[PATCH 6/9] riscv: dts: microchip: mpfs: Fix reference clock node

[Krzysztof Kozlowski]

On 03/12/2021 16:29, Conor.Dooley at microchip.com wrote:
> On 26/11/2021 10:16, conor wrote:
>> On 26/11/2021 09:48, Krzysztof Kozlowski wrote:
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>>> On 25/11/2021 16:31, Geert Uytterhoeven wrote:
>>>> "make dtbs_check" reports:
>>>>
>>>>      arch/riscv/boot/dts/microchip/microchip-mpfs-icicle-kit.dt.yaml: 
>>>> soc: refclk: {'compatible': ['fixed-clock'], '#clock-cells': [[0]], 
>>>> 'clock-frequency': [[600000000]], 'clock-output-names': 
>>>> ['msspllclk'], 'phandle': [[7]]} should not be valid under {'type': 
>>>> 'object'}
>>>>        From schema: dtschema/schemas/simple-bus.yaml
>>>>
>>>> Fix this by moving the node out of the "soc" subnode.
>>>> While at it, rename it to "msspllclk", and drop the now superfluous
>>>> "clock-output-names" property.
>>>>
>>>> Signed-off-by: Geert Uytterhoeven <geert at linux-m68k.org>
>>>> ---
>>>>   arch/riscv/boot/dts/microchip/microchip-mpfs.dtsi | 13 ++++++-------
>>>>   1 file changed, 6 insertions(+), 7 deletions(-)
>>>>
>>>
>>> It is also logical because refclk usually is not a property of the SoC.
>>> It actually might be a property of board...
>> This is one of the fun FPGAisms like the GPIO interrupt configuration. 
>> This clock setting is determined by what design has been loaded onto the 
>> FPGA - the msspll outputs are configurable, I could redo my FPGA design 
>> and change this to 500 MHz etc. In turn the msspll clock is set by 
>> another clock source that is actually on the board of either 100 or 125 
>> MHz.
>>
>> Since it's not set until bitstream programming time, I would agree that 
>> that property should be moved to out of mpfs.dtsi. (typo fixed)
> Geert/Krzysztof,
> Would the following make sense:
> - Since the refclk hardware is a part of the chip, move the refclk out 
> of the soc node but leave it in mfps.dtsi
> - The clk freq itself is set by the fpga bitstream, so move the 
> clock-frequency property to mpfs-icicle-kit.dts?

Yes, makes sense to me.


Best regards,
Krzysztof