1 // SPDX-License-Identifier: GPL-2.0-or-later 2 3 #include <linux/backlight.h> 4 #include <linux/export.h> 5 #include <linux/fb.h> 6 #include <linux/mutex.h> 7 8 #if IS_ENABLED(CONFIG_FB_BACKLIGHT) 9 /* 10 * This function generates a linear backlight curve 11 * 12 * 0: off 13 * 1-7: min 14 * 8-127: linear from min to max 15 */ 16 void fb_bl_default_curve(struct fb_info *fb_info, u8 off, u8 min, u8 max) 17 { 18 unsigned int i, flat, count, range = (max - min); 19 20 mutex_lock(&fb_info->bl_curve_mutex); 21 22 fb_info->bl_curve[0] = off; 23 24 for (flat = 1; flat < (FB_BACKLIGHT_LEVELS / 16); ++flat) 25 fb_info->bl_curve[flat] = min; 26 27 count = FB_BACKLIGHT_LEVELS * 15 / 16; 28 for (i = 0; i < count; ++i) 29 fb_info->bl_curve[flat + i] = min + (range * (i + 1) / count); 30 31 mutex_unlock(&fb_info->bl_curve_mutex); 32 } 33 EXPORT_SYMBOL_GPL(fb_bl_default_curve); 34 35 struct backlight_device *fb_bl_device(struct fb_info *info) 36 { 37 return info->bl_dev; 38 } 39 EXPORT_SYMBOL(fb_bl_device); 40 41 void fb_bl_notify_blank(struct fb_info *info, int old_blank) 42 { 43 bool on = info->blank == FB_BLANK_UNBLANK; 44 bool prev_on = old_blank == FB_BLANK_UNBLANK; 45 46 if (info->bl_dev) 47 backlight_notify_blank(info->bl_dev, info->device, on, prev_on); 48 else 49 backlight_notify_blank_all(info->device, on, prev_on); 50 } 51 #endif 52