of_ find_ compatible_ Node find all nodes

The main points of ：
（1） First call of_find_compatible_node When , The first parameter is zero NULL
（2） Follow up page n Secondary call of_find_compatible_node, The first parameter is the n-1 Secondary call of_find_compatible_node The return value of
（3）of_find_compatible_node The return value of node, After use Must call of_find_compatible_node or of_node_put release

#include <linux/of.h>
#include <linux/of_address.h> // of_address_to_resource
#include <linux/of_irq.h> // irq_of_parse_and_map
#include <linux/module.h>

static int __init test_init(void)
{
	int ret;
	struct device_node *node;
	struct resource res;
	unsigned int irq = 0;
	
	//  Loop through all specified in the device tree compatible The node of 
	// node Must be called after use of_find_compatible_node or of_node_put release 
	node = NULL;
	while ((node = of_find_compatible_node(node, NULL, "fsl,imx6ul-gpt")) != NULL)
	{
		ret = of_address_to_resource(node, 0, &res);
		if (ret == 0)
		{
			pr_err("name=%s, full_name=%s, start=0x%08x\n", node->name, node->full_name, res.start);
			if (res.start == 0x020e8000)
			{
				//  Already found gpt2 node 
				irq = irq_of_parse_and_map(node, 0); //  analysis interrupts attribute ,  obtain linux Interrupt number 
				pr_err("found gpt2 node: irq=%d\n", irq);
				of_node_put(node); //  The release of the node 
				break;
			}
		}
		else
			pr_err("name=%s, full_name=%s\n", node->name, node->full_name);
	}
	if (irq == 0)
	{
		//  Can't find gpt2 node ,  Or parsing gpt2 Node interrupts Property failed 
		pr_err("no IRQ found\n");
		return -ENODEV;
	}
	return 0;
}

static void __exit test_exit(void)
{
}

module_init(test_init);
module_exit(test_exit);
MODULE_AUTHOR("Oct1158");
MODULE_LICENSE("GPL");

Program run results ：

[email protected]:~/learn_drivers/dts_myboard2/gpiospi_test$ sudo insmod search_nodes.ko
[ 1265.669315] name=gpt, full_name=/soc/[email protected]/[email protected], start=0x02098000
[ 1265.677645] name=gpt, full_name=/soc/[email protected]/[email protected], start=0x020e8000
[ 1265.687307] found gpt2 node: irq=213