linux 串口触摸屏调试记录

ゝ一纸荒年。 2022-07-26 04:23 479阅读 0赞

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

  1. /*
  2.  *Egalax serial touchscreen driver
  3.  *
  4.  * Copyright (c) 2004-2016
  5.  *
  6.  * Based on Touchright driver (drivers/input/touchscreen/touchit213.c)
  7.  *
  8.  * Zolt??n B??sz??rm??nyi <zboszor@xxxxx>
  9.  */
  10. /*
  11.  * This program is free software; you can redistribute it and/or modify it
  12.  * under the terms of the GNU General Public License version 2 as published
  13.  * by the Free Software Foundation.
  14.  */
  16. #include <linux/errno.h>
  17. #include <linux/kernel.h>
  18. #include <linux/module.h>
  19. #include <linux/slab.h>
  20. #include <linux/input.h>
  21. #include <linux/serio.h>
  22. #include <linux/init.h>
  24. #define DRIVER_DESC    "EETI Egalax serial touchscreen driver"
  26. MODULE_AUTHOR("Zolt??n B??sz??rm??nyi <zboszor@xxxxx>");
  27. MODULE_DESCRIPTION(DRIVER_DESC);
  28. MODULE_LICENSE("GPL");
  30. /*
  31.  * Definitions & global arrays.
  32.  */
  33. #define SERIO_EGALAX    0x3f
  34. #define EGALAX_FORMAT_MAX_LENGTH 6
  35. #define EGALAX_RESPONSE_BEGIN_BYTE 0x80
  36. #define EGALAX_FORMAT_PRESSURE_BIT 0x40
  37. #define EGALAX_FORMAT_TOUCH_BIT 0x01
  38. #define EGALAX_FORMAT_RESOLUTION 0x06
  40. #define EGALAX_MIN_XC 0
  41. #define EGALAX_MAX_XC 0x4000
  42. #define EGALAX_MIN_YC 0
  43. #define EGALAX_MAX_YC 0x4000
  45. #define EGALAX_GET_XC(data, resbits, shift) ((((data[1] & (resbits)) << 7) | (data[2] & 0x7f)) << shift)
  46. #define EGALAX_GET_YC(data, resbits, shift) ((((data[3] & (resbits)) << 7) | (data[4] & 0x7f)) << shift)
  47. #define EGALAX_GET_TOUCHED(data) (EGALAX_FORMAT_TOUCH_BIT & data[0])
  49. /*
  50.  * Per-touchscreen data.
  51.  */
  53. struct egalax {
  54.     struct input_dev *dev;
  55.     struct serio *serio;
  56.     int idx;
  57.     int bytes;
  58.     int resbits;
  59.     int shift;
  60.     unsigned char data[EGALAX_FORMAT_MAX_LENGTH];
  61.     char phys[32];
  62. };
  64. static void egalax_process_data(struct egalax *pegalax)
  65. {
  66.     struct input_dev *dev = pegalax->dev;
  68.     if (++pegalax->idx == pegalax->bytes) {
  69.         input_report_abs(dev, ABS_X, EGALAX_GET_XC(pegalax->data, pegalax->resbits, pegalax->shift));
  70.         input_report_abs(dev, ABS_Y, EGALAX_GET_YC(pegalax->data, pegalax->resbits, pegalax->shift));
  71.         //input_report_key(dev, BTN_TOUCH, EGALAX_GET_TOUCHED(pegalax->data));
  72.         input_report_abs(dev, ABS_PRESSURE, EGALAX_GET_TOUCHED(pegalax->data));
  73.         input_sync(dev);
  74.         pegalax->idx = 0;
  75.     }
  76. }
  78. static irqreturn_t egalax_interrupt(struct serio *serio,
  79.         unsigned char data, unsigned int flags)
  80. {
  81.     struct egalax *pegalax = serio_get_drvdata(serio);
  83.     pegalax->data[pegalax->idx] = data;
  84.     if (EGALAX_RESPONSE_BEGIN_BYTE & pegalax->data[0]) {
  85.         pegalax->bytes = (EGALAX_FORMAT_PRESSURE_BIT & pegalax->data[0] ? 6 : 5);
  86.         switch ((EGALAX_FORMAT_RESOLUTION & pegalax->data[0]) >> 1) {
  87.         case 0:
  88.             pegalax->resbits = 0x0f;
  89.             pegalax->shift = 3;
  90.             break;
  91.         case 1:
  92.             pegalax->resbits = 0x1f;
  93.             pegalax->shift = 2;
  94.             break;
  95.         case 2:
  96.             pegalax->resbits = 0x3f;
  97.             pegalax->shift = 1;
  98.             break;
  99.         default:
  100.             pegalax->resbits = 0x7f;
  101.             pegalax->shift = 0;
  102.             break;
  103.         }
  104.         egalax_process_data(pegalax);
  105.     }
  106.     else
  107.         dev_dbg(&serio->dev, "unknown/unsynchronized data: %x\n",
  108.             pegalax->data[0]);
  110.     return IRQ_HANDLED;
  111. }
  113. static void egalax_disconnect(struct serio *serio)
  114. {
  115.     struct egalax *pegalax = serio_get_drvdata(serio);
  116.     input_get_device(pegalax->dev);
  117.     input_unregister_device(pegalax->dev);
  118.     serio_close(serio);
  119.     serio_set_drvdata(serio, NULL);
  120.     input_put_device(pegalax->dev);
  121.     kfree(pegalax);
  122. }
  124. /*
  125.  * egalax_connect() is the routine that is called when someone adds a
  126.  * new serio device that supports egalax protocol and registers it as
  127.  * an input device. This is usually accomplished using inputattach.
  128.  */
  130. static int egalax_connect(struct serio *serio, struct serio_driver *drv)
  131. {
  132.     struct egalax *pegalax;
  133.     struct input_dev *input_dev;
  134.     int err;
  135.     pegalax = kzalloc(sizeof(struct egalax), GFP_KERNEL);
  136.     input_dev = input_allocate_device();
  137.     if (!pegalax || !input_dev) {
  138.         err = -ENOMEM;
  139.         goto fail1;
  140.     }
  142.     pegalax->serio = serio;
  143.     pegalax->dev = input_dev;
  144.     snprintf(pegalax->phys, sizeof(pegalax->phys),
  145.          "%s/input1", serio->phys);
  147.     input_dev->name = "EETI eGalaxTouch Serial TouchScreen";
  148.     input_dev->phys = pegalax->phys;
  149.     input_dev->id.bustype = BUS_RS232;
  150.     input_dev->id.vendor = SERIO_EGALAX;
  151.     input_dev->id.product = 0;
  152.     input_dev->id.version = 0x0001;
  153.     input_dev->dev.parent = &serio->dev;
  154.     input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
  155.     //input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
  156.     input_set_abs_params(pegalax->dev, ABS_X,
  157.                  EGALAX_MIN_XC, EGALAX_MAX_XC, 0, 0);
  158.     input_set_abs_params(pegalax->dev, ABS_Y,
  159.                  EGALAX_MIN_YC, EGALAX_MAX_YC, 0, 0);
  160.     input_set_abs_params(pegalax->dev, ABS_PRESSURE, 0, 1, 0, 0);
  161.     serio_set_drvdata(serio, pegalax);
  163.     err = serio_open(serio, drv);
  164.     if (err)
  165.         goto fail2;
  167.     err = input_register_device(pegalax->dev);
  168.     if (err)
  169.         goto fail3;
  171.     return 0;
  173. fail3:    serio_close(serio);
  174. fail2:    serio_set_drvdata(serio, NULL);
  175. fail1:    input_free_device(input_dev);
  176.     kfree(pegalax);
  177.     return err;
  178. }
  180. /*
  181.  * The serio driver structure.
  182.  */
  184. static struct serio_device_id egalax_serio_ids[] = {
  185.     {
  186.         .type    = SERIO_RS232,
  187.         .proto    = SERIO_EGALAX,
  188.         .id    = SERIO_ANY,
  189.         .extra    = SERIO_ANY,
  190.     },
  191.     { 0 }
  192. };
  194. MODULE_DEVICE_TABLE(serio, egalax_serio_ids);
  196. static struct serio_driver egalax_drv = {
  197.     .driver        = {
  198.         .name    = "egalax",
  199.     },
  200.     .description    = DRIVER_DESC,
  201.     .id_table    = egalax_serio_ids,
  202.     .interrupt    = egalax_interrupt,
  203.     .connect    = egalax_connect,
  204.     .disconnect    = egalax_disconnect,
  205. };
  207. /*
  208.  * The functions for inserting/removing us as a module.
  209.  */
  211. static int __init egalax_init(void)
  212. {
  213.     return serio_register_driver(&egalax_drv);
  214. }
  216. static void __exit egalax_exit(void)
  217. {
  218.     serio_unregister_driver(&egalax_drv);
  219. }
  221. module_init(egalax_init);
  222. 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

  1. /*************************************
  3. NAME:seriotouch.c
  5. *************************************/
  7. #include <stdio.h>
  8. #include <unistd.h>
  9. #include <stdlib.h>
  10. #include <sys/types.h>
  11. #include <sys/stat.h>
  12. #include <sys/ioctl.h>
  13. #include <fcntl.h>
  14. #include <linux/fs.h>
  15. #include <errno.h>
  16. #include <string.h>
  17. #include <linux/fb.h>
  18. #include <malloc.h>
  19. #include <sys/mman.h>
  20. #include <termio.h>
  21. #include <linux/serio.h>
  23. #define SERIO_ANY    0xff
  24. #define SERIO_EGALAX    0x3f
  26. int main(int argc, char* argv[])
  27. {
  28.     int dev,ret;
  29.     char comdev[20];
  30.     int ldisc;
  31.     unsigned long type;
  32.     struct termios option;
  33.     int fd = -1;
  34.     if(argc != 2)
  35.     {
  36.         printf("-----------------------------------------\n");
  37.         printf("\nUsage: %s [serial device(1-5)]\n", argv[0]);
  38.         printf("Example: %s 5 n", argv[0]);
  39.         printf("-----------------------------------------\n");
  40.         return 0;
  41.     }
  43.     dev = strtol(argv[1],NULL,10);
  44.     sprintf(comdev,"/dev/ttyAMA%d",dev);
  45.     fd = open(comdev,O_RDWR|O_NONBLOCK|O_NOCTTY);
  46.     if (fd < 0) {
  47.         perror(comdev);
  48.         exit(1);
  49.     }
  51.     tcgetattr(fd, &option);
  52.     option.c_iflag = IGNPAR | IGNBRK;
  53.     option.c_cflag = HUPCL | CS8 | CREAD | CLOCAL | B9600;
  54.     option.c_cc[VMIN] = 1;
  55.     option.c_cc[VTIME] = 0;
  57.     cfsetispeed(&option,B9600);
  58.     cfsetospeed(&option,B9600);
  60.     ret = tcsetattr(fd, TCSANOW, &option);
  61.     if(ret < 0) {
  62.         perror("TCSANOW");
  63.         exit(1);
  64.     }
  66.     ldisc = N_MOUSE;
  67.     ret = ioctl(fd,TIOCSETD,&ldisc);
  68.     if(ret) {
  69.         perror("TIOCSETD");
  70.     }
  71.     type = SERIO_EGALAX | (SERIO_ANY << 8) | (SERIO_ANY << 16);
  72.     ret = ioctl(fd,SPIOCSTYPE, &type);
  73.     if(ret) {
  74.         perror("SPIOCSTYPE");
  75.     }
  76.     read(fd,NULL,0);
  77.     //close(fd);
  78.     return 0;
  79. }

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

SouthEast

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

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