lv15 平台总线驱动开发——ID匹配 3

4IOT2024-02-16 8:19

一、ID匹配之框架代码

id匹配（可想象成八字匹配）：一个驱动可以对应多个设备 ------优先级次低（上一章名称匹配只能1对1）

注意事项：

  1. device模块中，id的name成员必须与struct platform_device中的name成员内容一致，因此device模块中，struct platform_device中的name成员必须指定

  2. driver模块中，struct platform_driver成员driver的name成员必须指定，但与device模块中name可以不相同

1.1 用法展示：

cpp 复制代码 
/*platform device框架*/
#include <linux/module.h> 
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/platform_device.h>
​
//定义资源数组
​
static void device_release(struct device *dev)
{
    printk("platform: device release\n");
}
​
struct platform_device_id test_id = {   //<-------------
    .name = "test_device",   
};
​
struct platform_device test_device = {
    .name = "test_device",//必须初始化  //<------------必须一样
    .dev.release = device_release, 
    .id_entry = &test_id,
};
​
static int __init platform_device_init(void)
{
    platform_device_register(&test_device);
    return 0;
}
​
static void __exit platform_device_exit(void)
{
    platform_device_unregister(&test_device);
}
​
module_init(platform_device_init);
module_exit(platform_device_exit);
MODULE_LICENSE("Dual BSD/GPL");
cpp 复制代码 
/*platform driver框架*/
#include <linux/module.h> 
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/platform_device.h>
​
static int driver_probe(struct platform_device *dev)
{
    printk("platform: match ok!\n");
    return 0;
}
​
static int driver_remove(struct platform_device *dev)
{
    printk("platform: driver remove\n");
    return 0;
}
​
struct platform_device_id testdrv_ids[] =     //<---------------
{
    [0] = {.name = "test_device"},          //1对多匹配
    [1] = {.name = "abcxyz"},               //1对多匹配
    [2] = {}, //means ending                //结束符
};
​
struct platform_driver test_driver = {
    .probe = driver_probe,
    .remove = driver_remove,
    .driver = {
        .name = "xxxxx", //必须初始化 可以与device不一样
    },
    .id_table = testdrv_ids,   //<------------
};
​
static int __init platform_driver_init(void)
{
    platform_driver_register(&test_driver);
    return 0;
}
​
static void __exit platform_driver_exit(void)
{
    platform_driver_unregister(&test_driver);
}
​
module_init(platform_driver_init);
module_exit(platform_driver_exit);
MODULE_LICENSE("Dual BSD/GPL");
​

用到结构体数组，一般不指定大小，初始化时最后加{}表示数组结束

设备中增加资源，驱动中访问资源

1.2 test_device和test_driver示例改写

test_device_id.c

cpp 复制代码 
/*platform device框架*/
#include <linux/module.h> 
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/platform_device.h>


//<---------------设计成数组形式
struct resource test_dev_res [] =
{
	[0] = {.start = 0x1000, .end = 0x1003, .name = "reg1", .flags = IORESOURCE_MEM},
	[1] = {.start = 0x2000, .end = 0x2003, .name = "reg2", .flags = IORESOURCE_MEM},
	[2] = {.start = 10, .end = 10, .name = "irq1", .flags = IORESOURCE_IRQ},            //中断号10
	[3] = {.start = 0x3000, .end = 0x3003, .name = "reg3", .flags = IORESOURCE_MEM},
	[4] = {.start = 100, .end = 100, .name = "irq2", .flags = IORESOURCE_IRQ},
	[5] = {.start = 62, .end = 62, .name = "irq3", .flags = IORESOURCE_IRQ},
};


//定义资源数组

static void device_release(struct device *dev)
{
	printk("platform: device release\n");
}

struct platform_device_id test_id = {         //<--------------- 

	.name = "test_device",
};

struct platform_device test_device = {
	.id_entry = &test_id,                   //<--------------- 
	.name = "test_device",//必须初始化
	.dev.release = device_release,  
	.resource = test_dev_res,                      
    .num_resources = ARRAY_SIZE(test_dev_res),    
};



static int __init platform_device_init(void)
{
	platform_device_register(&test_device);
	return 0;
}

static void __exit platform_device_exit(void)
{
	platform_device_unregister(&test_device);
}

module_init(platform_device_init);
module_exit(platform_device_exit);
MODULE_LICENSE("Dual BSD/GPL");

test_driver_id.c

cpp 复制代码 
/*platform driver框架*/
#include <linux/module.h> 
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/platform_device.h>




static int driver_probe(struct platform_device *dev)
{
	struct resource * pres = NULL;                       
	printk("platform: match ok!\n");

	pres = platform_get_resource(dev,IORESOURCE_MEM,2);   
	printk("res.start = 0x%x\n",(unsigned int)pres->start);

	pres = platform_get_resource(dev,IORESOURCE_IRQ,1);   
	printk("res.start = %d\n",(int)pres->start);

	return 0;
}

static int driver_remove(struct platform_device *dev)
{
	printk("platform: driver remove\n");
	return 0;
}

struct platform_device_id testdrv_ids[] =          //<---------------
{
	[0] = {.name = "test_device"},
	[1] = {.name = "xyz"},
	[2] = {},          //表示结束符
};

struct platform_driver test_driver = {
	.probe = driver_probe,
	.remove = driver_remove,
	.driver = {
		.name = "abc", //必须初始化         //<------名字故意与device不一样
	},
	.id_table = testdrv_ids,  //<--------------- 
};

static int __init platform_driver_init(void)
{
	platform_driver_register(&test_driver);
	return 0;
}

static void __exit platform_driver_exit(void)
{
	platform_driver_unregister(&test_driver);
}

module_init(platform_driver_init);
module_exit(platform_driver_exit);
MODULE_LICENSE("Dual BSD/GPL");

Makefile

cpp 复制代码 
ifeq ($(KERNELRELEASE),)

ifeq ($(ARCH),arm)
KERNELDIR ?= /home/linux/Linux_4412/kernel/linux-3.14
ROOTFS ?= /opt/4412/rootfs
else
KERNELDIR ?= /lib/modules/$(shell uname -r)/build
endif
PWD := $(shell pwd)


modules:
	$(MAKE) -C $(KERNELDIR) M=$(PWD) modules

modules_install:
	$(MAKE) -C $(KERNELDIR) M=$(PWD) modules INSTALL_MOD_PATH=$(ROOTFS) modules_install

clean:
	rm -rf  *.o  *.ko  .*.cmd  *.mod.*  modules.order  Module.symvers   .tmp_versions

else

CONFIG_MODULE_SIG=n
#obj-m += fs4412_led_device.o
#obj-m += fs4412_led_driver.o
obj-m += test_driver_id.o
obj-m += test_device_id.o

endif

编译测试

二、ID匹配之led驱动

改写fs4412_led_device_idmatch.c

cpp 复制代码 
/*platform device框架*/
#include <linux/module.h> 
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/platform_device.h>


#include "leddrv.h"

#define GPX1CON 0x11000C20
#define GPX1DAT 0x11000C24

#define GPX2CON 0x11000C40
#define GPX2DAT 0x11000C44

#define GPF3CON 0x114001E0
#define GPF3DAT 0x114001E4

//<---------------修改寄存器地址
struct resource fs4412led_dev_res [] =
{
	[0] = {.start = GPX1CON, .end = GPX1CON+3, .name = "GPX1CON", .flags = IORESOURCE_MEM},
	[1] = {.start = GPX1DAT, .end = GPX1DAT+3, .name = "GPX1DAT", .flags = IORESOURCE_MEM},
	[2] = {.start = GPX2CON, .end = GPX2CON+3, .name = "GPX2CON", .flags = IORESOURCE_MEM},
	[3] = {.start = GPX2DAT, .end = GPX2DAT+3, .name = "GPX2DAT", .flags = IORESOURCE_MEM},
	[4] = {.start = GPF3CON, .end = GPF3CON+3, .name = "GPF3CON", .flags = IORESOURCE_MEM},
	[5] = {.start = GPF3DAT, .end = GPF3DAT+3, .name = "GPF3DAT", .flags = IORESOURCE_MEM},
};


//定义资源数组

static void fs4412led_dev_release(struct device *dev)
{
	printk("platform: fs4412led_dev_release is called\n");
}                         

struct platform_device_id fs4412led_id = {     //<----------

	.name = "fs4412led",
};                    

struct platform_device fs4412led_device = {
	.id_entry = &fs4412led_id,                   //<-------------
	.name = "fs4412led",//必须初始化
	.dev.release = fs4412led_dev_release,  
	.resource = fs4412led_dev_res,                     
    .num_resources = ARRAY_SIZE(fs4412led_dev_res),     
};



static int __init fs4412led_dev_init(void)
{
	platform_device_register(&fs4412led_device);
	return 0;
}

static void __exit fs4412led_dev_exit(void)
{
	platform_device_unregister(&fs4412led_device);
}

module_init(fs4412led_dev_init);
module_exit(fs4412led_dev_exit);
MODULE_LICENSE("Dual BSD/GPL");

改写改写fs4412_led_driver_idmatch.c

cpp 复制代码 
/*platform driver框架*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/fs.h>
#include <linux/cdev.h>
#include <linux/wait.h>
#include <linux/sched.h>
#include <linux/poll.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/io.h>
#include <asm/uaccess.h>
#include <asm/atomic.h>

#include "leddrv.h"


int major = 11;
int minor = 0;
int myled_num  = 1;

struct myled_dev
{
	struct cdev mydev;

	volatile unsigned long *pled2_con;  
	volatile unsigned long *pled2_dat;
	
	volatile unsigned long *pled3_con;
	volatile unsigned long *pled3_dat;

	volatile unsigned long *pled4_con;
	volatile unsigned long *pled4_dat;

	volatile unsigned long *pled5_con;
	volatile unsigned long *pled5_dat;
/*
volatile 防止优化。对这块指针指向的内存，有时候cpu会把外设寄存器中的值读到内部寄存器中，方便下次读的时候更快.加了voltatile就不会优化，否则cpu可能会从内部寄存器中读取，而不是去外设寄存器中读取。
*/
	struct class *cls;       //<-----------------
	struct device *dvs;       //<-----------------

};




struct myled_dev *pgmydev = NULL;

int myled_open(struct inode *pnode,struct file *pfile)
{
	pfile->private_data =(void *) (container_of(pnode->i_cdev,struct myled_dev,mydev));
	
	return 0;
}

int myled_close(struct inode *pnode,struct file *pfile)
{
	return 0;
}

void led_on(struct myled_dev *pmydev,int ledno)
{
	switch(ledno)
	{
		case 2:
			writel(readl(pmydev->pled2_dat) | (0x1 << 7),pmydev->pled2_dat);
			break;
		case 3:
			writel(readl(pmydev->pled3_dat) | (0x1),pmydev->pled3_dat);
			break;
		case 4:
			writel(readl(pmydev->pled4_dat) | (0x1 << 4),pmydev->pled4_dat);
			break;
		case 5:
			writel(readl(pmydev->pled5_dat) | (0x1 << 5),pmydev->pled5_dat);
			break;
	}
}

void led_off(struct myled_dev *pmydev,int ledno)
{
	switch(ledno)
	{
		case 2:
			writel(readl(pmydev->pled2_dat) & (~(0x1 << 7)),pmydev->pled2_dat);
			break;
		case 3:
			writel(readl(pmydev->pled3_dat) & (~(0x1)),pmydev->pled3_dat);
			break;
		case 4:
			writel(readl(pmydev->pled4_dat) & (~(0x1 << 4)),pmydev->pled4_dat);
			break;
		case 5:
			writel(readl(pmydev->pled5_dat) & (~(0x1 << 5)),pmydev->pled5_dat);
			break;
	}
}

long myled_ioctl(struct file *pfile,unsigned int cmd,unsigned long arg)
{
	struct myled_dev *pmydev = (struct myled_dev *)pfile->private_data;

	if(arg < 2 || arg > 5)
	{
		return -1;
	}
	switch(cmd)
	{
		case MY_LED_ON:
			led_on(pmydev,arg);
			break;
		case MY_LED_OFF:
			led_off(pmydev,arg);
			break;
		default:
			return -1;
	}

	return 0;
}

void ioremap_ledreg(struct myled_dev *pmydev,struct platform_device *p_pltdev)
{
	struct resource *pres = NULL;
	
	pres = platform_get_resource(p_pltdev,IORESOURCE_MEM,2);
	pmydev->pled2_con = ioremap(pres->start,4);

	pres = platform_get_resource(p_pltdev,IORESOURCE_MEM,3);
	pmydev->pled2_dat = ioremap(pres->start,4);

	pres = platform_get_resource(p_pltdev,IORESOURCE_MEM,0);
	pmydev->pled3_con = ioremap(pres->start,4);

	pres = platform_get_resource(p_pltdev,IORESOURCE_MEM,1);
	pmydev->pled3_dat = ioremap(pres->start,4);

	pres = platform_get_resource(p_pltdev,IORESOURCE_MEM,4);
	pmydev->pled4_con = ioremap(pres->start,4);

	pres = platform_get_resource(p_pltdev,IORESOURCE_MEM,5);
	pmydev->pled4_dat = ioremap(pres->start,4);

	pmydev->pled5_con = pmydev->pled4_con;
	pmydev->pled5_dat = pmydev->pled4_dat;
}

void iounmap_ledreg(struct myled_dev *pmydev)
{
	iounmap(pmydev->pled2_con);
	pmydev->pled2_con = NULL;
	iounmap(pmydev->pled2_dat);
	pmydev->pled2_dat = NULL;

	iounmap(pmydev->pled3_con);
	pmydev->pled3_con = NULL;
	iounmap(pmydev->pled3_dat);
	pmydev->pled3_dat = NULL;
	
	iounmap(pmydev->pled4_con);
	pmydev->pled4_con = NULL;
	iounmap(pmydev->pled4_dat);
	pmydev->pled4_dat = NULL;
	
	pmydev->pled5_con = NULL;
	pmydev->pled5_dat = NULL;
}

void set_output_ledconreg(struct myled_dev *pmydev)
{
	writel((readl(pmydev->pled2_con) & (~(0xF << 28))) | (0x1 << 28),pmydev->pled2_con);
	writel((readl(pmydev->pled3_con) & (~(0xF))) | (0x1),pmydev->pled3_con);
	writel((readl(pmydev->pled4_con) & (~(0xF << 16))) | (0x1 << 16),pmydev->pled4_con);
	writel((readl(pmydev->pled5_con) & (~(0xF << 20))) | (0x1 << 20),pmydev->pled5_con);

	writel(readl(pmydev->pled2_dat) & (~(0x1 << 7)),pmydev->pled2_dat);
	writel(readl(pmydev->pled3_dat) & (~(0x1)),pmydev->pled3_dat);
	writel(readl(pmydev->pled4_dat) & (~(0x1 << 4)),pmydev->pled4_dat);
	writel(readl(pmydev->pled5_dat) & (~(0x1 << 5)),pmydev->pled5_dat);
}

struct file_operations myops = {
	.owner = THIS_MODULE,
	.open = myled_open,
	.release = myled_close,
	.unlocked_ioctl = myled_ioctl,
};


static int fs4412led_driver_probe(struct platform_device *p_pltdev)
{
	int ret = 0;
	dev_t devno = MKDEV(major,minor);

	/*申请设备号*/
	ret = register_chrdev_region(devno,myled_num,"myled");
	if(ret)
	{
		ret = alloc_chrdev_region(&devno,minor,myled_num,"myled");
		if(ret)
		{
			printk("get devno failed\n");
			return -1;
		}
		major = MAJOR(devno);//容易遗漏，注意
	}

	pgmydev = (struct myled_dev *)kmalloc(sizeof(struct myled_dev),GFP_KERNEL);
	if(NULL == pgmydev)
	{
		unregister_chrdev_region(devno,myled_num);
		printk("kmalloc failed\n");
		return -1;
	}
	memset(pgmydev,0,sizeof(struct myled_dev)); //这里的memset并非c库的函数，而是内核自己实现的memset函数

	/*给struct cdev对象指定操作函数集*/	
	cdev_init(&pgmydev->mydev,&myops);

	/*将struct cdev对象添加到内核对应的数据结构里*/
	pgmydev->mydev.owner = THIS_MODULE;
	cdev_add(&pgmydev->mydev,devno,myled_num);

	/*ioremap*/
	ioremap_ledreg(pgmydev,p_pltdev);

	/*con-register set output*/
	set_output_ledconreg(pgmydev);

 
	pgmydev->cls = class_create(THIS_MODULE, "myled");    
	if(IS_ERR(pgmydev->cls))
	{
		printk("class_create failed\n");
		cdev_del(&pgmydev->mydev);
		unregister_chrdev_region(devno,myled_num);
		return -1;
	}
	
	pgmydev->dvs = device_create(pgmydev->cls, NULL, devno, NULL,"myled");   
	if(pgmydev->dvs == NULL)
	{
		printk("device_create failed\n");
		class_destroy(pgmydev->cls);
		cdev_del(&pgmydev->mydev);
		unregister_chrdev_region(devno,myled_num);
		return -1;
	}


	return 0;
}

static int fs4412led_driver_remove(struct platform_device *dev)
{
	dev_t devno = MKDEV(major,minor);

	/*iounmap*/
	iounmap_ledreg(pgmydev);

	cdev_del(&pgmydev->mydev);

	unregister_chrdev_region(devno,myled_num);

	kfree(pgmydev);
	pgmydev = NULL;

	printk("platform: driver remove\n");
	return 0;
}

struct platform_device_id fs4412led_ids[] =  //<---------------------
{
	[0] = {.name = "fs4412led"},            
	[1] = {.name = "xyz"},
	[2] = {},
};


struct platform_driver fs4412led_driver = {
	.probe = fs4412led_driver_probe,
	.remove = fs4412led_driver_remove,
	.driver = {
		.name = "abc", //必须初始化
	},
	.id_table = fs4412led_ids, //<-------------------------
};

static int __init fs4412led_driver_init(void)
{
	platform_driver_register(&fs4412led_driver);
	return 0;
}

static void __exit fs4412led_driver_exit(void)
{
	platform_driver_unregister(&fs4412led_driver);
	return;
}

module_init(fs4412led_driver_init);
module_exit(fs4412led_driver_exit);
MODULE_LICENSE("Dual BSD/GPL");

改写Makefile

cpp 复制代码 
ifeq ($(KERNELRELEASE),)

ifeq ($(ARCH),arm)
KERNELDIR ?= /home/linux/Linux_4412/kernel/linux-3.14
ROOTFS ?= /opt/4412/rootfs
else
KERNELDIR ?= /lib/modules/$(shell uname -r)/build
endif
PWD := $(shell pwd)


modules:
	$(MAKE) -C $(KERNELDIR) M=$(PWD) modules

modules_install:
	$(MAKE) -C $(KERNELDIR) M=$(PWD) modules INSTALL_MOD_PATH=$(ROOTFS) modules_install

clean:
	rm -rf  *.o  *.ko  .*.cmd  *.mod.*  modules.order  Module.symvers   .tmp_versions

else

CONFIG_MODULE_SIG=n
obj-m += fs4412_led_device_idmatch.o
obj-m += fs4412_led_driver_idmatch.o

endif

编译测试

三、设备树匹配

设备树匹配：内核启动时根据设备树自动产生的设备 ------ 优先级最高（大部分设备的方法）

注意事项：

  1. 无需编写device模块，只需编写driver模块

  2. 使用compatible属性进行匹配，注意设备树中compatible属性值不要包含空白字符（空格tab键不可以有）

  3. id_table可不设置，但struct platform_driver成员driver的name成员必须设置

  4. 可以1对多

cpp 复制代码 
/*platform driver框架*/
#include <linux/module.h> 
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/platform_device.h>
​
static int driver_probe(struct platform_device *dev)
{
    printk("platform: match ok!\n");
    return 0;
}
​
static int driver_remove(struct platform_device *dev)
{
    printk("platform: driver remove\n");
    return 0;
}
​
struct platform_device_id testdrv_ids[] = 
{
    [0] = {.name = "test_device"},
    [1] = {.name = "abcxyz"},
    [2] = {}, //means ending
};
​
struct of_device_id test_of_ids[] =   //<---------------------也可以1对多
{
    [0] = {.compatible = "xyz,abc"},
    [1] = {.compatible = "qwe,opq"},
    [2] = {},
};
​
struct platform_driver test_driver = {
    .probe = driver_probe,
    .remove = driver_remove,
    .driver = {
        .name = "xxxxx", //必须初始化
        .of_match_table = test_of_ids,   //<---------------------
    },
};
​
static int __init platform_driver_init(void)
{
    platform_driver_register(&test_driver);
    return 0;
}
​
static void __exit platform_driver_exit(void)
{
    platform_driver_unregister(&test_driver);
}
​
module_init(platform_driver_init);
module_exit(platform_driver_exit);
MODULE_LICENSE("Dual BSD/GPL");

四、设备树匹配之led驱动

改写leddrv_dt.c为fs4412_led_driver_treecmatch.c

改写重点创建struct platform_driver结构体，把init和exit改为probe和remove方式

j

这个成员匹配成功后的pnode成员

cpp 复制代码 
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/cdev.h>
#include <linux/wait.h>
#include <linux/sched.h>
#include <linux/poll.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/io.h>
#include <linux/gpio.h>
#include <linux/of_gpio.h>
#include <asm/uaccess.h>
#include <asm/atomic.h>

#include "leddrv.h"

int major = 11;
int minor = 0;
int myled_num  = 1;

//不会对寄存器直接操作，改为对设备编号操作
struct myled_dev
{
	struct cdev mydev;

	unsigned int led2gpio;
	unsigned int led3gpio;
	unsigned int led4gpio;
	unsigned int led5gpio;
};

struct myled_dev *pgmydev = NULL;


int myled_open(struct inode *pnode,struct file *pfile)
{
	pfile->private_data =(void *) (container_of(pnode->i_cdev,struct myled_dev,mydev));
	
	return 0;
}

int myled_close(struct inode *pnode,struct file *pfile)
{
	return 0;
}


void led_on(struct myled_dev *pmydev,int ledno)
{
	switch(ledno)
	{
		case 2:
			gpio_set_value(pmydev->led2gpio,1);
			break;
		case 3:
			gpio_set_value(pmydev->led3gpio,1);
			break;
		case 4:
			gpio_set_value(pmydev->led4gpio,1);
			break;
		case 5:
			gpio_set_value(pmydev->led5gpio,1);
			break;
	}
}

void led_off(struct myled_dev *pmydev,int ledno)
{
	switch(ledno)
	{
		case 2:
			gpio_set_value(pmydev->led2gpio,0);
			break;
		case 3:
			gpio_set_value(pmydev->led3gpio,0);
			break;
		case 4:
			gpio_set_value(pmydev->led4gpio,0);
			break;
		case 5:
			gpio_set_value(pmydev->led5gpio,0);
			break;
	}
}


long myled_ioctl(struct file *pfile,unsigned int cmd,unsigned long arg)
{
	struct myled_dev *pmydev = (struct myled_dev *)pfile->private_data;

	if(arg < 2 || arg > 5)
	{
		return -1;
	}
	switch(cmd)
	{
		case MY_LED_ON:
			led_on(pmydev,arg);
			break;
		case MY_LED_OFF:
			led_off(pmydev,arg);
			break;
		default:
			return -1;
	}

	return 0;
}

struct file_operations myops = {
	.owner = THIS_MODULE,
	.open = myled_open,
	.release = myled_close,
	.unlocked_ioctl = myled_ioctl,
};

//申请gpio编号，init中会调用
void request_leds_gpio(struct myled_dev *pmydev,struct device_node *pnode)
{
	pmydev->led2gpio = of_get_named_gpio(pnode,"led2-gpio",0);
	gpio_request(pmydev->led2gpio,"led2");
	
	pmydev->led3gpio = of_get_named_gpio(pnode,"led3-gpio",0);
	gpio_request(pmydev->led3gpio,"led3");
	
	pmydev->led4gpio = of_get_named_gpio(pnode,"led4-gpio",0);
	gpio_request(pmydev->led4gpio,"led4");
	
	pmydev->led5gpio = of_get_named_gpio(pnode,"led5-gpio",0);
	gpio_request(pmydev->led5gpio,"led5");
}

void set_leds_gpio_output(struct myled_dev *pmydev)
{
	gpio_direction_output(pmydev->led2gpio,0);
	gpio_direction_output(pmydev->led3gpio,0);
	gpio_direction_output(pmydev->led4gpio,0);
	gpio_direction_output(pmydev->led5gpio,0);
}

void free_leds_gpio(struct myled_dev *pmydev)
{
	gpio_free(pmydev->led2gpio);
	gpio_free(pmydev->led3gpio);
	gpio_free(pmydev->led4gpio);
	gpio_free(pmydev->led5gpio);
}

int fs4412led_driver_probe(struct platform_device *p_pltdev)
{
	int ret = 0;
	dev_t devno = MKDEV(major,minor);
	struct device_node *pnode = NULL;

//	pnode = of_find_node_by_path("/fs4412-leds");
//	if(NULL == pnode)
//	{
//		printk("find node by path failed\n");
//		return -1;
//	}
	
	pnode = p_pltdev->dev.of_node;   //<---------------------------修改为此种方式获取pnode

	/*申请设备号*/
	ret = register_chrdev_region(devno,myled_num,"myled");
	if(ret)
	{
		ret = alloc_chrdev_region(&devno,minor,myled_num,"myled");
		if(ret)
		{
			printk("get devno failed\n");
			return -1;
		}
		major = MAJOR(devno);//容易遗漏，注意
	}

	pgmydev = (struct myled_dev *)kmalloc(sizeof(struct myled_dev),GFP_KERNEL);
	if(NULL == pgmydev)
	{
		unregister_chrdev_region(devno,myled_num);
		printk("kmalloc failed\n");
		return -1;
	}
	memset(pgmydev,0,sizeof(struct myled_dev)); //这里的memset并非c库的函数，而是内核自己实现的memset函数

	/*给struct cdev对象指定操作函数集*/	
	cdev_init(&pgmydev->mydev,&myops);

	/*将struct cdev对象添加到内核对应的数据结构里*/
	pgmydev->mydev.owner = THIS_MODULE;
	cdev_add(&pgmydev->mydev,devno,myled_num);

	/*ioremap*/
	request_leds_gpio(pgmydev,pnode);

	/*con-register set output*/
	set_leds_gpio_output(pgmydev);

	return 0;
}

void fs4412led_driver_remove(struct platform_device *p_pltdev)
{
	dev_t devno = MKDEV(major,minor);

	/*iounmap*/
	free_leds_gpio(pgmydev);

	cdev_del(&pgmydev->mydev);

	unregister_chrdev_region(devno,myled_num);

	kfree(pgmydev);
	pgmydev = NULL;
}

struct of_device_id fs4412_of_ids[]=    //<--------------------
{
	[0] = {.compatible = "fs4412,led2-5"},  //<-----------------
	[1] = {.compatible = "qwe,led6-10"},
	[2] = {},
};

struct platform_driver fs4412led_driver = 
{
	.probe = fs4412led_driver_probe,
	.remove = fs4412led_driver_remove,
	.driver = {
		.name = "abcdef",
		.of_match_table = fs4412_of_ids, //<-----------------------
	},
};

int __init myled_init(void)
{
	platform_driver_register(&fs4412led_driver);
	return 0;
}

void __exit myled_exit(void)
{
	platform_driver_unregister(&fs4412led_driver);
	return;
}


MODULE_LICENSE("GPL");

module_init(myled_init);
module_exit(myled_exit);

改写Makefie

复制代码 
ifeq ($(KERNELRELEASE),)

ifeq ($(ARCH),arm)
KERNELDIR ?= /home/linux/Linux_4412/kernel/linux-3.14
ROOTFS ?= /opt/4412/rootfs
else
KERNELDIR ?= /lib/modules/$(shell uname -r)/build
endif
PWD := $(shell pwd)


modules:
	$(MAKE) -C $(KERNELDIR) M=$(PWD) modules

modules_install:
	$(MAKE) -C $(KERNELDIR) M=$(PWD) modules INSTALL_MOD_PATH=$(ROOTFS) modules_install

clean:
	rm -rf  *.o  *.ko  .*.cmd  *.mod.*  modules.order  Module.symvers   .tmp_versions

else

CONFIG_MODULE_SIG=n
#obj-m += fs4412_led_device_idmatch.o
#obj-m += fs4412_led_driver_idmatch.o
obj-m += fs4412_led_driver_treematch.o


endif

测试

五、一个编写驱动用的宏

熟悉这样的写法，等同于init和exit

cpp 复制代码 
struct platform_driver xxx = {  
    ...
};
module_platform_driver(xxx);
//最终展开后就是如下形式：
static int __init xxx_init(void)
{
        return platform_driver_register(&xxx);
}
module_init(xxx_init);
static void __exit xxx_init(void)
{
        return platform_driver_unregister(&xxx);
}
module_exit(xxx_exit)
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