Can WIO backlight intensity be adjusted?

So far, I found
digitalWrite(LCD_BACKLIGHT, HIGH);
digitalWrite(LCD_BACKLIGHT, LOW);
What happens is that HIGH turns on the backlight to a very bright setting, very well readable. LOW seems to turn it off completely, making the display unreadable.
Problem is that the display is far too bright in low-light conditions. And I also would like to save battery power.
I would like to use the built-in light sensor, enabled by pinMode(WIO_LIGHT, INPUT); and connected to A13 to adjust the backlight brightness.
Any idea if this is a possibility?