From 94a63da0ac1a67bfb8b30aec1086523c5031ea5a Mon Sep 17 00:00:00 2001 From: Linus Walleij Date: Thu, 6 Jun 2013 12:10:23 +0100 Subject: [PATCH] irqdomain: document the simple domain first_irq The first_irq needs to be zero to get a linear domain and that comes with special semantics. We want to simplify this going forward but some documentation never hurts. Signed-off-by: Linus Walleij Signed-off-by: Grant Likely --- kernel/irq/irqdomain.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c index 8c4c8ea6a205..54a4d5223238 100644 --- a/kernel/irq/irqdomain.c +++ b/kernel/irq/irqdomain.c @@ -143,7 +143,10 @@ static unsigned int irq_domain_legacy_revmap(struct irq_domain *domain, * irq_domain_add_simple() - Allocate and register a simple irq_domain. * @of_node: pointer to interrupt controller's device tree node. * @size: total number of irqs in mapping - * @first_irq: first number of irq block assigned to the domain + * @first_irq: first number of irq block assigned to the domain, + * pass zero to assign irqs on-the-fly. This will result in a + * linear IRQ domain so it is important to use irq_create_mapping() + * for each used IRQ, especially when SPARSE_IRQ is enabled. * @ops: map/unmap domain callbacks * @host_data: Controller private data pointer *