驱动之路三--------button驱动(input设备)

开发板：smdk6410

系统：Linux

按键是经常要用的，通过按键产生中断，可以处理不同的功能，键盘的输入就是这么一个原理，

键盘也可以作为一个字符设备去写，在 驱动之路二 中就详细阐述过设备分类的概念，也将LED驱动写成了misc设备的，在这要将button驱动基于input设备去写，现在开始写了，

先是头文件 s3c_button.h

#ifndef __BUTTON_H#define __BUTTON_H#include <linux/device.h>#include <linux/interrupt.h>#include <linux/input.h>struct button_info {char name[32];int user;int status;void __iomem *v;struct input_dev *dev;//input设备结构体int irq;//中断线int code;irqreturn_t (*do_button)(int no, void *data);。。中断处理函数};#define S3C_PA_BUTTON0x7f008000#define S3C_SZ_BUTTONSZ_4K#define GPNDAT0x834#define S3C_IRQ_BUTTON_SIRQ_EINT(0)#define S3C_IRQ_BUTTON_EIRQ_EINT(5)#define S3C_NUM_BUTTON 6#endif

头文件还是就一个button_info结构体，用于描述button这个设备，再就是相关宏定义，

设备文件的修改和之前的之前写的LED驱动相比，改动不大，

#include <linux/init.h>#include <linux/module.h>#include <linux/device.h>#include <linux/platform_device.h>#include "s3c_button.h"void b_release(struct device *dev){printk("Device is released\n");}//写button就需要两种资源了，这个需要注意struct resource b_res[] = {[0] = {.start = S3C_PA_BUTTON,.end = S3C_PA_BUTTON + S3C_SZ_BUTTON - 1,.flags = IORESOURCE_MEM,},[1] = {.start = S3C_IRQ_BUTTON_S,.end = S3C_IRQ_BUTTON_E,.flags = IORESOURCE_IRQ,}};struct platform_device dev = {.name = "s3c-button",.id = -1,.num_resources = ARRAY_SIZE(b_res),.resource = b_res,.dev = {.release = b_release,}};static __init int module_test_init(void){return platform_device_register(&dev);}static __exit void module_test_exit(void){platform_device_unregister(&dev);}module_init(module_test_init);module_exit(module_test_exit);MODULE_LICENSE("GPL");MODULE_AUTHOR("Musesea");MODULE_VERSION("1.0");MODULE_DESCRIPTION("Test for module");

设备文件没什么好说的。

下面是驱动文件

#include <linux/init.h>#include <linux/module.h>#include <asm/uaccess.h>#include <asm/io.h>#include <linux/device.h>#include <linux/slab.h>#include <linux/platform_device.h>#include <linux/input.h>#include "s3c_button.h"int if_down(struct button_info *b){//GPNDAT[5-0]return !(readl(b->v + GPNDAT) & (1 << (b->irq - S3C_IRQ_BUTTON_S)));}irqreturn_t button_handle(int no, void *data){struct button_info *b = data;if(if_down(b)){input_report_key(b->dev, b->code, 1);//上报事件，注意内核需要支持上报input_sync(b->dev);//不同步是什么事件都不能上报的}else{input_report_key(b->dev, b->code, 0);input_sync(b->dev);}return IRQ_HANDLED;}void s3c_button_exit(struct button_info *b){}void s3c_button_init(struct button_info *b, int start){int i;for(i = 0; i < S3C_NUM_BUTTON; i++){sprintf(b[i].name, "button%d", i);b[i].user = 0;b[i].irq = start + i;b[i].dev = b[0].dev;b[i].v = b[0].v;b[i].do_button = button_handle;}        //键码，就是每个键代表的意思        b[0].code = KEY_UP;b[1].code = KEY_DOWN;b[2].code = KEY_LEFT;b[3].code = KEY_RIGHT;b[4].code = KEY_ESC;b[5].code = KEY_ENTER;}int b_probe(struct platform_device *pdev){int ret;int i;struct resource *g_res, *irq_res;struct button_info *button;g_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);//获取资源irq_res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);if(!g_res || !irq_res)return -EBUSY;button = kzalloc(sizeof(struct button_info) * S3C_NUM_BUTTON, GFP_KERNEL);if(!button)return -ENOMEM;button->v = ioremap(g_res->start, g_res->end - g_res->start + 1);if(!button->v){ret = -ENOMEM;goto remap_error;}button->dev = input_allocate_device();//分配input设备if(!button->dev){ret = -ENOMEM;goto alloc_dev_error;}button->dev->name = pdev->name;button->dev->uniq = "20131113";button->dev->phys = "/dev/eventx";button->dev->id.bustype = BUS_HOST;button->dev->id.vendor = 110;button->dev->id.product = 120;button->dev->id.version = 119;//evbit[0] |= 1 << EV_KEY;//设置该设备要支持的事件类型set_bit(EV_KEY, button->dev->evbit);set_bit(EV_SYN, button->dev->evbit);//设置该设备要支持的key事件set_bit(KEY_UP, button->dev->keybit);set_bit(KEY_DOWN, button->dev->keybit);set_bit(KEY_LEFT, button->dev->keybit);set_bit(KEY_RIGHT, button->dev->keybit);set_bit(KEY_ESC, button->dev->keybit);set_bit(KEY_ENTER, button->dev->keybit);ret = input_register_device(button->dev);//注册input设备if(ret)goto register_error;platform_set_drvdata(pdev, button);//将button保存到pdev中s3c_button_init(button, irq_res->start);for(i = 0; i < S3C_NUM_BUTTON; i++)                //申请中断                ret = request_irq(button[i].irq, button[i].do_button, IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING, button[i].name, &button[i]);if(ret)goto request_irq_error;return 0;request_irq_error:while(i--)free_irq(button[i].irq, &button[i]);register_error:input_free_device(button->dev);alloc_dev_error:iounmap(button->v);remap_error:kfree(button);return ret;}int b_remove(struct platform_device *pdev){int i = 6;struct button_info *button;button = platform_get_drvdata(pdev);while(i--)free_irq(button[i].irq, &button[i]);s3c_button_exit(button);input_unregister_device(button->dev);input_free_device(button->dev);iounmap(button->v);kfree(button);return 0;}struct platform_driver drv = {.driver = {.name = "s3c-button",},.probe = b_probe,.remove = b_remove,};static __init int module_test_init(void){return platform_driver_register(&drv);}static __exit void module_test_exit(void){platform_driver_unregister(&drv);}module_init(module_test_init);module_exit(module_test_exit);MODULE_LICENSE("GPL");MODULE_AUTHOR("Musesea");MODULE_VERSION("1.0");MODULE_DESCRIPTION("Test for module");

OK了！又一个驱动算是完了。

还是那句话，大家若是发现什么问题一定要告诉我，大家一起学习