sdk/banjo/fuchsia.hardware.i2c/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.
@available(added=7)
library fuchsia.hardware.i2c;

using zx;

const I2C_10_BIT_ADDR_MASK uint32 = 0xF000;
const I2C_MAX_RW_OPS uint32 = 8;
const I2C_MAX_TOTAL_TRANSFER uint32 = 4096;

/// See `Transact` below for usage.
type I2cOp = struct {
    @buffer
    data vector<uint8>:MAX;
    is_read bool;
    stop bool;
};

@transport("Banjo")
@banjo_layout("ddk-protocol")
@handle_wrappers
protocol I2c {
    /// Writes and reads data on an i2c channel. Up to I2C_MAX_RW_OPS operations can be passed in
    /// with a maximum of I2C_MAX_TOTAL_TRANSFER total bytes transfered.
    /// For write ops, i2c_op_t.data points to data to write.  The data to write does not need to be
    /// kept alive after this call.  For read ops, i2c_op_t.data is ignored.  Any combination of
    /// reads and writes can be specified.  At least the last op must have the stop flag set.
    /// The results of the operations are returned asynchronously via the transact_cb.
    /// The cookie parameter can be used to pass your own private data to the transact_cb callback.
    @async
    Transact(struct {
        op vector<I2cOp>:MAX;
    }) -> (struct {
        status zx.status;
        op vector<I2cOp>:MAX;
    });
    /// Returns the maximum transfer size for read and write operations on the channel.
    GetMaxTransferSize() -> (struct {
        s zx.status;
        size uint64;
    });
};