Android灯光系统(1)——led_class驱动实现

#include <linux/kernel.h> 
#include <linux/module.h> 
#include <linux/miscdevice.h> 
#include <linux/device.h> 
#include <linux/fs.h> 
#include <linux/types.h> 
#include <linux/moduleparam.h> 
#include <linux/slab.h> 
#include <linux/ioctl.h> 
#include <linux/cdev.h> 
#include <linux/delay.h> 
 
#include <linux/gpio.h> 
#include <mach/gpio.h> 
#include <plat/gpio-cfg.h> 
 
#include <linux/leds.h> 
 
struct led_desc { 
    int gpio; 
    char *name; 
}; 
 
/*三星的goio引脚根本就不需要获取就可以直接使用*/ 
static struct led_desc led_gpios[] = { 
    {EXYNOS4212_GPM4(0), "led1"}, 
    {EXYNOS4212_GPM4(1), "led2"}, 
    {EXYNOS4212_GPM4(2), "led3"}, 
    {EXYNOS4212_GPM4(3), "led4"}, 
}; 
 
struct led_classdev_4412 { 
    struct led_classdev cdev; /*核心结构体*/ 
    int gpio; /*每一个led绑定的gpio*/ 
}; 
 
 
static struct led_classdev_4412 *led_devs; 
 
static void     brightness_set_4412(struct led_classdev *led_cdev, 
              enum led_brightness brightness) 
{ 
    struct led_classdev_4412 *dev = (struct led_classdev_4412 *)led_cdev; 
 
    led_cdev->brightness = brightness; 
 
    if (brightness != LED_OFF) 
        gpio_set_value(dev->gpio, 0); /*打开led*/ 
    else 
        gpio_set_value(dev->gpio, 1); /*关闭led*/ 
} 
 
 
static int leds_init(void) 
{ 
    int i; 
    int ret; 
 
    /* 1. alloc led_classdev */ 
    led_devs = kzalloc(sizeof(struct led_classdev_4412) * ARRAY_SIZE(led_gpios), GFP_KERNEL); 
    if (led_devs == NULL) { 
        printk("No memory for device\n"); 
        return -ENOMEM; 
    } 
 
    for (i = 0; i < ARRAY_SIZE(led_gpios); i++) 
    { 
        s3c_gpio_cfgpin(led_gpios[i].gpio, S3C_GPIO_OUTPUT); 
        /*默认led全部关闭*/ 
        gpio_set_value(led_gpios[i].gpio, 1); 
 
        /* 2. set 这里面哪些域需要设置由led-class.c的实现决定的*/ 
        led_devs[i].cdev.max_brightness = LED_FULL; 
        led_devs[i].cdev.brightness_set = brightness_set_4412; 
        led_devs[i].cdev.flags = LED_CORE_SUSPENDRESUME; 
        led_devs[i].cdev.brightness = LED_OFF; 
        led_devs[i].cdev.name = led_gpios[i].name; 
        led_devs[i].gpio = led_gpios[i].gpio; 
 
        //led_devs[i].cdev.default_trigger = "timer"; 
        //led_devs[i].cdev.blink_delay_on = 100; 
        //led_devs[i].cdev.blink_delay_off = 900; 
 
        /* 3. led_classdev_register */ 
        ret = led_classdev_register(NULL, &led_devs[i].cdev); 
        if (ret) { 
            i--; 
            while (i >= 0) { 
                led_classdev_unregister(&led_devs[i].cdev); 
                i--; 
            } 
            kfree(led_devs); 
            return -EIO; 
        } 
    } 
 
    return 0; 
} 
 
static void leds_exit(void) 
{ 
    int i; 
    for (i = 0; i < ARRAY_SIZE(led_gpios); i++) 
    { 
        led_classdev_unregister(&led_devs[i].cdev); 
    } 
    kfree(led_devs); 
} 
 
module_init(leds_init); 
module_exit(leds_exit); 
 
MODULE_LICENSE("GPL"); 
MODULE_AUTHOR("Mr.Sun");