diff options
Diffstat (limited to 'Documentation/core-api/irq/irq-domain.rst')
| -rw-r--r-- | Documentation/core-api/irq/irq-domain.rst | 22 |
1 files changed, 12 insertions, 10 deletions
diff --git a/Documentation/core-api/irq/irq-domain.rst b/Documentation/core-api/irq/irq-domain.rst index a77c24c27f7b..8214e215a8bf 100644 --- a/Documentation/core-api/irq/irq-domain.rst +++ b/Documentation/core-api/irq/irq-domain.rst @@ -42,10 +42,10 @@ irq_domain usage ================ 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 @@ -147,6 +147,7 @@ Legacy 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 @@ -169,13 +170,13 @@ supported. For example, ISA controllers would use the legacy map for 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. @@ -186,6 +187,7 @@ that the driver using the simple domain call irq_create_mapping() 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 |