cdev, platform_device, device_driver, class大杂烩

http://blog.chinaunix.net/uid-20718037-id-2465419.html

将前面的三篇中的代码整合起来代码如下：

#include<linux/module.h> #include<linux/init.h> #include<linux/fs.h> #include<linux/cdev.h> #include<linux/mm.h> #include<linux/ioport.h> #include<linux/interrupt.h> #include<linux/delay.h> #include<linux/device.h> #include<linux/platform_device.h> #include<asm/io.h> #include<asm/uaccess.h> MODULE_LICENSE("GPL"); MODULE_AUTHOR("zhanglong"); /*  *板子上的led1,2,4,8分别对应连在GPF4,5,6,7上  *  *GPFCON ==> 0x56000050  *GPFDAT ==> 0x56000054  *GPFUP ==> 0x56000058  *  */ #define IO_PHYS 0x56000000 #define GPFCON_OFFSET 0x50 #define GPFDAT_OFFSET 0x54 #define GPFUP_OFFSET 0x58 struct led_device_s {     struct cdev dev;     dev_t no;     struct class_device *led_classdev;     short *io_gpfcon;     char *io_gpfdat;     char *io_gpfup; }; struct led_device_s my_led; void zl_release(struct device*dev) {     printk("device release.\n"); } struct resource zl_res[]= {     {         .start = IO_PHYS,         .end = IO_PHYS + SZ_4K,         .flags = IORESOURCE_IO,     }, #if 0     {         .start = IRQ_EINT2,         .end = IRQ_EINT2,         .flags = IORESOURCE_IRQ,     }, #endif }; struct platform_device zl_dev = {     .name = "zl_device",        //this string will be show as /sys/devices/platform/zl_device.0     .dev = {         .release = zl_release,         .platform_data = &my_led,     },     .num_resources = ARRAY_SIZE(zl_res),     .resource = zl_res, }; unsigned int devnum = 0; struct class*my_class; ssize_t my_read(structfile *fp,char __user *buf, size_t count, loff_t*off) {     return 4;//不能返回0, 否则读相关设备时会卡住. } ssize_t my_write(structfile *fp,const char __user*buf,size_t count, loff_t*off) {     struct led_device_s *get = fp->private_data;     unsigned int minor;     char value;     copy_from_user(&value, buf, 1); #if 0     minor = MINOR(get->no);     *(get->io_gpfcon)&=~(3<<((minor* 2)+ 8));     *(get->io_gpfcon)|=(1 <<((minor* 2)+ 8));     *(get->io_gpfup)&=~(1<<(minor + 4));     if((*buf== 0)||(*buf== 48)){         *(get->io_gpfdat)&=~(1<<(minor + 4));     } else{         *(get->io_gpfdat)|=(1 <<(minor + 4));     } #else     *(get->io_gpfcon)&=~(0xff<< 8);     *(get->io_gpfcon)|=(0x55 << 8);     *(get->io_gpfup)&=~(0xf0);     if((value>= 0)&&(value <= 15)){         *(get->io_gpfdat)= ((value& 0xf)<< 4);     } elseif((value>='0')&&(value <='9')){         *(get->io_gpfdat)= ((value& 0xf)<< 4);     } elseif((value>='a')&&(value <='f')){         *(get->io_gpfdat)= ((value- 97 + 10)<< 4);     } elseif((value>='A')&&(value <='F')){         *(get->io_gpfdat)= ((value- 65 + 10)<< 4);     } else{     } #endif     return 4; } int my_open(struct inode*no,struct file*fp) {     fp->private_data= container_of(no->i_cdev,struct led_device_s, dev);     //printk(" kernel: open.\n");     return 0; } int my_release(struct inode*no,struct file*fp) {     //printk(" kernel: release.\n");     return 0; } struct file_operations my_ops = {     .open= my_open,     .release = my_release,     .read= my_read,     .write= my_write, }; int zl_probe(struct device* dev) {     struct platform_device *pdev = container_of(dev,struct platform_device, dev);     struct resource *res = pdev->resource;     struct led_device_s *pled = pdev->dev.platform_data;     int ret = 0;     char *virt = NULL;     u32 i;     for(i= 0; i< pdev->num_resources; i++){         if(IORESOURCE_IO& res[i].flags){             virt = ioremap(res[i].start,(res[i].end- res[i].start));             break;         }     }     if(virt==NULL){         printk("[%s-L%d]:virt == NULL\n",__func__,__LINE__);         return -1;     }     pled->io_gpfcon= virt + GPFCON_OFFSET;     pled->io_gpfdat= virt + GPFDAT_OFFSET;     pled->io_gpfup= virt + GPFUP_OFFSET;     pled->no= MKDEV(52, devnum);        cdev_init(&pled->dev,&my_ops);     cdev_add(&pled->dev, pled->no, 1);     pled->led_classdev= device_create(my_class,NULL, pled->no,&(pled->dev),"mydev_led.%d", devnum);     if(IS_ERR(pled->led_classdev)){         printk("[%s-L%d]: device_create.\n",__func__,__LINE__);         return PTR_ERR(pled->led_classdev);     }     devnum++;     printk("driver zl_probe.\n");     return ret; } int zl_remove(struct device* dev) {     struct platform_device *pdev = container_of(dev,struct platform_device, dev);     struct led_device_s *pled = pdev->dev.platform_data;     device_destroy(my_class, pled->no);     cdev_del(&pled->dev);     printk("driver zl_remove.\n");     return 0; } struct device_driver zl_driver_struct = {         .name = "zl_device",//this string will be show as /sys/bus/platform/drivers/zl_device         .bus = &platform_bus_type,         .probe = zl_probe,         .remove= zl_remove, }; int test_init(void) {     int ret = 0;     driver_register(&zl_driver_struct);     my_class = class_create(THIS_MODULE,"myclass_led");     if (IS_ERR(my_class)){         printk("[%s-%d]: class_create.\n",__func__,__LINE__);         return PTR_ERR(my_class);     }       ret = register_chrdev_region(MKDEV(52,0), 4, "my_led");     if (ret){         printk("[%s-L%d]: register_chrdev_region.\n",__func__,__LINE__);         return ret;     }     platform_device_register(&zl_dev);     return ret; } void test_exit(void) {     platform_device_unregister(&zl_dev);     class_destroy(my_class);     driver_unregister(&zl_driver_struct); } module_init(test_init); module_exit(test_exit);

Ｍakefile如下：

KERNEL    = /media/STUDY/linux/kernel/my2440-2.6.36 #KERNEL    = /lib/modules/$(shell uname-r)/build default:     make -C $(KERNEL) M=$(shell pwd) modules clean:     make -C $(KERNEL) M=$(shell pwd) modules clean modules_install:     make -C $(KERNEL) M=$(shell pwd) modules_install INSTALL_MOD_PATH=/home/zl/s3c2440_nfs     depmod -a -b /home/zl/s3c2440_nfs 2.6.36-MY2440 obj-m    += driver.o

插入生成的模块insmod driver.ko 后
/sys # ls devices/virtual/myclass_led/ -l
total 0
drwxr-xr-x    3 root     root             0 May 16 13:10 mydev_led.0
/sys #
/sys # ls class/myclass_led/ -l
total 0
lrwxrwxrwx    1 root     root             0 May 16 13:12 mydev_led.0 -> ../../devices/virtual/myclass_led/mydev_led.0
/sys #
/sys # ls bus/platform/devices/zl_device.0/ -l
total 0
lrwxrwxrwx    1 root     root             0 May 16 13:13 driver -> ../../../bus/platform/drivers/zl_device
-r--r--r--    1 root     root          4096 May 16 13:13 modalias
drwxr-xr-x    2 root     root             0 May 16 13:13 power
lrwxrwxrwx    1 root     root             0 May 16 13:13 subsystem -> ../../../bus/platform
-rw-r--r--    1 root     root          4096 May 16 13:13 uevent
/sys #
/sys # ls bus/platform/drivers/zl_device/ -l
total 0
--w-------    1 root     root          4096 May 16 13:15 bind
--w-------    1 root     root          4096 May 16 13:15 uevent
--w-------    1 root     root          4096 May 16 13:15 unbind
lrwxrwxrwx    1 root     root             0 May 16 13:15 zl_device.0 -> ../../../../devices/platform/zl_device.0
/sys # ls /dev/mydev_led.0 -l
crw-rw----    1 root     root       52,   0 May 16 13:10 /dev/mydev_led.0
/sys #

其中class_create函数, device_create函数, struct device_driver(及struct platform_device)结构体传入的名字串，在/sys目录都能找到相应的目录或文件。

插入此模块后，不必手工创建设备结点，在命令行输入:
    "echo 0 > /dev/mydev_led.0"
    "echo 1 > /dev/mydev_led.0"
        ...
    "echo f > /dev/mydev_led.0"
就可控制LED了。