On Thursday, August 24, 2023 5:48 PM, Maxime Ripard [off-list ref] wrote: 

On Wed, Aug 23, 2023 at 08:47:51AM +0000, Ying Liu wrote:

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This dt-binding just follows generic dt-binding rule to describe the DPU

IP

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hardware, not the software implementation.  DPU internal units do not
constitute separate devices.

I mean, your driver does split them into separate devices so surely it
constitutes separate devices.

My driver treats them as DPU internal units, especially not Linux devices.

Let's avoid Linuxisms when implementing this dt-binding and just be simple
to describe necessary stuff exposing to DPU's embodying system/SoC, like
reg, interrupts, clocks and power-domains.

Let's focus the conversation here, because it's redundant with the rest.

Your driver registers two additional devices, that have a different
register space, different clocks, different interrupts, different power
domains, etc. That has nothing to do with Linux, it's hardware
properties.

That alone is a very good indication to me that these devices should be
modeled as such. And your driver agrees.

Whether or not the other internal units need to be described as separate
devices, I can't really tell, I don't have the datasheet.

i.MX8qxp and i.MX8qm SoC reference manuals can be found at(I think
registration is needed first):
https://www.nxp.com/webapp/Download?colCode=IMX8DQXPRM
https://www.nxp.com/webapp/Download?colCode=IMX8QMRM

Sorry for putting this in a short way, but the DPU is one IP, so one dt-binding.

But at least the CRTC and the interrupt controller should be split away,
or explained and detailed far better than "well it's just convenient".

CRTC is Linuxisms, which cannot be referenced to determine dt-binding.

DPU as Display Controller is listed as a standalone module/IP in RM.
This is how the IP is designed in the first place, not for any convenient
purpose.

Regards,
Liu Ying

Maxime

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