2.2 KiB
KScan sideband behavior
The kscan sideband behavior driver will be used to trigger the soft off behavior "out of band" from the normal keymap processing. To do so, it will decorate/wrap an underlying kscan driver.
For the matrix-integrated approach you will supplement the existing kscan matrix by adding the additional pin as another entry in
the row-gpios/col-gpios for whichever pins are used to read the matrix state. This approach requires a matrix transform to be present. As an example, consider the following existing kscan matrix:
/ {
kscan: kscan {
compatible = "zmk,kscan-gpio-matrix";
diode-direction = "col2row";
wakeup-source;
col-gpios
= <&gpio0 12 GPIO_ACTIVE_HIGH>
, <&gpio1 9 GPIO_ACTIVE_HIGH>
;
row-gpios
= <&gpio0 19 (GPIO_ACTIVE_HIGH | GPIO_PULL_DOWN)>
, <&gpio0 4 (GPIO_ACTIVE_HIGH | GPIO_PULL_DOWN)>
;
};
};
To supplement it with a soft off input, you would add another row value (without changing the matrix transform):
/ {
kscan: kscan {
compatible = "zmk,kscan-gpio-matrix";
diode-direction = "col2row";
wakeup-source;
col-gpios
= <&gpio0 12 GPIO_ACTIVE_HIGH>
, <&gpio1 9 GPIO_ACTIVE_HIGH>
;
row-gpios
= <&gpio0 19 (GPIO_ACTIVE_HIGH | GPIO_PULL_DOWN)>
, <&gpio0 4 (GPIO_ACTIVE_HIGH | GPIO_PULL_DOWN)>
, <&gpio0 2 (GPIO_ACTIVE_HIGH | GPIO_PULL_DOWN)>
;
};
};
With that in place, you would decorate the kscan driver:
/ {
side_band_behavior_triggers: side_band_behavior_triggers {
compatible = "zmk,kscan-sideband-behaviors";
wakeup-source;
kscan = <&kscan>;
soft_off {
column = <0>;
row = <2>;
bindings = <&hw_soft_off>;
};
};
};
Critically, the column and row values would correspond to the location of the added entry. The properties of the kscan-sideband-behaviors node can be found in the appropriate configuration section.