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

[Roger Quadros]

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.

>>
>> Let me know what you think,
>> Maxime
>>
>> Signed-off-by: Maxime Ripard <mripard at kernel.org>
>> ---
>> Maxime Ripard (4):
>>       pinctrl: Create a select_state variant with the ofnode
>>       net: ti: am65-cpsw-nuss: Enforce pinctrl state on the MDIO child node
>>       fixup! arm: dts: k3-am62: Bump dtsi from linux v6.5-rc1
>>       fixup! arm: dts: k3-am62: Bump dtsi from linux v6.5-rc1
>>
>>  arch/arm/dts/k3-am625-sk-u-boot.dtsi |  7 ++++--
>>  drivers/net/ti/am65-cpsw-nuss.c      | 49 ++++++++++++++++++++++++++++++++++++
>>  drivers/pinctrl/pinctrl-uclass.c     | 15 ++++++-----
>>  include/dm/pinctrl.h                 | 26 ++++++++++++++-----
>>  4 files changed, 83 insertions(+), 14 deletions(-)
>> ---
>> base-commit: acff6e7c553d5a839e885730a4018465a34ba5a7
>> change-id: 20230720-ti-mdio-pinmux-a12525dba973
>>
>> Best regards,
> 
> Adding Roger

-- 
cheers,
-roger