linux sys属性节点创建

1. #include <linux/module.h>
2. #include <linux/slab.h>
3. #include <linux/kobject.h>
4. #include <linux/platform_device.h>
5.  
6. struct att_dev{
7. struct platform_device *pdev;
8. struct kobject *kobj;
9. };
10.  
11. static ssize_t att_store(struct device *dev,
12. struct device_attribute *attr,
13. const char *buf, size_t count)
14. {
15. printk("echo debug bufn");
16.  
17. return count;
18. }
19.  
20. static ssize_t att_show(struct device *dev,
21. struct device_attribute *attr,
22. char *buf)
23. {
24. printk("cat debug bufn");
25. return 0;
26. }
27. static DEVICE_ATTR(test,0777,att_show,att_store);
28.  
29. static struct att_dev *dev = NULL;
30.  
31. static __devinit int att_probe(struct platform_device *ppdev){
32. int ret;
33.  
34. dev->kobj = kobject_create_and_add("attkobj", NULL); //( 节点位置?????)
35. if(dev->kobj == NULL){
36. ret = -ENOMEM;
37. goto kobj_err;
38. }
39.  
40. ret = sysfs_create_file(&dev->pdev->dev.kobj,&dev_attr_test.attr);
41. if(ret < 0){
42. goto file_err;
43. }
44. return 0;
45.  
46. file_err:
47. kobject_del(dev->kobj);
48. kobj_err:
49. return ret;
50. }
51.  
52. static struct platform_driver att_driver = {
53. .probe = att_probe,
54. .driver = {
55. .owner = THIS_MODULE,
56. .name = "att_test",
57. },
58. };
59.  
60. static int __init att_init(void)
61. {
62. int ret;
63.  
64. dev = kzalloc(sizeof(struct att_dev),GFP_KERNEL);
65. if(dev == NULL){
66. printk("%s get dev memory errorn",__func__);
67. return -ENOMEM;
68. }
69.  
70. dev->pdev = platform_device_register_simple("att_test", -1, NULL, 0);
71. if(IS_ERR(dev->pdev)){
72. PTR_ERR(dev->pdev);
73. printk("%s pdev errorn",__func__);
74. return -1;
75. }
76.  
77. ret = platform_driver_register(&att_driver);
78. if(ret < 0){
79. printk("%s register driver errorn",__func__);
80. return ret;
81. }
82.  
83. return 0;
84. }
85.  
86. static void __exit att_exit(void)
87. {
88.  
89. }
90.  
91. module_init(att_init);
92. module_exit(att_exit);
93. MODULE_LICENSE("GPL");
94. MODULE_AUTHOR("driverSir");

Makefile原代码：

ifeq ($(KERNELRELEASE),)

#KERNEL_DIR:=/lib/modules/$(shell uname -r)/build/

KERNEL_DIR:=/usr/src/linux-headers-3.2.0-29-generic-pae

PWD:=$(shell pwd)

modules:

$(MAKE) -C $(KERNEL_DIR) M=$(PWD) modules

modules_install:

$(MAKE) -C $(KERNEL_DIR) M=$(PWD) modules_install

clean:

rm -rf .*.cmd *.ko *.o modules.order Module.symvers *mod.c

.PHONY: modules modules_install clean

else

modules-objs := att.o

obj-m := att.o

endif

安装之后/sys/devices/platform/att_test/test

echo 1 > test

cat test

dmesg之后会看到内核打印出

[ 424.793357] echo debug buf

[ 427.122139] cat debug buf

说明在echo 1 > test 时调用了att_store,cat test 的时候调用了att_show