字符设备驱动(四)按键中断

硬件IO

 *S2      eint0   GPF0*S3      eint2   GPF2*S4      eint11  GPG3*S5      eint19  GPG11

程序设计

中断配置

配置中断引脚,配置中断触发方式,这是在request_irq中配置的,根据irqflags去调用中断数组中的chip结构成员进行芯片相关的操作设置desc->chip->set_type

int request_irq(unsigned int irq, irq_handler_t handler,unsigned long irqflags, const char *devname, void *dev_id)irq:中断号
handler：处理函数
irqflags:上升沿触发，下降沿触发，边沿触发等。指定了快速中断或中断共享等中断处理属性.
*devname：中断名字。通常是设备驱动程序的名称。改值用在 /proc/interrupt 系统 (虚拟)
文件上，或内核发生中断错误时使用。
dev_id 可作为共享中断时的中断区别参数，也可以用来指定中断服务函数需要参考的数据地址。也用于卸载action

确定中断号,可以查看这个函数的调用s3c24xx_init_irq很明显的看到能够使用的宏在include/asm-arm/arch/irqs.h中定义

#define IRQ_EINT0      S3C2410_IRQ(0)     /* 16 */
#define IRQ_EINT2      S3C2410_IRQ(2)
#define IRQ_EINT11     S3C2410_IRQ(39)
#define IRQ_EINT19     S3C2410_IRQ(47)

中断标志irqflags,同样在s3c24xx_init_irq找到相关的set_irq_chip,找到对应的chip

//中断0
set_irq_chip(irqno, &s3c_irq_eint0t4);
set_irq_handler(irqno, handle_edge_irq);
set_irq_flags(irqno, IRQF_VALID);
//中断4-23
set_irq_chip(irqno, &s3c_irqext_chip);
set_irq_handler(irqno, handle_edge_irq);
set_irq_flags(irqno, IRQF_VALID);//0~3
static struct irq_chip s3c_irq_eint0t4 = {.name       = "s3c-ext0",.ack        = s3c_irq_ack,.mask       = s3c_irq_mask,.unmask     = s3c_irq_unmask,.set_wake   = s3c_irq_wake,.set_type   = s3c_irqext_type,
};
//4~23
static struct irq_chip s3c_irqext_chip = {.name       = "s3c-ext",.mask       = s3c_irqext_mask,.unmask     = s3c_irqext_unmask,.ack        = s3c_irqext_ack,.set_type   = s3c_irqext_type,.set_wake   = s3c_irqext_wake
};

深入分析下set_type函数,可以找到对应的irqflags使用者s3c_irqext_type中的参数type也就是标志irqflags,定义在include/asm-arm/irq.h

#define IRQT_NOEDGE   (0)
#define IRQT_RISING   (__IRQT_RISEDGE)
#define IRQT_FALLING  (__IRQT_FALEDGE)
#define IRQT_BOTHEDGE (__IRQT_RISEDGE|__IRQT_FALEDGE)
#define IRQT_LOW  (__IRQT_LOWLVL)
#define IRQT_HIGH (__IRQT_HIGHLVL)
#define IRQT_PROBE    IRQ_TYPE_PROBE//s3c_irqext_type
switch (type){case IRQT_NOEDGE:printk(KERN_WARNING "No edge setting!\n");break;case IRQT_RISING:newvalue = S3C2410_EXTINT_RISEEDGE;break;case IRQT_FALLING:newvalue = S3C2410_EXTINT_FALLEDGE;break;case IRQT_BOTHEDGE:newvalue = S3C2410_EXTINT_BOTHEDGE;break;case IRQT_LOW:newvalue = S3C2410_EXTINT_LOWLEV;break;case IRQT_HIGH:newvalue = S3C2410_EXTINT_HILEV;break;default:printk(KERN_ERR "No such irq type %d", type);return -1;}

这里选择双边触发IRQT_BOTHEDGE,

char *devname中断名随便取名
dev_id可用作释放中断函数中删除action的标识,这里可以先写作1

综上,代码为

/* 配置GPF0,2为输入引脚 */
/* 配置GPG3,11为输入引脚 */
request_irq(IRQ_EINT0,  buttons_irq, IRQT_BOTHEDGE, "S2", &pins_desc[0]);
request_irq(IRQ_EINT2,  buttons_irq, IRQT_BOTHEDGE, "S3", &pins_desc[1]);
request_irq(IRQ_EINT11, buttons_irq, IRQT_BOTHEDGE, "S4", &pins_desc[2]);
request_irq(IRQ_EINT19, buttons_irq, IRQT_BOTHEDGE, "S5", &pins_desc[3]);

中断关闭

这里需要增加释放删除action链表的函数

int drv_close(struct inode *inode, struct file *file)
{free_irq(IRQ_EINT0, &pins_desc[0]);free_irq(IRQ_EINT2, &pins_desc[1]);free_irq(IRQ_EINT11, &pins_desc[2]);free_irq(IRQ_EINT19, &pins_desc[3]);return 0;
}
static struct file_operations drv_fops = {.owner   =  THIS_MODULE,    /* 这是一个宏，推向编译模块时自动创建的__this_module变量 */.open    =  drv_open,     .read    =  drv_read,      .release =  drv_close,
};

中断函数

在request_irq中会去注册中断函数到action链表,查看使用request_irq的地方参考定义形式.比如随便艘多一个static irqreturn_t aaci_irq(int irq, void *devid)仿照定义,打印下中断号

static irqreturn_t buttons_irq(int irq, void *dev_id)
{printk("irq%d\r\n",irq);return IRQ_RETVAL(IRQ_HANDLED);
}

共享中断号

这里按键不要使用共享中断号,取用单独的中断号区分好处理

#define IRQ_EINT4t7    S3C2410_IRQ(4)       /* 20 */
// 使用下面的
#define IRQ_EINT4      S3C2410_IRQ(32)     /* 48 */
#define IRQ_EINT5      S3C2410_IRQ(33)
#define IRQ_EINT6      S3C2410_IRQ(34)
#define IRQ_EINT7      S3C2410_IRQ(35)
#define IRQ_EINT8      S3C2410_IRQ(36)

测试

加载驱动

# insmod dri.ko
# lsmod
Module                  Size  Used by    Not tainted
dri                     2748  2

验证驱动安装,查看并没有我们的中断

# cat /proc/interruptsCPU030:      95434         s3c  S3C2410 Timer Tick32:          0         s3c  s3c2410-lcd33:          0         s3c  s3c-mci34:          0         s3c  I2SSDI35:          0         s3c  I2SSDO37:         12         s3c  s3c-mci42:          0         s3c  ohci_hcd:usb143:          0         s3c  s3c2440-i2c51:       1241     s3c-ext  eth060:          0     s3c-ext  s3c-mci70:         70   s3c-uart0  s3c2440-uart71:        121   s3c-uart0  s3c2440-uart79:          0     s3c-adc  s3c2410_action80:          0     s3c-adc  s3c2410_action83:          0           -  s3c2410-wdt
Err:          0

以前使用测试程序调用open,这里可以使用 exec 5</dev/xyz0来打开设备,这个意思是打开这个设备到5去,接着就可以看到中断被打开了

# ls /dev/xyz0
/dev/xyz0# exec 5</dev/xyz0# cat /proc/interruptsCPU016:          0    s3c-ext0  S218:          0    s3c-ext0  S355:          0     s3c-ext  S463:          0     s3c-ext  S5
Err:          0

按键测试一下会打印中断号
```
# 按键按下会打印
# irq55
irq55
```

可以查看下中断次数,这里因为有按下中断和弹起中断,所以中断次数为2

# cat /proc/interruptsCPU016:          0    s3c-ext0  S218:          0    s3c-ext0  S355:          2     s3c-ext  S463:          0     s3c-ext  S5
Err:          0

查看下进程ps,查看sh的pid,查看其打开的文件/dev/xyz0

# psPID  Uid        VSZ Stat Command770 0          3096 S   -sh# ls -l /proc/770/fd
lrwx------    1 0        0              64 Jan  1 00:07 0 -> /dev/console
lrwx------    1 0        0              64 Jan  1 00:07 1 -> /dev/console
lrwx------    1 0        0              64 Jan  1 00:07 10 -> /dev/tty
lrwx------    1 0        0              64 Jan  1 00:07 2 -> /dev/console
lr-x------    1 0        0              64 Jan  1 00:07 5 -> /dev/xyz0

关闭文件,可以发现文件已经关闭,中断也没有了

#  exec 5<&-
# ls -l /proc/770/fd
lrwx------    1 0        0              64 Jan  1 00:07 0 -> /dev/console
lrwx------    1 0        0              64 Jan  1 00:07 1 -> /dev/console
lrwx------    1 0        0              64 Jan  1 00:07 10 -> /dev/tty
lrwx------    1 0        0              64 Jan  1 00:07 2 -> /dev/console# cat /proc/interrupts
#无相关中断了

完整的程序

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/irq.h>
#include <asm/uaccess.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <asm/arch/regs-gpio.h>
#include <asm/hardware.h>
//#include <linux/interrupt.h>volatile unsigned long *gpfcon;
volatile unsigned long *gpfdat;
volatile unsigned long *gpgcon;
volatile unsigned long *gpgdat;static struct class *drv_class;
static struct class_device  *drv_class_dev;static irqreturn_t buttons_irq(int irq, void *dev_id)
{printk("irq%d\r\n",irq);return IRQ_HANDLED;
}static int drv_open(struct inode *inode, struct file *file)
{/* 配置GPF0,2为输入引脚 *//* 配置GPG3,11为输入引脚 */request_irq(IRQ_EINT0,  buttons_irq, IRQT_BOTHEDGE, "S2", 1);request_irq(IRQ_EINT2,  buttons_irq, IRQT_BOTHEDGE, "S3", 1);request_irq(IRQ_EINT11, buttons_irq, IRQT_BOTHEDGE, "S4", 1);request_irq(IRQ_EINT19, buttons_irq, IRQT_BOTHEDGE, "S5", 1);   return 0;
}int drv_close(struct inode *inode, struct file *file)
{free_irq(IRQ_EINT0, 1);free_irq(IRQ_EINT2, 1);free_irq(IRQ_EINT11,1);free_irq(IRQ_EINT19,1);return 0;
}static ssize_t drv_write(struct file *file, const char __user *buf, size_t count, loff_t * ppos)
{//int minor =  MINOR(file->f_dentry->d_inode->i_rdev);//printk("drv_write=%d\n",minor);return 0;
}static ssize_t drv_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
{return 0;
}static struct file_operations drv_fops = {.owner  =   THIS_MODULE,    /* 这是一个宏，推向编译模块时自动创建的__this_module变量 */.open   =   drv_open,     .write  =   drv_write,.read   =   drv_read,    .release =  drv_close,
};static int major;
static int drv_init(void)
{int minor=0;major=register_chrdev(0, "drv", &drv_fops); // 注册, 告诉内核drv_class = class_create(THIS_MODULE, "drv");drv_class_dev = class_device_create(drv_class, NULL, MKDEV(major, 0), NULL, "xyz%d", minor);gpfcon = (volatile unsigned long *)ioremap(0x56000050, 16);gpfdat = gpfcon + 1;gpgcon = (volatile unsigned long *)ioremap(0x56000060, 16);gpgdat = gpgcon + 1;return 0;
}static void drv_exit(void)
{unregister_chrdev(major, "drv"); // 卸载class_device_unregister(drv_class_dev);class_destroy(drv_class);iounmap(gpfcon);iounmap(gpgcon);
}module_init(drv_init);
module_exit(drv_exit);
MODULE_LICENSE("GPL");

转载于:https://www.cnblogs.com/zongzi10010/p/10009173.html