我的内核学习笔记3：我的platform驱动模板文件

前面的例子已经实现platform驱动了，可以将之前的字符设备驱动整合到这个驱动中，实际上我也做了这一步。因为没有什么技术含量，所以忽视它的存在(就不发表出来)。这篇文章是将实现好的基于platform模型的字符设备驱动简化成一个可用的模板。如要实现字符设备，可直接套用此模板。

由于注释写得比较多，不再花笔墨作多余的事了。

/** * @file   foo_drv.c * @author Late Lee <[e-mail]> * @date   Tue Nov 12 22:21:19 2013 *  * @brief  platform模型示例 *  * @note   基于platform模型的字符设备驱动示例，添加自动创建设备文件功能。此部分代码可在init时做，也可在probe中做。 */#include <linux/module.h>#include <linux/kernel.h>       /**< printk() */#include <linux/init.h>#include <linux/platform_device.h>#include <linux/cdev.h>         /**< cdev_* */#include <linux/fs.h>#include <asm/uaccess.h>        /**< copy_*_user */#include <linux/types.h>        /**< size_t */#include <linux/errno.h>        /**< error codes */#include <linux/string.h>// 避免删掉模块时出现警告static void foo_dev_release(struct device* dev){//    printk(KERN_NOTICE "do %s case of: Device xxx does not have a release() function, it is broken and must be fixed.\n", __func__);    return;}// platform设备static struct platform_device foo_device = {    .name    = "foo",    .id      = -1,    .dev     = {        //.platform_data = &foo_pdata,        .release = &foo_dev_release,    },};#define DEBUG#ifdef DEBUG/* KERN_INFO */#define debug(fmt, ...) printk(KERN_NOTICE fmt, ##__VA_ARGS__)#else#define debug(fmt, ...)#endif#define DEV_NAME "foo"// 指定设备号或自动创建设备号//#define HAVE_MAJOR#ifdef HAVE_MAJOR#define DEVICE_MAJOR 248#else#define DEVICE_MAJOR 0 #endif#define FOO_NR_DEVS 1static struct cdev foo_cdev;static int foo_major = DEVICE_MAJOR;static int foo_minor = 0;static int foo_nr_devs = FOO_NR_DEVS;static dev_t foo_devno;static struct class* foo_class;static int foo_open(struct inode *inode, struct file *filp){    //debug("in %s()\n", __func__);    //debug("%s() inode: 0x%08x\n", __func__, inode->i_rdev);    return 0;}// close时调用此函数static int foo_release(struct inode *inode, struct file *filp){    //debug("in %s()\n", __func__);    return 0;}static ssize_t foo_read(struct file *filp, char *buf, size_t count, loff_t *f_ops){    int ret = 0;    return ret;}static ssize_t foo_write(struct file *filp, const char *buf, size_t count, loff_t *f_ops){    int ret = 0;    return ret;}static int foo_ioctl(struct inode *inode, struct file *filp, unsigned int cmd, unsigned long arg)// 2.6.36及以上版本使用下列函数// static long foo_ioctl(struct file *filp, unsigned int cmd, unsigned long arg){    return 0;}static struct file_operations foo_fops = {    .owner   = THIS_MODULE,    .open    = foo_open,    .release = foo_release,    .read    = foo_read,    .write   = foo_write,    .ioctl   = foo_ioctl,//2.6.36及以上版本使用下列接口//    .unlocked_ioctl   = foo_ioctl,};static int foo_remove(struct platform_device *dev){    unregister_chrdev_region(foo_devno, 1);    cdev_del(&foo_cdev);    device_destroy(foo_class, foo_devno);    class_destroy(foo_class);    //printk(KERN_NOTICE "remove...\n");    return 0;}static int foo_probe(struct platform_device *dev){    int ret = 0;    // 初始化，关联文件操作结构体    cdev_init(&foo_cdev, &foo_fops);    foo_cdev.owner = THIS_MODULE;    if (foo_major)    {        foo_devno = MKDEV(foo_major, foo_minor);        ret = register_chrdev_region(foo_devno, foo_nr_devs, DEV_NAME);    }    else    {        ret = alloc_chrdev_region(&foo_devno, foo_minor, foo_nr_devs, DEV_NAME); /* get devno */        foo_major = MAJOR(foo_devno); /* get major */    }    if (ret < 0)    {        dev_err(&foo_device.dev, "can't get major %d\n", foo_major);        return -EINVAL;    }        ret = cdev_add(&foo_cdev, foo_devno, 1);    if (ret < 0)    {        dev_err(&foo_device.dev, "cdev_add failure!\n");        return -EINVAL;    }    // 自动创建/dev下的节点，名称为DEV_NAME    foo_class = class_create(THIS_MODULE, DEV_NAME);    if (IS_ERR(foo_class))    {        dev_err(&foo_device.dev, "failed to create class.\n");        return -EINVAL;    }    device_create(foo_class, NULL, foo_devno, NULL, DEV_NAME);    dev_info(&foo_device.dev, "Register /dev/%s ok: major: %d minor: %d devno: 0x%08x\n", DEV_NAME, foo_major, foo_minor, foo_devno);    return ret;}// driverstatic struct platform_driver foo_driver = {    .probe        = foo_probe,    .remove        = foo_remove,    .driver        = {        .name        = "foo",        .owner        = THIS_MODULE,    },};static int __init foo_drv_init(void){    int ret = 0;    // 先注册设备(适用于静态定义设备结构体)    ret = platform_device_register(&foo_device);    if (ret)    {        dev_err(&foo_device.dev, "platform_device_register failed!\n");        return ret;    }    // 再注册驱动    ret = platform_driver_register(&foo_driver);    if (ret)    {        dev_err(&foo_device.dev, "platform_driver_register failed!\n");        return ret;    }        dev_info(&foo_device.dev, "Init %s OK!\n", DEV_NAME);        return ret;}static void __exit foo_drv_exit(void){    // 先卸载驱动    platform_driver_unregister(&foo_driver);    // 再卸载设备    platform_device_unregister(&foo_device);}module_init(foo_drv_init);module_exit(foo_drv_exit);MODULE_AUTHOR("Late Lee");MODULE_DESCRIPTION("Simple platform driver");MODULE_LICENSE("GPL");MODULE_ALIAS("platform:foo");