Re: [PATCH 5/6] soc: renesas: Add support for Renesas RZ/N1 GPIO Interrupt Multiplexer

[Herve Codina <herve.codina@bootlin.com>]

Hi Rob,

On Wed, 30 Jul 2025 15:47:33 -0500
Rob Herring <robh@kernel.org> wrote:

...
> > > > +
> > > > +static int irqmux_imap_cb(void *data, const __be32 *imap,
> > > > +			  const struct of_phandle_args *parent_args)
> > > > +{
> > > > +	struct irqmux_cb_data *priv = data;
> > > > +	u32 src_hwirq;
> > > > +	int index;
> > > > +
> > > > +	/*
> > > > +	 * The child #address-cells is 0. Already checked in irqmux_setup().
> > > > +	 * The first value in imap is the src_hwirq
> > > > +	 */
> > > > +	src_hwirq = be32_to_cpu(*imap);    
> > > 
> > > The iterator should take care of the endianness conversion.  
> > 
> > Ok, it will take care.
> >   
> > >   
> > > > +
> > > > +	/*
> > > > +	 * Get the index in our interrupt array that matches the parent in the
> > > > +	 * interrupt-map
> > > > +	 */
> > > > +	index = irqmux_find_interrupt_index(priv->dev, priv->np, parent_args);
> > > > +	if (index < 0)
> > > > +		return dev_err_probe(priv->dev, index, "output interrupt not found\n");
> > > > +
> > > > +	dev_info(priv->dev, "interrupt %u mapped to output interrupt[%u]\n",
> > > > +		 src_hwirq, index);    
> > > 
> > > Do you even need "interrupts"? Just make the "interrupt-map" index 
> > > important and correspond to the hw index. That would greatly simplify 
> > > all this.  
> > 
> > I would like to avoid to be based on the interrupt-map index.
> > 
> > Indeed, IMHO, it is less robust. I don't thing that we can enforce the
> > interrupt-map items order. Based on interrupt-map index, we need to ensure
> > that the first item is related to GIC 103, the second one to GIC 104 and so
> > on.  
> 
> How exactly are you enforcing that order for "interrupts"? You can't.

I can impose interrupt-names property in the binding and at least, those
names are to be in order (checked by dtbs_check).

Based on that if a mismatch is present between interrupt-names and
interrupts it is an issue in the dts used.

With interrupt-map, nothing can be imposed and so nothing can be checked.

> 
> Aren't you just duplicating the information in "interrupts" in the 
> interrupt-map.
> 

I will remove 'interrupts' in the next iteration and use only 'interrupt-map'.

I will add some information related to the order of the interrup-map item in the
binding (description of the interrupt-map property).

Best regards,
Hervé