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// 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 MAX_TRANSFER_SIZE uint32 = 8196; // More than enough for I2C
const MAX_COUNT_SEGMENTS uint32 = 8; // Enough for all known transfer configurations.
const MAX_I2C_CHANNEL uint32 = 128; // Enough for every address to be used in 7-bit mode.
type SegmentType = strict enum {
/// Flags the end of a serialized list of segments.
END = 1;
/// Segment to be read from the I2C device.
READ = 2;
/// Segment to be written to the I2C device.
WRITE = 3;
};
/// Used to inform the i2c driver about an attached i2c device.
type I2CChannel = table {
/// ID of the bus that this device is on.
1: bus_id uint32;
/// Adress of the device.
2: address uint16;
/// Class of the device.
/// TODO(fxbug.dev/78198): remove this once x86 uses ACPI properly.
3: i2c_class uint32;
/// Vendor ID. Used when binding via platform bus device IDs.
4: vid uint32;
/// Product ID. Used when binding via platform bus device IDs.
5: pid uint32;
/// Device ID. Used when binding via platform bus device IDs.
6: did uint32;
// Bus configuration.
/// Are we in charge of the bus?
7: is_bus_controller bool;
/// Is this device using 10-bit addressing mode (if false, use 7-bit).
8: is_ten_bit bool;
/// Speed of the bus.
9: bus_speed uint32;
};
/// Passed to the i2c driver in metadata as DEVICE_METADATA_I2C_CHANNELS.
type I2CBusMetadata = table {
1: channels vector<I2CChannel>:MAX_I2C_CHANNEL;
};
// A previous `Device` is now removed.
@discoverable
protocol Device2 {
/// Write and read segments of data for a particular I2C device.
///
/// The `segments_is_write` vector specifies the type (write or read) of each segment.
/// The `write_segments_data` vector of segments specifies the data to write for each write
/// segment. Each segment itself is a vector of uint8s, so `write_segments_data` is a vector of
/// vectors of uint8s.
/// The `read_segments_length` vector specifies the length of the read segments. No entry may be
/// larger than MAX_TRANSFER_SIZE.
/// If there is no error, `read_segments_data` returns a vector of segments, with each segment
/// data itself returned in vectors.
///
/// For a simple I2C read, for instance 2 bytes write followed by one byte read,
/// `segments_is_write` would be a vector with 2 elements: true, false and
/// `write_segments_data` would be a vector with 1 element including the 2 bytes address of the
/// read. Upon success `read_segments_data` would return a vector with one element, the byte
/// read.
Transfer(struct {
segments_is_write vector<bool>:MAX_COUNT_SEGMENTS;
write_segments_data vector<vector<uint8>:MAX_TRANSFER_SIZE>:MAX_COUNT_SEGMENTS;
read_segments_length vector<uint32>:MAX_COUNT_SEGMENTS;
}) -> (struct {
read_segments_data vector<vector<uint8>:MAX_TRANSFER_SIZE>:MAX_COUNT_SEGMENTS;
}) error zx.status;
};