linux_dsm_epyc7002/Documentation/devicetree/bindings/pps/pps-gpio.txt
Tom Burkart 652e22185a dt-bindings: pps: pps-gpio PPS ECHO implementation
This patch implements the device tree binding changes required for the
PPS ECHO functionality for pps-gpio, that sysfs claims is available
already.

It adds two DT properties for configuring the PPS ECHO functionality.

This patch is provided separated from the rest of the patch per
Documentation/devicetree/bindings/submitting-patches.txt.

This patch was originally written by Lukas Senger as part of a masters
thesis project and modified for inclusion into the linux kernel by Tom
Burkart.

Link: http://lkml.kernel.org/r/20190324043305.6627-3-tom@aussec.com
Signed-off-by: Tom Burkart <tom@aussec.com>
Signed-off-by: Lukas Senger <lukas@fridolin.com>
Acked-by: Rodolfo Giometti <giometti@enneenne.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Cc: Philipp Zabel <philipp.zabel@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14 19:52:51 -07:00

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Device-Tree Bindings for a PPS Signal on GPIO
These properties describe a PPS (pulse-per-second) signal connected to
a GPIO pin.
Required properties:
- compatible: should be "pps-gpio"
- gpios: one PPS GPIO in the format described by ../gpio/gpio.txt
Additional required properties for the PPS ECHO functionality:
- echo-gpios: one PPS ECHO GPIO in the format described by ../gpio/gpio.txt
- echo-active-ms: duration in ms of the active portion of the echo pulse
Optional properties:
- assert-falling-edge: when present, assert is indicated by a falling edge
(instead of by a rising edge)
Example:
pps {
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_pps>;
gpios = <&gpio1 26 GPIO_ACTIVE_HIGH>;
assert-falling-edge;
echo-gpios = <&gpio1 27 GPIO_ACTIVE_HIGH>;
echo-active-ms = <100>;
compatible = "pps-gpio";
};