Linux2.6内核下键盘输入设备驱动的实现

实验环境：1）Ubuntu9.10 OS

2）arm-linux-gcc 4.3.2交叉编译器

3）勤研S3C2440开发板(Linux2.6.29内核)

实现的功能：键盘驱动通过input子系统将按键事件上报给上层的应用程序，应用程序将相应的按键事件打印出来

关于input子系统的相关知识可以参考博文《Linux设备模型之input子系统详解》

http://blogold.chinaunix.net/u1/51562/showart_1090628.html

废话不多说，附上源码：

1) s3c2440键盘驱动源代码，参考2.6.29内核中触摸屏驱动s3c2410_ts.c实现

/* * Copyright (c) 2011 Shen Yunlong * syl272365943@126.com * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 as published by * the Free Software Foundation. */#include <linux/kernel.h>#include <linux/module.h>#include <linux/input.h>#include <linux/errno.h>#include <linux/irq.h>#include <asm/io.h>#include <mach/regs-gpio.h>#include <mach/irqs.h>#include <linux/interrupt.h>#include <linux/irqreturn.h>#include <mach/regs-irq.h>#include <linux/bitops.h>MODULE_LICENSE("GPL");MODULE_AUTHOR("SYL_USST");static struct input_dev *dev;static char *s3c2440_keyboard_name = "s3c2440_keyboard_syl";/** * Set GPF0,GPF1,GPF2,GPF3 ports used as EINT[0],EINT[1],EINT[2],EINT[3] * Set GPG0,GPG1 used as EINT[8],EINT[9] */static inline void s3c2440_keyboard_connect(void){s3c2410_gpio_cfgpin(S3C2410_GPF0, S3C2410_GPF0_EINT0);s3c2410_gpio_cfgpin(S3C2410_GPF1, S3C2410_GPF1_EINT1);s3c2410_gpio_cfgpin(S3C2410_GPF2, S3C2410_GPF2_EINT2);s3c2410_gpio_cfgpin(S3C2410_GPF3, S3C2410_GPF3_EINT3);s3c2410_gpio_cfgpin(S3C2410_GPG0, S3C2410_GPG0_EINT8);s3c2410_gpio_cfgpin(S3C2410_GPG1, S3C2410_GPG1_EINT9);}/** * Interrupt Handlers of EINT[0]~EINT[3] & EINT[8] & EINT[9] * * Note: once the ISR has reported a key with a specified value, * then the next time it (the key with the same value) will be 'filtered'. * It means that the program in user-space can not get the input_event from the kernel. */static irqreturn_t keyboard_sw1_action(int irq, void *dev_id){//printk(KERN_INFO "sw1 is pressed !/n");unsigned int updown = ioread32(S3C2410_GPFDAT) & 0x1;if(updown)/* the key BTN_0 is raised */input_report_key(dev, BTN_0, 0);else/* the key BTN_0 is pressed*/input_report_key(dev, BTN_0, 1);input_sync(dev);return IRQ_HANDLED;}static irqreturn_t keyboard_sw2_action(int irq, void *dev_id){//printk(KERN_INFO "sw2 is pressed !/n");unsigned int updown = ioread32(S3C2410_GPFDAT) & (0x1<<1);if(updown)input_report_key(dev, BTN_1, 0);elseinput_report_key(dev, BTN_1, 1);input_sync(dev);return IRQ_HANDLED;}static irqreturn_t keyboard_up_action(int irq, void *dev_id){//printk(KERN_INFO "up is pressed !/n");unsigned int updown = ioread32(S3C2410_GPFDAT) & (0x1<<2);if(updown)input_report_key(dev, BTN_2, 0);elseinput_report_key(dev, BTN_2, 1);input_sync(dev);return IRQ_HANDLED;}static irqreturn_t keyboard_down_action(int irq, void *dev_id){//printk(KERN_INFO "down is pressed !/n");unsigned int updown = ioread32(S3C2410_GPFDAT) & (0x1<<3);if(updown)input_report_key(dev, BTN_3, 0);elseinput_report_key(dev, BTN_3, 1);input_sync(dev);return IRQ_HANDLED;}static irqreturn_t keyboard_left_action(int irq, void *dev_id){//printk(KERN_INFO "left is pressed !/n");unsigned int updown = ioread32(S3C2410_GPGDAT) & 0x1;if(updown)input_report_key(dev, BTN_4, 0);elseinput_report_key(dev, BTN_4, 1);input_sync(dev);return IRQ_HANDLED;}static irqreturn_t keyboard_right_action(int irq, void *dev_id){//printk(KERN_INFO "right is pressed !/n");unsigned int updown = ioread32(S3C2410_GPGDAT) & (0x1<<1);if(updown)input_report_key(dev, BTN_5, 0);elseinput_report_key(dev, BTN_5, 1);input_sync(dev);return IRQ_HANDLED;}/** * s3c2440 my_keyboard module initialization */static int __init s3c2440_keyboard_init(void){printk("s3c2440 my_keyboard module start/n");struct input_dev *input_dev;/* Configure S3C2440 GPIOs*/s3c2440_keyboard_connect();printk("GPIO has configured/n");/* Set EINT0~EINT3 and EINT8,EINT9 rising edge triggered*/set_irq_type(IRQ_EINT0, IRQ_TYPE_EDGE_BOTH);set_irq_type(IRQ_EINT1, IRQ_TYPE_EDGE_BOTH);set_irq_type(IRQ_EINT2, IRQ_TYPE_EDGE_BOTH);set_irq_type(IRQ_EINT3, IRQ_TYPE_EDGE_BOTH);set_irq_type(IRQ_EINT8, IRQ_TYPE_EDGE_BOTH);set_irq_type(IRQ_EINT9, IRQ_TYPE_EDGE_BOTH);input_dev = input_allocate_device();if(!input_dev){printk(KERN_ERR "Unable to allocate the input device!!/n");return -ENOMEM;}dev = input_dev;dev->evbit[0] = BIT(EV_SYN) | BIT(EV_KEY);/* Do Not forget to set keybit[] of BTN_0--BTN_5*/dev->keybit[BIT_WORD(BTN_0)] = BIT_MASK(BTN_0) | BIT_MASK(BTN_1) | BIT_MASK(BTN_2) | BIT_MASK(BTN_3) | BIT_MASK(BTN_4) | BIT_MASK(BTN_5);dev->name = s3c2440_keyboard_name;//dev->id.bustype//dev->id.vendor//dev->id.product//dev->id.versionprintk("input device has allocated/n");/* Register an Interrupt Handler to IRQ_EINT0*/if(request_irq(IRQ_EINT0, keyboard_sw1_action, IRQF_SAMPLE_RANDOM, "s3c2440_keyboard_action", dev)){printk(KERN_ERR "my_keyboard.c: Could not allocate keyboard IRQ_EINT0 !/n");return -EIO;}if(request_irq(IRQ_EINT1, keyboard_sw2_action, IRQF_SAMPLE_RANDOM, "s3c2440_keyboard_action", dev)){printk(KERN_ERR "my_keyboard.c: Could not allocate keyboard IRQ_EINT1 !/n");return -EIO;}if(request_irq(IRQ_EINT2, keyboard_up_action, IRQF_SAMPLE_RANDOM, "s3c2440_keyboard_action", dev)){printk(KERN_ERR "my_keyboard.c: Could not allocate keyboard IRQ_EINT2 !/n");return -EIO;}if(request_irq(IRQ_EINT3, keyboard_down_action, IRQF_SAMPLE_RANDOM, "s3c2440_keyboard_action", dev)){printk(KERN_ERR "my_keyboard.c: Could not allocate keyboard IRQ_EINT3 !/n");return -EIO;}if(request_irq(IRQ_EINT8, keyboard_left_action, IRQF_SAMPLE_RANDOM, "s3c2440_keyboard_action", dev)){printk(KERN_ERR "my_keyboard.c: Could not allocate keyboard IRQ_EINT8 !/n");return -EIO;}if(request_irq(IRQ_EINT9, keyboard_right_action, IRQF_SAMPLE_RANDOM, "s3c2440_keyboard_action", dev)){printk(KERN_ERR "my_keyboard.c: Could not allocate keyboard IRQ_EINT9 !/n");return -EIO;}printk(KERN_INFO "%s successfully loaded/n", s3c2440_keyboard_name);input_register_device(dev);return 0;}/** * s3c2440 my_keyboard module exit function */static void __exit s3c2440_keyboard_exit(void){disable_irq(IRQ_EINT0);disable_irq(IRQ_EINT1);disable_irq(IRQ_EINT2);disable_irq(IRQ_EINT3);disable_irq(IRQ_EINT8);disable_irq(IRQ_EINT9);free_irq(IRQ_EINT0, dev);free_irq(IRQ_EINT1, dev);free_irq(IRQ_EINT2, dev);free_irq(IRQ_EINT3, dev);free_irq(IRQ_EINT8, dev);free_irq(IRQ_EINT9, dev);input_unregister_device(dev);}module_init(s3c2440_keyboard_init);module_exit(s3c2440_keyboard_exit);

2) 一个简单的上层应用程序，通过读取键盘对应的设备文件将input子系统上报的键盘事件打印出来

以上代码在勤研2440的开发板上测试成功！

这是鄙人第一个完成的linux设备驱动，兴奋之余，知道以上内容肯定会有不足甚至错误之处，希望有兴趣的童鞋可以不吝赐教。

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