On Wed, 7 Jan 2026 09:58:07 +0100
Lorenzo Pieralisi [off-list ref] wrote:

On Mon, Jan 05, 2026 at 12:01:08PM +0000, Jonathan Cameron wrote:

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On Thu, 18 Dec 2025 11:14:29 +0100
Lorenzo Pieralisi [off-list ref] wrote:
  

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The GICv5 driver IRQ domain hierarchy requires adding a parent field to
struct irqchip_fwid so that core code can reference a fwnode_handle parent
for a given fwnode.

Add a parent field to struct irqchip_fwid and update the related kernel API
functions to initialize and handle it.

Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Cc: Thomas Gleixner <redacted>
Cc: Marc Zyngier <maz@kernel.org>  

Hi Lorenzo,

Happy new year.  

Happy New Year !

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---
 include/linux/irqdomain.h | 30 ++++++++++++++++++++++++++----
 kernel/irq/irqdomain.c    | 14 +++++++++++++-
 2 files changed, 39 insertions(+), 5 deletions(-)

diff --git a/include/linux/irqdomain.h b/include/linux/irqdomain.h
index 62f81bbeb490..b9df84b447a1 100644
--- a/include/linux/irqdomain.h
+++ b/include/linux/irqdomain.h

@@ -257,7 +257,8 @@ static inline void irq_domain_set_pm_device(struct irq_domain *d, struct device
 
 #ifdef CONFIG_IRQ_DOMAIN
 struct fwnode_handle *__irq_domain_alloc_fwnode(unsigned int type, int id,
-						const char *name, phys_addr_t *pa);
+						const char *name, phys_addr_t *pa,
+						struct fwnode_handle *parent);
 
 enum {
 	IRQCHIP_FWNODE_REAL,

@@ -267,18 +268,39 @@ enum {
 
 static inline struct fwnode_handle *irq_domain_alloc_named_fwnode(const char *name)
 {
-	return __irq_domain_alloc_fwnode(IRQCHIP_FWNODE_NAMED, 0, name, NULL);
+	return __irq_domain_alloc_fwnode(IRQCHIP_FWNODE_NAMED, 0, name, NULL, NULL);
+}
+
+static inline
+struct fwnode_handle *irq_domain_alloc_named_fwnode_parent(const char *name,
+							   struct fwnode_handle *parent)  

The name of this makes me think it's allocating the named fwnode parent, rather that
the named fwnode + setting it's parent.

There aren't all that many calls to irq_domain_named_fwnode(), maybe to avoid challenge
of a new name, just add the parameter to all of them? (25ish)  Mind you the current
pattern for similar cases is a helper, so maybe not.  

Similar cases ? Have you got anything specific I can look into ?

I meant all the different irq_domain_alloc_xxxxx variants that call
__irq_domain_alloc_fwnode() with a subset of parameters set to NULL.

That seems to say there is a precedence for making the presence of the parameter
part of the name rather than requiring callers to set the ones they don't want to
NULL.  So it argues for a helper like this one just for consistency.

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Or go with something similar to named and have

irq_domain_alloc_named_parented_fwnode()?  

Or I can add a set_parent() helper (though that's a bit of churn IMO) ?

If Thomas has a preference I will follow that, all of the above is doable
for me.

Agreed. Let's see what Thomas prefers (i.e. make the decision his problem ;)

Jonathan

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I'm not that bothered though if you think the current naming is the best we can do.  

I think you have a point - as per my comment above.

Thanks,
Lorenzo

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Jonathan
  

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+{
+	return __irq_domain_alloc_fwnode(IRQCHIP_FWNODE_NAMED, 0, name, NULL, parent);
 }