linux 串口触摸屏调试记录

这几天在调试串口触摸屏，网上找了下似乎说的都不大清楚，这里记录下.

实现方法网上说有好几种，这里是将串口作为一个serio总线设备，利用linux内核提供serio总线驱动，通过设置对应的串口，调用serport提供的函数将串口当做serio总线设备，在驱动里面需要按照serio总线设备驱动的框架来实现，在内核源码drivers/input/touchscreen下提供了两个例子,touchright.c和touchit123.c，可以参考这两个例子编写驱动.我的驱动是在网上抄的，源码如下

/* *Egalax serial touchscreen driver * * Copyright (c) 2004-2016 * * Based on Touchright driver (drivers/input/touchscreen/touchit213.c) * * Zolt??n B??sz??rm??nyi <zboszor@xxxxx> *//* * 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/errno.h>#include <linux/kernel.h>#include <linux/module.h>#include <linux/slab.h>#include <linux/input.h>#include <linux/serio.h>#include <linux/init.h>#define DRIVER_DESC"EETI Egalax serial touchscreen driver"MODULE_AUTHOR("Zolt??n B??sz??rm??nyi <zboszor@xxxxx>");MODULE_DESCRIPTION(DRIVER_DESC);MODULE_LICENSE("GPL");/* * Definitions & global arrays. */#define SERIO_EGALAX0x3f#define EGALAX_FORMAT_MAX_LENGTH 6#define EGALAX_RESPONSE_BEGIN_BYTE 0x80#define EGALAX_FORMAT_PRESSURE_BIT 0x40#define EGALAX_FORMAT_TOUCH_BIT 0x01#define EGALAX_FORMAT_RESOLUTION 0x06#define EGALAX_MIN_XC 0#define EGALAX_MAX_XC 0x4000#define EGALAX_MIN_YC 0#define EGALAX_MAX_YC 0x4000#define EGALAX_GET_XC(data, resbits, shift) ((((data[1] & (resbits)) << 7) | (data[2] & 0x7f)) << shift)#define EGALAX_GET_YC(data, resbits, shift) ((((data[3] & (resbits)) << 7) | (data[4] & 0x7f)) << shift)#define EGALAX_GET_TOUCHED(data) (EGALAX_FORMAT_TOUCH_BIT & data[0])/* * Per-touchscreen data. */struct egalax {struct input_dev *dev;struct serio *serio;int idx;int bytes;int resbits;int shift;unsigned char data[EGALAX_FORMAT_MAX_LENGTH];char phys[32];};static void egalax_process_data(struct egalax *pegalax){struct input_dev *dev = pegalax->dev;if (++pegalax->idx == pegalax->bytes) {input_report_abs(dev, ABS_X, EGALAX_GET_XC(pegalax->data, pegalax->resbits, pegalax->shift));input_report_abs(dev, ABS_Y, EGALAX_GET_YC(pegalax->data, pegalax->resbits, pegalax->shift));//input_report_key(dev, BTN_TOUCH, EGALAX_GET_TOUCHED(pegalax->data));input_report_abs(dev, ABS_PRESSURE, EGALAX_GET_TOUCHED(pegalax->data));input_sync(dev);pegalax->idx = 0;}}static irqreturn_t egalax_interrupt(struct serio *serio,unsigned char data, unsigned int flags){struct egalax *pegalax = serio_get_drvdata(serio);pegalax->data[pegalax->idx] = data;if (EGALAX_RESPONSE_BEGIN_BYTE & pegalax->data[0]) {pegalax->bytes = (EGALAX_FORMAT_PRESSURE_BIT & pegalax->data[0] ? 6 : 5);switch ((EGALAX_FORMAT_RESOLUTION & pegalax->data[0]) >> 1) {case 0:pegalax->resbits = 0x0f;pegalax->shift = 3;break;case 1:pegalax->resbits = 0x1f;pegalax->shift = 2;break;case 2:pegalax->resbits = 0x3f;pegalax->shift = 1;break;default:pegalax->resbits = 0x7f;pegalax->shift = 0;break;}egalax_process_data(pegalax);}elsedev_dbg(&serio->dev, "unknown/unsynchronized data: %x\n",pegalax->data[0]);return IRQ_HANDLED;}static void egalax_disconnect(struct serio *serio){struct egalax *pegalax = serio_get_drvdata(serio);input_get_device(pegalax->dev);input_unregister_device(pegalax->dev);serio_close(serio);serio_set_drvdata(serio, NULL);input_put_device(pegalax->dev);kfree(pegalax);}/* * egalax_connect() is the routine that is called when someone adds a * new serio device that supports egalax protocol and registers it as * an input device. This is usually accomplished using inputattach. */static int egalax_connect(struct serio *serio, struct serio_driver *drv){struct egalax *pegalax;struct input_dev *input_dev;int err;pegalax = kzalloc(sizeof(struct egalax), GFP_KERNEL);input_dev = input_allocate_device();if (!pegalax || !input_dev) {err = -ENOMEM;goto fail1;}pegalax->serio = serio;pegalax->dev = input_dev;snprintf(pegalax->phys, sizeof(pegalax->phys), "%s/input1", serio->phys);input_dev->name = "EETI eGalaxTouch Serial TouchScreen";input_dev->phys = pegalax->phys;input_dev->id.bustype = BUS_RS232;input_dev->id.vendor = SERIO_EGALAX;input_dev->id.product = 0;input_dev->id.version = 0x0001;input_dev->dev.parent = &serio->dev;input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);//input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);input_set_abs_params(pegalax->dev, ABS_X,     EGALAX_MIN_XC, EGALAX_MAX_XC, 0, 0);input_set_abs_params(pegalax->dev, ABS_Y,     EGALAX_MIN_YC, EGALAX_MAX_YC, 0, 0);input_set_abs_params(pegalax->dev, ABS_PRESSURE, 0, 1, 0, 0);serio_set_drvdata(serio, pegalax);err = serio_open(serio, drv);if (err)goto fail2;err = input_register_device(pegalax->dev);if (err)goto fail3;return 0;fail3:serio_close(serio);fail2:serio_set_drvdata(serio, NULL);fail1:input_free_device(input_dev);kfree(pegalax);return err;}/* * The serio driver structure. */static struct serio_device_id egalax_serio_ids[] = {{.type= SERIO_RS232,.proto= SERIO_EGALAX,.id= SERIO_ANY,.extra= SERIO_ANY,},{ 0 }};MODULE_DEVICE_TABLE(serio, egalax_serio_ids);static struct serio_driver egalax_drv = {.driver= {.name= "egalax",},.description= DRIVER_DESC,.id_table= egalax_serio_ids,.interrupt= egalax_interrupt,.connect= egalax_connect,.disconnect= egalax_disconnect,};/* * The functions for inserting/removing us as a module. */static int __init egalax_init(void){return serio_register_driver(&egalax_drv);}static void __exit egalax_exit(void){serio_unregister_driver(&egalax_drv);}module_init(egalax_init);module_exit(egalax_exit);

只是修改了最后一点,其中egalax_serio_ids中的几个参数在应用程序中需要用到，加上驱动编译内核更新后，此时这个驱动是没有起作用的，需要通过应用程序将串口与之绑定，后才能正常工作.

应用程序如下,这个代码网上也有

/*************************************NAME:seriotouch.c*************************************/#include <stdio.h>#include <unistd.h>#include <stdlib.h>#include <sys/types.h>#include <sys/stat.h>#include <sys/ioctl.h>#include <fcntl.h>#include <linux/fs.h>#include <errno.h>#include <string.h>#include <linux/fb.h>#include <malloc.h>#include <sys/mman.h>#include <termio.h>#include <linux/serio.h>#define SERIO_ANY0xff#define SERIO_EGALAX0x3fint main(int argc, char* argv[]){int dev,ret;char comdev[20];int ldisc;unsigned long type;struct termios option;int fd = -1;if(argc != 2){printf("-----------------------------------------\n");printf("\nUsage: %s [serial device(1-5)]\n", argv[0]);printf("Example: %s 5 n", argv[0]);printf("-----------------------------------------\n");return 0;}dev = strtol(argv[1],NULL,10);sprintf(comdev,"/dev/ttyAMA%d",dev);fd = open(comdev,O_RDWR|O_NONBLOCK|O_NOCTTY);if (fd < 0) {perror(comdev);exit(1);}tcgetattr(fd, &option);    option.c_iflag = IGNPAR | IGNBRK;option.c_cflag = HUPCL | CS8 | CREAD | CLOCAL | B9600;option.c_cc[VMIN] = 1;option.c_cc[VTIME] = 0;cfsetispeed(&option,B9600);cfsetospeed(&option,B9600);ret = tcsetattr(fd, TCSANOW, &option);if(ret < 0) {perror("TCSANOW");exit(1);}ldisc = N_MOUSE;ret = ioctl(fd,TIOCSETD,&ldisc);if(ret) {perror("TIOCSETD");}type = SERIO_EGALAX | (SERIO_ANY << 8) | (SERIO_ANY << 16);ret = ioctl(fd,SPIOCSTYPE, &type);if(ret) {perror("SPIOCSTYPE");}read(fd,NULL,0);//close(fd);return 0;}

需要注意的是，应用程序最后这个read一定要执行，不然驱动里不会进行连接.

编译生成可执行文件seriotouch

应用程序配制完串口后需要与之前的驱动连接，看设置spiocstype的设置，需要保证这里的几个参数与驱动进行对应。

系统启动后执行seriotouch 5 &

后面这个５对应的是串口号,执行这个后会看到驱动里的connect执行了，同时会生成一个input节点，如下图

此时将tslib里的tsdevice修改为这个，进行校准后，就可以正常使用了