Device Tree信息获取

Device Tree信息获取：
添加节点：

/* 添加 led 节点 */
led {
	#address-cells = <1>;
	#size-cells = <1>;

	/* 蓝灯子节点 */
	blue_led@0xe0200240 {
		compatible = "s5pv210, blue_led";
		reg = <0xe0200240 0x8>;
		status = "okay";
	};
};

设备树信息获取代码：

#include <linux/module.h>		
#include <linux/init.h>

/* dts */
#include <linux/of.h> 

struct dts_info
{
	struct device_node	* led_parent;

	struct device_node	* led_child_blue;
	struct property * led_child_blue_property;
};

static struct dts_info g_dts_info = {0};

// 模块安装函数
static int __init chrdev_init(void)
{
	int blue_compatible_size = 0;
	int ret = -1;
	int out_values[2] = {0};
	const char * status = NULL;
	/*
	of_find_node_by_path: 根据节点路径寻找节点函数
	*/
	g_dts_info.led_parent = of_find_node_by_path("/led");
	if (NULL == g_dts_info.led_parent)
	{
		printk(KERN_ERR "led_test is NULL\n");
		return -EINVAL;
	}
	printk(KERN_INFO "led_parent name:%s\n", g_dts_info.led_parent->name);
	printk(KERN_INFO "child name:%s\n", g_dts_info.led_parent->child->name);

	/*
	of_get_next_child: 寻找子节点函数
	*/
	g_dts_info.led_child_blue = of_get_next_child(g_dts_info.led_parent, NULL);
	if (NULL == g_dts_info.led_child_blue)
	{
		printk(KERN_ERR "cof_get_next_child is NULL\n");
		return -EINVAL;
	}
	printk(KERN_INFO "current child name:%s\n", g_dts_info.led_child_blue->name);
	printk(KERN_INFO "parent name:%s\n", g_dts_info.led_child_blue->parent->name);

	/*
	of_find_property: 查找节点属性函数
	*/
	g_dts_info.led_child_blue_property = of_find_property(g_dts_info.led_child_blue, "compatible", &blue_compatible_size);
	if (NULL == g_dts_info.led_child_blue_property)
	{
		printk(KERN_ERR "of_find_property is NULL\n");
		return -EINVAL;
	}
	printk(KERN_INFO "size:%d\n", blue_compatible_size);
	printk(KERN_INFO "name:%s\n", g_dts_info.led_child_blue_property->name);
	printk(KERN_INFO "value:%s\n", (char *)g_dts_info.led_child_blue_property->value);
	printk(KERN_INFO "length:%d\n", g_dts_info.led_child_blue_property->length);

	/*
	of_property_read_u32_array: 读取整型属性函数
	*/
	ret = of_property_read_u32_array(g_dts_info.led_child_blue, "reg", out_values, 2);
	if (ret)
	{
		printk(KERN_ERR "of_property_read_u32_array error\n");
		return -EINVAL;
	}
	printk(KERN_INFO "0x%08X\n", out_values[0]);
    printk(KERN_INFO "0x%08X\n", out_values[1]);

    /*
    of_property_read_string: 读取字符串属性函数
    */
    ret = of_property_read_string(g_dts_info.led_child_blue, "status", &status);
    if (ret)
    {
    	printk(KERN_ERR "of_property_read_string error\n");
		return -EINVAL;
    }
    printk(KERN_INFO "status=%s\n", status);
	return 0;
}

// 模块卸载函数
static void __exit chrdev_exit(void)
{
	printk(KERN_INFO "chrdev_exit helloworld exit\n");
}


module_init(chrdev_init);
module_exit(chrdev_exit);

// MODULE_xxx这种宏作用是用来添加模块描述信息
MODULE_LICENSE("GPL");				// 描述模块的许可证
MODULE_AUTHOR("Mark");				// 描述模块的作者
MODULE_DESCRIPTION("test for driver");	// 描述模块的介绍信息
MODULE_ALIAS("alias test");			// 描述模块的别名信息

部分资源来源于网络，若有侵权，请联系作者删除，谢谢