// SPDX-License-Identifier: GPL-2.0-or-later #include <linux/backlight.h>#include <linux/export.h>#include <linux/fb.h>#include <linux/mutex.h> #if IS_ENABLED(CONFIG_FB_BACKLIGHT)/* * This function generates a linear backlight curve * *     0: off *   1-7: min * 8-127: linear from min to max */void fb_bl_default_curve(struct fb_info *fb_info, u8 off, u8 min, u8 max){	unsigned int i, flat, count, range = (max - min); 	mutex_lock(&fb_info->bl_curve_mutex); 	fb_info->bl_curve[0] = off; 	for (flat = 1; flat < (FB_BACKLIGHT_LEVELS / 16); ++flat)		fb_info->bl_curve[flat] = min; 	count = FB_BACKLIGHT_LEVELS * 15 / 16;	for (i = 0; i < count; ++i)		fb_info->bl_curve[flat + i] = min + (range * (i + 1) / count); 	mutex_unlock(&fb_info->bl_curve_mutex);}EXPORT_SYMBOL_GPL(fb_bl_default_curve); struct backlight_device *fb_bl_device(struct fb_info *info){	return info->bl_dev;}EXPORT_SYMBOL(fb_bl_device); void fb_bl_notify_blank(struct fb_info *info, int old_blank){	bool on = info->blank == FB_BLANK_UNBLANK;	bool prev_on = old_blank == FB_BLANK_UNBLANK; 	if (info->bl_dev)		backlight_notify_blank(info->bl_dev, info->device, on, prev_on);	else		backlight_notify_blank_all(info->device, on, prev_on);}#endif