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首先,分析下 FT5406 的基本电路接口: 基本都是通用的接口,如 I2C 接口,INT,WAKE,RST。如图: 以上可知,我们在驱动中必须定义一个中断口,来启动接收触摸数据,一个gpio脚来复位FT5406。wake:主要靠cpu发送一个唤醒指令给FT5406。 查看tiny4412原理图 再次,需确认FT5406的从地址,以便于I2C访问得到。这个可以根据FT5406数据手册查找到. 可知从地址高位必须为:3,低位必须根据 i2ccon 设定的值来确定,这点很奇怪。 我这边找到的从地址为:0x38 i2ccon 暂时未找到出处,可以用 i2c tools 探测一下 /mnt # ./i2cdetect -y 1 0 1 2 3 4 5 6 7 8 9 a b c d e f 00: -- -- -- -- -- -- -- -- -- -- -- -- -- 10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 30: -- -- -- -- -- -- -- -- 38 -- -- -- -- -- -- -- 40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 70: -- -- -- -- -- -- -- -- 基本的东西确认好后,剩下的就是根据FT5406数据手册上的指令,开始写驱动了。 在此之前,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,然后上报就行。格式如图: 解释: 02h : 捕获的触摸点个数 03h- 1eh :对应每个点的x,y坐标数值。 touch id 表示触点编号,对应于typeB的slot 驱动参考:Ft6236.c (drivers\input\touchscreen) touch_demo{ compatible = "tiny4412,touch_demo"; interrupts = ; interrupt-parent = ; status = "okay"; }; &i2c_1{ status = "okay"; touch@38{ compatible = "tiny4412,touch"; reg = ; }; }; #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define uchar unsigned char static void touch_read_handler(struct work_struct *work); DECLARE_WORK(touch_read_work, touch_read_handler); static struct i2c_client *touch_client; static struct input_dev *touch_dev; static int irq; static void touch_read(unsigned char sAddr, unsigned char *buf, unsigned int len) { struct i2c_msg msg[2]; int i, ret; unsigned char address; for (i = 0; i < len; i++) { /* 先写入要读取的寄存器地址 */ address = sAddr + i; msg[0].addr = touch_client->addr; /* 目的 */ msg[0].buf = &address; /* 源 */ msg[0].len = 1; /* 地址=1 byte */ msg[0].flags = 0; /* 表示写 */ /* 然后启动读操作 */ msg[1].addr = touch_client->addr; /* 源 */ msg[1].buf = &buf[i]; /* 目的 */ msg[1].len = 1; /* 数据=1 byte */ msg[1].flags = I2C_M_RD; /* 表示读 */ ret = i2c_transfer(touch_client->adapter, msg, 2); if (ret < 0) { printk("i2c_transfer eror\n"); } mdelay(10); } } static void touch_read_handler(struct work_struct *work) { unsigned char buf[13]; unsigned char touches, i, event, id; unsigned short x, y; bool act; /* read tp resister by i2c */ touch_read(0x00, buf, 13); /* number of touch points */ touches = buf[2] & 0x0f; //printk("point num %d\n", touches); if (touches > 2) { printk("%s touch read touches error\n",__func__); touches = 2; } for (i = 0; i < touches; i++) { y = ((buf[5 + i * 6] & 0x0f) 6; //event flags id = buf[5 + i * 6] >> 4; //touch id //printk("event %d id %d\n", event, id); //down or contact act = (event == 0x00 || event == 0x02); input_mt_slot(touch_dev, id); input_mt_report_slot_state(touch_dev, MT_TOOL_FINGER, act); //if up return if (!act) continue; input_report_abs(touch_dev, ABS_MT_POSITION_X, x); input_report_abs(touch_dev, ABS_MT_POSITION_Y, y); } input_mt_sync_frame(touch_dev); input_sync(touch_dev); } static irqreturn_t touch_isr(int irq, void *dev_id) { schedule_work(&touch_read_work); return IRQ_HANDLED; } static int touch_probe(struct i2c_client *client, const struct i2c_device_id *id) { unsigned char buf; int ret; touch_client = client; printk("%s %s %d\n", __FILE__, __FUNCTION__, __LINE__); touch_read(0xa3, &buf, 1); printk("Chip vendor ID %x\n", buf); touch_read(0xa6, &buf, 1); printk("Firmware ID %x\n", buf); touch_read(0xa8, &buf, 1); printk("CTPM Vendor ID %x\n", buf); touch_read(0x00, &buf, 1); printk("DEVIDE_MODE %x\n", buf); touch_read(0x80, &buf, 1); printk("ID_G_THGROUP. %x\n", buf); touch_read(0x88, &buf, 1); printk("ID_G_PERIODACTIVE. %x\n", buf); touch_dev = input_allocate_device(); if (touch_dev == NULL) { printk("%s, allocate input device, error\n", __func__); return -1; } //告诉input能够支持哪些事件 input_set_abs_params(touch_dev, ABS_MT_POSITION_X, 0, 800, 0, 0); input_set_abs_params(touch_dev, ABS_MT_POSITION_Y, 0, 480, 0, 0); ret = input_mt_init_slots(touch_dev, 2, INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED); if (ret) { printk("%s, input_mt_init_slots error\n", __func__); return ret; } touch_dev->name = "touch"; touch_dev->id.bustype = BUS_I2C; touch_dev->dev.parent = &(touch_client)->dev; ret = input_register_device(touch_dev); if (ret) { printk("%s, register input device, error\n", __func__); return ret; } printk("irq is %d\n", irq); ret = devm_request_threaded_irq(&touch_client->dev, irq, touch_isr, NULL, IRQF_TRIGGER_FALLING | IRQF_ONESHOT, "touch1", NULL); if (ret < 0) { printk("failed to request_irq %d\n", ret); } return 0; } static int touch_remove(struct i2c_client *client) { return 0; } static const struct i2c_device_id touch_id_table[] = { { "touch", 0 }, {} }; /* 1. 分配/设置i2c_driver */ static struct i2c_driver touch_driver = { .driver = { .name = "touch", .owner = THIS_MODULE, }, .probe = touch_probe, .remove = touch_remove, .id_table = touch_id_table, }; static int int_demo_remove(struct platform_device *pdev) { printk("%s enter.\n", __func__); return 0; } static int int_demo_probe(struct platform_device *pdev) { irq = platform_get_irq(pdev, 0); printk("int_demo_probe %d\n", irq); return 0; } static const struct of_device_id touch_demo_dt_ids[] = { { .compatible = "tiny4412,touch_demo", }, {}, }; MODULE_DEVICE_TABLE(of, touch_demo_dt_ids); static struct platform_driver touch_demo_driver = { .driver = { .name = "touch_demo", .of_match_table = of_match_ptr(touch_demo_dt_ids), }, .probe = int_demo_probe, .remove = int_demo_remove, }; static int touch_drv_init(void) { int ret; /* 1.注册平台设备驱动 */ ret = platform_driver_register(&touch_demo_driver); if (ret) printk(KERN_ERR "int demo: probe failed: %d\n", ret); /* 2. 注册i2c_driver */ i2c_add_driver(&touch_driver); return 0; } static void touch_drv_exit(void) { i2c_del_driver(&touch_driver); platform_driver_unregister(&touch_demo_driver); } module_init(touch_drv_init); module_exit(touch_drv_exit); MODULE_LICENSE("GPL"); |
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