Re: [PATCH v2 1/2] clk: ti: mux: resolve parent clocks by DT index, not by name

["Mathieu Dubois-Briand" <mathieu.dubois-briand@bootlin.com>]

Hi Geert,

On Tue Aug 18, 2026 at 6:02 PM CEST, Geert Uytterhoeven wrote:
> Hi Mathieu,
>
> On Mon, 27 Jul 2026 at 09:44, Mathieu Dubois-Briand
> <mathieu.dubois-briand@bootlin.com> wrote:
>> Resolve parent clocks by their index into the device tree "clocks"
>> property rather than matching names as strings. Name-based matching is
>> fragile because a clock's "clock-output-names" value in its provider
>> node can differ from the name used to reference it in a consumer node,
>> and because names must be globally unique across all clock providers.
>>
>> On AM335x, this caused broken clock trees where some clocks failed to
>> enable because their parents could not be found.
>>
>> Replace of_clk_parent_fill() with a clk_parent_data array that sets
>> .index to the array position.
>>
>> Fixes: ec7aa25fa483 ("ARM: dts: Use clock-output-names for am3")
>> Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
>
> Thanks for your patch, which is now commit 667f420c09f1417c ("clk: ti:
> mux: resolve parent clocks by DT index, not by name") in clk/clk-next.
>
> This breaks booting BeagleBone Black for me: I don't get any output
> on the serial console, even with "earlycon keep_bootcon".  When the
> watchdog kicks in (or on kernel panic?), the system reboots.
>

Sorry for that!

It's a bit unexpected, as the beaglebone black was one of my test
platforms and I didn't see any issue.

> Reverting this commit fixes the issue.
> After reverting, I added debug code to print all parents, and compared
> them to the DTB, but didn't see any discrepancies.
>
> Your similar change to drivers/clk/ti/composite.c does not cause any
> issues for me.
>
> Do you have a clue?
> Thanks!

Can you describe what bootloader and device tree you are using for your
tests? Any specific configuration?

On my side, I have:
- BeagleBone Black Wireless A5
- am335x-boneblack-wireless.dtb
- U-boot 2025.10-ti-g6825d60bea17. Maybe I should try with u-boot master
  branch.

Thanks,
Mathieu

-- 
Mathieu Dubois-Briand, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com