C180_oyster_driver/backlight.c

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/cdev.h>
#include <linux/device.h>
#include <linux/uaccess.h>
#include <linux/slab.h>
#include <linux/pci.h>
#include <linux/i2c.h>
#include <linux/acpi.h>
#include <linux/interrupt.h>
#include <linux/wait.h>
#include <linux/sched.h>
#include <linux/poll.h>
#include <linux/mutex.h>
#include <linux/delay.h>
#include "light_ring.h"


extern struct kobject *vfiec_kobj;
static struct kobject *backlight_kobj = NULL;


/* ==================== mode ==================== */
static ssize_t brightness_show(struct kobject *kobj, struct kobj_attribute *attr,
                         char *buf)
{
    static int count = 0;
    count++;

    return sprintf(buf, "mode_show count=%d\n", count);
}

static ssize_t brightness_store(struct kobject *kobj, struct kobj_attribute *attr,
                          const char *buf, size_t count)
{
    printk("mode_store kernel rev:%s\n", buf);
    return count;
}

static struct kobj_attribute brightness =
    __ATTR(brightness, 0644, brightness_show, brightness_store);

/* ==================== 属性组 ==================== */
static struct attribute *backlight_attrs[] = {
    &brightness.attr,
    NULL,
};

static struct attribute_group backlight_attr_group = {
    .attrs = backlight_attrs,
};

int backlight_init(void)
{
    int ret;
        /* 创建 /sys/kernel/vfiec/lightring */
    backlight_kobj = kobject_create_and_add("backlight", vfiec_kobj);
    if (!backlight_kobj)
    {
        ret = -ENOMEM;
    }

    /* 创建属性文件 */
    ret = sysfs_create_group(backlight_kobj, &backlight_attr_group);
    if (ret)
    {
        pr_err("Faibacklight to create sysfs group: %d\n", ret);
    }

    return ret;
}

void backlight_exit(void)
{
    sysfs_remove_group(backlight_kobj, &backlight_attr_group);
    kobject_put(backlight_kobj);
}