RTT PIN驱动框架分析

#RT-Thread #PIN驱动

I/O设备模型框架

基础分析

设备驱动层：具体实现如stm32_pin_write_pin(int pin,int value){hal_write_pin(int pin,int value);}
设备驱动框架层：套壳，实现统一接口rt_write_pin(int pin,int value){hw_write_pin(stm32->write_pin,int pin,int value);}

PIN设备API

PIN设备通过PIN设备管理接口访问GPIO
PIN设备API

框架分析

在project/rt-thread/components/drivers/pin/dev_pin.c下有驱动框架层

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/* Get pin number by name, such as PA.0, P0.12 */
rt_base_t rt_pin_get(const char *name)
{
    RT_ASSERT(_hw_pin.ops != RT_NULL);

    if (_hw_pin.ops->pin_get == RT_NULL)
    {
        return -RT_ENOSYS;
    }
    return _hw_pin.ops->pin_get(name);
}

定位static struct rt_device_pin _hw_pin;，这个变量下有ops函数，找初始化赋值的地方

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int rt_device_pin_register(const char *name, const struct rt_pin_ops *ops, void *user_data)
{
    _hw_pin.parent.type         = RT_Device_Class_Pin;
    _hw_pin.parent.rx_indicate  = RT_NULL;
    _hw_pin.parent.tx_complete  = RT_NULL;

#ifdef RT_USING_DEVICE_OPS
    _hw_pin.parent.ops          = &pin_ops;
#else
    _hw_pin.parent.init         = RT_NULL;
    _hw_pin.parent.open         = RT_NULL;
    _hw_pin.parent.close        = RT_NULL;
    _hw_pin.parent.read         = _pin_read;
    _hw_pin.parent.write        = _pin_write;
    _hw_pin.parent.control      = _pin_control;
#endif

    _hw_pin.ops                 = ops;
    _hw_pin.parent.user_data    = user_data;

    /* register a character device */
    rt_device_register(&_hw_pin.parent, name, RT_DEVICE_FLAG_RDWR);

    return 0;
}

这是注册函数，全局搜索找驱动层具体实现，在project/libraries/HAL_Drivers/drivers/drv_gpio.c

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int rt_hw_pin_init(void)
{
#if defined(__HAL_RCC_GPIOA_CLK_ENABLE)
    __HAL_RCC_GPIOA_CLK_ENABLE();
#endif

//... ...

    return rt_device_pin_register("pin", &_stm32_pin_ops, RT_NULL);
}

static const struct rt_pin_ops _stm32_pin_ops =
{
    stm32_pin_mode,
    stm32_pin_write,
    stm32_pin_read,
    stm32_pin_attach_irq,
    stm32_pin_dettach_irq,
    stm32_pin_irq_enable,
    stm32_pin_get,
    RT_NULL,
};

由此可以实现驱动框架层到驱动层的具体实现，即_hw_pin.ops = _stm32_pin_ops;

rt_get_pin()

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/* e.g. PE.7 */
static rt_base_t stm32_pin_get(const char *name)
{
    rt_base_t pin = 0;
    int hw_port_num, hw_pin_num = 0;
    int i, name_len;

    name_len = rt_strlen(name);

    if ((name_len < 4) || (name_len >= 6))
    {
        goto out;
    }
    if ((name[0] != 'P') || (name[2] != '.'))
    {
        goto out;
    }

    if ((name[1] >= 'A') && (name[1] <= 'Z'))
    {
        hw_port_num = (int)(name[1] - 'A');
    }
    else
    {
        goto out;
    }

    for (i = 3; i < name_len; i++)
    {
        hw_pin_num *= 10;
        hw_pin_num += name[i] - '0';
    }

    pin = PIN_NUM(hw_port_num, hw_pin_num);

    return pin;

out:
    rt_kprintf("Px.y  x:A~Z  y:0-15, e.g. PA.0\n");
    return -RT_EINVAL;
}

不止一种方式可以获取编号，后者直接使用rt_pin_write(后者在nano版下的也可以用)

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#define GET_PIN(PORTx,PIN) (rt_uint64_t)((((rt_uint64_t)GPIO_PIN_##PIN) << 32) | (rt_uint64_t)(rt_ubase_t)GPIO##PORTx)

rt_pin_mode()

上层调用rt_pin_mode()，向下调用stm32_pin_mode()使用具体的驱动函数

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/* RT-Thread Hardware PIN APIs */
void rt_pin_mode(rt_base_t pin, rt_uint8_t mode)
{
    RT_ASSERT(_hw_pin.ops != RT_NULL);
    _hw_pin.ops->pin_mode(&_hw_pin.parent, pin, mode);
}
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static void stm32_pin_mode(rt_device_t dev, rt_base_t pin, rt_uint8_t mode)
{
    GPIO_InitTypeDef GPIO_InitStruct;

    if (PIN_PORT(pin) >= PIN_STPORT_MAX)
    {
        return;
    }

    /* Configure GPIO_InitStructure */
    GPIO_InitStruct.Pin = PIN_STPIN(pin);
    GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;

    if (mode == PIN_MODE_OUTPUT)
    {
        /* output setting */
        GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
        GPIO_InitStruct.Pull = GPIO_NOPULL;
    }
    else if (mode == PIN_MODE_INPUT)
    {
        /* input setting: not pull. */
        GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
        GPIO_InitStruct.Pull = GPIO_NOPULL;
    }
    else if (mode == PIN_MODE_INPUT_PULLUP)
    {
        /* input setting: pull up. */
        GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
        GPIO_InitStruct.Pull = GPIO_PULLUP;
    }
    else if (mode == PIN_MODE_INPUT_PULLDOWN)
    {
        /* input setting: pull down. */
        GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
        GPIO_InitStruct.Pull = GPIO_PULLDOWN;
    }
    else if (mode == PIN_MODE_OUTPUT_OD)
    {
        /* output setting: od. */
        GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_OD;
        GPIO_InitStruct.Pull = GPIO_NOPULL;
    }

    HAL_GPIO_Init(PIN_STPORT(pin), &GPIO_InitStruct);
}

中断

调用链HAL->pin_irq_hdr()
通过rt_pin_attach_irq()和rt_pin_detach_irq()注册和注销中断回调函数

注销中断回调函数不会关闭中断
底层同样是stm32_pin_attach_irq()


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