irqchip/renesas-rzg2l: Fix missing put_device

rzg2l_irqc_common_init() calls of_find_device_by_node(), but the
corresponding put_device() call is missing.  This also gets reported by
make coccicheck.

Make use of the cleanup interfaces from cleanup.h to call into
__free_put_device(), which in turn calls into put_device when leaving
function rzg2l_irqc_common_init() and variable "dev" goes out of scope.

To prevent that the device is put on successful completion, assign NULL to
"dev" to prevent __free_put_device() from calling into put_device() within
the successful path.

"make coccicheck" will still complain about missing put_device() calls,
but those are false positives now.

Fixes: 3fed095 ("irqchip: Add RZ/G2L IA55 Interrupt Controller driver")
Signed-off-by: Fabrizio Castro <fabrizio.castro.jz@renesas.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20241011172003.1242841-1-fabrizio.castro.jz@renesas.com

Author: Fabrizio Castro

drivers/irqchip/irq-renesas-rzg2l.c

@@ -8,6 +8,7 @@
  */
 
 #include <linux/bitfield.h>
+#include <linux/cleanup.h>
 #include <linux/clk.h>
 #include <linux/err.h>
 #include <linux/io.h>
@@ -530,12 +531,12 @@ static int rzg2l_irqc_parse_interrupts(struct rzg2l_irqc_priv *priv,
 static int rzg2l_irqc_common_init(struct device_node *node, struct device_node *parent,
 				  const struct irq_chip *irq_chip)
 {
+	struct platform_device *pdev = of_find_device_by_node(node);
+	struct device *dev __free(put_device) = pdev ? &pdev->dev : NULL;
 	struct irq_domain *irq_domain, *parent_domain;
-	struct platform_device *pdev;
 	struct reset_control *resetn;
 	int ret;
 
-	pdev = of_find_device_by_node(node);
 	if (!pdev)
 		return -ENODEV;
 
@@ -591,6 +592,17 @@ static int rzg2l_irqc_common_init(struct device_node *node, struct device_node *
 
 	register_syscore_ops(&rzg2l_irqc_syscore_ops);
 
+	/*
+	 * Prevent the cleanup function from invoking put_device by assigning
+	 * NULL to dev.
+	 *
+	 * make coccicheck will complain about missing put_device calls, but
+	 * those are false positives, as dev will be automatically "put" via
+	 * __free_put_device on the failing path.
+	 * On the successful path we don't actually want to "put" dev.
+	 */
+	dev = NULL;
+
 	return 0;
 
 pm_put: