system/fidl/ddk/protocols/gpio.fidl

// Copyright 2018 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

library ddk.protocol.gpio;

using zx;


/// Flags for `ConfigIn`.
const uint32 GPIO_PULL_DOWN = 0x0;
const uint32 GPIO_PULL_UP = 0x10;
const uint32 GPIO_NO_PULL = 0x20;
const uint32 GPIO_PULL_MASK = 0x30;

/// Values for `SetPolarity`.
enum GpioPolarity : uint32 {
    LOW = 0x0;
    HIGH = 0x1;
};

/// In the functions below, the GPIO index is relative to the list of GPIOs for the device.
/// For example, the list of GPIOs a platform device has access to would likely be a small
/// subset of the total number of GPIOs, while a platform bus implementation driver would
/// have access to the complete set of GPIOs.
[Layout="ddk-protocol"]
interface Gpio {
    /// Configures a GPIO for input.
    1: ConfigIn(uint32 index, uint32 flags) -> (zx.status s);
    /// Configures a GPIO for output.
    2: ConfigOut(uint32 index, uint8 initial_value) -> (zx.status s);
    /// Configures the GPIO pin for an alternate function (I2C, SPI, etc)
    /// the interpretation of "function" is platform dependent.
    3: SetAltFunction(uint32 index, uint64 function) -> (zx.status s);
    /// Reads the current value of a GPIO (0 or 1).
    4: Read(uint32 index) -> (zx.status s, uint8 value);
    /// Sets the current value of the GPIO (any non-zero value maps to 1).
    5: Write(uint32 index, uint8 value) -> (zx.status s);
    /// Gets an interrupt object pertaining to a particular GPIO pin.
    6: GetInterrupt(uint32 index, uint32 flags) -> (zx.status s, handle<interrupt> irq);
    /// Release the interrupt.
    7: ReleaseInterrupt(uint32 index) -> (zx.status s);
    /// Set GPIO polarity.
    8: SetPolarity(uint32 index, GpioPolarity polarity) -> (zx.status s);
};