基于FT5x06嵌入式Linux电容触摸屏驱动

嵌入式

基于FT5x06嵌入式Linux电容触摸屏驱动

2019-07-13 00:17发布生成海报

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作者：EasyWave 时间：2013.02.06 类别：Linux 内核驱动源码分析声明：转载，请保留链接 注意：如有错误，欢迎指正。这些是我学习的日志文章...... *************************************************************************************************************************** 一:FT5X06电容触摸IC简介 FT5x06系列ICs是单芯片电容式触摸屏控制器IC，带有一个内置的8位微控制器单元（MCU）。采用互电容的方法，在配合的相互的电容式触摸面板，它支持真正的多点触摸功能。FT5x06具有用户友好的输入的功能，这可以应用在许多便携式设备，例如蜂窝式电话，移动互联网设备，上网本和笔记本个人电脑。FT5x06系列IC包括FT5206/FT5306/FT5406。具体的功能如下图所示：

二：硬件接口设计 从FT5X06的datasheet中，我们可以看到，FT5X06既可以工作的SPI的接口方式，也可以工作在I2C的接口方式，不管工作在SPI，还是工作在I2C，从硬件的接口设计上来说，这下面的几个控制口，都是需要要接的。如下图所示：

1）：INT引脚，这个脚是一个中端信号，它用来通知HOST端FT5X06已经准备好，可以进行读操作了。 2）：WAKE引脚：这个功能主要的作用是将FT5X06从睡眠状态转换到工作状态。 3）：/RST引脚：FT5X06的芯片复位信号。如何来设计硬件接口呢，这个我们可以从FT5X06的datasheet看出来，首先我们来看下FT5X06的上电时序，如下图所示：

FT5X06的上电时序

FT5X06的RESET时序

FT5X06的wakeup时序 各自的最小的时间限制如下所所示：

因此，从上面的图片和表格中，我们可以看出，在poweron中，必须确保在上电后，wakeup的电平为高电平，至于INT信号，只要确保无INT信号时，这个INT为高即可，这个可以从poweron的时序可以看出，它是一个低电平的动作，这个是驱动中来做的事情了。接下来就是确定I2C的从地址，如下图所示：[以下引用自网络]

从地址高位必须为：3，低位必须根据i2ccon设定的值来确定。

根据FT5406数据手册上的指令，我们先了解下驱动如何实现电容屏的多点触摸，其实很简单，主要需要触摸屏IC FT5406 能够捕获多点数据，这点电容屏基本多能支持到捕获2点以上，而FT5406 可以捕获5个触摸点，编写驱动时，只要去获取这几个点的数据，然后上报就可以了。如下图所示：[以下引用自网络]

02H ：捕获的触摸点个数 03H- 1EH ：对应每个点的x,y坐标数值。 三：Linux驱动源码 I2C的驱动需要根据具体的ARM芯片，一般来说，IC原厂，一般会将在linux的bsp中都会有I2C的驱动，这个部分不需要我们去写的，我们只需要将FT5X06和BSP包中的I2C驱动匹配起来就好了。而整个FT5X06也是这样做的。在linu内核中关于i2c的一般会有这个函数：i2c_board_info（）i2c_board_info用于构建信息表来列出存在的I2C设备。这一信息用于增长新型I2C驱动的驱动模型树。对于主板，它使用i2c_register_board_info()来静态创建。对于子板，利用已知的适配器使用i2c_new_device()动态创建。 [cpp] view plain copy print ?

struct i2c_board_info {
char type[I2C_NAME_SIZE];
unsigned short flags;
unsigned short addr;
void *platform_data;
struct dev_archdata *archdata;
int irq;
};
static struct i2c_board_info i2c_devs0[] __initdata = {
#ifdef CONFIG_TOUCHSCREEN_CDTLCD
{
I2C_BOARD_INFO("ft5x0x_ts", 0x3x),
.irq = IRQ_EINT1,
},
#endif
};

struct i2c_board_info {
    char type[I2C_NAME_SIZE];  
    unsigned short flags;  
    unsigned short addr;  
    void *platform_data;  
    struct dev_archdata *archdata;  
    int irq;  
};
static struct i2c_board_info i2c_devs0[] __initdata = {
#ifdef CONFIG_TOUCHSCREEN_CDTLCD
{
I2C_BOARD_INFO("ft5x0x_ts", 0x3x),
.irq = IRQ_EINT1,
},
#endif 
};

最后在内核初始化的部分调用int i2c_register_board_info(int busnum, struct i2c_board_info const *info, unsigned len);函数即可。如下详细的解释：
@busnum: 指定这些设备属于哪个总线
@info: I2C设备描述符向量
@len: 向量中描述符的数量；为了预留特定的总线号，可以是0。
i2c_register_board_info(0, i2c_devs0, ARRAY_SIZE(i2c_devs0));
下面贴出部分代码：[下面的代码是Android下的Linux驱动，如果要修改到通用的Linux内核中，需要修改代码的] [cpp] view plain copy print ?

static int
ft5x0x_ts_probe(struct i2c_client *client, const struct i2c_device_id *id)
{
struct ft5x0x_ts_data *ft5x0x_ts;
struct input_dev *input_dev;
int err = 0;
unsigned char uc_reg_value;
#if CFG_SUPPORT_TOUCH_KEY
int i;
#endif
printk("[FTS] ft5x0x_ts_probe, driver version is %s. ", CFG_FTS_CTP_DRIVER_VERSION);
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
err = -ENODEV;
goto exit_check_functionality_failed;
}
ft5x0x_ts = kzalloc(sizeof(struct ft5x0x_ts_data), GFP_KERNEL);
//ft5x0x_ts = kmalloc(sizeof(struct ft5x0x_ts_data), GFP_KERNEL);
if (!ft5x0x_ts) {
err = -ENOMEM;
goto exit_alloc_data_failed;
}
//memset(ft5x0x_ts, 0, sizeof(struct ft5x0x_ts_data));
this_client = client;
i2c_set_clientdata(client, ft5x0x_ts);
mutex_init(&ft5x0x_ts->device_mode_mutex);
INIT_WORK(&ft5x0x_ts->pen_event_work, ft5x0x_ts_pen_irq_work);
ft5x0x_ts->ts_workqueue = create_singlethread_workqueue(dev_name(&client->dev));
if (!ft5x0x_ts->ts_workqueue) {
err = -ESRCH;
goto exit_create_singlethread;
}
err = request_irq(IRQ_EINT(6), ft5x0x_ts_interrupt, IRQF_TRIGGER_FALLING, "ft5x0x_ts", ft5x0x_ts);
if (err < 0) {
dev_err(&client->dev, "ft5x0x_probe: request irq failed ");
goto exit_irq_request_failed;
}
disable_irq(IRQ_EINT(6));
input_dev = input_allocate_device();
if (!input_dev) {
err = -ENOMEM;
dev_err(&client->dev, "failed to allocate input device ");
goto exit_input_dev_alloc_failed;
}
ft5x0x_ts->input_dev = input_dev;
set_bit(ABS_MT_TOUCH_MAJOR, input_dev->absbit);
set_bit(ABS_MT_POSITION_X, input_dev->absbit);
set_bit(ABS_MT_POSITION_Y, input_dev->absbit);
set_bit(ABS_MT_WIDTH_MAJOR, input_dev->absbit);
input_set_abs_params(input_dev,
ABS_MT_POSITION_X, 0, SCREEN_MAX_X, 0, 0);
input_set_abs_params(input_dev,
ABS_MT_POSITION_Y, 0, SCREEN_MAX_Y, 0, 0);
input_set_abs_params(input_dev,
ABS_MT_TOUCH_MAJOR, 0, PRESS_MAX, 0, 0);
input_set_abs_params(input_dev,
ABS_MT_WIDTH_MAJOR, 0, 200, 0, 0);
input_set_abs_params(input_dev,
ABS_MT_TRACKING_ID, 0, 5, 0, 0);
set_bit(EV_KEY, input_dev->evbit);
set_bit(EV_ABS, input_dev->evbit);
#if CFG_SUPPORT_TOUCH_KEY
//setup key code area
set_bit(EV_SYN, input_dev->evbit);
set_bit(BTN_TOUCH, input_dev->keybit);
input_dev->keycode = tsp_keycodes;
for(i = 0; i < CFG_NUMOFKEYS; i++)
{
input_set_capability(input_dev, EV_KEY, ((int*)input_dev->keycode)[i]);
tsp_keystatus[i] = KEY_RELEASE;
}
#endif
input_dev->name = FT5X0X_NAME; //dev_name(&client->dev)
err = input_register_device(input_dev);
if (err) {
dev_err(&client->dev,
"ft5x0x_ts_probe: failed to register input device: %s ",
dev_name(&client->dev));
goto exit_input_register_device_failed;
}
#ifdef CONFIG_HAS_EARLYSUSPEND
printk("==register_early_suspend = ");
ft5x0x_ts->early_suspend.level = EARLY_SUSPEND_LEVEL_BLANK_SCREEN + 1;
ft5x0x_ts->early_suspend.suspend = ft5x0x_ts_suspend;
ft5x0x_ts->early_suspend.resume = ft5x0x_ts_resume;
register_early_suspend(&ft5x0x_ts->early_suspend);
#endif
msleep(150); //make sure CTP already finish startup process
//get some register information
uc_reg_value = ft5x0x_read_fw_ver();
printk("[FTS] Firmware version = 0x%x ", uc_reg_value);
ft5x0x_read_reg(FT5X0X_REG_PERIODACTIVE, &uc_reg_value);
printk("[FTS] report rate is %dHz. ", uc_reg_value * 10);
ft5x0x_read_reg(FT5X0X_REG_THGROUP, &uc_reg_value);
printk("[FTS] touch threshold is %d. ", uc_reg_value * 4);
#if CFG_SUPPORT_AUTO_UPG
fts_ctpm_auto_upg();
#endif
#if CFG_SUPPORT_UPDATE_PROJECT_SETTING
fts_ctpm_update_project_setting();
#endif
enable_irq(IRQ_EINT(6));
//create sysfs
err = sysfs_create_group(&client->dev.kobj, &ft5x0x_attribute_group);
if (0 != err)
{
dev_err(&client->dev, "%s() - ERROR: sysfs_create_group() failed: %d ", __FUNCTION__, err);
sysfs_remove_group(&client->dev.kobj, &ft5x0x_attribute_group);
}
else
{
printk("ft5x0x:%s() - sysfs_create_group() succeeded. ", __FUNCTION__);
}
printk("[FTS] ==probe over = ");
return 0;
exit_input_register_device_failed:
input_free_device(input_dev);
exit_input_dev_alloc_failed:
// free_irq(client->irq, ft5x0x_ts);
free_irq(IRQ_EINT(6), ft5x0x_ts);
exit_irq_request_failed:
//exit_platform_data_null:
cancel_work_sync(&ft5x0x_ts->pen_event_work);
destroy_workqueue(ft5x0x_ts->ts_workqueue);
exit_create_singlethread:
printk("==singlethread error = ");
i2c_set_clientdata(client, NULL);
kfree(ft5x0x_ts);
exit_alloc_data_failed:
exit_check_functionality_failed:
return err;
}
static int __devexit ft5x0x_ts_remove(struct i2c_client *client)
{
struct ft5x0x_ts_data *ft5x0x_ts;
printk("==ft5x0x_ts_remove= ");
ft5x0x_ts = i2c_get_clientdata(client);
unregister_early_suspend(&ft5x0x_ts->early_suspend);
// free_irq(client->irq, ft5x0x_ts);
mutex_destroy(&ft5x0x_ts->device_mode_mutex);
free_irq(IRQ_EINT(6), ft5x0x_ts);
input_unregister_device(ft5x0x_ts->input_dev);
kfree(ft5x0x_ts);
cancel_work_sync(&ft5x0x_ts->pen_event_work);
destroy_workqueue(ft5x0x_ts->ts_workqueue);
i2c_set_clientdata(client, NULL);
del_timer(&test_timer);
return 0;
}
static const struct i2c_device_id ft5x0x_ts_id[] = {
{ FT5X0X_NAME, 0x3x },{ }
};
MODULE_DEVICE_TABLE(i2c, ft5x0x_ts_id);
static struct i2c_driver ft5x0x_ts_driver = {
.probe = ft5x0x_ts_probe,
.remove = __devexit_p(ft5x0x_ts_remove),
.id_table = ft5x0x_ts_id,
.driver = {
.name = FT5X0X_NAME,
.owner = THIS_MODULE,
},
};
static int __init ft5x0x_ts_init(void)
{
int ret;
printk("==ft5x0x_ts_init== ");
ret = i2c_add_driver(&ft5x0x_ts_driver);
printk("ret=%d ",ret);
return ret;
}
static void __exit ft5x0x_ts_exit(void)
{
printk("==ft5x0x_ts_exit== ");
i2c_del_driver(&ft5x0x_ts_driver);
}
module_init(ft5x0x_ts_init);
module_exit(ft5x0x_ts_exit);
MODULE_AUTHOR("");
MODULE_DESCRIPTION("FocalTech ft5x0x TouchScreen driver");
MODULE_LICENSE("GPL");

static int 
ft5x0x_ts_probe(struct i2c_client *client, const struct i2c_device_id *id)
{
	struct ft5x0x_ts_data *ft5x0x_ts;
	struct input_dev *input_dev;
	int err = 0;
	unsigned char uc_reg_value; 
#if CFG_SUPPORT_TOUCH_KEY
    int i;
#endif
	
	printk("[FTS] ft5x0x_ts_probe, driver version is %s.
", CFG_FTS_CTP_DRIVER_VERSION);
	
	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
		err = -ENODEV;
		goto exit_check_functionality_failed;
	}

	ft5x0x_ts = kzalloc(sizeof(struct ft5x0x_ts_data), GFP_KERNEL);
	//ft5x0x_ts = kmalloc(sizeof(struct ft5x0x_ts_data), GFP_KERNEL);
	if (!ft5x0x_ts)	{
		err = -ENOMEM;
		goto exit_alloc_data_failed;
	}
	//memset(ft5x0x_ts, 0, sizeof(struct ft5x0x_ts_data));

	this_client = client;
	i2c_set_clientdata(client, ft5x0x_ts);

	mutex_init(&ft5x0x_ts->device_mode_mutex);
	INIT_WORK(&ft5x0x_ts->pen_event_work, ft5x0x_ts_pen_irq_work);

	ft5x0x_ts->ts_workqueue = create_singlethread_workqueue(dev_name(&client->dev));
	if (!ft5x0x_ts->ts_workqueue) {
		err = -ESRCH;
		goto exit_create_singlethread;
	}


	err = request_irq(IRQ_EINT(6), ft5x0x_ts_interrupt, IRQF_TRIGGER_FALLING, "ft5x0x_ts", ft5x0x_ts);
	if (err < 0) {
		dev_err(&client->dev, "ft5x0x_probe: request irq failed
");
		goto exit_irq_request_failed;
	}


	disable_irq(IRQ_EINT(6));

	input_dev = input_allocate_device();
	if (!input_dev) {
		err = -ENOMEM;
		dev_err(&client->dev, "failed to allocate input device
");
		goto exit_input_dev_alloc_failed;
	}
	
	ft5x0x_ts->input_dev = input_dev;

	set_bit(ABS_MT_TOUCH_MAJOR, input_dev->absbit);
	set_bit(ABS_MT_POSITION_X, input_dev->absbit);
	set_bit(ABS_MT_POSITION_Y, input_dev->absbit);
	set_bit(ABS_MT_WIDTH_MAJOR, input_dev->absbit);

	input_set_abs_params(input_dev,
			     ABS_MT_POSITION_X, 0, SCREEN_MAX_X, 0, 0);
	input_set_abs_params(input_dev,
			     ABS_MT_POSITION_Y, 0, SCREEN_MAX_Y, 0, 0);
	input_set_abs_params(input_dev,
			     ABS_MT_TOUCH_MAJOR, 0, PRESS_MAX, 0, 0);
	input_set_abs_params(input_dev,
			     ABS_MT_WIDTH_MAJOR, 0, 200, 0, 0);
    input_set_abs_params(input_dev,
			     ABS_MT_TRACKING_ID, 0, 5, 0, 0);


    set_bit(EV_KEY, input_dev->evbit);
    set_bit(EV_ABS, input_dev->evbit);

#if CFG_SUPPORT_TOUCH_KEY
    //setup key code area
    set_bit(EV_SYN, input_dev->evbit);
    set_bit(BTN_TOUCH, input_dev->keybit);
    input_dev->keycode = tsp_keycodes;
    for(i = 0; i < CFG_NUMOFKEYS; i++)
    {
        input_set_capability(input_dev, EV_KEY, ((int*)input_dev->keycode)[i]);
        tsp_keystatus[i] = KEY_RELEASE;
    }
#endif

	input_dev->name		= FT5X0X_NAME;		//dev_name(&client->dev)
	err = input_register_device(input_dev);
	if (err) {
		dev_err(&client->dev,
		"ft5x0x_ts_probe: failed to register input device: %s
",
		dev_name(&client->dev));
		goto exit_input_register_device_failed;
	}

#ifdef CONFIG_HAS_EARLYSUSPEND
	printk("==register_early_suspend =
");
	ft5x0x_ts->early_suspend.level = EARLY_SUSPEND_LEVEL_BLANK_SCREEN + 1;
	ft5x0x_ts->early_suspend.suspend = ft5x0x_ts_suspend;
	ft5x0x_ts->early_suspend.resume	= ft5x0x_ts_resume;
	register_early_suspend(&ft5x0x_ts->early_suspend);
#endif

    msleep(150);  //make sure CTP already finish startup process
    
    //get some register information
    uc_reg_value = ft5x0x_read_fw_ver();
    printk("[FTS] Firmware version = 0x%x
", uc_reg_value);
    ft5x0x_read_reg(FT5X0X_REG_PERIODACTIVE, &uc_reg_value);
    printk("[FTS] report rate is %dHz.
", uc_reg_value * 10);
    ft5x0x_read_reg(FT5X0X_REG_THGROUP, &uc_reg_value);
    printk("[FTS] touch threshold is %d.
", uc_reg_value * 4);

#if CFG_SUPPORT_AUTO_UPG
    fts_ctpm_auto_upg();
#endif    

#if CFG_SUPPORT_UPDATE_PROJECT_SETTING
    fts_ctpm_update_project_setting();
#endif

    enable_irq(IRQ_EINT(6));
   //create sysfs
   err = sysfs_create_group(&client->dev.kobj, &ft5x0x_attribute_group);
   if (0 != err)
  {
	dev_err(&client->dev, "%s() - ERROR: sysfs_create_group() failed: %d
", __FUNCTION__, err);
	sysfs_remove_group(&client->dev.kobj, &ft5x0x_attribute_group);
  }
   else
    {
        printk("ft5x0x:%s() - sysfs_create_group() succeeded.
", __FUNCTION__);
    }

	printk("[FTS] ==probe over =
");
    return 0;

exit_input_register_device_failed:
	input_free_device(input_dev);
exit_input_dev_alloc_failed:
//	free_irq(client->irq, ft5x0x_ts);
	free_irq(IRQ_EINT(6), ft5x0x_ts);
exit_irq_request_failed:
//exit_platform_data_null:
	cancel_work_sync(&ft5x0x_ts->pen_event_work);
	destroy_workqueue(ft5x0x_ts->ts_workqueue);
exit_create_singlethread:
	printk("==singlethread error =
");
	i2c_set_clientdata(client, NULL);
	kfree(ft5x0x_ts);
exit_alloc_data_failed:
exit_check_functionality_failed:
	return err;
}
static int __devexit ft5x0x_ts_remove(struct i2c_client *client)
{
	struct ft5x0x_ts_data *ft5x0x_ts;
	printk("==ft5x0x_ts_remove=
");
	ft5x0x_ts = i2c_get_clientdata(client);
	unregister_early_suspend(&ft5x0x_ts->early_suspend);
//	free_irq(client->irq, ft5x0x_ts);
	mutex_destroy(&ft5x0x_ts->device_mode_mutex);
	free_irq(IRQ_EINT(6), ft5x0x_ts);
	input_unregister_device(ft5x0x_ts->input_dev);
	kfree(ft5x0x_ts);
	cancel_work_sync(&ft5x0x_ts->pen_event_work);
	destroy_workqueue(ft5x0x_ts->ts_workqueue);
	i2c_set_clientdata(client, NULL); 
	del_timer(&test_timer);
	return 0;
}

static const struct i2c_device_id ft5x0x_ts_id[] = {
	{ FT5X0X_NAME, 0x3x },{ }
};


MODULE_DEVICE_TABLE(i2c, ft5x0x_ts_id);

static struct i2c_driver ft5x0x_ts_driver = {
	.probe		= ft5x0x_ts_probe,
	.remove		= __devexit_p(ft5x0x_ts_remove),
	.id_table	= ft5x0x_ts_id,
	.driver	= {
		.name	= FT5X0X_NAME,
		.owner	= THIS_MODULE,
	},
};

static int __init ft5x0x_ts_init(void)
{
	int ret;
	printk("==ft5x0x_ts_init==
");
	ret = i2c_add_driver(&ft5x0x_ts_driver);
	printk("ret=%d
",ret);
	return ret;
}

static void __exit ft5x0x_ts_exit(void)
{
	printk("==ft5x0x_ts_exit==
");
	i2c_del_driver(&ft5x0x_ts_driver);
}

module_init(ft5x0x_ts_init);
module_exit(ft5x0x_ts_exit);

MODULE_AUTHOR("");
MODULE_DESCRIPTION("FocalTech ft5x0x TouchScreen driver");
MODULE_LICENSE("GPL");

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