linux sys属性节点创建

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#include <linux/module.h>#include <linux/slab.h>#include <linux/kobject.h>#include <linux/platform_device.h>struct att_dev{struct platform_device *pdev;struct kobject *kobj;};static ssize_t att_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) {printk("echo debug buf\n");return count;}static ssize_t att_show(struct device *dev,                 struct device_attribute *attr,                 char *buf){printk("cat debug buf\n");return 0;}static DEVICE_ATTR(test,0777,att_show,att_store);static struct att_dev *dev = NULL;static __devinit int att_probe(struct platform_device *ppdev){int ret;dev->kobj = kobject_create_and_add("attkobj", NULL); if(dev->kobj == NULL){ret = -ENOMEM;goto kobj_err;}ret = sysfs_create_file(&dev->pdev->dev.kobj,&dev_attr_test.attr);if(ret < 0){goto file_err;}return 0;file_err: kobject_del(dev->kobj);  kobj_err:return ret;}static struct platform_driver att_driver = {.probe = att_probe,.driver = {.owner = THIS_MODULE,.name = "att_test",},};static int __init att_init(void){int ret;dev = kzalloc(sizeof(struct att_dev),GFP_KERNEL);if(dev == NULL){printk("%s get dev memory error\n",__func__);return -ENOMEM;}dev->pdev = platform_device_register_simple("att_test", -1, NULL, 0);  if(IS_ERR(dev->pdev)){PTR_ERR(dev->pdev); printk("%s pdev error\n",__func__);return -1;}    ret = platform_driver_register(&att_driver);    if(ret < 0){        printk("%s register driver error\n",__func__);        return ret;    }return 0;}static void __exit att_exit(void){}module_init(att_init);module_exit(att_exit);MODULE_LICENSE("GPL");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