Linux设备模型

simple.c

#include <linux/device.h>#include <linux/module.h>#include <linux/kernel.h>#include <linux/init.h>#include <linux/string.h>#include <linux/sysfs.h>#include <linux/stat.h>MODULE_AUTHOR("haoyu");MODULE_LICENSE("Dual BSD/GPL");struct my_kobject{    int value;    struct kobject kobj;};    struct my_kobject my_kobj;void kobject_release(struct kobject *kobject);ssize_t kobject_attr_show(struct kobject *kobject, struct attribute *attr,char *buf);ssize_t kobject_attr_store(struct kobject *kobject,struct attribute *attr,const char *buf, size_t count);struct attribute kobject_attr1 = {    .name = "name",    .mode = S_IRWXUGO,};struct attribute kobject_attr2 = {    .name = "value",    .mode = S_IRWXUGO,};static struct attribute *kobject_def_attrs[] = {    &kobject_attr1,    &kobject_attr2,    NULL,};struct sysfs_ops kobject_sysfs_ops ={    .show = kobject_attr_show,    .store = kobject_attr_store,};struct kobj_type ktype ={    .release = kobject_release,    .sysfs_ops = &kobject_sysfs_ops,    .default_attrs = kobject_def_attrs,};void kobject_release(struct kobject *kobject){    printk("kobject release.\n");}ssize_t kobject_attr_show(struct kobject *kobject, struct attribute *attr,char *buf){    int count = 0;    struct my_kobject *my_kobj = container_of(kobject, struct my_kobject, kobj);    printk("kobject attribute show.\n");    if(strcmp(attr->name, "name") == 0)        count = sprintf(buf, "%s\n", kobject->name);    else if(strcmp(attr->name, "value") == 0)        count = sprintf(buf, "%d\n", my_kobj->value);    else        printk("no this attribute.\n");        return count;}ssize_t kobject_attr_store(struct kobject *kobject,struct attribute *attr,const char *buf, size_t count){    int val;    struct my_kobject *my_kobj = container_of(kobject, struct my_kobject, kobj);    printk("kobject attribute store.\n");    if(strcmp(attr->name, "name") == 0)        printk("Can not change name.\n");    else if(strcmp(attr->name, "value") == 0)    {        val = buf[0] - '0';        if(val == 0 || val == 1)            my_kobj->value = val;        else            printk("value is '0' or '1'\n");    }    else        printk("no this attribute.\n");            return count;}static int kobject_test_init(void){    printk("kboject test init.\n");    kobject_init_and_add(&my_kobj.kobj,&ktype,NULL,"kobject_test");    return 0;}static void kobject_test_exit(void){    printk("kobject test exit.\n");    kobject_del(&my_kobj.kobj);}module_init(kobject_test_init);module_exit(kobject_test_exit);

Makefile

# To build modules outside of the kernel tree, we run "make"# in the kernel source tree; the Makefile these then includes this# Makefile once again.# This conditional selects whether we are being included from the# kernel Makefile or not.ifeq ($(KERNELRELEASE),)    # Assume the source tree is where the running kernel was built    # You should set KERNELDIR in the environment if it's elsewhere    KERNELDIR ?= /lib/modules/$(shell uname -r)/build    # The current directory is passed to sub-makes as argument    PWD := $(shell pwd)modules:$(MAKE) -C $(KERNELDIR) M=$(PWD) modulesmodules_install:$(MAKE) -C $(KERNELDIR) M=$(PWD) modules_installclean:rm -rf *.o *~ core .depend .*.cmd *.ko* *.mod.c .tmp_versions Module* module*.PHONY: modules modules_install cleanelse    # called from kernel build system: just declare what our modules are    obj-m := jiq.o endif