irqchip/ti-sci-intr: Allow parsing interrupt-types per-line

Some INTR router instances act as simple passthroughs that preserve the
source interrupt type unchanged at the output line, rather than
converting all interrupts to a fixed type.

When interrupt sources are not homogeneous with respect to trigger type,
the driver needs to read each source's interrupt type from DT and pass
it unchanged to its interrupt parent.

Add support to check for absence of "ti,intr-trigger-type" to indicate
passthrough mode. When this property is absent, parse interrupt type
per-line from the DT fwspec provided by the interrupt source. Else, use
the global setting for all interrupt lines.

Signed-off-by: Aniket Limaye <[e-mail]>
Signed-off-by: Thomas Gleixner <[e-mail]>
Link: https://patch.msgid.link/[e-mail]

drivers/irqchip/irq-ti-sci-intr.c

···
 {
 	struct ti_sci_intr_irq_domain *intr = domain->host_data;
 
-	if (fwspec->param_count != 1)
-		return -EINVAL;
+	if (intr->type) {
+		/* Global interrupt-type */
+		if (fwspec->param_count != 1)
+			return -EINVAL;
 
-	*hwirq = fwspec->param[0];
-	*type = intr->type;
+		*hwirq = fwspec->param[0];
+		*type = intr->type;
+	} else {
+		/* Per-Line interrupt-type */
+		if (fwspec->param_count != 2)
+			return -EINVAL;
 
+		*hwirq = fwspec->param[0];
+		*type = fwspec->param[1];
+	}
 	return 0;
 }
 
···
  * @domain:	Pointer to the interrupt router IRQ domain
  * @virq:	Corresponding Linux virtual IRQ number
  * @hwirq:	Corresponding hwirq for the IRQ within this IRQ domain
+ * @hwirq_type:	Corresponding hwirq trigger type for the IRQ within this IRQ domain
  *
  * Returns intr output irq if all went well else appropriate error pointer.
  */
-static int ti_sci_intr_alloc_parent_irq(struct irq_domain *domain,
-					unsigned int virq, u32 hwirq)
+static int ti_sci_intr_alloc_parent_irq(struct irq_domain *domain, unsigned int virq,
+					u32 hwirq, u32 hwirq_type)
 {
 	struct ti_sci_intr_irq_domain *intr = domain->host_data;
 	struct device_node *parent_node;
···
 		fwspec.param_count = 3;
 		fwspec.param[0] = 0;	/* SPI */
 		fwspec.param[1] = p_hwirq - 32; /* SPI offset */
-		fwspec.param[2] = intr->type;
+		fwspec.param[2] = hwirq_type;
 	} else {
 		/* Parent is Interrupt Router */
-		fwspec.param_count = 1;
-		fwspec.param[0] = p_hwirq;
+		u32 parent_trigger_type;
+
+		if (!of_property_read_u32(parent_node, "ti,intr-trigger-type",
+					  &parent_trigger_type)) {
+			/* Parent has global trigger type */
+			fwspec.param_count = 1;
+			fwspec.param[0] = p_hwirq;
+		} else {
+			/* Parent supports per-line trigger types */
+			fwspec.param_count = 2;
+			fwspec.param[0] = p_hwirq;
+			fwspec.param[1] = hwirq_type;
+		}
 	}
 
 	err = irq_domain_alloc_irqs_parent(domain, virq, 1, &fwspec);
···
 					void *data)
 {
 	struct irq_fwspec *fwspec = data;
+	unsigned int hwirq_type;
 	unsigned long hwirq;
-	unsigned int flags;
 	int err, out_irq;
 
-	err = ti_sci_intr_irq_domain_translate(domain, fwspec, &hwirq, &flags);
+	err = ti_sci_intr_irq_domain_translate(domain, fwspec, &hwirq, &hwirq_type);
 	if (err)
 		return err;
 
-	out_irq = ti_sci_intr_alloc_parent_irq(domain, virq, hwirq);
+	out_irq = ti_sci_intr_alloc_parent_irq(domain, virq, hwirq, hwirq_type);
 	if (out_irq < 0)
 		return out_irq;
 
···
 		return -ENOMEM;
 
 	intr->dev = dev;
-	ret = of_property_read_u32(dev_of_node(dev), "ti,intr-trigger-type",
-				   &intr->type);
-	if (ret) {
-		dev_err(dev, "missing ti,intr-trigger-type property\n");
-		return -EINVAL;
-	}
+
+	if (of_property_read_u32(dev_of_node(dev), "ti,intr-trigger-type", &intr->type))
+		intr->type = IRQ_TYPE_NONE;
 
 	intr->sci = devm_ti_sci_get_by_phandle(dev, "ti,sci");
 	if (IS_ERR(intr->sci))