# Modify the Screen Backlight Driver

(modify-lcd-bl-c-file)=
## Modify the Copied Driver File
Here, we use the aw9364 backlight driver as an example:
### Initialization
In the `aw9364_init` function, the control pin `LCD_BACKLIGHT_CONTROL_PIN` is initialized as a GPIO output, and it is set to low (turn off the backlight).

### Set Backlight Brightness
In the callback function `backligt_set`, the brightness percentage passed from the upper layer is converted (based on the brightness levels supported by the backlight IC) and then passed to the `sif_aw9364_set_backlight` function to set the brightness.

### Read Backlight Brightness
In the callback function `backligt_get`, the brightness is returned using the variable `aw9364_bl`, as this backlight chip does not support reading the brightness level.