嵌入式linux字符设备驱动--步进电机驱动

步进电机驱动主要要用到内核定时器，内核定时器就是在内核驱动程序里面定时

stepmotor.c

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/ide.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/gpio.h>
#include <asm/mach/map.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#include <linux/cdev.h>
#include <linux/device.h>


/* 寄存器物理地址 */
#define CCM_CCGR1_BASE (0X020C406C) 
#define SW_MUX_GPIO1_IO04_BASE (0X020E006c)
#define SW_PAD_GPIO1_IO04_BASE (0X020E02F8)
#define SW_MUX_GPIO1_IO05_BASE (0X020E0070)
#define SW_PAD_GPIO1_IO05_BASE (0X020E02Fc)
#define SW_MUX_GPIO1_IO06_BASE (0X020E0074)
#define SW_PAD_GPIO1_IO06_BASE (0X020E0300)
#define SW_MUX_GPIO1_IO07_BASE (0X020E0078)
#define SW_PAD_GPIO1_IO07_BASE (0X020E0304)
#define GPIO1_DR_BASE (0X0209C000)
#define GPIO1_GDIR_BASE (0X0209C004)

/* 映射后的寄存器虚拟地址指针 */
static void __iomem *IMX6U_CCM_CCGR1;
static void __iomem *SW_MUX_GPIO1_IO04;
static void __iomem *SW_PAD_GPIO1_IO04;
static void __iomem *SW_MUX_GPIO1_IO05;
static void __iomem *SW_PAD_GPIO1_IO05;
static void __iomem *SW_MUX_GPIO1_IO06;
static void __iomem *SW_PAD_GPIO1_IO06;
static void __iomem *SW_MUX_GPIO1_IO07;
static void __iomem *SW_PAD_GPIO1_IO07;
static void __iomem *GPIO1_DR;
static void __iomem *GPIO1_GDIR;

static int stepmotor_angle = 0;
#define stepmotor_CNT 1 /* 设备号个数 */
#define stepmotor_NAME "mystepmotor" /* 名字 */

/* stepmotor 设备结构体 */
struct stepmotor_dev{
	dev_t devid; /* 设备号 */
	struct cdev cdev; /* cdev */
	struct class *class; /* 类 */
	struct device *device; /* 设备 */
	int major; /* 主设备号 */
	int minor; /* 次设备号 */
};
 
struct stepmotor_dev stepmotor; /* stepmotor 设备 */
static struct timer_list tm;


static void stepmotor_gpio_config(void)
{
	u32 val = 0;

	/* 初始化 stepmotor */
	/* 1、寄存器地址映射 */
	IMX6U_CCM_CCGR1 = ioremap(CCM_CCGR1_BASE, 4);
	SW_MUX_GPIO1_IO04 = ioremap(SW_MUX_GPIO1_IO04_BASE, 4);
	SW_PAD_GPIO1_IO04 = ioremap(SW_PAD_GPIO1_IO04_BASE, 4);
	SW_MUX_GPIO1_IO05 = ioremap(SW_MUX_GPIO1_IO05_BASE, 4);
	SW_PAD_GPIO1_IO05 = ioremap(SW_PAD_GPIO1_IO05_BASE, 4);
	SW_MUX_GPIO1_IO06 = ioremap(SW_MUX_GPIO1_IO06_BASE, 4);
	SW_PAD_GPIO1_IO06 = ioremap(SW_PAD_GPIO1_IO06_BASE, 4);
	SW_MUX_GPIO1_IO07 = ioremap(SW_MUX_GPIO1_IO07_BASE, 4);
	SW_PAD_GPIO1_IO07 = ioremap(SW_PAD_GPIO1_IO07_BASE, 4);
	GPIO1_DR = ioremap(GPIO1_DR_BASE, 4);
	GPIO1_GDIR = ioremap(GPIO1_GDIR_BASE, 4);

	/* 2、使能 GPIO1 时钟 */
	val = readl(IMX6U_CCM_CCGR1);
	val &= ~(3 << 26); /* 清除以前的设置 */
	val |= (3 << 26); /* 设置新值 */
	writel(val, IMX6U_CCM_CCGR1);

	/* 3、设置 GPIO1_IO04 5 6 7 的复用功能，将其复用为
	 * GPIO1_IO03，最后设置 IO 属性。
	*/
	writel(5, SW_MUX_GPIO1_IO04);
	writel(5, SW_MUX_GPIO1_IO05);
	writel(5, SW_MUX_GPIO1_IO06);
	writel(5, SW_MUX_GPIO1_IO07);

	/* 寄存器 SW_PAD_GPIO1_IO03 设置 IO 属性 */
	writel(0x10B0, SW_PAD_GPIO1_IO04);
	writel(0x10B0, SW_PAD_GPIO1_IO05);
	writel(0x10B0, SW_PAD_GPIO1_IO06);
	writel(0x10B0, SW_PAD_GPIO1_IO07);

	/* 4、设置 GPIO1_IO04 5 6 7 为输出功能 */
	val = readl(GPIO1_GDIR);
	val &= ~((1 << 4)|(1 << 5)|(1 << 6)|(1 << 7)); /* 清除以前的设置 */
	val |= (1 << 4)|(1 << 5)|(1 << 6)|(1 << 7); /* 设置为输出 */
	writel(val, GPIO1_GDIR);

	/* 5、默认关闭 stepmotor */
	val = readl(GPIO1_DR);
	val &= ~((1 << 4)|(1 << 5)|(1 << 6)|(1 << 7)); 
	writel(val, GPIO1_DR);
}

static void stepmotor_call(void)
{
	unsigned long tmp = 0;
	static char steps = 0;
	
#define MOTOR_IO_H(X) {tmp = readl(GPIO1_DR);\
		tmp |= (1 << X);\
		writel(tmp, GPIO1_DR);}
#define MOTOR_IO_L(X) {tmp = readl(GPIO1_DR);\
		tmp &= ~(1 << X);\
		writel(tmp, GPIO1_DR);}
	if(stepmotor_angle > 0)
	{steps++;stepmotor_angle--;}
	else if(stepmotor_angle < 0)
	     {steps--;stepmotor_angle++;}
	     else
		return ;
	if(steps > 3 || steps < 0)
		steps = 0;
	switch(steps)
	{
		case 0:MOTOR_IO_L(4);MOTOR_IO_H(5);MOTOR_IO_H(6);MOTOR_IO_H(7);
			break;
		case 1:MOTOR_IO_H(4);MOTOR_IO_L(5);MOTOR_IO_H(6);MOTOR_IO_H(7);
			break;
		case 2:MOTOR_IO_H(4);MOTOR_IO_H(5);MOTOR_IO_L(6);MOTOR_IO_H(7);
			break;
		case 3:MOTOR_IO_H(4);MOTOR_IO_H(5);MOTOR_IO_H(6);MOTOR_IO_L(7);
			break;
			default:steps = 0;break;
	}
}

void iTimer_callback(unsigned long arg)  
{  
    	//struct timeval tv;  
   	char *strp = (char*)arg;
  
    	printk(KERN_EMERG "%s: %lu, %s\n", __func__, jiffies, strp);  
	stepmotor_call();
    	mod_timer(&tm,jiffies+2*HZ); //使用mod_timer或再次add_timer函数重新触发
    	//tm.expires = jiffies+1*HZ;
    	//add_timer(&tm);
}  

void iTimer_init(void)
{
	init_timer(&tm);  
    	tm.function= iTimer_callback;  
   	tm.data = (unsigned long)"I am timer";
    	tm.expires = jiffies+1*HZ;  
    	add_timer(&tm);  
}

static int stepmotor_open (struct inode * inode, struct file * file)
{
	printk(" device open\n");
	file->private_data = &stepmotor; /* 设置私有数据 */
	return 0;
}

static int stepmotor_release (struct inode * inode, struct file * file)
{
	printk(" device release\n");
	return 0;
}

ssize_t stepmotor_read (struct file *filp, char __user * buf, size_t count, loff_t *ppos)
{
	printk(" device read\n");
	return 0;
}

ssize_t stepmotor_write (struct file *filp, const char __user * buf, size_t cnt, loff_t *ppos)
{
	int retvalue;
	unsigned char databuf[2];
	int stepmotorstat;
	
	retvalue = copy_from_user(databuf, buf, cnt);
	if(retvalue < 0) 
	{
		printk("kernel write faistepmotor!\r\n");
		return -EFAULT;
	}
	stepmotorstat = databuf[0]*256 + databuf[1]; /* 获取状态值 */
	stepmotor_angle = stepmotorstat;

	printk(" device write %d \n",stepmotor_angle);
	return 0;
}

/* 设备操作函数 */
static struct file_operations stepmotor_fops = {
	.owner = THIS_MODULE,
	.open = stepmotor_open,
	.read = stepmotor_read,
	.write = stepmotor_write,
	.release = stepmotor_release,
};

static int __init stepmotor_init(void)
{
	stepmotor_gpio_config();
	iTimer_init();
	
	/* 1、创建设备号 */
	if (stepmotor.major) 
	{ /* 定义了设备号 */
		stepmotor.devid = MKDEV(stepmotor.major, 0);
		register_chrdev_region(stepmotor.devid, stepmotor_CNT, stepmotor_NAME);
	} 
	else 
	{ /* 没有定义设备号 */
		alloc_chrdev_region(&stepmotor.devid, 0, stepmotor_CNT,stepmotor_NAME); /* 申请设备号 */
		stepmotor.major = MAJOR(stepmotor.devid); /* 获取主设备号 */
		stepmotor.minor = MINOR(stepmotor.devid); /* 获取次设备号 */
	}
	printk("newchestepmotor major=%d,minor=%d\r\n",stepmotor.major,stepmotor.minor);

	/* 2、初始化 cdev */
	stepmotor.cdev.owner = THIS_MODULE;
	cdev_init(&stepmotor.cdev, &stepmotor_fops);

	/* 3、添加一个 cdev */
	cdev_add(&stepmotor.cdev, stepmotor.devid, stepmotor_CNT);

	/* 4、创建类 */
	stepmotor.class = class_create(THIS_MODULE, stepmotor_NAME);
	if (IS_ERR(stepmotor.class)) 
	{
		return PTR_ERR(stepmotor.class);
	}
	 
	/* 5、创建设备 */
	stepmotor.device = device_create(stepmotor.class, NULL,
	stepmotor.devid, NULL, stepmotor_NAME);
	if (IS_ERR(stepmotor.device)) 
	{
		return PTR_ERR(stepmotor.device);
	}

	printk(" device insmod ok\n");
	return 0;
}

static void __exit stepmotor_exit(void)
{
	/* 取消映射 */
	iounmap(IMX6U_CCM_CCGR1);
	iounmap(SW_MUX_GPIO1_IO04);
	iounmap(SW_PAD_GPIO1_IO04);
	iounmap(SW_MUX_GPIO1_IO05);
	iounmap(SW_PAD_GPIO1_IO05);
	iounmap(SW_MUX_GPIO1_IO06);
	iounmap(SW_PAD_GPIO1_IO06);
	iounmap(SW_MUX_GPIO1_IO07);
	iounmap(SW_PAD_GPIO1_IO07);
	iounmap(GPIO1_DR);
	iounmap(GPIO1_GDIR);
	
	del_timer(&tm); 
	/* 注销字符设备 */
	cdev_del(&stepmotor.cdev);/* 删除 cdev */
	unregister_chrdev_region(stepmotor.devid, stepmotor_CNT);

	device_destroy(stepmotor.class, stepmotor.devid);
	class_destroy(stepmotor.class);

	printk(" device rmmod ok\n");
}

module_init(stepmotor_init);
module_exit(stepmotor_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("guoguo");

Makefile

#内核源码树路径
KERN_DIR := /home/z/imax6ull/kernel
ARCH=arm
CROSS_COMPILE=arm-linux-gnueabihf-

export  ARCH  CROSS_COMPILE

#目标文件
obj-m += stepmotor.o

all:
	$(MAKE) -C $(KERN_DIR) M=$(CURDIR) modules

.PHONY:clean
clean:
	#$(MAKE) -C $(KERNEL_DIR) M=$(CURDIR) clean
	rm -f *.o *.ko *.order *.symvers

应用测试程序stepmotortest.c

#include "stdio.h"
#include "unistd.h"
#include "sys/types.h"
#include "sys/stat.h"
#include "fcntl.h"
#include "stdlib.h"
#include "string.h"

static int fd = 0;

void stepmotor_init()
{
	/* 打开 stepmotor 驱动 */
	fd = open("/dev/mystepmotor", O_RDWR);
	if(fd < 0)
	{
		printf("file %s open faistepmotor!\r\n");
		return -1;
	}
}

int stepmotor_set(unsigned int x)
{
	int ret = 0;
	unsigned char buff[2];
	
	buff[0] = x/256;
	buff[1] = x&0xff;
	ret = write(fd, buff, sizeof(buff));
	if(ret < 0)
	{
		printf("stepmotor Control Faistepmotor!\r\n");
		close(fd);
		return -1;
	}
}

int main()
{
	stepmotor_init();
	while(1)
	{
		stepmotor_set(5);
		sleep(10);
		stepmotor_set(8);
		sleep(10);
	}
	close(fd); /* 关闭文件 */
	return 0;
}

编译驱动 make
会在当前目录生成stepmotor.ko

编译应用程序 arm-linux-gnueabihf-gcc stepmotortest.c-o stepmotortest

加载驱动 insmod stepmotor.ko
运行应用测试 ./stepmotortest