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feat(docs): Note GPIO flags and add examples

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Cem Aksoylar 2023-09-02 14:45:25 -07:00 • committed by Pete Johanson
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docs/docs/config/kscan.md
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@ -86,6 +86,18 @@ By default, a switch will drain current through the internal pull up/down resist
`toggle-mode` applies to all switches handled by the instance of the driver. To use a toggle switch with other, non-toggle, direct GPIO switches, create two instances of the direct GPIO driver, one with `toggle-mode` and the other without. Then, use a [composite driver](#composite-driver) to combine them.
Assuming the switches connect each GPIO pin to the ground, the [GPIO flags](https://docs.zephyrproject.org/3.2.0/hardware/peripherals/gpio.html#api-reference) for the elements in `input-gpios` should be `(GPIO_ACTIVE_LOW | GPIO_PULL_UP)`:
```devicetree
kscan0: kscan {
compatible = "zmk,kscan-gpio-direct";
input-gpios
= <&pro_micro 4 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>
, <&pro_micro 5 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>
;
};
```
## Matrix Driver
Keyboard scan driver where keys are arranged on a matrix with one GPIO per row and column.
@ -122,6 +134,24 @@ The `diode-direction` property must be one of:
| `"row2col"` | Diodes point from rows to columns (cathodes are connected to columns) |
| `"col2row"` | Diodes point from columns to rows (cathodes are connected to rows) |
Given the `diode-direction`, the [GPIO flags](https://docs.zephyrproject.org/3.2.0/hardware/peripherals/gpio.html#api-reference) for the elements in `row-` and `col-gpios` should be set appropriately.
The output pins (e.g. columns for `col2row`) should have the flag `GPIO_ACTIVE_HIGH`, and input pins (e.g. rows for `col2row`) should have the flags `(GPIO_ACTIVE_HIGH | GPIO_PULL_DOWN)`:
```devicetree
kscan0: kscan {
compatible = "zmk,kscan-gpio-matrix";
diode-direction = "col2row";
col-gpios
= <&pro_micro 4 GPIO_ACTIVE_HIGH>
, <&pro_micro 5 GPIO_ACTIVE_HIGH>
;
row-gpios
= <&pro_micro 6 (GPIO_ACTIVE_HIGH | GPIO_PULL_DOWN)>
, <&pro_micro 7 (GPIO_ACTIVE_HIGH | GPIO_PULL_DOWN)>
;
};
```
## Composite Driver
Keyboard scan driver which combines multiple other keyboard scan drivers.