On 14/12/2022 10:53, Alexander Stein wrote: > This adds bindings for a GPIO enable/disable delay driver. > > Signed-off-by: Alexander Stein <alexander.stein@xxxxxxxxxxxxxxx> > --- > .../devicetree/bindings/gpio/gpio-delay.yaml | 75 +++++++++++++++++++ > 1 file changed, 75 insertions(+) > create mode 100644 Documentation/devicetree/bindings/gpio/gpio-delay.yaml > > diff --git a/Documentation/devicetree/bindings/gpio/gpio-delay.yaml b/Documentation/devicetree/bindings/gpio/gpio-delay.yaml > new file mode 100644 > index 000000000000..20871356e9b5 > --- /dev/null > +++ b/Documentation/devicetree/bindings/gpio/gpio-delay.yaml > @@ -0,0 +1,75 @@ > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) > +%YAML 1.2 > +--- > +$id: http://devicetree.org/schemas/gpio/gpio-delay.yaml# > +$schema: http://devicetree.org/meta-schemas/core.yaml# > + > +title: GPIO delay controller > + > +maintainers: > + - Alexander Stein <linux@xxxxxxxxxxxxxxx> > + > +description: | > + This binding describes an electrical setup where setting an GPIO output > + is delayed by some external setup, e.g. RC curcuit. > + > + +----------+ +-----------+ > + | | VCC_B | | > + | | | | | > + | | VCC_A _ | | > + | GPIO | | | R | Consumer | > + |controller| ___ |_| | | > + | | | | | | | > + | [IOx|-------| |--+-----|-----+ | > + | | |___| | | input | > + | | | | | > + +----------+ --- C +-----------+ > + --- > + | > + - > + GND > + > + If the input on the consumer is controlled by an open-drain signal If IOx is open-drain, what is the VCC_A on the diagram? I think it wasn't present in original Laurent's diagram. > + attached to an RC curcuit the ramp-up delay is not under control > + of the GPIO controller. > + > +properties: > + compatible: > + const: gpio-delay > + > + "#gpio-cells": > + description: | > + Specifies the pin, ramp-up and ramp-down delays. The > + delays are specified in microseconds. > + const: 3 > + > + input-gpios: > + description: Array of GPIOs which output signal change is delayed maxItems: 32 or some other reasonable value > + > + gpio-controller: true > + > + gpio-line-names: true and then the same maxItems. > + > +required: > + - compatible > + - "#gpio-cells" > + - gpio-controller > + - input-gpios > + > +additionalProperties: false > + > +examples: > + - | > + #include <dt-bindings/gpio/gpio.h> > + > + enable_delay: enable-delay { > + compatible = "gpio-delay"; I am not sure whether the naming is the most accurate - it represents desired behavior (so the delay in rising signal), not actual hardware (RC filter), but maybe that's a bit more generic. Anyway look fine for me. > + #gpio-cells = <3>; > + gpio-controller; > + input-gpios = <&gpio0 3 GPIO_ACTIVE_LOW>, > + <&gpio3 1 GPIO_ACTIVE_HIGH>; > + }; > + > + consumer { > + enable-gpios = <&enable_delay 0 130000 30000>; > + }; Best regards, Krzysztof
