Re: [PATCH v2] spmi: Fix controller->node != parent->node breakage

[Konrad Dybcio]

On 1/14/25 19:30, Stephen Boyd wrote:
> Quoting Konrad Dybcio (2025-01-13 14:12:28)
> > On 1/13/25 22:52, Stephen Boyd wrote:
> > > Quoting Konrad Dybcio (2025-01-13 05:02:58)
> > > > Make controller->node specifiable to both benefit from Joe's refcount
> > > > improvements and un-break the aforementioned platforms.
> > >
> > > How is it broken? I see spmi_pmic_arb_bus_init() calls
> > > devm_spmi_controller_alloc() which sets the of_node to the parent device
> > > and then spmi_pmic_arb_bus_init() overwrites that with
> > > 'ctrl->dev.of_node = node' later on in the same function. That will
> > > cause one more of_node_put() than is expected. I don't see that removed
> > > in this patch though, so the leak is still there?
> > >
> > > > Fixes: 821b07853e32 ("spmi: hisi-spmi-controller: manage the OF node reference in device initialization and cleanup")
> > >
> > > I've dropped this patch from my queue. I don't know if we're really
> > > doing anything better by managing the of_node lifetime in that function
> > > vs. letting the callers assign the node they want and manage the
> > > lifetime themselves. Maybe we don't need to do anything? Presumably the
> > > parent device driver will unregister the controller anyway, so the
> > > lifetime of the of_node will be ensured regardless. For subnodes like
> > > qcom SPMI, the subnodes are child nodes of the parent device so they
> > > won't be removed. If they are dynamic nodes, then the caller can manage
> > > the lifetime.
> >
> > Stephen, the wrong node gets assigned in the qcom driver with
> > multi-master controllers, resulting in probe failures.
> >
> > Since the introduction of the commit referenced in fixes,
> > of_spmi_register_devices() sees the controller's subnodes
> > (which describe each of the two masters) as slave devices
> > - meaning no "real" devices ever get to probe
>
> Ok, I see that I was reading the already reverted state of the tree
> where the 'ctrl->dev.of_node = node' assignment came back. So there's
> nothing to do besides drop the patch in fixes, which I already did. We
> can then apply this patch to drop the duplicate assignment as a cleanup
> and to avoid a refcount bump on the of_node that isn't needed.
>
> ----8<---
> diff --git a/drivers/spmi/hisi-spmi-controller.c b/drivers/spmi/hisi-spmi-controller.c
> index 3cafdf22c909..122140b97579 100644
> --- a/drivers/spmi/hisi-spmi-controller.c
> +++ b/drivers/spmi/hisi-spmi-controller.c
> @@ -300,9 +300,6 @@ static int spmi_controller_probe(struct platform_device *pdev)
>   
>   	spin_lock_init(&spmi_controller->lock);
>   
> -	ctrl->dev.parent = pdev->dev.parent;
> -	ctrl->dev.of_node = of_node_get(pdev->dev.of_node);
> -
>   	/* Callbacks */
>   	ctrl->read_cmd = spmi_read_cmd;
>   	ctrl->write_cmd = spmi_write_cmd;

That works for me, thank you

Konrad