// 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.
@available(added=7)
library fuchsia.hardware.i2cimpl;

using zx;

const I2C_IMPL_10_BIT_ADDR_MASK uint32 = 0xF000;
/// The maximum number of I2cImplOp's that may be passed to Transact.
const I2C_IMPL_MAX_RW_OPS uint32 = 8;
/// The maximum length of all read or all write transfers in bytes.
const I2C_IMPL_MAX_TOTAL_TRANSFER uint32 = 4096;

/// See `Transact` below for usage.
type I2cImplOp = struct {
    address uint16;
    @buffer
    @mutable
    data vector<uint8>:MAX;
    is_read bool;
    stop bool;
};

/// Low-level protocol for i2c drivers.
@transport("Banjo")
@banjo_layout("ddk-protocol")
closed protocol I2cImpl {
    strict GetMaxTransferSize() -> (struct {
        s zx.Status;
        size uint64;
    });
    /// Sets the bitrate for the i2c bus in KHz units.
    strict SetBitrate(struct {
        bitrate uint32;
    }) -> (struct {
        s zx.Status;
    });
    /// |Transact| assumes that all ops buf are not null.
    /// |Transact| assumes that all ops length are not zero.
    /// |Transact| assumes that at least the last op has stop set to true.
    strict Transact(struct {
        op vector<I2cImplOp>:MAX;
    }) -> (struct {
        status zx.Status;
    });
};