diff --git a/README b/README
index a5c8a74..3759ebf 100644
--- a/README
+++ b/README
@@ -25,6 +25,15 @@ useful resources:
 		https://www.kernel.org/doc/html/latest/spi/spidev.html
 		https://hub.libre.computer/t/how-to-enable-spi-on-aml-s905x-cc-le-potato/285
 
+	GPIO:
+		https://git.kernel.org/pub/scm/libs/libgpiod/libgpiod.git/tree/README
+		https://git.kernel.org/pub/scm/libs/libgpiod/libgpiod.git/tree/include/gpiod.h
+		https://github.com/starnight/libgpiod-example/blob/master/libgpiod-led/main.c
+		https://libgpiod.readthedocs.io/en/latest/index.html
+
 	MCP4921 datasheet:
 		https://ww1.microchip.com/downloads/aemDocuments/documents/OTH/ProductDocuments/DataSheets/22248a.pdf
 
+	AML-S905X-CC:
+		https://hub.libre.computer/t/libre-computer-wiring-tool/40
+		https://hub.libre.computer/t/aml-s905x-cc-wiring-tool-overlays-description/62