[PATCH] pmdomain: imx: gpc: set fwnode from parent device

[Emil Kronborg Andersen]

On Tue, Oct 24, 2023 at 14:42 +0200, Ulf Hansson wrote:
> I had a bit closer look at this. If I understand things correctly,
> this problem is because the imx_gpc_driver's ->probe() (imx_gpc_probe)
> is allocating/adding a new platform device, per child-of-node to
> represent a power-domain.
> 
> I suspect in most other cases where a platform device is being
> allocated per child node, is when the child node has a
> compatible-string and the parent driver is calling
> of_platform_populate(), or similar. In those cases, the "dev.fwnode"
> would be set accordingly, but not in the imx_gpc_driver case as it
> needs to be set explicitly.
> 
> That said, it looks like we should move forward with the $subject
> patch. However, it looks like the patch [1] from Pengfei Li is more
> correct than the $subject patch.
> 
> Kind regards
> Uffe
> 
> [1]
> https://lore.kernel.org/all/20231020185949.537083-1-pengfei.li_1@nxp.com/

That is also how I understand it works.

I was unsure if the patch from Pengfei Li [1] solves the same issue as
this patch, since there are no errors included in the commit message.
However, after testing the patch in [1], I can confirm that it fixes:

[    1.039830] imx-gpc 20dc000.gpc: Failed to create device link (0x180) with 20c8000.anatop:regulator-vddpu

I based my solution on other patches, where device_set_node() is used.
For example, a26cc2934331 ("drm/mipi-dsi: Set the fwnode for
mipi_dsi_device") and 6dbe6c07f94f ("gpio: Propagate firmware node from
a parent"). I am curious: Why is the approach in [1] considered more
correct? It seems logical to set the fwnode as early as possible from
the parent its device.

Thanks!

Best regards,
Emil

[1]
https://lore.kernel.org/all/20231020185949.537083-1-pengfei.li_1@nxp.com/