[PATCH 0/4] net: ti: am65-cpsw-nuss: Fix DT binding handling of pinctrl

Nishanth Menon nm at ti.com
Thu Jul 20 16:00:19 CEST 2023

On 16:56-20230720, Roger Quadros wrote:
> Hi,
> On 20/07/2023 16:33, Ravi Gunasekaran wrote:
> > 
> > 
> > On 7/20/2023 3:25 PM, Maxime Ripard wrote:
> >> Hi,
> >>
> >> This series is based on:
> >> https://lore.kernel.org/all/20230713072019.3153871-1-nm@ti.com/
> >>
> >> It fixes the issue of Linux booting from the DT embedded by U-boot. The
> >> main issue there is that U-Boot doesn't handle the MDIO child node that
> >> might have resources attached to it.
> >>
> >> Thus, any pinctrl configuration that could be attached to the MDIO
> >> child node is effectively ignored. Unfortunately, starting with 6.5-rc1,
> >> Linux does just that.
> I didn't get this part. Linux does not ignore pinctrl configuration attached
> to MDIO child node. What changed in 6.5-rc1?
> >>
> >> This was solved by duplicating the pinctrl configuration onto the MAC
> If I remember right, there is no driver model driver for MDIO in u-boot and
> adding the mdio pinctrl into CPSW DT node was a hack in u-boot.
> >> device node. Unfortunately, this doesn't work for Linux since now it has
> >> two devices competing for the same pins.
> What has really changed here is that you are passing u-boot's device tree to Linux.
> This has nothing to do with 6.5-rc1 right?
> I suppose your solution is still a hack but of lesser evil than
> duplicating MDIO pinctrl in CPSW node.
> The proper solution would be to implement driver model for the davinci MDIO driver.
> Siddharth has been working on this. If that is close to ready we should just use
> that instead.

But this allows for a cleaner device tree while the driver can be fixed
up independently, correct? Unfortunately, Siddharth's driver model work,
from what I understand, is around 2024 timeframe.. which is probably not
something that helps us in the community at this point.

Nishanth Menon
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