linux设备模型 （2） led设备驱动

接上文，本文记录 led工程中 driver/目录下的3个文件 s5pc100_led.h s5pc100_leddriver.c Makefile

s5pc100_led.h 这个文件和上文一样，不列举了，主要是s5pc100_leddriver.c，先列出完整的函数内容：

#include <linux/init.h>#include <linux/module.h>#include <linux/types.h>#include <linux/fs.h>#include <linux/proc_fs.h>#include <linux/device.h>#include <asm/uaccess.h>#include <linux/ioport.h>#include <asm/io.h>#include <plat/gpio-cfg.h>#include <linux/platform_device.h>#include "s5pc100_led.h"//主设备和从设备号变量static int led_major = 0;static int led_minor = 0;#define mem_size 0x4  typedef unsigned int long U32;  //设备类别和设备变量static struct class* led_class = NULL;static struct led_android_dev* led_dev = NULL;//传统的设备文件操作方法static int led_open(struct inode* inode, struct file* filp);static int led_ioctl(struct inode *inode,struct file *file,unsigned int cmd, unsigned long arg);//设备文件操作方法表static struct file_operations led_fops = {.owner = THIS_MODULE,.open = led_open,.ioctl=led_ioctl,};//定义设备属性//访问设置属性方法static ssize_t led_val_show(struct device* dev, struct device_attribute* attr,  char* buf);static ssize_t led_val_store(struct device* dev, struct device_attribute* attr, const char* buf, size_t count);static DEVICE_ATTR(val, S_IRUGO | S_IWUSR, led_val_show, led_val_store);//访问设置属性方法//proc文件系统访问设备方法static ssize_t led_proc_read(char* page, char** start, off_t off, int count, int* eof, void* data);static ssize_t led_proc_write(struct file* filp, const char __user *buff, unsigned long len, void* data);//打开设备方法static int led_open(struct inode* inode, struct file* filp) {struct led_android_dev* dev; //将自定义设备结构体保存在文件指针的私有数据域中，以便访问设备时拿来用dev = container_of(inode->i_cdev, struct led_android_dev, dev);filp->private_data = dev;unsigned long gpncon_reg;gpncon_reg&=0xfffffff0;//将N类引脚的最低一位配置为输出gpncon_reg|=0x00000001;*(volatile unsigned long *)(U32)led_dev->pc100_ncon=gpncon_reg;//典型应用 重点return 0;}static int led_ioctl(struct inode *inode,struct file *file,unsigned int cmd,unsigned long arg){unsigned int long Dat;if(arg>1){return -EINVAL;}Dat=*(volatile unsigned long *)((U32)led_dev->pc100_ndat);switch(cmd){case 0: Dat|=0x00000001;printk("set led on\n");break;case 1: Dat|=0x00000000;printk("set led off\n");break;default :break;}*(volatile unsigned long *)((U32)led_dev->pc100_ndat) = Dat;}//读取寄存器val的值到缓冲区buf中，内部使用static ssize_t __led_get_val(struct led_android_dev* dev, char* buf) {int val = 0;if(down_interruptible(&(dev->sem))) {  //同步访问     return -ERESTARTSYS;  }  val = dev->val;  up(&(dev->sem));  return snprintf(buf, PAGE_SIZE, "%d\n", val);}//把缓冲区buf的值写到设备寄存器val中去，内部使用static ssize_t __led_set_val(struct led_android_dev* dev, const char* buf, size_t count) {int val = 0;  val = simple_strtol(buf, NULL, 10); //将字符串转换成数字  if(down_interruptible(&(dev->sem))) {//同步访问     return -ERESTARTSYS;  }    dev->val = val;  up(&(dev->sem));return count;}//读取设备属性valstatic ssize_t led_val_show(struct device* dev, struct device_attribute* attr, char* buf) {struct led_android_dev* hdev = (struct led_android_dev*)dev_get_drvdata(dev);        return __led_get_val(hdev, buf);}//写设备属性valstatic ssize_t led_val_store(struct device* dev, struct device_attribute* attr, const char* buf, size_t count) {struct led_android_dev* hdev = (struct led_android_dev*)dev_get_drvdata(dev);  return __led_set_val(hdev, buf,count);}//读取设备寄存器val的值，保存在page缓冲区中static ssize_t led_proc_read(char* page, char** start, off_t off, int count, int* eof, void* data) {if(off > 0) {*eof = 1;return 0;}return __led_get_val(led_dev, page);}//把缓冲区的值buff保存到设备寄存器val中去static ssize_t led_proc_write(struct file* filp, const char __user *buff, unsigned long len, void* data) {int err = 0;char* page = NULL;if(len > PAGE_SIZE) {printk(KERN_ALERT"The buff is too large: %lu.\n", len);return -EFAULT;}page = (char*)__get_free_page(GFP_KERNEL);if(!page) {                printk(KERN_ALERT"Failed to alloc page.\n");return -ENOMEM;}    if(copy_from_user(page, buff, len)) {//先把用户提供的缓冲区值拷贝到内核缓冲区中去printk(KERN_ALERT"Failed to copy buff from user.\n");                err = -EFAULT;goto out;}err = __led_set_val(led_dev, page, len);out:free_page((unsigned long)page);return err;}static void led_create_proc(void) {//创建/proc/led文件struct proc_dir_entry* entry;entry = create_proc_entry(LED_DEVICE_PROC_NAME, 0, NULL);if(entry) {entry->owner = THIS_MODULE;entry->read_proc = led_proc_read;entry->write_proc = led_proc_write;}}static void led_remove_proc(void) {//删除/proc/led文件remove_proc_entry(LED_DEVICE_PROC_NAME, NULL);}static int  __led_setup_dev(struct led_android_dev* dev) {//初始化设备int err;dev_t devno = MKDEV(led_major, led_minor);memset(dev, 0, sizeof(struct led_android_dev));cdev_init(&(dev->dev), &led_fops);dev->dev.owner = THIS_MODULE;dev->dev.ops = &led_fops;err = cdev_add(&(dev->dev),devno, 1);//注册字符设备if(err) {return err;}init_MUTEX(&(dev->sem));//初始化信号量和寄存器val的值dev->val = 0;return 0;}void init_led(void){int err = -1;dev_t dev = 0;struct device* temp = NULL;printk(KERN_ALERT"Initializing led device.\n");err = alloc_chrdev_region(&dev, 0, 1, LED_DEVICE_NODE_NAME);//动态分配主设备和从设备号if(err < 0) {printk(KERN_ALERT"Failed to alloc char dev region.\n");goto fail;}led_major = MAJOR(dev);led_minor = MINOR(dev);led_dev = kmalloc(sizeof(struct led_android_dev), GFP_KERNEL);//分配led设备结构体变量if(!led_dev) {err = -ENOMEM;printk(KERN_ALERT"Failed to alloc led_dev.\n");goto unregister;}err = __led_setup_dev(led_dev);//初始化设备if(err) {printk(KERN_ALERT"Failed to setup dev: %d.\n", err);goto cleanup;}led_class = class_create(THIS_MODULE, LED_DEVICE_CLASS_NAME);//在/sys/class/目录下创建设备类别目录ledif(IS_ERR(led_class)) {err = PTR_ERR(led_class);printk(KERN_ALERT"Failed to create led class.\n");goto destroy_cdev;}temp = device_create(led_class, NULL, dev, "%s", LED_DEVICE_FILE_NAME);//在/dev/目录和/sys/class/led目录下分别创建设备文件ledif(IS_ERR(temp)) {err = PTR_ERR(temp);printk(KERN_ALERT"Failed to create led device.");goto destroy_class;}err = device_create_file(temp, &dev_attr_val);//在/sys/class/led/led目录下创建属性文件valif(err < 0) {printk(KERN_ALERT"Failed to create attribute val.");                goto destroy_device;}dev_set_drvdata(temp, led_dev);led_create_proc();//创建/proc/led文件printk(KERN_ALERT"Succedded to initialize led device.\n");return 0;destroy_device:device_destroy(led_class, dev);destroy_class:class_destroy(led_class);destroy_cdev:cdev_del(&(led_dev->dev));cleanup:kfree(led_dev);unregister:unregister_chrdev_region(MKDEV(led_major, led_minor), 1);fail:return err;}int led_driver_probe(struct platform_device *pdev){//查询特定设备是否存在，以及是否能够才操作该设备，然后再进行设备操作。//check_led();//自己假设一下检查设备unsigned long phys,virt;//struct resource *mm;init_led();//mm=platform_get_resource(pdev,IORESOURCE_MEM,0);//关键函数 获取 设备的资源 io 内存  dma 等 这里获取io内存phys = pdev->resource[0].start;//struct led_plat_data *pdata= pdev->dev.platform_data;//获得设备的私有数据virt= ioremap(phys, 8);led_dev->pc100_ncon = virt + 0x0;led_dev->pc100_ndat = virt + 0x4;  return 0;}int led_driver_remove(struct platform_device *dev){dev_t devno = MKDEV(led_major, led_minor);printk(KERN_ALERT"Destroy led device.\n");led_remove_proc(); //删除/proc/led文件if(led_class) {//销毁设备类别和设备device_destroy(led_class, MKDEV(led_major, led_minor));class_destroy(led_class);}if(led_dev) {//删除字符设备和释放设备内存cdev_del(&(led_dev->dev));kfree(led_dev);}unregister_chrdev_region(devno, 1);//释放设备号    return 0;}struct platform_driver led_drv = {//结构体中不需要指定总线的成员，交由platform_device_register来完成    .probe = led_driver_probe,    .remove = led_driver_remove,    .driver = {        .name = "led",//在/sys/中的驱动目录名字.owner = THIS_MODULE,},};static int __init led_driver_init(void){    int ret;    ret = platform_driver_register(&led_drv);//驱动注册，注册成功后在/sys/platform/led/driver目录下创建目录    if(ret){        printk("driver register failed!\n");        return ret;    }    printk("led driver init\n");    return 0;}static void __exit led_driver_exit(void){    platform_driver_unregister(&led_drv);    printk("led driver bye!\n");}module_init(led_driver_init);module_exit(led_driver_exit);MODULE_LICENSE("GPL");MODULE_AUTHOR("kevin");