrieb Dragan Simic:
>>>> On 2024-08-04 15:20, Yao Zi wrote:
>>>>> On Sun, Aug 04, 2024 at 12:05:11PM +0200, Krzysztof Kozlowski wrote:
>>>>>> On 03/08/2024 14:55, Yao Zi wrote:
>>>>>>> This initial device tree describes CPU, interrupts and UART on the chip
>>>>>>> and is able to boot into basic kernel with only UART. Cache information
>>>>>>> is omitted for now as there is no precise documentation. Support for
>>>>>>> other features will be added later.
>>>>>>>
>>>>>>> Signed-off-by: Yao Zi <ziyao@disroot.org>
>>>>>>> ---
>>>>>>>  arch/arm64/boot/dts/rockchip/rk3528.dtsi | 182 +++++++++++++++++++++++
>>>>>>>  1 file changed, 182 insertions(+)
>>>>>>>  create mode 100644 arch/arm64/boot/dts/rockchip/rk3528.dtsi
>>>>>>>
>>>>>>> diff --git a/arch/arm64/boot/dts/rockchip/rk3528.dtsi b/arch/arm64/boot/dts/rockchip/rk3528.dtsi
>>>>>>> new file mode 100644
>>>>>>> index 000000000000..77687d9e7e80
>>>>>>> --- /dev/null
>>>>>>> +++ b/arch/arm64/boot/dts/rockchip/rk3528.dtsi
>>>>>>> @@ -0,0 +1,182 @@
>>>>>>> +// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
>>>>>>> +/*
>>>>>>> + * Copyright (c) 2022 Rockchip Electronics Co., Ltd.
>>>>>>> + * Copyright (c) 2024 Yao Zi <ziyao@disroot.org>
>>>>>>> + */
>>>>>>> +
>>>>>>> +#include <dt-bindings/interrupt-controller/arm-gic.h>
>>>>>>> +#include <dt-bindings/interrupt-controller/irq.h>
>>>>>>> +
>>>>>>> +/ {
>>>>>>> +	compatible = "rockchip,rk3528";
>>>>>>> +
>>>>>>> +	interrupt-parent = <&gic>;
>>>>>>> +	#address-cells = <2>;
>>>>>>> +	#size-cells = <2>;
>>>>>>> +
>>>>>>> +	aliases {
>>>>>>> +		serial0 = &uart0;
>>>>>>> +		serial1 = &uart1;
>>>>>>> +		serial2 = &uart2;
>>>>>>> +		serial3 = &uart3;
>>>>>>> +		serial4 = &uart4;
>>>>>>> +		serial5 = &uart5;
>>>>>>> +		serial6 = &uart6;
>>>>>>> +		serial7 = &uart7;
>>>>>>> +	};
>>>>>>> +
>>>>>>> +	cpus {
>>>>>>> +		#address-cells = <1>;
>>>>>>> +		#size-cells = <0>;
>>>>>>> +
>>>>>>> +		cpu-map {
>>>>>>> +			cluster0 {
>>>>>>> +				core0 {
>>>>>>> +					cpu = <&cpu0>;
>>>>>>> +				};
>>>>>>> +				core1 {
>>>>>>> +					cpu = <&cpu1>;
>>>>>>> +				};
>>>>>>> +				core2 {
>>>>>>> +					cpu = <&cpu2>;
>>>>>>> +				};
>>>>>>> +				core3 {
>>>>>>> +					cpu = <&cpu3>;
>>>>>>> +				};
>>>>>>> +			};
>>>>>>> +		};
>>>>>>> +
>>>>>>> +		cpu0: cpu@0 {
>>>>>>> +			device_type = "cpu";
>>>>>>> +			compatible = "arm,cortex-a53";
>>>>>>> +			reg = <0x0>;
>>>>>>> +			enable-method = "psci";
>>>>>>> +		};
>>>>>>> +
>>>>>>> +		cpu1: cpu@1 {
>>>>>>> +			device_type = "cpu";
>>>>>>> +			compatible = "arm,cortex-a53";
>>>>>>> +			reg = <0x1>;
>>>>>>> +			enable-method = "psci";
>>>>>>> +		};
>>>>>>> +
>>>>>>> +		cpu2: cpu@2 {
>>>>>>> +			device_type = "cpu";
>>>>>>> +			compatible = "arm,cortex-a53";
>>>>>>> +			reg = <0x2>;
>>>>>>> +			enable-method = "psci";
>>>>>>> +		};
>>>>>>> +
>>>>>>> +		cpu3: cpu@3 {
>>>>>>> +			device_type = "cpu";
>>>>>>> +			compatible = "arm,cortex-a53";
>>>>>>> +			reg = <0x3>;
>>>>>>> +			enable-method = "psci";
>>>>>>> +		};
>>>>>>> +	};
>>>>>>> +
>>>>>>> +	psci {
>>>>>>> +		compatible = "arm,psci-1.0", "arm,psci-0.2";
>>>>>>> +		method = "smc";
>>>>>>> +	};
>>>>>>> +
>>>>>>> +	timer {
>>>>>>> +		compatible = "arm,armv8-timer";
>>>>>>> +		interrupts = <GIC_PPI 13 (GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>,
>>>>>>> +			     <GIC_PPI 14 (GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>,
>>>>>>> +			     <GIC_PPI 11 (GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>,
>>>>>>> +			     <GIC_PPI 10 (GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>;
>>>>>>> +	};
>>>>>>> +
>>>>>>> +	xin24m: xin24m {
>>>>>>
>>>>>> Please use name for all fixed clocks which matches current format
>>>>>> recommendation: 'clock-([0-9]+|[a-z0-9-]+)+'
>>>>>
>>>>> Will be fixed in next revision.
>>>>
>>>> Hmm, why should we apply that rule to the xin24m clock, which is
>>>> named exactly like that everywhere else in Rockchip SoC dtsi files?
>>>> It's much better to remain consistent.
>>>
>>> bindings or how we write devicetrees evolve over time ... similarly the
>>> xin24m name comes from more than 10 years ago.
>>>
>>> We also name all those regulator nodes regulator-foo now, which in turn
>>> automatically does enforce a nice sorting rule to keep all the 
>>> regulators
>>> around the same area ;-)
>>>
>>> So I don't see a problem of going with xin24m: clock-xin24m {}
>>
>> I agree that using "clock-xin24m" makes more sense in general, but the
>> trouble is that we can't rename the already existing instances of 
>> "xin24m",
>> because that has become part of the ABI.  Thus, I'm not sure that 
>> breaking
>> away from the legacy brings benefits in this particular case.
> 
> In the regulator case, we have _new_ boards using the new _node_-names
> but I don't see any renaming of old boards and also don't think we should.
> 
> But that still does not keep us from using the nicer naming convention in
> new boards ;-) .
> 
> 
> Same with xin24m. We're talking only about the node-name here. The
> phandle stays the same and also the actual clock name stays the same and
> really only the actual node name you need to look for in /proc/device-tree
> changes ;-) .
> 
> So I don't see the need to go about changing all the old socs, but new
> additions should use improved naming conventions.
> 
> xin24m: clock-xin24m {
> 	compatible = "fixed-clock";
> 	#clock-cells = <0>;
> 	clock-frequency = <24000000>;
> 	clock-output-names = "xin24m";

Just to make it clear - doc clearly says the preferred name is:
"clock-frequency".

Best regards,
Krzysztof