[RFC PATCH v3 05/17] ACPI: irq: Add support for deferred probe in acpi_register_gsi()

[Sunil V L]

The chip which provides the GSI support may not be initialized at the
time of acpi_register_gsi(). Return -EPROBE_DEFER to support deferred
probing similar to acpi_irq_get().

This is required to support ResourceSource as supported by ACPI spec for
Interrupt resource.

Signed-off-by: Sunil V L <sunilvl at ventanamicro.com>
---
 drivers/acpi/irq.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/acpi/irq.c b/drivers/acpi/irq.c
index b3409e2e2041..c4605fdcda77 100644
--- a/drivers/acpi/irq.c
+++ b/drivers/acpi/irq.c
@@ -52,6 +52,7 @@ EXPORT_SYMBOL_GPL(acpi_gsi_to_irq);
  *
  * Returns: a valid linux IRQ number on success
  *          -EINVAL on failure
+ *          -EPROBE_DEFER if irqdomain not created yet
  */
 int acpi_register_gsi(struct device *dev, u32 gsi, int trigger,
 		      int polarity)
@@ -65,6 +66,9 @@ int acpi_register_gsi(struct device *dev, u32 gsi, int trigger,
 		return -EINVAL;
 	}
 
+	if (!irq_find_matching_fwnode(fwspec.fwnode, DOMAIN_BUS_ANY))
+		return -EPROBE_DEFER;
+
 	fwspec.param[0] = gsi;
 	fwspec.param[1] = acpi_dev_get_irq_type(trigger, polarity);
 	fwspec.param_count = 2;
-- 
2.39.2