irqdomain: Introduce irq_domain_create_simple() API

Linus Walleij pointed out that ird_domain_add_simple() gained
additional functionality and can't be anymore replaced with
a simple conditional. In preparation to upgrade GPIO library
to use fwnode, introduce irq_domain_create_simple() API which is
functional equivalent to the existing irq_domain_add_simple(),
but takes a pointer to the struct fwnode_handle as a parameter.

While at it, amend documentation to mention irq_domain_create_*()
functions where it makes sense.

Signed-off-by: Andy Shevchenko <[e-mail]>
Acked-by: Marc Zyngier <[e-mail]>
Signed-off-by: Bartosz Golaszewski <[e-mail]>

Documentation/core-api/irq/irq-domain.rst

···
 ================
 
 An interrupt controller driver creates and registers an irq_domain by
-calling one of the irq_domain_add_*() functions (each mapping method
-has a different allocator function, more on that later).  The function
-will return a pointer to the irq_domain on success.  The caller must
-provide the allocator function with an irq_domain_ops structure.
+calling one of the irq_domain_add_*() or irq_domain_create_*() functions
+(each mapping method has a different allocator function, more on that later).
+The function will return a pointer to the irq_domain on success. The caller
+must provide the allocator function with an irq_domain_ops structure.
 
 In most cases, the irq_domain will begin empty without any mappings
 between hwirq and IRQ numbers.  Mappings are added to the irq_domain
···
 	irq_domain_add_simple()
 	irq_domain_add_legacy()
 	irq_domain_add_legacy_isa()
+	irq_domain_create_simple()
 	irq_domain_create_legacy()
 
 The Legacy mapping is a special case for drivers that already have a
···
 mapping Linux IRQs 0-15 so that existing ISA drivers get the correct IRQ
 numbers.
 
-Most users of legacy mappings should use irq_domain_add_simple() which
-will use a legacy domain only if an IRQ range is supplied by the
-system and will otherwise use a linear domain mapping. The semantics
-of this call are such that if an IRQ range is specified then
+Most users of legacy mappings should use irq_domain_add_simple() or
+irq_domain_create_simple() which will use a legacy domain only if an IRQ range
+is supplied by the system and will otherwise use a linear domain mapping.
+The semantics of this call are such that if an IRQ range is specified then
 descriptors will be allocated on-the-fly for it, and if no range is
-specified it will fall through to irq_domain_add_linear() which means
-*no* irq descriptors will be allocated.
+specified it will fall through to irq_domain_add_linear() or
+irq_domain_create_linear() which means *no* irq descriptors will be allocated.
 
 A typical use case for simple domains is where an irqchip provider
 is supporting both dynamic and static IRQ assignments.
···
 before any irq_find_mapping() since the latter will actually work
 for the static IRQ assignment case.
 
+irq_domain_add_simple() and irq_domain_create_simple() as well as
 irq_domain_add_legacy() and irq_domain_create_legacy() are functionally
 equivalent, except for the first argument is different - the former
 accepts an Open Firmware specific 'struct device_node', while the latter

include/linux/irqdomain.h

···
 				    irq_hw_number_t hwirq_max, int direct_max,
 				    const struct irq_domain_ops *ops,
 				    void *host_data);
-struct irq_domain *irq_domain_add_simple(struct device_node *of_node,
-					 unsigned int size,
-					 unsigned int first_irq,
-					 const struct irq_domain_ops *ops,
-					 void *host_data);
+struct irq_domain *irq_domain_create_simple(struct fwnode_handle *fwnode,
+					    unsigned int size,
+					    unsigned int first_irq,
+					    const struct irq_domain_ops *ops,
+					    void *host_data);
 struct irq_domain *irq_domain_add_legacy(struct device_node *of_node,
 					 unsigned int size,
 					 unsigned int first_irq,
···
 		d = irq_find_matching_host(node, DOMAIN_BUS_ANY);
 
 	return d;
+}
+
+static inline struct irq_domain *irq_domain_add_simple(struct device_node *of_node,
+						       unsigned int size,
+						       unsigned int first_irq,
+						       const struct irq_domain_ops *ops,
+						       void *host_data)
+{
+	return irq_domain_create_simple(of_node_to_fwnode(of_node), size, first_irq, ops, host_data);
 }
 
 /**

kernel/irq/irqdomain.c

···
 EXPORT_SYMBOL_GPL(irq_domain_update_bus_token);
 
 /**
- * irq_domain_add_simple() - Register an irq_domain and optionally map a range of irqs
- * @of_node: pointer to interrupt controller's device tree node.
+ * irq_domain_create_simple() - Register an irq_domain and optionally map a range of irqs
+ * @fwnode: firmware node for the interrupt controller
  * @size: total number of irqs in mapping
  * @first_irq: first number of irq block assigned to the domain,
  *	pass zero to assign irqs on-the-fly. If first_irq is non-zero, then
···
  * irqs get mapped dynamically on the fly. However, if the controller requires
  * static virq assignments (non-DT boot) then it will set that up correctly.
  */
-struct irq_domain *irq_domain_add_simple(struct device_node *of_node,
-					 unsigned int size,
-					 unsigned int first_irq,
-					 const struct irq_domain_ops *ops,
-					 void *host_data)
+struct irq_domain *irq_domain_create_simple(struct fwnode_handle *fwnode,
+					    unsigned int size,
+					    unsigned int first_irq,
+					    const struct irq_domain_ops *ops,
+					    void *host_data)
 {
 	struct irq_domain *domain;
 
-	domain = __irq_domain_add(of_node_to_fwnode(of_node), size, size, 0, ops, host_data);
+	domain = __irq_domain_add(fwnode, size, size, 0, ops, host_data);
 	if (!domain)
 		return NULL;
 
···
 		if (IS_ENABLED(CONFIG_SPARSE_IRQ)) {
 			/* attempt to allocated irq_descs */
 			int rc = irq_alloc_descs(first_irq, first_irq, size,
-						 of_node_to_nid(of_node));
+						 of_node_to_nid(to_of_node(fwnode)));
 			if (rc < 0)
 				pr_info("Cannot allocate irq_descs @ IRQ%d, assuming pre-allocated\n",
 					first_irq);
···
 
 	return domain;
 }
-EXPORT_SYMBOL_GPL(irq_domain_add_simple);
+EXPORT_SYMBOL_GPL(irq_domain_create_simple);
 
 /**
  * irq_domain_add_legacy() - Allocate and register a legacy revmap irq_domain.