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The gpio-matrix-keypad driver normally sets inactive columns as inputs while scanning. This does not work for all hardware, which may require the inactive columns to be actively driven in order to overcome any pull-ups/downs on the columns. Signed-off-by: David Rivshin <drivshin@allworx.com> Acked-by: Rob Herring <robh@kernel.org> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
50 lines
1.7 KiB
Plaintext
50 lines
1.7 KiB
Plaintext
* GPIO driven matrix keypad device tree bindings
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GPIO driven matrix keypad is used to interface a SoC with a matrix keypad.
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The matrix keypad supports multiple row and column lines, a key can be
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placed at each intersection of a unique row and a unique column. The matrix
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keypad can sense a key-press and key-release by means of GPIO lines and
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report the event using GPIO interrupts to the cpu.
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Required Properties:
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- compatible: Should be "gpio-matrix-keypad"
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- row-gpios: List of gpios used as row lines. The gpio specifier
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for this property depends on the gpio controller to
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which these row lines are connected.
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- col-gpios: List of gpios used as column lines. The gpio specifier
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for this property depends on the gpio controller to
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which these column lines are connected.
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- linux,keymap: The definition can be found at
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bindings/input/matrix-keymap.txt
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Optional Properties:
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- linux,no-autorepeat: do no enable autorepeat feature.
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- wakeup-source: use any event on keypad as wakeup event.
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(Legacy property supported: "linux,wakeup")
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- debounce-delay-ms: debounce interval in milliseconds
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- col-scan-delay-us: delay, measured in microseconds, that is needed
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before we can scan keypad after activating column gpio
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- drive-inactive-cols: drive inactive columns during scan,
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default is to turn inactive columns into inputs.
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Example:
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matrix-keypad {
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compatible = "gpio-matrix-keypad";
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debounce-delay-ms = <5>;
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col-scan-delay-us = <2>;
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row-gpios = <&gpio2 25 0
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&gpio2 26 0
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&gpio2 27 0>;
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col-gpios = <&gpio2 21 0
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&gpio2 22 0>;
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linux,keymap = <0x0000008B
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0x0100009E
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0x02000069
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0x0001006A
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0x0101001C
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0x0201006C>;
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};
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