linux2.6.37.4内核在XC2440开发板上移植（十三）LED驱动移植

内核中带有GPIO控制LED的驱动，通用的驱动文件为：drivers/leds/leds-gpio.c

硬件接法：

LED1 -->  GPF0

LED2 -->  GPF1

LED3 -->  GPF2

LED4 -->  GPF3

低电平点亮，高电平熄灭

在mach-xc2440.c中添加LED驱动的支持：

加入必要的头文件：

#include

在xc2440_devices[ ]结构体中加入：

    &xc2440_device_led,

构建LED设备的platform_device:

static struct platform_device xc2440_device_led = {
    .name        = "leds-gpio",
    .id        = -1,
    .dev        = {
        .platform_data = &xc2440_gpio_led_pdata,
    },
};

构建LED设备的platform_data:

/* LEDS */
static struct gpio_led xc2440_leds[] = {
    [0] = {
        .name = "led1",
        .gpio = S3C2410_GPF(0),
        .active_low = 1,
    },
    [1] = {
        .name = "led2",
        .gpio = S3C2410_GPF(1),
        .active_low = 1,
    },
    [2] = {
        .name = "led3",
        .gpio = S3C2410_GPF(2),
        .active_low = 1,
    },
    [3] = {
        .name = "led4",
        .gpio = S3C2410_GPF(3),
        .active_low = 1,
    },
};

static struct gpio_led_platform_data xc2440_gpio_led_pdata = {
    .num_leds = ARRAY_SIZE(xc2440_leds),
    .leds      = xc2440_leds,
};

参数说明：

name: led的name，一个字符串

gpio：操作它的GPIO管脚

active_low：为1是低电平点亮，为0是高电平点亮

配置内核，支持LED驱动：

Device Drivers --->
    [*] LED Support  --->
<*>   LED Support for GPIO connected LEDs
[*]     Platform device bindings for GPIO LEDs(NEW)

查看设备：

/sys/class/leds/ledx   （x为0,1,2,3）

操作方法：

#echo 1 > /sys/class/leds/led0/brightness     让LED0亮

#echo 0 > /sys/class/leds/led0/brightness     让LED0灭