docs/extra-build-config.md: Infrared

Add instructions how to use variable ENABLE_IR for infrared
support, for example with LIRC.

Signed-off-by: Leon Anavi <leon.anavi@konsulko.com>
This commit is contained in:
Leon Anavi 2020-06-24 15:03:38 +03:00 committed by Andrei Gherzan
parent 770a69f18d
commit 260b89ecd1

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@ -261,6 +261,18 @@ In order to use Pican2 CAN module, set the following variables:
See: <http://skpang.co.uk/catalog/pican2-canbus-board-for-raspberry-pi-23-p-1475.html> See: <http://skpang.co.uk/catalog/pican2-canbus-board-for-raspberry-pi-23-p-1475.html>
## Enable infrared
Users who want to enable infrared support, for example for using LIRC (Linux
Infrared Remote Control), have to explicitly set in local.conf:
ENABLE_IR = "1"
This will add device tree overlays gpio-ir and gpio-ir-tx to config.txt.
Appropriate kernel modules will be also included in the image. By default the
GPIO pin for gpio-ir is set to 18 and the pin for gpio-ir-tx is 17. Both pins
can be easily changed by modifying variables `GPIO_IR` and `GPIO_IR_TX`.
## Manual additions to config.txt ## Manual additions to config.txt
The `RPI_EXTRA_CONFIG` variable can be used to manually add additional lines to The `RPI_EXTRA_CONFIG` variable can be used to manually add additional lines to