Wiegand write-only driver requires definitions of two GPIO lines in the devicetree. This adds the documentation of their definitions. Signed-off-by: Martin Zaťovič <m.zatovic1@xxxxxxxxx> --- .../devicetree/bindings/bus/wiegand-gpio.yaml | 66 +++++++++++++++++++ MAINTAINERS | 1 + 2 files changed, 67 insertions(+) create mode 100644 Documentation/devicetree/bindings/bus/wiegand-gpio.yaml diff --git a/Documentation/devicetree/bindings/bus/wiegand-gpio.yaml b/Documentation/devicetree/bindings/bus/wiegand-gpio.yaml new file mode 100644 index 000000000000..74733aadc61e --- /dev/null +++ b/Documentation/devicetree/bindings/bus/wiegand-gpio.yaml @@ -0,0 +1,66 @@ +# SPDX-License-Identifier: GPL-2.0-only + +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/bus/wiegand-gpio.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Wiegand write-only GPIO driver + +maintainers: + - Martin Zaťovič <m.zatovic1@xxxxxxxxx> + +description: | + Wiegand interface is a wiring standard popularized in the 1980s. To this day + many card readers, fingerprint readers, sensors, etc. use Wiegand interface + particularly for access control applications. It utilizes two wires to + transmit the data - D0 and D1. + + Both data lines are initially pulled up. To send a bit of value 1, the D1 + line is set low. Similarly to send a bit of value 0, the D0 line is set low. + Standard Wiegand formats include 26, 36 and 37 bit and they reserve the first + and last bits for parity. The first(MSB) parity bit is set to 1 if the parity + of the first half of the payload is odd. The last(LSB) parity bit is set to 1 + if the parity of the second half of the payload even. + +properties: + $nodename: + pattern: "^wiegand-gpio(@[0-9a-f]+)?$" + + compatible: + contains: + const: gpio,wiegand-gpio + description: + Shall contain "wiegand-gpio" for the driver to match with this node. + + wiegand-data-hi-gpios: + description: + gpio used to transmit bits the value of which is 1, it should be + flagged as active high with GPIO_ACTIVE_HIGH from + <dt-bindings/gpio/gpio.h>. + maxItems: 1 + + wiegand-data-lo-gpios: + description: + gpio used to transmit bits the value of which is 1, it should be + flagged as active high with GPIO_ACTIVE_HIGH from + <dt-bindings/gpio/gpio.h>. + maxItems: 1 + +required: + - compatible + - wiegand-data-hi-gpios + - wiegand-data-lo-gpios + +additionalProperties: true + +examples: + - | + wiegand-gpio { + compatible = "wiegand-gpio"; + pinctrl-names = "default"; + pinctrl-0 = <&pinctrl_uart1_wiegand>; + wiegand-data-hi-gpios = <&gpio2 1 GPIO_ACTIVE_HIGH>; + wiegand-data-lo-gpios = <&gpio2 2 GPIO_ACTIVE_HIGH>; + status = "okay"; + }; diff --git a/MAINTAINERS b/MAINTAINERS index 9a519530e44e..c7db1e41cc02 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -21589,6 +21589,7 @@ F: drivers/rtc/rtc-sd3078.c WIEGAND WRITE-ONLY GPIO DRIVER M: Martin Zaťovič <m.zatovic1@xxxxxxxxx> S: Maintained +F: Documentation/devicetree/bindings/bus/wiegand-gpio.yaml F: drivers/bus/wiegand-gpio.c F: drivers/bus/wiegand-gpio.h -- 2.37.1
