Add a new TP driver

Adding a new TP driver mainly includes:

  1. Add macro definitions for the driver IC in the Kconfig file

  2. Copy similar driver code and add it to the compilation

  3. Modify the copied TP driver file

Add macro definitions for the driver IC in the Kconfig file

Open the SDK\customer\peripherals\Kconfig file which contains many configs like TSC_USING_XXX, and append a new config:

config TSC_USING_GT911
    bool
    default n

Copy similar driver code and add it to the compilation

  • 在SDK\customer\peripherals目录下找一个类似且已适配过的TP驱动，

  • Copy the entire directory and rename it to “gt911”

  • 里面的屏驱.c/.h文件也改成gt911.c/.h, 并修改里面的内容。

  • Change the depend macro in the SConscript file to the previously added ‘TSC_USING_GT911’ so that the newly added files are included in the compilation

Modify the copied TP driver file

Modify the registered semaphore name

static int rt_tp_device_init(void)
{
    ...
    driver.isr_sem = rt_sem_create("gt911", 0, RT_IPC_FLAG_FIFO); //Change this semaphore name to gt911
    rt_touch_drivers_register(&driver);
    return 0;
}

Modify the communication interface in the probe function

Probe函数一般做几件事情：

  1. Open the communication interface (e.g., I2C), configure the interface frequency, timeout, etc.

  2. Read a certain register and return the status based on whether the TP is present (e.g., a certain status register of the TP).（If multi-TP driver compatibility is not required, you can directly return RT_EOK (TP is present))

Modify the Init function

驱动的初始化函数里面主要做：

  1. Reset the TP

  2. Configure the trigger condition of the TP interrupt GPIO, and register the interrupt callback handling function

It is recommended to use the following interfaces instead of rt_pin_xxx interfaces:

  • rt_touch_irq_pin_attach(PIN_IRQ_MODE_FALLING, irq_handler, NULL); Register the TP interrupt

  • rt_touch_irq_pin_enable(v) Enable and disable interrupts

Modify the interrupt callback function

中断回调一般不需要修改，处理一般都是：

  1. Turn off the GPIO interrupt enable

  2. Release the semaphore (trigger the upper layer to call read_point to read data)

Modify the read TP data callback function

读TP数据函数的实现一般是：

  1. Read TP data through the communication interface (e.g., I2C)

  2. Enable the TP interrupt after reading is completed (to trigger the next read)

  3. 将数据转存并返回，注意：返回值不能始终返回RT_EOK, 否则会陷入死循环。如果读取触控数据结束，请返回RT_EEMPTY。

static rt_err_t read_point(touch_msg_t p_msg)
{
    gt911_piont_t i2c_result;

    i2c_read_(0x8150, 6, &i2c_result); //Read TP data via I2C
    
    rt_touch_irq_pin_enable(1); //Enable the TP interrupt

    /*Return TP data to p_msg*/
    p_msg->event = i2c_result.status ? TOUCH_EVENT_DOWN : TOUCH_EVENT_UP;
    p_msg->x = i2c_result.x;
    p_msg->y = i2c_result.y;

    return RT_EEMPTY; //RT_EEMPTY - Indicates that the data has been read completely.
}