正点原子IMX6UL 多路按键中断实际案例

1 前言

项目上需要多个按键输入, 因此记录一下多个按键的中断如何做

2 修改设备树

     pinctrl_gpio_keys: gpio-keys {fsl,pins = <MX6UL_PAD_SNVS_TAMPER2__GPIO5_IO02    0x80000000  /* KEY1 */MX6ULL_PAD_SNVS_TAMPER8__GPIO5_IO08 0x80000000    /* KEY2 */MX6ULL_PAD_SNVS_TAMPER0__GPIO5_IO00   0x80000000  /* KEY3 */MX6ULL_PAD_SNVS_TAMPER1__GPIO5_IO01   0x80000000  /* KEY4 */MX6ULL_PAD_SNVS_TAMPER4__GPIO5_IO04   0x80000000  /* KEY5 */>;};

    input_keys {#address-cells = <1>;#size-cells = <0>;compatible = "gpio-keys";pinctrl-names = "default";pinctrl-0 = <&pinctrl_gpio_keys>;status = "okay";key1@1 {label = "KEY1";interrupt-parent = <&gpio5>;interrupts = <2 IRQ_TYPE_EDGE_BOTH>;gpios = <&gpio5 2 GPIO_ACTIVE_LOW>;};key2@2 {label = "KEY2";interrupt-parent = <&gpio5>;interrupts = <8 IRQ_TYPE_EDGE_BOTH>;gpios = <&gpio5 8 GPIO_ACTIVE_LOW>;};key3@3 {label = "KEY3";linux,code = <>;interrupt-parent = <&gpio5>;interrupts = <0 IRQ_TYPE_EDGE_BOTH>;gpios = <&gpio5 0 GPIO_ACTIVE_LOW>;};key4@4 {label = "KEY4";interrupt-parent = <&gpio5>;interrupts = <1 IRQ_TYPE_EDGE_BOTH>;gpios = <&gpio5 1 GPIO_ACTIVE_LOW>;};key5@5 {label = "KEY5";interrupt-parent = <&gpio5>;interrupts = <4 IRQ_TYPE_EDGE_BOTH>;gpios = <&gpio5 4 GPIO_ACTIVE_LOW>;};};

3 创建字符驱动

需要注意的是,在注册中断的时候, 对于每个中断都要有不同的中断函数和中断值, 不然就会注册失败返回-22

#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 <linux/cdev.h>
#include <linux/device.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_gpio.h>
#include <linux/semaphore.h>
#include <linux/timer.h>
#include <linux/of_irq.h>
#include <linux/irq.h>
#include <linux/wait.h>
#include <linux/poll.h>
#include <asm/mach/map.h>
#include <asm/uaccess.h>
#include <asm/io.h>#define KEY_NUM                5           /* 按键数量     */
#define IMX6UIRQ_NAME       "/input_keys" /* 名字       */
#define IMX6UIRQ_PROPETY_NAME   "gpios"
#define INVAKEY             0XFF        /* 无效的按键值 */
char key_value[] = {0x01,0x02,0x03,0x04,0x05};/* 中断IO描述结构体 */
struct irq_keydesc {int gpio;                               /* gpio */int irqnum;                               /* 中断号     */unsigned char value;                   /* 按键对应的键值 */char name[10];                         /* 名字 */irqreturn_t (*handler)(int, void *);    /* 中断服务函数 */
};/* imx6uirq设备结构体 */
struct imx6uirq_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 device_node  *nd; /* 设备节点 */ atomic_t keyvalue;      /* 有效的按键键值 */atomic_t releasekey;   /* 标记是否完成一次完成的按键，包括按下和释放 */struct timer_list timer;/* 定义一个定时器*/struct irq_keydesc irqkeydesc[KEY_NUM];   /* 按键init述数组 */unsigned char curkeynum;             /* 当前init按键号 */wait_queue_head_t r_wait;    /* 读等待队列头 */
};struct imx6uirq_dev imx6uirq; /* irq设备 *//* @description     : 中断服务函数，开启定时器       *                     定时器用于按键消抖。* @param - irq     : 中断号 * @param - dev_id    : 设备结构。* @return           : 中断执行结果*/
static irqreturn_t key0_handler(int irq, void *dev_id)
{struct imx6uirq_dev *dev = (struct imx6uirq_dev*)dev_id;dev->curkeynum = 0;dev->timer.data = (volatile long)dev_id;mod_timer(&dev->timer, jiffies + msecs_to_jiffies(10));    /* 10ms定时 */return IRQ_RETVAL(IRQ_HANDLED);
}static irqreturn_t key1_handler(int irq, void *dev_id)
{struct imx6uirq_dev *dev = (struct imx6uirq_dev*)dev_id;dev->curkeynum = 1;dev->timer.data = (volatile long)dev_id;mod_timer(&dev->timer, jiffies + msecs_to_jiffies(10));    /* 10ms定时 */return IRQ_RETVAL(IRQ_HANDLED);
}
static irqreturn_t key2_handler(int irq, void *dev_id)
{struct imx6uirq_dev *dev = (struct imx6uirq_dev*)dev_id;dev->curkeynum = 2;dev->timer.data = (volatile long)dev_id;mod_timer(&dev->timer, jiffies + msecs_to_jiffies(10));    /* 10ms定时 */return IRQ_RETVAL(IRQ_HANDLED);
}
static irqreturn_t key3_handler(int irq, void *dev_id)
{struct imx6uirq_dev *dev = (struct imx6uirq_dev*)dev_id;dev->curkeynum = 3;dev->timer.data = (volatile long)dev_id;mod_timer(&dev->timer, jiffies + msecs_to_jiffies(10));    /* 10ms定时 */return IRQ_RETVAL(IRQ_HANDLED);
}
static irqreturn_t key4_handler(int irq, void *dev_id)
{struct imx6uirq_dev *dev = (struct imx6uirq_dev*)dev_id;dev->curkeynum = 4;dev->timer.data = (volatile long)dev_id;mod_timer(&dev->timer, jiffies + msecs_to_jiffies(10));    /* 10ms定时 */return IRQ_RETVAL(IRQ_HANDLED);
}/* @description   : 定时器服务函数，用于按键消抖，定时器到了以后*               再次读取按键值，如果按键还是处于按下状态就表示按键有效。* @param - arg    : 设备结构变量* @return      : 无*/
void timer_function(unsigned long arg)
{unsigned char value;unsigned char num;struct irq_keydesc *keydesc;struct imx6uirq_dev *dev = (struct imx6uirq_dev *)arg;num = dev->curkeynum;keydesc = &dev->irqkeydesc[num];value = gpio_get_value(keydesc->gpio);   /* 读取IO值 */if(value == 0){                        /* 按下按键 */atomic_set(&dev->keyvalue, keydesc->value);}else{                                   /* 按键松开 */atomic_set(&dev->keyvalue, 0x80 | keydesc->value);atomic_set(&dev->releasekey, 1);   /* 标记松开按键，即完成一次完整的按键过程 */}               /* 唤醒进程 */if(atomic_read(&dev->releasekey)) {    /* 完成一次按键过程 *//* wake_up(&dev->r_wait); */wake_up_interruptible(&dev->r_wait);}
}/** @description  : 按键IO初始化* @param      : 无* @return       : 无*/
static int keyio_init(void)
{unsigned char i = 0;char name[10];int ret = 0;// 找节点imx6uirq.nd = of_find_node_by_path(IMX6UIRQ_NAME);if (imx6uirq.nd== NULL){printk("key node not find!\r\n");return -EINVAL;} // 中断函数imx6uirq.irqkeydesc[0].handler = key0_handler;imx6uirq.irqkeydesc[1].handler = key1_handler;imx6uirq.irqkeydesc[2].handler = key2_handler;imx6uirq.irqkeydesc[3].handler = key3_handler;imx6uirq.irqkeydesc[4].handler = key4_handler;/* 提取GPIO */struct device_node *cnp;struct device_node *prev = NULL;for(i=0;i<KEY_NUM;i++){cnp = of_get_next_child(imx6uirq.nd, prev);if(cnp==NULL){break;}prev = cnp;// 获取GPIO  imx6uirq.irqkeydesc[i].gpio = of_get_named_gpio(cnp, IMX6UIRQ_PROPETY_NAME, 0);memset(imx6uirq.irqkeydesc[i].name, 0, sizeof(name)); /* 缓冲区清零 */sprintf(imx6uirq.irqkeydesc[i].name, "KEY%d", i);      /* 组合名字 */gpio_request(imx6uirq.irqkeydesc[i].gpio, name);gpio_direction_input(imx6uirq.irqkeydesc[i].gpio);    // 获取中断号imx6uirq.irqkeydesc[i].irqnum = irq_of_parse_and_map(cnp, 0);// 设置中段值imx6uirq.irqkeydesc[i].value = key_value[i];/* 申请中断 */ret = request_irq(imx6uirq.irqkeydesc[i].irqnum, imx6uirq.irqkeydesc[i].handler, IRQF_TRIGGER_FALLING|IRQF_TRIGGER_RISING, imx6uirq.irqkeydesc[i].name, &imx6uirq);if(ret < 0){printk("irq ret: %d %d request failed!\r\n", ret,imx6uirq.irqkeydesc[i].irqnum);return -EFAULT;}}// not calc allif(i!=KEY_NUM){printk("node find not enought!\r\n");return -1;}/* 创建定时器 */init_timer(&imx6uirq.timer);imx6uirq.timer.function = timer_function;/* 初始化等待队列头 */init_waitqueue_head(&imx6uirq.r_wait);return 0;
}/** @description      : 打开设备* @param - inode     : 传递给驱动的inode* @param - filp   : 设备文件，file结构体有个叫做private_data的成员变量*                       一般在open的时候将private_data指向设备结构体。* @return             : 0 成功;其他 失败*/
static int imx6uirq_open(struct inode *inode, struct file *filp)
{filp->private_data = &imx6uirq;    /* 设置私有数据 */return 0;
}/** @description     : 从设备读取数据 * @param - filp    : 要打开的设备文件(文件描述符)* @param - buf     : 返回给用户空间的数据缓冲区* @param - cnt     : 要读取的数据长度* @param - offt    : 相对于文件首地址的偏移* @return          : 读取的字节数，如果为负值，表示读取失败*/
static ssize_t imx6uirq_read(struct file *filp, char __user *buf, size_t cnt, loff_t *offt)
{int ret = 0;unsigned char keyvalue = 0;unsigned char releasekey = 0;struct imx6uirq_dev *dev = (struct imx6uirq_dev *)filp->private_data;if (filp->f_flags & O_NONBLOCK) { /* 非阻塞访问 */if(atomic_read(&dev->releasekey) == 0)    /* 没有按键按下，返回-EAGAIN */return -EAGAIN;} else {                            /* 阻塞访问 *//* 加入等待队列，等待被唤醒,也就是有按键按下 */ret = wait_event_interruptible(dev->r_wait, atomic_read(&dev->releasekey)); if (ret) {goto wait_error;}}keyvalue = atomic_read(&dev->keyvalue);releasekey = atomic_read(&dev->releasekey);if (releasekey) { /* 有按键按下 */  if (keyvalue & 0x80) {keyvalue &= ~0x80;ret = copy_to_user(buf, &keyvalue, sizeof(keyvalue));} else {goto data_error;}atomic_set(&dev->releasekey, 0);/* 按下标志清零 */} else {goto data_error;}return 0;wait_error:return ret;
data_error:return -EINVAL;
}/** @description     : poll函数，用于处理非阻塞访问* @param - filp    : 要打开的设备文件(文件描述符)* @param - wait    : 等待列表(poll_table)* @return          : 设备或者资源状态，*/
unsigned int imx6uirq_poll(struct file *filp, struct poll_table_struct *wait)
{unsigned int mask = 0;struct imx6uirq_dev *dev = (struct imx6uirq_dev *)filp->private_data;poll_wait(filp, &dev->r_wait, wait);    /* 将等待队列头添加到poll_table中 */if(atomic_read(&dev->releasekey)) {        /* 按键按下 */mask = POLLIN | POLLRDNORM;          /* 返回PLLIN */}return mask;
}/* 设备操作函数 */
static struct file_operations imx6uirq_fops = {.owner = THIS_MODULE,.open = imx6uirq_open,.read = imx6uirq_read,.poll = imx6uirq_poll,
};/** @description : 驱动入口函数* @param       : 无* @return       : 无*/
static int __init imx6uirq_init(void)
{/* 1、构建设备号 */if (imx6uirq.major) {imx6uirq.devid = MKDEV(imx6uirq.major, 0);register_chrdev_region(imx6uirq.devid, KEY_NUM, IMX6UIRQ_NAME);} else {alloc_chrdev_region(&imx6uirq.devid, 0, KEY_NUM, IMX6UIRQ_NAME);imx6uirq.major = MAJOR(imx6uirq.devid);imx6uirq.minor = MINOR(imx6uirq.devid);}/* 2、注册字符设备 */cdev_init(&imx6uirq.cdev, &imx6uirq_fops);cdev_add(&imx6uirq.cdev, imx6uirq.devid, KEY_NUM);/* 3、创建类 */imx6uirq.class = class_create(THIS_MODULE, IMX6UIRQ_NAME);if (IS_ERR(imx6uirq.class)) { return PTR_ERR(imx6uirq.class);}/* 4、创建设备 */imx6uirq.device = device_create(imx6uirq.class, NULL, imx6uirq.devid, NULL, IMX6UIRQ_NAME);if (IS_ERR(imx6uirq.device)) {return PTR_ERR(imx6uirq.device);}/* 5、始化按键 */atomic_set(&imx6uirq.keyvalue, INVAKEY);atomic_set(&imx6uirq.releasekey, 0);keyio_init();return 0;
}/** @description  : 驱动出口函数* @param       : 无* @return       : 无*/
static void __exit imx6uirq_exit(void)
{unsigned i = 0;/* 删除定时器 */del_timer_sync(&imx6uirq.timer);    /* 删除定时器 *//* 释放中断 */   for (i = 0; i < KEY_NUM; i++) {free_irq(imx6uirq.irqkeydesc[i].irqnum, &imx6uirq);}cdev_del(&imx6uirq.cdev);unregister_chrdev_region(imx6uirq.devid, KEY_NUM);device_destroy(imx6uirq.class, imx6uirq.devid);class_destroy(imx6uirq.class);
}   module_init(imx6uirq_init);
module_exit(imx6uirq_exit);
MODULE_LICENSE("GPL");

4 应用测试

#include "stdio.h"
#include "unistd.h"
#include "sys/types.h"
#include "sys/stat.h"
#include "fcntl.h"
#include "stdlib.h"
#include "string.h"
#include "poll.h"
#include "sys/select.h"
#include "sys/time.h"
#include "linux/ioctl.h"
/***************************************************************
Copyright © ALIENTEK Co., Ltd. 1998-2029. All rights reserved.
文件名     : noblockApp.c
作者      : 左忠凯
版本      : V1.0
描述      : 非阻塞访问测试APP
其他      : 无
使用方法    ：./blockApp /dev/blockio 打开测试App
论坛      : www.openedv.com
日志      : 初版V1.0 2019/9/8 左忠凯创建
***************************************************************//** @description       : main主程序* @param - argc   : argv数组元素个数* @param - argv    : 具体参数* @return            : 0 成功;其他 失败*/
int main(int argc, char *argv[])
{int fd;int ret = 0;char *filename;struct pollfd fds;fd_set readfds;struct timeval timeout;unsigned char data;if (argc != 2) {printf("Error Usage!\r\n");return -1;}filename = argv[1];fd = open(filename, O_RDWR | O_NONBLOCK);  /* 非阻塞访问 */if (fd < 0) {printf("Can't open file %s\r\n", filename);return -1;}while (1) { FD_ZERO(&readfds);FD_SET(fd, &readfds);/* 构造超时时间 */timeout.tv_sec = 0;timeout.tv_usec = 500000; /* 500ms */ret = select(fd + 1, &readfds, NULL, NULL, &timeout);switch (ret) {case 0:   /* 超时 *//* 用户自定义超时处理 */break;case -1:   /* 错误 *//* 用户自定义错误处理 */break;default:  /* 可以读取数据 */if(FD_ISSET(fd, &readfds)) {ret = read(fd, &data, sizeof(data));if (ret < 0) {/* 读取错误 */} else {if (data)printf("key value=%d\r\n", data);}}break;}   }close(fd);return ret;
}

5 测试结果

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正点原子IMX6UL 多路按键中断实际案例

1 前言

2 修改设备树

3 创建字符驱动

4 应用测试

5 测试结果

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