system/fidl/ddk/protocols/i2c.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.i2c;

using zx;

const uint32 I2C_10_BIT_ADDR_MASK = 0xF000;

[Layout="ddk-protocol"]
interface I2c {
    /// Writes and reads data on an i2c channel. If both write_length and read_length
    /// are greater than zero, this call will perform a write operation immediately followed
    /// by a read operation with no other traffic occuring on the bus in between.
    /// If read_length is zero, then i2c_transact will only perform a write operation,
    /// and if write_length is zero, then it will only perform a read operation.
    /// The results of the operation are returned asynchronously via the complete_cb.
    /// The cookie parameter can be used to pass your own private data to the complete_cb callback.
    [Async]
    1: Transact(uint32 index, vector<void> write, usize read_length) -> (zx.status status,
                                                                         vector<void> read);
    /// Returns the maximum transfer size for read and write operations on the channel.
    2: GetMaxTransferSize(uint32 index) -> (zx.status s, usize size);
};