Hi @philippe.tx
I’ve had some success on point 1. I’ve amended the apalis_imx6.c file with a patch, where I’ve changed the RGB_BACKLIGHT_GP GPIO from the default (3, 13) to my actual BLEN pin (1, 1), and then changed the direction to 0 as mentioned above. This has partially addressed the problem, as the backlight stays off during U-Boot now as desired. However, as I’ve set my BLEN pin (GPIO1 1) as ACTIVE_HIGH in the device tree, the backlight turns on momentarily when the board is first powered, and then turns off once U-Boot starts, then turns on again when the kernel starts.
As such, it would seem I need to configure my BLEN pin with a pull down so it remains off in the reset/uncontrolled state, but then have the kernel pull it high. I.e. the following process:
- Device powered up, BLEN pulled low (as per GPIO_ACTIVE_LOW definition in .dts patch)
- U-Boot
- Kernel begins
- Kernel splash displayed on framebuffer
- BLEN toggled HIGH
- Hand over to operating system
How would I go about toggling the BLEN pin, ensuring it’s toggled immediately after the splash routine has been run in the kernel?