这一节我们讲设备树简单驱动例程
#include <linux/init.h> #include <linux/module.h> #include <linux/platform_device.h> #include <linux/of_gpio.h> #include <linxu/of.h> #include <stdio.h> MODULE_LICENSE("Dual BSD/GPL"); #define device_name "test" static const struct of_device_id of_test_dt_match[] = { {.compatible = device_name }, {}, }; MODULE_DEVICE_TABLE(of,of_test_dt_match); static struct platform_driver test_driver= { .probe = test_probe, .remove = test_remove, .driver= { .name=device_name, .owner= THIS_MODULE, .of_match_table= } }; static int test_remove(struct platform_device * pdev) { return 0; } static int test_probe(struct platform_device * pdev) { return 0; } static int test_init(void) { printf("init_test\r\n"); return platform_driver_register(&test_driver); } static void test_exit(void) { printf("init_test\r\n"); platform_driver_unregister(&test_driver); } module_init(test_init); module_exit(test_exit);下面添加一些属性的获取。 我们在probe添加属性的获取 设备树中使用 device_node 结构体描述节点，of.h中的API需要device_node作为参数传入 struct device_node { const char *name; //节点名称 const char *type; //设备类型 phandle phandle; const char *full_name; //全路径节点 struct fwnode_handle fwnode;
struct property *properties; struct property *deadprops; /* removed properties */ struct device_node *parent; //父节点指针 struct device_node *child; //子节点指针 struct device_node *sibling; struct kobject kobj; unsigned long _flags; void *data;#if defined(CONFIG_SPARC) const char *path_component_name; unsigned int unique_id; struct of_irq_controller *irq_trans; #endif }; 驱动中获取device_node方法： struct device_node *node = pdev->dev.of_node; 获取属性参数的函数：
根据属性名称，提取属性值 struct property *of_find_property(const struct device_node *np, const char name, int lenp); /
of_find_property - 提取指定属性的值@np - 设备树节点指针@name - 属性名称@lenp - 属性值的字节数返回值：成功，属性值的首地址；失败：NULL */ static int test_probe(struct platform_device * pdev) { struct device_node *node = pdev->dev.of_node; printf("node name is %s!\n",node->name); struct property *comprop = NULL; comprop = of_find_property(node,"compatible",NULL); printf("comprop name is %s!\n",comprop->name); return 0; }