Question

在pandaboard OMAP4的GPIO_39上每10ms产生一次中断。我已在Linux驱动程序代码中为此注册了一个处理程序，但由于未检测到中断，因此未调用处理程序。

我确保在硬件级别（通过探测gpio引脚）确实正在生成中断。它只是软件无法检测到它。

我的驱动程序代码中包含以下内容。

#define GPIO_NO     39

  iowrite16(0x3, gpio_39_address + 2); /* Configured the pin 22 to be used as gpio. */

  ret = gpio_request(GPIO_NO, "Claiming GPIO");
  if(ret < 0)
  {
    printk(KERN_ALERT "%s: Claiming GPIO_%d failed\n", __func__, GPIO_NO);
    return -1;
  }
  else
  {
    printk(KERN_INFO "%s: Claiming GPIO_%d successful\n", __func__, GPIO_NO);
  }

  ret = gpio_direction_input(GPIO_NO);  
  if(ret < 0)
  {
    printk(KERN_INFO "%s: Setting GPIO direction to input failed\n", __func__);
    return -1;
  }
  else
  {
    printk(KERN_INFO "%s: Direction of GPIO_%d set to input\n", __func__, GPIO_NO);
  }

  GPIO_IRQ = gpio_to_irq(GPIO_NO);

  if(GPIO_IRQ < 0)
  {
    printk(KERN_INFO "%s: Mapping GPIO_%d to IRQ failed\n", __func__, GPIO_NO);
    return -1;
  }
  else
  {
    printk(KERN_INFO "%s: Mapping GPIO_%d to IRQ_%d successful\n", __func__, GPIO_NO, GPIO_IRQ);
  }

  if((request_irq(GPIO_IRQ, ten_ms_int, IRQF_TRIGGER_FALLING, DEVICE_NAME, NULL)))
  {
    printk(KERN_ALERT "%s: requeseting GPIO_IRQ %d failed\n", __func__, GPIO_IRQ);
    return -1;
  }
  else
  {
    printk(KERN_INFO "%s: requesting GPIO_IRQ %d successful\n", __func__, GPIO_IRQ);
  }

irqreturn_t ten_ms_int(int irq, void *dev_id)
{
  T_UINT32 l;
  /* Enable spi channel */
  l = ioread32(spi_base + SPI_CHCONF0);
  l |= SPI_CHCONF0_FORCE;
  iowrite32(l, (spi_base +  SPI_CHCONF0));

  l = ioread32(spi_base + SPI_CHCTRL0);
  l |= SPI_CHCTRL_EN;
  iowrite32(l, (spi_base + SPI_CHCTRL0));

  /* Enable dma channel 0 */
  l = ioread32(sdma_base + SDMA_CCR(CHANNEL0));
  l |= SDMA_CCR_ENABLE;
  iowrite32(l, sdma_base + SDMA_CCR(CHANNEL0));

  /* Enable dma channel 1 */
  l = ioread32(sdma_base + SDMA_CCR(CHANNEL1));
  l |= SDMA_CCR_ENABLE;
  iowrite32(l, sdma_base + SDMA_CCR(CHANNEL1));
  //printk(KERN_INFO "%s: 10ms interrupt detected %d\n", __func__, irq); /* I know that I've to remove this printk statement */
  return IRQ_HANDLED;
}

GPIO_39属于银行GPIO2，相应的中断号为32.但是，gpio_to_irq()的返回值为199.这是另一个引起关注的原因。

如果代码中出现问题或错过了某些内容，请告诉我。

Answer 1

明确地使GPIO引脚检测下降沿。

在gpio模块级别，必须启用gpio的 FALLING_DETECT 。

如何在嵌入式Linux中检测GPIO线路上的中断？

1 个答案: