Program for Linux USB-devices driver step by step (ONE)

Program for Linux USB-devices driver

開始啃硬骨头~ 这里我打算一步步给出USB device driver 的demo。希望有心能可以共同交流学习. 希望认识很多其它对Linux有兴趣的geek.

眼下因为环境和自身能力方面原因还没能做实物的測试，篇章的最后打算给出一个在x86上模拟USB读写的driver。以后可以做实物測试之后再更新this blog

我的联系方式： 

jasonleaster@gmail.com（因为偶不能登QQ，所以thunder bird的邮件仅仅要电脑开着就一直在线~）

測试环境：

Ubuntu 14.0

kernel: 3.13.0

以下我比較具体的对代码进行了凝视，要点都在代码中啦~

这段代码不过个样例，相当于第一个驱动设备hello world一样，力求最简单化概括性的给出USB设备插入，拔出相关的处理过程，后面慢慢的写的更深入的时候。代码也就越来越”复杂“

我整理了USB device driver 代码相关的结构体。做了文件夹便于查阅

/**************************************************************
code writer 	: EOF
code date	: 2014.08.18
code file	        : ./USB_1/usb_1.c
e-mail		: jasonleaster@gmail.com

code purpose:
	This is a demo for how to code for a USB device driver.

	If there is something wrong with my code, please touch 
me by e-mail. Thank you. 	

*************************************************************/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/usb.h>
#include <linux/module.h>
#include <linux/moduleparam.h>

/*
**  	This two Macro used to create a structure -- 
** 'usb_device_id' by 'USB_DEVICE'
*/
#define VENDOR_ID	0x08f7
#define PRODUCT_ID	0x0002

#define DEVICE_NAME	"usb_1"

MODULE_AUTHOR("EOF");
MODULE_LICENSE("Dual BSD/GPL");

/*
**  id_table stored many USB device's 'usb_device_id' structure 
*/
static struct usb_device_id id_table[] = 
{
	{ USB_DEVICE(VENDOR_ID, PRODUCT_ID)},
	{ },
};

/*
**	The 'MODULE_DEVICE_TABLE' Macro marks device in the
** module image so that the module can be loaded on demand if 
** the device is hotplugged.
*/

MODULE_DEVICE_TABLE(usb,id_table);


/*
**	The probe() method is invoked by khubd after device enumeration.
**
**	@interface	:contains information gleaned during the 
**  enumeration process.
**
**	@id		: the entry in the driver's 'usb_device_id' table
**  that matches the values read from the USB-device.
**	
*/
static int usb_probe(struct usb_interface * interface,
		     const struct usb_device_id *id)
{
	dev_info(&interface->dev,"USB device now attached
");

	return 0;
}

/*
** 	disconnect() method is called when the device is unplugged or
** when the module is unloaded.
*/
static void usb_disconnect(struct usb_interface* interface)
{
	dev_info(&interface->dev,"USB device now disconnect
");
}

/*
**	Each USB device has a 'usb_driver' data structure.
*/
static struct usb_driver usb_driver = 
{
	.name	=	DEVICE_NAME,
	.probe	=	usb_probe,
	.disconnect =	usb_disconnect,
	.id_table   =	id_table,
};

static int usb_init(void)
{
	return usb_register(&usb_driver);
}

static void usb_exit(void)
{
	usb_deregister(&usb_driver);
}

module_init(usb_init);
module_exit(usb_exit);

update: 2014.08.18 14:25

逐步完好 

这里旨在说明

 'usb_get_dev()' and 'usb_set_intfdata'

http://blog.csdn.net/cinmyheart/article/details/38628387#t21

上面的link。按文件夹查找相关函数定义就可以

/**************************************************************
code writer 	: EOF
code date	: 2014.08.18
code file	: ./USB_2/usb_2.c
e-mail		: jasonleaster@gmail.com

code purpose:
	This is a demo for how to code for a USB device driver.
I emphasize to demo for function 'usb_get_dev()' and 'usb_set_intfdata'

	If there is something wrong with my code, please touch 
me by e-mail. Thank you. 	

*************************************************************/

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/usb.h>
#include <linux/slab.h>

#define VENDOR_ID	0x08f7
#define PRODUCT_ID	0x0002

static struct usb_device_id id_table[] = 
{
	{USB_DEVICE(VENDOR_ID,PRODUCT_ID)},
	{ },
};

MODULE_DEVICE_TABLE(usb,id_table);

struct my_usb
{
	struct usb_device *udev;
	int temp;
};

static int usb_probe(struct usb_interface* interface,const struct usb_device_id*id)
{
	struct usb_device* udev = interface_to_usbdev(interface);
	struct my_usb * my_dev;

	my_dev = kzalloc(sizeof(struct my_usb),GFP_KERNEL);

	if(!my_dev)
	{
		dev_err(&interface->dev,"Out of memory
");

		return -ENOMEM;
	}

	/* 
	** 	increase the reference about probe() method 
	*/
	my_usb->udev = usb_get_dev(udev);

	usb_set_intfdata(interface,my_usb);

	dev_info(&interface->dev,"USB device now attached
");

	return 0;
}


static void usb_disconnect(struct usb_interface * interface)
{
	struct my_usb *my_dev;

	/*
	**	Get 'struct my_usb' from interface and then free 
	** free 'my_dev->udev'.	
	*/
	my_dev = usb_get_intfdata(interface);

	/* 
	** 	decrease the reference about probe() method 
	*/
	usb_put_dev(my_dev->udev);

	kfree(my_dev);

	dev_info(&interface->dev,"USB device now disconnected]n");
}

static struct usb_driver my_usb_driver = 
{
	.name		=	"usb_2",
	.probe		=	usb_probe,
	.disconnect 	=	usb_disconnect,
	.id_table	=	id_table,
};


static int usb_init(void)
{
	return usb_register(&my_usb_driver);
}

static void usb_exit(void)
{
	usb_deregister(&my_usb_driver);
}

MODULE_AUTHOR("EOF");
MODULE_LICENSE("Dual BSD/GPL");

module_init(usb_init);
module_exit(usb_exit);

衡山日出

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