如何在嵌入式Linux中检测GPIO线路上的中断？

在pandaboard OMAP4中,GPIO_39上每隔10ms产生一次中断.我已在Linux驱动程序代码中为此注册了处理程序,但由于未检测到中断,因此未处理该处理程序.

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

我在驱动程序代码中有以下内容.

#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 failedn",__func__,GPIO_NO);
    return -1;
  }
  else
  {
    printk(KERN_INFO "%s: Claiming GPIO_%d successfuln",GPIO_NO);
  }

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

  GPIO_IRQ = gpio_to_irq(GPIO_NO);

  if(GPIO_IRQ < 0)
  {
    printk(KERN_INFO "%s: Mapping GPIO_%d to IRQ failedn",GPIO_NO);
    return -1;
  }
  else
  {
    printk(KERN_INFO "%s: Mapping GPIO_%d to IRQ_%d successfuln",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 failedn",GPIO_IRQ);
    return -1;
  }
  else
  {
    printk(KERN_INFO "%s: requesting GPIO_IRQ %d successfuln",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 %dn",irq); /* I know that I've to remove this printk statement */
  return IRQ_HANDLED;
}

GPIO_39属于存储体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.

如果代码中有问题或错过了某些内容,请告诉我.

在gpio模块级别,必须启用gpio的FALLING_DETECT.

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