irqdomain: Introduce is_fwnode_irqchip helper

Since there will be several places checking if fwnode.type
is equal FWNODE_IRQCHIP, this patch adds a convenient function
for this purpose.
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
(cherry picked from commit 75aba7b0)
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

drivers/irqchip/irq-gic.c

@@ -972,7 +972,7 @@ static int gic_irq_domain_translate(struct irq_domain *d,
 		return 0;
 	}
 
-	if (fwspec->fwnode->type == FWNODE_IRQCHIP) {
+	if (is_fwnode_irqchip(fwspec->fwnode)) {
 		if(fwspec->param_count != 2)
 			return -EINVAL;
 

include/linux/irqdomain.h

@@ -211,6 +211,11 @@ static inline struct fwnode_handle *of_node_to_fwnode(struct device_node *node)
 	return node ? &node->fwnode : NULL;
 }
 
+static inline bool is_fwnode_irqchip(struct fwnode_handle *fwnode)
+{
+	return fwnode && fwnode->type == FWNODE_IRQCHIP;
+}
+
 static inline struct irq_domain *irq_find_matching_host(struct device_node *node,
 							enum irq_domain_bus_token bus_token)
 {

kernel/irq/irqdomain.c

@@ -70,7 +70,7 @@ void irq_domain_free_fwnode(struct fwnode_handle *fwnode)
 {
 	struct irqchip_fwid *fwid;
 
-	if (WARN_ON(fwnode->type != FWNODE_IRQCHIP))
+	if (WARN_ON(!is_fwnode_irqchip(fwnode)))
 		return;
 
 	fwid = container_of(fwnode, struct irqchip_fwid, fwnode);