[RFC PATCH v2 04/21] ACPI: irq: Add support for deferred probe in acpi_register_gsi()

[Sunil V L <sunilvl@xxxxxxxxxxxxxxxx>]

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().

Signed-off-by: Sunil V L <sunilvl@xxxxxxxxxxxxxxxx>
---
 drivers/acpi/irq.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/acpi/irq.c b/drivers/acpi/irq.c
index 1687483ff319..c06cfc9725cb 100644
--- a/drivers/acpi/irq.c
+++ b/drivers/acpi/irq.c
@@ -51,19 +51,23 @@ EXPORT_SYMBOL_GPL(acpi_gsi_to_irq);
  * @polarity: polarity of the GSI to be mapped
  *
  * Returns: a valid linux IRQ number on success
+ *          -EPROBE_DEFER if irqdomain is not available.
  *          -EINVAL on failure
  */
 int acpi_register_gsi(struct device *dev, u32 gsi, int trigger,
 		      int polarity)
 {
+	struct irq_domain *domain;
 	struct irq_fwspec fwspec;
 	unsigned int irq;
 
 	fwspec.fwnode = acpi_get_gsi_domain_id(gsi);
-	if (WARN_ON(!fwspec.fwnode)) {
-		pr_warn("GSI: No registered irqchip, giving up\n");
-		return -EINVAL;
-	}
+	if (!fwspec.fwnode)
+		return -EPROBE_DEFER;
+
+	domain = irq_find_matching_fwnode(fwspec.fwnode, DOMAIN_BUS_ANY);
+	if (!domain)
+		return -EPROBE_DEFER;
 
 	fwspec.param[0] = gsi;
 	fwspec.param[1] = acpi_dev_get_irq_type(trigger, polarity);
-- 
2.39.2