genode/repos/os/include/i2c_session/i2c_session.h
Stefan Kalkowski ed7d6c74f4 i2c: extend API to support transactions
Introduces the notion of a transaction that consists of one or more
messages. Whereby a message has a read or write direction and consists
of one or more bytes.

Issue #4170
Fixes #4169
2021-05-28 14:16:45 +02:00

98 lines
2.1 KiB
C++

/*
* \brief I2C session client implementation
* \author Jean-Adrien Domage <jean-adrien.domage@gapfruit.com>
* \date 2021-02-25
*/
/*
* Copyright (C) 2013-2021 Genode Labs GmbH
* Copyright (C) 2021 gapfruit AG
*
* This file is part of the Genode OS framework, which is distributed
* under the terms of the GNU Affero General Public License version 3.
*/
#ifndef _INCLUDE__I2C_SESSION__I2C_SESSION_H_
#define _INCLUDE__I2C_SESSION__I2C_SESSION_H_
#include <session/session.h>
#include <base/stdint.h>
#include <util/array.h>
namespace I2c {
using namespace Genode;
struct Session;
}
struct I2c::Session : public Genode::Session
{
/**
* \noapi
*/
static char const *service_name() { return "I2c"; }
enum { CAP_QUOTA = 2 };
/***************
** Exception **
***************/
/**
* Exception thrown in case of a bus error
*
* This exception is thrown by the driver in case of a timeout, device missing
* acknowledgement and bus arbitration lost.
*/
class Bus_error : public Exception {};
using Byte_array = Array<uint8_t, 8>;
/**
* A message to an I2C slave is either a read or write of one or more bytes
*/
struct Message : Byte_array
{
enum Type { READ, WRITE };
Type type { READ };
Message() {}
template<typename ... ARGS>
Message(Type type, ARGS ... args)
: Byte_array(args...), type(type) {}
};
/**
* A transaction to an I2C slave consists of one, or several messages
*/
struct Transaction : Array<Message,2>
{
using Base = Array<Message,2>;
using Base::Base;
};
/***********************
** Session interface **
***********************/
/**
* Initiate a transaction on the bus
*
* \param transaction The transaction to be transmitted to the I2c host
*
* \throw I2c::Session::Bus_error An error occured while performing an operation on the bus
*/
virtual void transmit(Transaction & transaction) = 0;
GENODE_RPC_THROW(Rpc_transmit, void, transmit,
GENODE_TYPE_LIST(Bus_error), Transaction &);
GENODE_RPC_INTERFACE(Rpc_transmit);
};
#endif /* _INCLUDE__I2C_SESSION__I2C_SESSION_H_ */