Thread (117 messages) 117 messages, 15 authors, 2024-10-19

Re: [PATCH 08/11] misc: rp1: RaspberryPi RP1 misc driver

From: Krzysztof Kozlowski <krzk@kernel.org>
Date: 2024-09-03 18:27:25
Also in: linux-arch, linux-arm-kernel, linux-clk, linux-devicetree, linux-gpio, linux-pci, lkml

On 03/09/2024 17:15, Andrea della Porta wrote:
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+				rp1_clocks: clocks@c040018000 {
Why do you mix MMIO with non-MMIO nodes? This really does not look
correct.
Right. This is already under discussion here:
https://lore.kernel.org/all/ZtBzis5CzQMm8loh@apocalypse/ (local)

IIUC you proposed to instantiate the non-MMIO nodes (the three clocks) by
using CLK_OF_DECLARE.
Depends. Where are these clocks? Naming suggests they might not be even
part of this device. But if these are part of the device, then why this
is not a clock controller (if they are controllable) or even removed
(because we do not represent internal clock tree in DTS).
xosc is a crystal connected to the oscillator input of the RP1, so I would
consider it an external fixed-clock. If we were in the entire dts, I would have
put it in root under /clocks node, but here we're in the dtbo so I'm not sure
where else should I put it.
But physically, on which PCB, where is this clock located?
Regarding pclk and hclk, I'm still trying to understand where they come from.
If they are external clocks (since they are fixed-clock too), they should be
in the same node as xosc. CLK_OF_DECLARE does not seem to fit here because
There is no such node as "/clocks" so do not focus on that. That's just
placeholder but useless and it is inconsistent with other cases (e.g.
regulators).

If this is external oscillator then it is not part of RP1 and you cannot
put it inside just to satisfy your drivers.
there's no special management of these clocks, so no new clock definition is
needed.
If they are internal tree, I cannot simply get rid of them because rp1_eth node
references these two clocks (see clocks property), so they must be decalred 
somewhere. Any hint about this?.
Describe the hardware. Show the diagram or schematics where is which device.

Best regards,
Krzysztof
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