Add documentation for gpio-shutdown

Signed-off-by: Otto Esko <otto.esko@gmail.com>
This commit is contained in:
Otto Esko 2021-12-09 21:11:09 +02:00 committed by Andrei Gherzan
parent bf2d2eae4e
commit 2e3ed68f9d

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@ -320,6 +320,24 @@ 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`.
## Enable gpio-shutdown
When using device tree kernels, set this variable to enable gpio-shutdown:
ENABLE_GPIO_SHUTDOWN = "1"
This will add the corresponding device tree overlay to config.txt and include
the gpio-keys kernel module in the image. If System V init is used, additional
mapping is applied to bind the button event to shutdown command. Systemd init
should handle the event out of the box.
By default the feature uses gpio pin 3 (except RPi 1 Model B rev 1 enumerates
the pin as gpio 1). This conflicts with the I2C bus. If you set `ENABLE_I2C`
to `1` or enabled `PiTFT` support, or otherwise want to use another pin, use
`GPIO_SHUTDOWN_PIN` to assign another pin. Example using gpio pin 25:
GPIO_SHUTDOWN_PIN = "25"
## Manual additions to config.txt
The `RPI_EXTRA_CONFIG` variable can be used to manually add additional lines to