irqdomain: Let irq_domain_set_{info,hwirq_and_chip} take a const irq_chip

In order to let a const irqchip be fed to the irqchip layer, adjust
the various prototypes. An extra cast in irq_domain_set_hwirq_and_chip()
is required to avoid a warning.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20220209162607.1118325-2-maz@kernel.org

Author: Marc Zyngier

include/linux/irqdomain.h

@@ -479,7 +479,8 @@ int irq_destroy_ipi(unsigned int irq, const struct cpumask *dest);
 extern struct irq_data *irq_domain_get_irq_data(struct irq_domain *domain,
 						unsigned int virq);
 extern void irq_domain_set_info(struct irq_domain *domain, unsigned int virq,
-				irq_hw_number_t hwirq, struct irq_chip *chip,
+				irq_hw_number_t hwirq,
+				const struct irq_chip *chip,
 				void *chip_data, irq_flow_handler_t handler,
 				void *handler_data, const char *handler_name);
 extern void irq_domain_reset_irq_data(struct irq_data *irq_data);
@@ -522,7 +523,7 @@ extern int irq_domain_alloc_irqs_hierarchy(struct irq_domain *domain,
 extern int irq_domain_set_hwirq_and_chip(struct irq_domain *domain,
 					 unsigned int virq,
 					 irq_hw_number_t hwirq,
-					 struct irq_chip *chip,
+					 const struct irq_chip *chip,
 					 void *chip_data);
 extern void irq_domain_free_irqs_common(struct irq_domain *domain,
 					unsigned int virq,

kernel/irq/irqdomain.c

@@ -1319,7 +1319,8 @@ EXPORT_SYMBOL_GPL(irq_domain_get_irq_data);
  * @chip_data:	The associated chip data
  */
 int irq_domain_set_hwirq_and_chip(struct irq_domain *domain, unsigned int virq,
-				  irq_hw_number_t hwirq, struct irq_chip *chip,
+				  irq_hw_number_t hwirq,
+				  const struct irq_chip *chip,
 				  void *chip_data)
 {
 	struct irq_data *irq_data = irq_domain_get_irq_data(domain, virq);
@@ -1328,7 +1329,7 @@ int irq_domain_set_hwirq_and_chip(struct irq_domain *domain, unsigned int virq,
 		return -ENOENT;
 
 	irq_data->hwirq = hwirq;
-	irq_data->chip = chip ? chip : &no_irq_chip;
+	irq_data->chip = (struct irq_chip *)(chip ? chip : &no_irq_chip);
 	irq_data->chip_data = chip_data;
 
 	return 0;
@@ -1347,7 +1348,7 @@ EXPORT_SYMBOL_GPL(irq_domain_set_hwirq_and_chip);
  * @handler_name:	The interrupt handler name
  */
 void irq_domain_set_info(struct irq_domain *domain, unsigned int virq,
-			 irq_hw_number_t hwirq, struct irq_chip *chip,
+			 irq_hw_number_t hwirq, const struct irq_chip *chip,
 			 void *chip_data, irq_flow_handler_t handler,
 			 void *handler_data, const char *handler_name)
 {
@@ -1853,7 +1854,7 @@ EXPORT_SYMBOL_GPL(irq_domain_get_irq_data);
  * @handler_name:	The interrupt handler name
  */
 void irq_domain_set_info(struct irq_domain *domain, unsigned int virq,
-			 irq_hw_number_t hwirq, struct irq_chip *chip,
+			 irq_hw_number_t hwirq, const struct irq_chip *chip,
 			 void *chip_data, irq_flow_handler_t handler,
 			 void *handler_data, const char *handler_name)
 {