[tip: irq/core] platform: Add firmware-agnostic irq and affinity retrieval interface

["tip-bot2 for Marc Zyngier" <tip-bot2@linutronix.de>]

The following commit has been merged into the irq/core branch of tip:

Commit-ID:     0d5daa938c94b8b9183e9b257a88dc0929d59409
Gitweb:        https://git.kernel.org/tip/0d5daa938c94b8b9183e9b257a88dc0929d59409
Author:        Marc Zyngier <maz@kernel.org>
AuthorDate:    Mon, 20 Oct 2025 13:29:21 +01:00
Committer:     Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Mon, 27 Oct 2025 17:16:32 +01:00

platform: Add firmware-agnostic irq and affinity retrieval interface

Expand platform_get_irq_optional() to also return an affinity if available,
renaming it to platform_get_irq_affinity() in the process.

platform_get_irq_optional() is preserved with its current semantics by
calling into the new helper with a NULL affinity pointer.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Will Deacon <will@kernel.org>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Link: https://patch.msgid.link/20251020122944.3074811-5-maz@kernel.org
---
 drivers/base/platform.c         | 71 +++++++++++++++++++++++++-------
 include/linux/platform_device.h |  2 +-
 2 files changed, 58 insertions(+), 15 deletions(-)

diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index 0945034..b45d41b 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -150,25 +150,37 @@ devm_platform_ioremap_resource_byname(struct platform_device *pdev,
 EXPORT_SYMBOL_GPL(devm_platform_ioremap_resource_byname);
 #endif /* CONFIG_HAS_IOMEM */
 
+static const struct cpumask *get_irq_affinity(struct platform_device *dev,
+					      unsigned int num)
+{
+	const struct cpumask *mask = NULL;
+#ifndef CONFIG_SPARC
+	struct fwnode_handle *fwnode = dev_fwnode(&dev->dev);
+
+	if (is_of_node(fwnode))
+		mask = of_irq_get_affinity(to_of_node(fwnode), num);
+	else if (is_acpi_device_node(fwnode))
+		mask = acpi_irq_get_affinity(ACPI_HANDLE_FWNODE(fwnode), num);
+#endif
+
+	return mask ?: cpu_possible_mask;
+}
+
 /**
- * platform_get_irq_optional - get an optional IRQ for a device
- * @dev: platform device
- * @num: IRQ number index
+ * platform_get_irq_affinity - get an optional IRQ and its affinity for a device
+ * @dev:	platform device
+ * @num:	interrupt number index
+ * @affinity:	optional cpumask pointer to get the affinity of a per-cpu interrupt
  *
- * Gets an IRQ for a platform device. Device drivers should check the return
- * value for errors so as to not pass a negative integer value to the
- * request_irq() APIs. This is the same as platform_get_irq(), except that it
- * does not print an error message if an IRQ can not be obtained.
- *
- * For example::
- *
- *		int irq = platform_get_irq_optional(pdev, 0);
- *		if (irq < 0)
- *			return irq;
+ * Gets an interupt for a platform device. Device drivers should check the
+ * return value for errors so as to not pass a negative integer value to
+ * the request_irq() APIs. Optional affinity information is provided in the
+ * affinity pointer if available, and NULL otherwise.
  *
- * Return: non-zero IRQ number on success, negative error number on failure.
+ * Return: non-zero interrupt number on success, negative error number on failure.
  */
-int platform_get_irq_optional(struct platform_device *dev, unsigned int num)
+int platform_get_irq_affinity(struct platform_device *dev, unsigned int num,
+			      const struct cpumask **affinity)
 {
 	int ret;
 #ifdef CONFIG_SPARC
@@ -236,8 +248,37 @@ out_not_found:
 out:
 	if (WARN(!ret, "0 is an invalid IRQ number\n"))
 		return -EINVAL;
+
+	if (ret > 0 && affinity)
+		*affinity = get_irq_affinity(dev, num);
+
 	return ret;
 }
+EXPORT_SYMBOL_GPL(platform_get_irq_affinity);
+
+/**
+ * platform_get_irq_optional - get an optional interrupt for a device
+ * @dev:	platform device
+ * @num:	interrupt number index
+ *
+ * Gets an interrupt for a platform device. Device drivers should check the
+ * return value for errors so as to not pass a negative integer value to
+ * the request_irq() APIs. This is the same as platform_get_irq(), except
+ * that it does not print an error message if an interrupt can not be
+ * obtained.
+ *
+ * For example::
+ *
+ *		int irq = platform_get_irq_optional(pdev, 0);
+ *		if (irq < 0)
+ *			return irq;
+ *
+ * Return: non-zero interrupt number on success, negative error number on failure.
+ */
+int platform_get_irq_optional(struct platform_device *dev, unsigned int num)
+{
+	return platform_get_irq_affinity(dev, num, NULL);
+}
 EXPORT_SYMBOL_GPL(platform_get_irq_optional);
 
 /**
diff --git a/include/linux/platform_device.h b/include/linux/platform_device.h
index 074754c..ad66333 100644
--- a/include/linux/platform_device.h
+++ b/include/linux/platform_device.h
@@ -102,6 +102,8 @@ devm_platform_ioremap_resource_byname(struct platform_device *pdev,
 
 extern int platform_get_irq(struct platform_device *, unsigned int);
 extern int platform_get_irq_optional(struct platform_device *, unsigned int);
+extern int platform_get_irq_affinity(struct platform_device *, unsigned int,
+				     const struct cpumask **);
 extern int platform_irq_count(struct platform_device *);
 extern int devm_platform_get_irqs_affinity(struct platform_device *dev,
 					   struct irq_affinity *affd,