Re: Issue with Clock Parent Assignment on AM335x SoC (Watchdog Timer)

[Tony Lindgren <tony@atomide.com>]

* Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com> [260430 12:29]:
> On Thu Apr 30, 2026 at 5:40 AM CEST, Tony Lindgren wrote:
> > Just a quick guess.. You can use assigned-clocks in the dts file to
> > configure how your board is wired up.
> 
> Just to be clear: I believe this is entirely independent from how the
> board is wired up. On both my custom board and the Beagle Bone Black, I
> can successfully use any of the two muxing possibilities, if I manually
> write the correct data into the registers. My only issue is the kernel
> does not handle the clocks correctly when one these muxing possibilities
> is enabled.

OK

> Yet I tried to add an assigned-clocks property to the clock-wdt1-fck@538
> node. Is that what you had in mind? This had no visible effect.

Yes I was thinking adding assigned-clocks and assigned-clock-parents
similar to what the timers do.

There's also the am33xx_dt_clk_init() reparenting of wdt1_fck that's worth
checking for why the chosen parent is not getting set.

> > Please check the system timers configuration too, sounds like timers may
> > not be configured properly either. Some timer examples can be seen with:
> >
> > $ git grep -A10 "Preferred " arch/arm/boot/dts/
> 
> So I had a look at existing preferred timer configurations, but they are
> all applied to the "timer.*_target" [1][2] nodes, that do correspond to
> SoC timers (DMTIMER.*) and I fail to see how this is linked with the
> peripheral clocks involved here (in CM_PER module) and my current clock
> issues.
> 
> Nevertheless, I can see these being defined in
> arch/arm/boot/dts/ti/omap/am33xx.dtsi [3][4], so they are indeed applied
> in my situation.
> 
> So, I believe timers configuration are correct. Should I add something
> else?

OK no, so the issue is limited to wdt1 like you described earlier.

> [1]: https://elixir.bootlin.com/linux/v7.0.1/source/arch/arm/boot/dts/ti/omap/am33xx-l4.dtsi#L357
> [2]: https://elixir.bootlin.com/linux/v7.0.1/source/arch/arm/boot/dts/ti/omap/am33xx-l4.dtsi#L1280
> [3]: https://elixir.bootlin.com/linux/v7.0.1/source/arch/arm/boot/dts/ti/omap/am33xx.dtsi#L702
> [4]: https://elixir.bootlin.com/linux/v7.0.1/source/arch/arm/boot/dts/ti/omap/am33xx.dtsi#L715