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

On Thu Jul 16, 2026 at 7:49 PM CEST, Brian Masney wrote:
> Hi Mathieu,
>
> On Wed, Jul 15, 2026 at 05:09:56PM +0200, Mathieu Dubois-Briand 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 <[email protected]>
>
> So this only updates of_mux_clk_setup(). of_ti_composite_mux_clk_setup()
> calls ti_clk_add_component(), which does a name based matching as well.
> It would be nice to have this consistent within the same driver. I know
> this is going to require a larger refactor.
>
> Otherwise your fix looks correct to me.
>
> Brian

Hi Brian,

Thanks for your comment.

Yes, it does make sense to make everything consistent here. I'm not
really comfortable with this driver, but I can give it a try.

Just to be sure, are you talking only about drivers/clk/ti/composite.c
or is it about more files in drivers/clk/ti/? I'm not sure to understand
the whole interactions between each components here.

Fixing drivers/clk/ti/composite.c to use clk_parent_data looks easy, I
can definitely send a patch for that. But you are talking about a larger
refactor, so I suspect you would like to see more changes.

I had a look at the other files in drivers/clk/ti/, here are my first
thoughts:
- drivers/clk/ti/apll.c, drivers/clk/ti/dpll.c, drivers/clk/ti/fapll.c:
  Changes would be similar to what was made here.
- drivers/clk/ti/divider.c, drivers/clk/ti/gate.c,
  drivers/clk/ti/interface.c, drivers/clk/ti/adpll.c: I believe we have
  to stick with matching parents by name. This could be made using
  clk_parent_data .name field if we really want to switch to
  clk_parent_data structure. Is that a target?
- drivers/clk/ti/clkctrl.c: similarly, I believe we have to stick to
  clock names. Using clk_parent_data structure requires a lot of changes
  in drivers/clk/ti/clk-* files, but these changes should be trivial.

What would be the relevant changes here?

Thanks,
Mathieu

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