This adds a binding for a generic GPIO reset driver. This driver is designed to easily add a GPIO-based reset to a driver which expected a reset controller. It offers greater flexibility than a reset-gpios property, and allows for one code path to be shared for GPIO resets and MMIO-based resets. Signed-off-by: Sean Anderson <sean.anderson@xxxxxxxx> --- .../devicetree/bindings/reset/gpio-reset.yaml | 93 +++++++++++++++++++ 1 file changed, 93 insertions(+) create mode 100644 Documentation/devicetree/bindings/reset/gpio-reset.yaml diff --git a/Documentation/devicetree/bindings/reset/gpio-reset.yaml b/Documentation/devicetree/bindings/reset/gpio-reset.yaml new file mode 100644 index 000000000000..de2ab074cea3 --- /dev/null +++ b/Documentation/devicetree/bindings/reset/gpio-reset.yaml @@ -0,0 +1,93 @@ +# SPDX-License-Identifier: (GPL-2.0+ OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/reset/gpio-reset.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Generic GPIO reset driver + +maintainers: + - Sean Anderson <seanga2@xxxxxxxxx> + +description: | + This is a generic GPIO reset driver which can provide a reset-controller + interface for GPIO-based reset lines. This driver always operates with + logical GPIO values; to invert the polarity, specify GPIO_ACTIVE_LOW in the + GPIO's flags. + +properties: + compatible: + const: gpio-reset + + '#reset-cells': + const: 1 + + reset-gpios: + description: | + GPIOs to assert when asserting a reset. There is a one-to-one mapping + between the reset specifier and the index of the GPIO in this list to + assert. + + done-gpios: + description: | + GPIOs which indicate that the device controlled by the GPIO has exited + reset. There must be one done GPIO for each reset GPIO, or no done GPIOs + at all. The driver will wait for up to done-timeout-us for the + corresponding done GPIO to assert before returning. + + pre-assert-us: + default: 0 + description: | + Microseconds to delay between when the reset was requested to be + asserted, and asserting the reset GPIO + + post-assert-us: + default: 0 + description: | + Microseconds to delay after asserting the reset GPIO and before returning + to the caller. + + pre-deassert-us: + default: 0 + description: | + Microseconds to delay between when the reset was requested to be + deasserted, and asserting the reset GPIO + + post-deassert-us: + default: 0 + description: | + Microseconds to delay after deasserting the reset GPIO and before + returning to the caller. This delay is always present, even if the done + GPIO goes high earlier. + + done-timeout-us: + default: 1000 + description: + Microseconds to wait for the done GPIO to assert after deasserting the + reset GPIO. If post-deassert-us is present, this property defaults to 10 + times that delay. The timeout starts after waiting for the post deassert + delay. + +required: + - '#reset-cells' + - compatible + - reset-gpios + +additionalProperties: false + +examples: + - | + #include <dt-bindings/gpio/gpio.h> + pcs_reset: reset-pcs { + #reset-cells = <1>; + compatible = "gpio-reset"; + reset-gpios = <&gpio 0 GPIO_ACTIVE_LOW>, + <&gpio 1 GPIO_ACTIVE_LOW>, + <&gpio 2 GPIO_ACTIVE_LOW>, + <&gpio 3 GPIO_ACTIVE_LOW>; + done-gpios = <&gpio 4 GPIO_ACTIVE_HIGH>, + <&gpio 5 GPIO_ACTIVE_HIGH>, + <&gpio 6 GPIO_ACTIVE_HIGH>, + <&gpio 7 GPIO_ACTIVE_HIGH>; + post-deassert-us = <100>; + }; -- 2.25.1
