A20 GPIO中断类型差别结果迥异的问题思考

A20GPIO中断类型差别结果迥异的问题思考

最近在使用全志A20做开发时，发现在处理中断的时候，用电平触发模式，报中断比较乱，用边沿触发则很稳定，不会乱报。笔者感到比较困惑，笔者用电平触发写的code如下：

   reverseHandle = sw_gpio_irq_request(gReverseCar_gpio_hdle.gpio, TRIG_LEVL_HIGH, \
   	                                          &sw_reverseCar_irq_Handle, &privateData);
	if (!reverseHandle) {
			printk("Failed to get gpio irq for reverse car detection\n");
	}

   privateData.trigtype = TRIG_LEVL_HIGH;

static int sw_reverseCar_irq_Handle(void *para){
	printk("IRQ sw_reverseCar_irq: %d ", privateData.trigtype);

	printk("IO:%d, value:%d\n",gReverseCar_gpio_hdle.gpio, \
		                    __gpio_get_value(gReverseCar_gpio_hdle.gpio));

    sw_gpio_eint_set_enable(gReverseCar_gpio_hdle.gpio, 0);
	sw_gpio_eint_clr_irqpd_sta(gReverseCar_gpio_hdle.gpio);
	//TRIG_LEVL_LOW  TRIG_LEVL_HIGH TRIG_EDGE_POSITIVE TRIG_EDGE_NEGATIVE
	if(privateData.trigtype == TRIG_LEVL_HIGH) {
		if(0 == sw_gpio_eint_set_trigtype(gReverseCar_gpio_hdle.gpio,TRIG_LEVL_LOW))
		   privateData.trigtype = TRIG_LEVL_LOW;
	} else if(privateData.trigtype == TRIG_LEVL_LOW) {
	   if(0 == sw_gpio_eint_set_trigtype(gReverseCar_gpio_hdle.gpio,TRIG_LEVL_HIGH))
		   privateData.trigtype = TRIG_LEVL_HIGH;

    }

   sw_gpio_eint_set_enable(gReverseCar_gpio_hdle.gpio, 1);

	return 0;
}

中断类型设置成DEBO中断打印信息有问题，具体如下：

root@android:/ # [  519.018955] IRQ sw_reverseCar_irq: 2 IO:188, value:1
[  519.024773] IRQ sw_reverseCar_irq: 3 IO:188, value:1
[  519.030576] IRQ sw_reverseCar_irq: 2 IO:188, value:1
[  519.036378] IRQ sw_reverseCar_irq: 3 IO:188, value:1
[  519.042169] IRQ sw_reverseCar_irq: 2 IO:188, value:1

[  520.898643] IRQ sw_reverseCar_irq: 3 IO:188, value:0
[  520.904456] IRQ sw_reverseCar_irq: 2 IO:188, value:0
[  520.910363] IRQ sw_reverseCar_irq: 3 IO:188, value:0
[  520.916215] IRQ sw_reverseCar_irq: 2 IO:188, value:0
[  520.921995] IRQ sw_reverseCar_irq: 3 IO:188, value:0
[  520.927832] IRQ sw_reverseCar_irq: 2 IO:188, value:0
[  520.933612] IRQ sw_reverseCar_irq: 3 IO:188, value:0
[  520.939432] IRQ sw_reverseCar_irq: 2 IO:188, value:0
[  520.945317] IRQ sw_reverseCar_irq: 3 IO:188, value:0

用边沿触发写的code如下，

   gPrivData.trigtype = TRIG_EDGE_POSITIVE;
   gPrivData.irqReqHandle = sw_gpio_irq_request(gPrivData.gpio_hdle.gpio, TRIG_EDGE_POSITIVE, \
   	               (peint_handle)&sw_reverseCar_irq_Handle, (void *)&gPrivData);
static int sw_reverseCar_irq_Handle(void *para){
	//printk("IRQ sw_reverseCar_irq: %d ", gPrivData.trigtype);

	gPrivData.CarStatus = __gpio_get_value(gPrivData.gpio_hdle.gpio);
	//printk("io:%d, value:%d\n",gPrivData.gpio_hdle.gpio, gPrivData.CarStatus);

    /*if app has no capacity for handle reverse event, system need reboot*/
	if(1 == gPrivData.needRebootFlag) {
         printk("Reboot for handle reverse in boot now!\n");
         *(volatile __u32 *)(0xf1c20c94) = 0x3;
	}

	up(&gPrivData.sem_lock);

    sw_gpio_eint_set_enable(gPrivData.gpio_hdle.gpio, 0);
	sw_gpio_eint_clr_irqpd_sta(gPrivData.gpio_hdle.gpio);

	if(gPrivData.trigtype == TRIG_EDGE_POSITIVE) {
		if(0 == sw_gpio_eint_set_trigtype(gPrivData.gpio_hdle.gpio,TRIG_EDGE_NEGATIVE))
		   gPrivData.trigtype = TRIG_EDGE_NEGATIVE;
	} else if(gPrivData.trigtype == TRIG_EDGE_NEGATIVE) {
	   if(0 == sw_gpio_eint_set_trigtype(gPrivData.gpio_hdle.gpio,TRIG_EDGE_POSITIVE))
		   gPrivData.trigtype = TRIG_EDGE_POSITIVE;

    }

   sw_gpio_eint_set_enable(gPrivData.gpio_hdle.gpio, 1);

	return 0;
}

EDGE时还可以设置中断类型为TRIG_EDGE_DOUBLE，笔者暂时没有采用，中断打印信息正常，如下：

root@android:/ # [  517.116361] IRQ sw_reverseCar_irq: 0 io:188, value:1
[  518.103095] IRQ sw_reverseCar_irq: 1 io:188, value:0

root@android:/ # [  520.918512] IRQ sw_reverseCar_irq: 0 io:188, value:1
[  521.876038] IRQ sw_reverseCar_irq: 1 io:188, value:0
[  527.796107] IRQ sw_reverseCar_irq: 0 io:188, value:1
[  528.843397] IRQ sw_reverseCar_irq: 1 io:188, value:0
[  531.335858] IRQ sw_reverseCar_irq: 0 io:188, value:1
[  532.306660] IRQ sw_reverseCar_irq: 1 io:188, value:0
[  534.552011] IRQ sw_reverseCar_irq: 0 io:188, value:1
[  535.101586] IRQ sw_reverseCar_irq: 1 io:188, value:0

笔者不清楚原因，怀疑是芯片驱动的问题，但是驱动也就那样写了啊，难道是芯片设计的问题，当然这种也就是在刚有中断时会有乱irq上来，如果用delaywork延时一下处理也是可以绕过去的。望哪位大侠清楚的解释一下。