/*!
* \file /utl/com/i2c.h
* \brief An Abstract base class interface for the i2c bus
*
* Copyright (C) 2018 Christos Choutouridis
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation, either version 3
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see .
*
*/
#ifndef _utl_com_i2c_h__
#define _utl_com_i2c_h__
#include
#include
#include
namespace utl {
/*!
* \ingroup Communication
* \brief Abstract base class for i2c bus
*/
//!@{
/*!
* \brief
* this class force a common interface for I2C communication
* protocol implementations using CRTP
* \param impl_t The CRTP type (the derived/implementation class typename).
*/
template
class i2c_i {
_CRTP_IMPL(impl_t);
public:
using type = i2c_i; //!< Export type as identity meta-function
//! I2C transmit/receive sequence
enum class Sequence {
BYTE =0, //!< Only read/write byte [8 clocks]
ACK, //!< Only send/receive ack [1 clock]
BYTEnACK //!< Read/Write byte and ack [9 clocks]
};
/*!
* \name Object lifetime
*/
//!@{
protected:
i2c_i () = default; //!< Allow constructor from derived only
~i2c_i () = default; //!< Allow destructor from derived only
i2c_i (const type&) = delete; //!< No copies
type& operator= (const type&) = delete;
//!@}
/*!
* \name Implementation requirements
* \note
* In order for the implementation to have the following as private members
* it also need to declare this class as friend
*/
//!@{
//! uint32_t _frequency () const; < clock frequency of the bus [Hz]
//! void _frequency (uint32_t); < set clock frequency of the bus [Hz]
//! void _start(); < Send start functionality
//! void _stop(); < Send stop functionality
//! byte_t _read (bool ack, Sequence seq); < Receive a byte from the i2c bus.
//! bool _write (byte_t byte, Sequence seq);< Transmit a byte to the i2c bus.
//!@}
/*!
* \name Get/Set functions
*/
//!@{
public:
uint32_t frequency () const { return impl()._frequency (); } //!< \return clock frequency of the bus
void frequency (uint32_t f) { impl()._frequency (f); } //!< \brief set clock frequency of the bus
//!@}
/*!
* \name User functions
*/
//!@{
public:
void start() { impl()._start (); } //!< Send start functionality
void stop () { impl()._stop (); } //!< Send stop functionality
/*!
* \brief
* Receive a byte from the i2c bus.
* \param ack Optional ack bit.
* \arg 1 ACK the reception
* \arg 0 Don't ACK the reception.
* \param seq The operation sequence to execute
* \arg Sequence::BYTE Receive only the byte, do not send ack clock
* \arg Sequence::ACK Send only the ack bit
* \arg Sequence::BYTEnACK Receive the byte and send the ack bit
* \return The byte received.
*/
byte_t read (bool ack, Sequence seq =Sequence::BYTEnACK) {
return impl()._read (ack, seq);
}
/*!
* \brief
* Transmit a byte to the i2c bus.
* \param byte The byte to send.
* \param seq The operation sequence to execute
* \arg Sequence::BYTE Transmit only the byte, do not read ack bit
* \arg Sequence::ACK Read only the ack bit
* \arg Sequence::BYTEnACK Transmit the byte and read the ack bit
* \return Slave's ACK bit
* \arg false Slave didn't ACK
* \arg true Slave did ACK
*/
bool write (byte_t byte, Sequence seq =Sequence::BYTEnACK) {
return impl()._write (byte, seq);
}
//!@}
};
/*!
* \brief
* A virtual base class specialization
* \param impl_t = virtual_tag
*/
template<>
class i2c_i {
public:
using type = i2c_i ; //!< Export type as identity meta-function
//! I2C transmit/receive sequence
enum class Sequence {
BYTE=0, //!< Only read/write byte [8 clocks]
ACK, //!< Only send/receive ack [1 clock]
BYTEnACK //!< Read/Write byte and ack [9 clocks]
};
/*!
* \name Object lifetime
*/
//!@{
protected:
i2c_i () = default; //!< Allow constructor from derived only
i2c_i (const type&) = delete; //!< No copies
type& operator= (const type&) = delete;
public:
virtual ~i2c_i () = default; //!< Virtual default destructor
//!@}
/*!
* \name Implementation requirements
*/
//!@{
private:
virtual uint32_t _frequency () const = 0; //!< \return clock frequency of the bus [Hz]
virtual void _frequency (uint32_t) = 0; //!< \brief set clock frequency of the bus [Hz]
virtual void _start() = 0; //!< Send start functionality
virtual void _stop() = 0; //!< Send stop functionality
virtual byte_t _read (bool ack, Sequence seq) = 0; //!< Receive a byte from the i2c bus.
virtual bool _write (byte_t byte, Sequence seq) = 0; //!< Transmit a byte to the i2c bus.
//!@}
/*!
* \name Get/Set functions
*/
//!@{
public:
uint32_t frequency () const { return _frequency(); } //!< \return clock frequency of the bus [Hz]
void frequency (uint32_t f) { _frequency(f); } //!< \brief set clock frequency of the bus [Hz]
//!@}
/*!
* \name User functions
*/
//!@{
public:
void start () { _start(); }
void stop () { _stop(); }
/*!
* \brief
* Receive a byte from the i2c bus.
* \param ack Optional ack bit.
* \arg 1 ACK the reception
* \arg 0 Don't ACK the reception.
* \param seq The operation sequence to execute
* \arg Sequence::BYTE Receive only the byte, do not send ack clock
* \arg Sequence::ACK Send only the ack bit
* \arg Sequence::BYTEnACK Receive the byte and send the ack bit
* \return The byte received.
*/
byte_t read (bool ack, Sequence seq =Sequence::BYTEnACK) {
return _read (ack, seq);
}
/*!
* \brief
* Transmit a byte to the i2c bus.
* \param byte The byte to send.
* \param seq The operation sequence to execute
* \arg Sequence::BYTE Transmit only the byte, do not read ack bit
* \arg Sequence::ACK Read only the ack bit
* \arg Sequence::BYTEnACK Transmit the byte and read the ack bit
* \return Slave's ACK bit
* \arg false Slave didn't ACK
* \arg true Slave did ACK
*/
bool write (byte_t byte, Sequence seq =Sequence::BYTEnACK) {
return _write (byte, seq);
}
//!@}
};
#if defined _utl_have_concepts
/*!
* i2c interface concept
*/
template
concept bool i2c_c = requires (T t, const T ct, typename T::Sequence s) {
// Object type
requires not_::value>::value;
requires not_::value>::value;
// Methods
{ct.frequency()} -> uint32_t;
{t.frequency(0)} -> void;
{t.start()} -> void;
{t.stop()} -> void;
{t.read (1, s)} -> byte_t;
{t.write(0, s)} -> bool;
};
#else
namespace i2c_i_cnpt {
using std::declval;
template using try_cfreq_t = decltype (declval().frequency());
template using try_freq_t = decltype (declval<_Tp>().frequency(declval()));
template using try_start_t = decltype (declval<_Tp>().start());
template using try_stop_t = decltype (declval<_Tp>().stop());
template using try_read_t
= decltype (declval<_Tp>().read (declval(), declval()));
template using try_write_t
= decltype (declval<_Tp>().write (declval(), declval()));
//! Primary template to catch any non I2C interface types
template
struct is_i2c_ : false_ { };
//! template to catch a proper I2C interface type
template
struct is_i2c_ <_Tp,
void_t <
typename _Tp::Sequence,
use_if_same_t >,
use_if_same_t >,
use_if_same_t >,
use_if_same_t >,
use_if_same_t >,
use_if_same_t >
> //!^ SFINAE may apply inside if_same_t<> also
> : true_ { };
}
/*!
* Value meta-programming function alias for I2C interface checking
* \param _Tp Type to check
* \return True if _Tp is a i2c interface
*/
template
constexpr bool i2c_c = i2c_i_cnpt::is_i2c_<_Tp>::value;
#endif
//!@}
} // namespace utl
#endif // _utl_com_i2c_h__