目录
title: 字符设备驱动(四)按键中断
tags: linux
date: 2018-11-23 17:26:57
toc: true
---
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/interrupts CPU0 30: 95434 s3c S3C2410 Timer Tick 32: 0 s3c s3c2410-lcd 33: 0 s3c s3c-mci 34: 0 s3c I2SSDI 35: 0 s3c I2SSDO 37: 12 s3c s3c-mci 42: 0 s3c ohci_hcd:usb1 43: 0 s3c s3c2440-i2c 51: 1241 s3c-ext eth0 60: 0 s3c-ext s3c-mci 70: 70 s3c-uart0 s3c2440-uart 71: 121 s3c-uart0 s3c2440-uart 79: 0 s3c-adc s3c2410_action 80: 0 s3c-adc s3c2410_action 83: 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/interrupts CPU0 16: 0 s3c-ext0 S2 18: 0 s3c-ext0 S3 55: 0 s3c-ext S4 63: 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/interrupts CPU0 16: 0 s3c-ext0 S2 18: 0 s3c-ext0 S3 55: 2 s3c-ext S4 63: 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# ps PID Uid VSZ Stat Command 770 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");