gpio-keys 我已经配置了 2 个事件，但我只能接收其中一个

Question

我正在使用基于 i.MX8X 的板，我需要通过输入从另一个板接收一些事件。为此，我决定使用 gpio-keys，因此我按照以下步骤操作：

1. 配置设备树。我添加了以下节点：

    gpio-keys {
        compatible = "gpio-keys";
   
        gpio1_fpga_cpu {
            label = "BTN_TRIGGER_HAPPY1";
            gpios = <&lsio_gpio4 22 GPIO_ACTIVE_LOW>;
            linux,code = <BTN_TRIGGER_HAPPY1>;
        };
   
        gpio2_fpga_cpu {
            label = "BTN_TRIGGER_HAPPY2";
            gpios = <&lsio_gpio4 21 GPIO_ACTIVE_LOW>;
            linux,code = <BTN_TRIGGER_HAPPY2>;
        };
    };
   

执行此操作后，我可以在 /proc/bus/input/devices 中看到这样的事件：

I: Bus=0019 Vendor=0001 Product=0001 Version=0100
N: Name="gpio-keys"
P: Phys=gpio-keys/input0
S: Sysfs=/devices/platform/gpio-keys/input/input0
U: Uniq=
H: Handlers=event0
B: PROP=0
B: EV=3
B: KEY=3 0 0 0 0 0 0 0 0 0 0 0

问题是当我在文件描述符（“/dev/input/event0”）上使用“select”时，我只接收到 BTN_TRIGGER_HAPPY2 而从不接收 BTN_TRIGGER_HAPPY1。我已经验证了多次执行“cat /sys/kernel/debug/gpio”，我可以看到 GPIO 是如何切换其值的，所以我应该从两者接收事件，不是吗？

gpiochip4: GPIOs 128-159, parent: platform/5d0c0000.gpio, 5d0c0000.gpio:
gpio-129 ( |enable ) out hi ACTIVE LOW
gpio-149 ( |BTN_TRIGGER_HAPPY2 ) in hi IRQ ACTIVE LOW
gpio-150 ( |BTN_TRIGGER_HAPPY1 ) in lo IRQ ACTIVE LOW
gpio-155 ( |enable ) out hi ACTIVE LOW

root@sce-dropid1:~# cat /sys/kernel/debug/gpio
gpiochip4: GPIOs 128-159, parent: platform/5d0c0000.gpio, 5d0c0000.gpio:
gpio-129 ( |enable ) out hi ACTIVE LOW
gpio-149 ( |BTN_TRIGGER_HAPPY2 ) in lo IRQ ACTIVE LOW
gpio-150 ( |BTN_TRIGGER_HAPPY1 ) in hi IRQ ACTIVE LOW
gpio-155 ( |enable ) out hi ACTIVE LOW

这是我用来读取事件的函数（它们不可能同时发生）：

static int handle_gpio_keys_event()
{
    int ret = MAIN_ERR_SUCCESS;
    int fd = -1;
    struct input_event ev; /** One per possible allowed event */
    int rd;
    fd_set rdfs;
    int i = 0;
    if ((fd = open(DP_EVENT_INPUT, O_RDONLY)) < 0)
    {
        if (errno == EACCES && getuid() != 0)
            fprintf(stderr, "You do not have access to %s. Try "
                    "running as root instead.\n",
                    DP_EVENT_INPUT);
        ret = MAIN_ERR_EVENT_FILE_PERMISSION;
    }
    else
    {
        FD_ZERO(&rdfs);
        FD_SET(fd, &rdfs);
        // ret = select(fd + 1, &rdfs, NULL, NULL, &tiomeout);
        ret = select(fd + 1, &rdfs, NULL, NULL, NULL);
        if (ret == -1)
        {
            ret = MAIN_ERR_UNEXPECTED_EVENT_READ;
            printf("Entered: %s (%d)- ret %d\n", __func__, __LINE__, ret);
        }
        else if (ret)
        {
            rd = read(fd, (void *)&ev, sizeof(ev));

            if (rd / sizeof(struct input_event) != 1)
            {/** More than one event was received and it is not valid for this application */
                printf("Entered: %s (%d)- number of events %ld\n", __func__, __LINE__, rd / sizeof(struct input_event));
            }
            else
            {
                printf("Entered: %s (%d)- number of events %ld\n", __func__, __LINE__, rd / sizeof(struct input_event));
                if(rd == (int) sizeof(struct input_event))
                {
                    printf("Entered: %s (%d)- ev.type %d\n", __func__, __LINE__, ev.type);
                    if (ev.type == EV_KEY)
                    {
                        printf("Entered: %s (%d)- ev.type %d\n", __func__, __LINE__, ev.code);
                        if (ev.code == BTN_TRIGGER_HAPPY1)
                        {
                            ev.code = BTN_TRIGGER_HAPPY1;
                            printf("%s(%d) BTN_TRIGGER_HAPPY1 received\n", __func__, __LINE__);
                            ret = 0; // SUCCESS
                        }
                        else if (ev.code == BTN_TRIGGER_HAPPY2)
                        {
                            ev.code = BTN_TRIGGER_HAPPY2;
                            printf("%s(%d) BTN_TRIGGER_HAPPY2 received\n", __func__, __LINE__);
                            ret = 0; // SUCCESS
                        }
                        else
                        {
                            printf("Entered: %s (%d)- UNEXPECTED EVENT: %d \n", __func__, __LINE__, ev.code);
                            // ret = -1;
                            ret = 0;
                        }
                            
                    }
                    else
                    {/** ERROR */
                        printf("Entered: %s (%d)- return -2, and EV TYPE: %d\n", __func__, __LINE__, ev.type);
                        ret = -2;
                    }
                }
                else if (rd > 0 && rd != (int) sizeof(struct input_event))
                {
                    ret = MAIN_ERR_UNEXPECTED_EVENT_RECEPTION;
                    printf("Entered: %s (%d)- ret %d\n", __func__, __LINE__, ret);
                }
                else
                {
                    ret = MAIN_ERR_UNEXPECTED_EVENT_READ;
                    printf("Entered: %s (%d)- ret %d\n", __func__, __LINE__, ret);
                }
            }
        }
        else
        {
            ret = MAIN_ERR_EVENT_RECEPTION_TIMEOUT;
            printf("%s(%d) - TIMEOUT \n", __func__, __LINE__);
        }
    }
    printf("%s LINE: %d ret: %d\n", __func__, __LINE__, ret);
    return ret;
}

知道我缺少什么吗？ 提前致谢。

福尔戈。

Answer 1

好的...我没有阅读所有事件，只是阅读了一个...抱歉浪费您的时间。