Android灯光系统框架分析， Linux的led class驱动

root@android-virtual-machine:/sys/class/leds# cd /
root@android-virtual-machine:/# find ./ -name 'leds_4412*'
./work/linux-3.0.86/drivers/char/leds_4412.o
./work/linux-3.0.86/drivers/char/leds_4412.c
root@android-virtual-machine:/#

#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;
};

static struct led_desc led_gpios[] = {

{EXYNOS4212_GPM4(0), "led1"},
   {EXYNOS4212_GPM4(1), "led2"},
   {EXYNOS4212_GPM4(2), "led3"},
   //{EXYNOS4212_GPM4(3), "led4"},
       {EXYNOS4212_GPM4(3),"led4"},
};

//struct led_classdev_4412 {
// struct led_classdev cdev;
// int gpio;
//};

   struct led_classdev_4412 {
       struct led_classdev cdev;
       int gpio;
   }

//static struct led_classdev_4412 *led_devs;
static struct led_classdev_4412 *led_devs;

//static void   brightness_set_4412(struct led_classdev *led_cdev,
       //   enum led_brightness brightness)

       static struct brightness_set_4412 (struct led_classdev *led_cdev,
       enum led_brightness brightness
       )
{
   //struct led_classdev_4412 *dev = (struct led_classdev_4412 *)led_cdev;
   //struct led_classdev_4412 *dev = (struct led_classdev_4412 *)led_cdev;
   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);
       gpio_set_value(dev->gpio,0);
   else
       gpio_set_value(dev->gpio, 1);
}

static int leds_init(void)
{
   int i;
   int ret;
   /*1. alloc led_classdev*/

//led_devs = kzalloc(sizeof(struct led_classdev_4412) * sizeof(led_gpios)/sizeof(led_gpios[0]), GFP_KERNEL);

   led_devs = kzalloc(sizeof(struct led_classdev_4412) * sizeof(led_gpios) /
   sizeof(led_gpios[0]),GFP_KERNEL);
   if (led_devs == NULL) {
       printk("No memory for device\n");
       return -ENOMEM;
   }

   for (i = 0; i < sizeof(led_gpios)/sizeof(led_gpios[0]); i++)
   {

       s3c_gpio_cfgpin(led_gpios[i].gpio, S3C_GPIO_OUTPUT);
       gpio_set_value(led_gpios[i].gpio, 1);

       /* 2. set */
       led_devs[i].cdev.max_brightness = LED_FULL;
       //led_devs[i].cdev.brightness_set = brightness_set_4412;
       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].cdev.default_trigger = "timer";
       led_devs[i].gpio = led_gpios[i].gpio;

       /* 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 < sizeof(led_gpios)/sizeof(led_gpios[0]); i++)
   {
       led_classdev_unregister(&led_devs[i].cdev);
   }
   kfree(led_devs);
}

module_init(leds_init);
module_exit(leds_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("www.100ask.net");

把 leds_4412.c 放到drivers/leds
修改 drivers/leds/Makefile:
obj-y += leds_4412.o

make menuconfig

./work/linux-3.0.86/drivers

drivers/leds/leds_4412.c:47:11: error: two or more data types in declaration specifiers
drivers/leds/leds_4412.c:52:38: error: expected identifier or '(' before 'struct'
drivers/leds/leds_4412.c: In function 'leds_init':
drivers/leds/leds_4412.c:95:37: error: 'brightness_set_4412' undeclared (first use in this function)
drivers/leds/leds_4412.c:95:37: note: each undeclared identifier is reported only once for each function it appears in
make[2]: *** [drivers/leds/leds_4412.o] Error 1
make[1]: *** [drivers/leds] Error 2
make: *** [drivers] Error 2
root@android-virtual-machine:/work/linux-3.0.86#

来源：oschina

链接：https://my.oschina.net/u/4382386/blog/4320787

标签

gPM

Linux

android

Android灯光系统 框架分析 ， Linux的led class驱动

Android灯光系统框架分析， Linux的led class驱动