字符設(shè)備驅(qū)動-LED驅(qū)動
[導(dǎo)讀]寫一個LED點燈驅(qū)動：
①框架(在Linux字符設(shè)備驅(qū)動開發(fā)基礎(chǔ)已經(jīng)搭建好)
②完善：硬件的操作
a.看原理圖-確定引腳
b.看2440數(shù)據(jù)手冊
c.寫代碼
寫代碼注意：裸機
寫一個LED點燈驅(qū)動：
①框架(在Linux字符設(shè)備驅(qū)動開發(fā)基礎(chǔ)已經(jīng)搭建好)
②完善：硬件的操作
a.看原理圖-確定引腳
b.看2440數(shù)據(jù)手冊
c.寫代碼
寫代碼注意：裸機代碼用的是物理地址PA，驅(qū)動代碼用的是虛擬地址VA<虛擬地址需要用ioremap函數(shù)映射>
驅(qū)動程序first_drv.c
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
static struct class *firstdrv_class;
static struct class_device *firstdrv_class_dev;
/*第一步 根據(jù)原理圖定義操作寄存器*/
volatile unsigned long *gpfcon = NULL;
volatile unsigned long *gpfdat = NULL;
static int first_drv_open(struct inode *inode,struct file *file)
{
printk("first_drv_openn");
//配置GPF456為輸出引腳
/*第四步 配置Open函數(shù) 將引腳配置為輸出模式*/
*gpfcon &= ~((0x3<<4*2) | (0x3<<5*2) | (0x3<<6*2));
*gpfcon |= ((1<<4*2) | (1<<5*2) | (1<<6*2));
return 0;
}
static ssize_t first_drv_write(struct file *file,const char __user *buf, size_t count,loff_t *ppos)
{
int val;
printk("first_drv_writen");
/*第五步 將用戶空間的操作內(nèi)容傳給內(nèi)核*/
copy_from_user(&val,buf,count);
if(1 == val)
{
*gpfdat &= ~((1<<4) | (1<<5) | (1<<6));
}
else
{
*gpfdat |= ((1<<4) | (1<<5) | (1<<6));
}
return 0;
}
static struct file_operations first_drv_fops = {
.owner = THIS_MODULE, /* 這是一個宏，推向編譯模塊時自動創(chuàng)建的__this_module變量 */
.open = first_drv_open,
.write = first_drv_write,
};
int major;
static int first_drv_init(void)
{
major = register_chrdev(0,"first_drv",&first_drv_fops);// 注冊，告訴內(nèi)核
//printk("first_drv_initn");
firstdrv_class = class_create(THIS_MODULE, "firstdrv");
firstdrv_class_dev = class_device_create(firstdrv_class, NULL, MKDEV(major, 0), NULL, "xyz"); /* /dev/xyz */
/*第二步 根據(jù)數(shù)據(jù)手冊 入口函數(shù)映射VA*/
gpfcon = (volatile unsigned long *)ioremap(0x56000050,16);
gpfdat = gpfcon + 1;
return 0;
}
static void first_drv_exit(void)
{
unregister_chrdev(major,"first_drv");//卸載
class_device_unregister(firstdrv_class_dev);
class_destroy(firstdrv_class);
/*第三步 出口函數(shù)去掉映射*/
iounmap(gpfcon);
}
module_init(first_drv_init);
module_exit(first_drv_exit);
MODULE_LICENSE("GPL");
驅(qū)動測試程序firstdrvtest.c
#include
#include
#include
#include
/* firstdrvtest on
* firstdrvtest off
*/
int main(int argc, char **argv)
{
int fd;
int val = 1;
fd = open("/dev/xyz",O_RDWR);
if(fd < 0)
{
printf("can't open!n");
}
if (argc != 2)
{
printf("Usage : n");
printf("%s n", argv[0] );
return 0;
}
if (strcmp(argv[1],"on") == 0)
{
val = 1 ;
}
else
{
val = 0 ;
}
write(fd,&val,4);
return 0;
}
①make -編譯驅(qū)動程序
②arm-linux-gcc -o firstdrvtest firstdrvtest.c -編譯驅(qū)動測試程序
③cp first_drv.ko /work/nfs_root/czg -拷貝至nfs文件夾
④cp firstdrvtest /work/nfs_root/czg -拷貝至nfs文件夾
⑤rmmod first_drv -卸載先前驅(qū)動//cat proc/devices 查看
⑥insmod first_drv.ko -加載驅(qū)動
⑦./firstdrvtest -測試驅(qū)動
（1）根據(jù)修改傳入?yún)?shù)，執(zhí)行多種操作
（2）通過此設(shè)備號的不同來實現(xiàn)，執(zhí)行不同的硬件操作
驅(qū)動程序myleds.c
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#define DEVICE_NAME "leds" /* 加載模式后，執(zhí)行”cat /proc/devices”命令看到的設(shè)備名稱 */
#define LED_MAJOR 231 /* 主設(shè)備號 */
static struct class *leds_class;
static struct class_device *leds_class_devs[4];
/* bit0<=>D10, 0:亮, 1:滅
* bit1<=>D11, 0:亮, 1:滅
* bit2<=>D12, 0:亮, 1:滅
*/
static char leds_status = 0x0;
static DECLARE_MUTEX(leds_lock); // 定義賦值
//static int minor;
static unsigned long gpio_va;
#define GPIO_OFT(x) ((x) - 0x56000000)
#define GPFCON (*(volatile unsigned long *)(gpio_va + GPIO_OFT(0x56000050)))
#define GPFDAT (*(volatile unsigned long *)(gpio_va + GPIO_OFT(0x56000054)))
/* 應(yīng)用程序?qū)υO(shè)備文件/dev/leds執(zhí)行open(...)時，
* 就會調(diào)用s3c24xx_leds_open函數(shù)
*/
static int s3c24xx_leds_open(struct inode *inode, struct file *file)
{
int minor = MINOR(inode->i_rdev); //MINOR(inode->i_cdev);
switch(minor)
{
case 0: /* /dev/leds */
{
// 配置3引腳為輸出
//s3c2410_gpio_cfgpin(S3C2410_GPF4, S3C2410_GPF4_OUTP);
GPFCON &= ~(0x3<<(4*2));
GPFCON |= (1<<(4*2));
//s3c2410_gpio_cfgpin(S3C2410_GPF5, S3C2410_GPF5_OUTP);
GPFCON &= ~(0x3<<(5*2));
GPFCON |= (1<<(5*2));
//s3c2410_gpio_cfgpin(S3C2410_GPF6, S3C2410_GPF6_OUTP);
GPFCON &= ~(0x3<<(6*2));
GPFCON |= (1<<(6*2));
// 都輸出0
//s3c2410_gpio_setpin(S3C2410_GPF4, 0);
GPFDAT &= ~(1<<4);
//s3c2410_gpio_setpin(S3C2410_GPF5, 0);
GPFDAT &= ~(1<<5);
//s3c2410_gpio_setpin(S3C2410_GPF6, 0);
GPFDAT &= ~(1<<6);
down(&leds_lock);
leds_status = 0x0;
up(&leds_lock);
break;
}
case 1: /* /dev/led1 */
{
s3c2410_gpio_cfgpin(S3C2410_GPF4, S3C2410_GPF4_OUTP);
s3c2410_gpio_setpin(S3C2410_GPF4, 0);
down(&leds_lock);
leds_status &= ~(1<<0);
up(&leds_lock);
break;
}
case 2: /* /dev/led2 */
{
s3c2410_gpio_cfgpin(S3C2410_GPF5, S3C2410_GPF5_OUTP);
s3c2410_gpio_setpin(S3C2410_GPF5, 0);
leds_status &= ~(1<<1);
break;
}
case 3: /* /dev/led3 */
{
s3c2410_gpio_cfgpin(S3C2410_GPF6, S3C2410_GPF6_OUTP);
s3c2410_gpio_setpin(S3C2410_GPF6, 0);
down(&leds_lock);
leds_status &= ~(1<<2);
up(&leds_lock);
break;
}
}
return 0;
}
static int s3c24xx_leds_read(struct file *filp, char __user *buff,
size_t count, loff_t *offp)
{
int minor = MINOR(filp->f_dentry->d_inode->i_rdev);
char val;
switch (minor)
{
case 0: /* /dev/leds */
{
copy_to_user(buff, (const void *)&leds_status, 1);
break;
}
case 1: /* /dev/led1 */
{
down(&leds_lock);
val = leds_status & 0x1;
up(&leds_lock);
copy_to_user(buff, (const void *)&val, 1);
break;
}
case 2: /* /dev/led2 */
{
down(&leds_lock);
val = (leds_status>>1) & 0x1;
up(&leds_lock);
copy_to_user(buff, (const void *)&val, 1);
break;
}
case 3: /* /dev/led3 */
{
down(&leds_lock);
val = (leds_status>>2) & 0x1;
up(&leds_lock);
copy_to_user(buff, (const void *)&val, 1);
break;
}
}
return 1;
}
static ssize_t s3c24xx_leds_write(struct file *file, const char __user *buf, size_t count, loff_t * ppos)
{
//int minor = MINOR(inode->i_rdev); //MINOR(inode->i_cdev);
int minor = MINOR(file->f_dentry->d_inode->i_rdev);
char val;
copy_from_user(&val, buf, 1);
switch (minor)
{
case 0: /* /dev/leds */
{
s3c2410_gpio_setpin(S3C2410_GPF4, (val & 0x1));
s3c2410_gpio_setpin(S3C2410_GPF5, (val & 0x1));
s3c2410_gpio_setpin(S3C2410_GPF6, (val & 0x1));
down(&leds_lock);
leds_status = val;
up(&leds_lock);
break;
}
case 1: /* /dev/led1 */
{
s3c2410_gpio_setpin(S3C2410_GPF4, val);
if (val == 0)
{
down(&leds_lock);
leds_status &= ~(1<<0);
up(&leds_lock);
}
else
{
down(&leds_lock);
leds_status |= (1<<0);
up(&leds_lock);
}
break;
}
case 2: /* /dev/led2 */
{
s3c2410_gpio_setpin(S3C2410_GPF5, val);
if (val == 0)
{
down(&leds_lock);
leds_status &= ~(1<<1);
up(&leds_lock);
}
else
{
down(&leds_lock);
leds_status |= (1<<1);
up(&leds_lock);
}
break;
}
case 3: /* /dev/led3 */
{
s3c2410_gpio_setpin(S3C2410_GPF6, val);
if (val == 0)
{
down(&leds_lock);
leds_status &= ~(1<<2);
up(&leds_lock);
}
else
{
down(&leds_lock);
leds_status |= (1<<2);
up(&leds_lock);
}
break;
}
}
return 1;
}
/* 這個結(jié)構(gòu)是字符設(shè)備驅(qū)動程序的核心
* 當(dāng)應(yīng)用程序操作設(shè)備文件時所調(diào)用的open、read、write等函數(shù)，
* 最終會調(diào)用這個結(jié)構(gòu)中指定的對應(yīng)函數(shù)
*/
static struct file_operations s3c24xx_leds_fops = {
.owner = THIS_MODULE, /* 這是一個宏，推向編譯模塊時自動創(chuàng)建的__this_module變量 */
.open = s3c24xx_leds_open,
.read = s3c24xx_leds_read,
.write = s3c24xx_leds_write,
};
/*
* 執(zhí)行insmod命令時就會調(diào)用這個函數(shù)
*/
static int __init s3c24xx_leds_init(void)
//static int __init init_module(void)
{
int ret;
int minor = 0;
gpio_va = ioremap(0x56000000, 0x100000);
if (!gpio_va) {
return -EIO;
}
/* 注冊字符設(shè)備
* 參數(shù)為主設(shè)備號、設(shè)備名字、file_operations結(jié)構(gòu)；
* 這樣，主設(shè)備號就和具體的file_operations結(jié)構(gòu)聯(lián)系起來了，
* 操作主設(shè)備為LED_MAJOR的設(shè)備文件時，就會調(diào)用s3c24xx_leds_fops中的相關(guān)成員函數(shù)
* LED_MAJOR可以設(shè)為0，表示由內(nèi)核自動分配主設(shè)備號
*/
ret = register_chrdev(LED_MAJOR, DEVICE_NAME, &s3c24xx_leds_fops);
if (ret < 0) {
printk(DEVICE_NAME " can't register major numbern");
return ret;
}
leds_class = class_create(THIS_MODULE, "leds");
if (IS_ERR(leds_class))
return PTR_ERR(leds_class);
leds_class_devs[0] = class_device_create(leds_class, NULL, MKDEV(LED_MAJOR, 0), NULL, "leds"); /* /dev/leds */
for (minor = 1; minor < 4; minor++) /* /dev/led1,2,3 */
{
leds_class_devs[minor] = class_device_create(leds_class, NULL, MKDEV(LED_MAJOR, minor), NULL, "led%d", minor);
if (unlikely(IS_ERR(leds_class_devs[minor])))
return PTR_ERR(leds_class_devs[minor]);
}
printk(DEVICE_NAME " initializedn");
return 0;
}
/*
* 執(zhí)行rmmod命令時就會調(diào)用這個函數(shù)
*/
static void __exit s3c24xx_leds_exit(void)
{
int minor;
/* 卸載驅(qū)動程序 */
unregister_chrdev(LED_MAJOR, DEVICE_NAME);
for (minor = 0; minor < 4; minor++)
{
class_device_unregister(leds_class_devs[minor]);
}
class_destroy(leds_class);
iounmap(gpio_va);
}
/* 這兩行指定驅(qū)動程序的初始化函數(shù)和卸載函數(shù) */
module_init(s3c24xx_leds_init);
module_exit(s3c24xx_leds_exit);
/* 描述驅(qū)動程序的一些信息，不是必須的 */
MODULE_AUTHOR("http://www.100ask.net");
MODULE_VERSION("0.1.0");
MODULE_DESCRIPTION("S3C2410/S3C2440 LED Driver");
MODULE_LICENSE("GPL"); 驅(qū)動測試程序ledtest.c
#include
#include
#include
#include
/*
* ledtest
*/
void print_usage(char *file)
{
printf("Usage:n");
printf("%s n",file);
printf("eg. n");
printf("%s /dev/leds onn", file);
printf("%s /dev/leds offn", file);
printf("%s /dev/led1 onn", file);
printf("%s /dev/led1 offn", file);
}
int main(int argc, char **argv)
{
int fd;
char* filename;
char val;
if (argc != 3)
{
print_usage(argv[0]);
return 0;
}
filename = argv[1];
fd = open(filename, O_RDWR);
if (fd < 0)
{
printf("error, can't open %sn", filename);
return 0;
}
if (!strcmp("on", argv[2]))
{
// 亮燈
val = 0;
write(fd, &val, 1);
}
else if (!strcmp("off", argv[2]))
{
// 滅燈
val = 1;
write(fd, &val, 1);
}
else
{
print_usage(argv[0]);
return 0;
}
return 0;
}
Makefile
KERN_DIR = /work/system/linux-2.6.22.6
all:
make -C $(KERN_DIR) M=`pwd` modules
clean:
make -C $(KERN_DIR) M=`pwd` modules clean
rm -rf modules.order
obj-m += myleds.o
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