/*!
* \file /utl/com/spi.h
* \brief An Abstract base class interface for the spi 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_spi_h__
#define _utl_com_spi_h__
#include
#include
#include
namespace utl {
/*!
* \ingroup Communication
* \brief Abstract base class for spi bus
*/
//!@{
namespace spi {
/*!
* SPI implementation bit order
*/
enum class bitOrder {
LSB_First =0x01, //!< Most significant first
MSB_First =0x80 //!< Less significant first
};
/*!
* SPI implementation Clock Polarity
*/
enum class cpol {
LOW =0, //!< LOW
HIGH //!< HIGH
};
/*!
* SPI implementation Clock Phase
*/
enum class cpha {
LOW =0, //!< LOW
HIGH //!< HIGH
};
}
/*!
* Template base class for SPI communication interface using CRTP
* This class force a common interface for SPI communication
* protocol implementations.
* \param impl_t The CRTP type (the derived/implementation class typename).
*/
template
class spi_i {
_CRTP_IMPL(impl_t); //! \brief Syntactic sugar to CRTP casting
public:
using type = spi_i; //!< Export type as identity meta-function
/*!
* \name Object lifetime
*/
//!@{
protected:
spi_i () = default; //!< Allow constructor from derived only
~spi_i () = default; //!< Allow destructor from derived only
spi_i (const type&) = delete; //!< No copies
spi_i& operator= (const spi_i&) = 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
*/
//! @{
private:
uint32_t _clock () const { return impl()._clock (); } //!< clock frequency of the bus [Hz]
void _clock (uint32_t c) { impl()._clock (c); } //!< set clock frequency of the bus [Hz]
byte_t _tx_data (byte_t b) { return impl()._tx_data (b); } //!< Transmit a byte on the bus and return the response
//! @}
/*!
* \name Get/Set functions provided by the interface
*/
//!@{
public:
uint32_t clock () const { return _clock (); } //!< \return clock frequency of the bus
void clock (uint32_t c) { _clock (c); } //!< \brief set clock frequency of the bus
//!@}
/*!
* \name I/O functions provided by the interface
*/
//!@{
public:
/*!
* Transmit a byte to spi bus and return the response
*/
byte_t tx_data (byte_t out) {
return _tx_data (out);
}
/*!
* \brief
* Transmit a number of bytes to the spi bus and read the response.
* \param out Pointer to data to send to the bus
* \param in Pointer to buffer to store the data from the bus
* \param n The number of bytes to transmit/receive
* \return The number of bytes.
*/
size_t tx_data (const byte_t *out, byte_t *in, size_t n);
/*!
* Receive a byte from spi bus while transmitting 0xFF
*/
byte_t rx_data () {
return _tx_data(0xFF);
}
/*!
* \brief
* Receive a number of bytes from the spi bus while transmitting 0xFFs.
* \param in Pointer to buffer to store the data
* \param n The number of bytes to read
* \return The number of received bytes.
*/
size_t rx_data (byte_t *in, size_t n);
//!@}
};
/*!
* \brief
* Transmit a number of bytes to the spi bus and read the response.
* \param out Pointer to data to send to the bus
* \param in Pointer to buffer to store the data from the bus
* \param n The number of bytes to transmit/receive
* \return The number of bytes.
*/
template
size_t spi_i<_I>::tx_data (const byte_t *out, byte_t *in, size_t n) {
for (size_t nn {n} ; nn ; --nn)
*in++ = _tx_data (*out++);
return n;
}
/*!
* \brief
* Receive a number of bytes from the spi bus while transmitting 0xFFs.
* \param in Pointer to buffer to store the data
* \param n The number of bytes to read
* \return The number of received bytes.
*/
template
size_t spi_i<_I>::rx_data (byte_t *in, size_t n) {
for (size_t nn {n} ; nn ; --nn)
*in++ = _tx_data (0xFF);
return n;
}
/*!
* \brief
* A virtual base class implementation
* \param none
*/
template <>
class spi_i {
public:
using type = spi_i; //!< Export type as identity meta-function
/*!
* \name Object lifetime
*/
//!@{
protected:
spi_i () = default; //!< Allow constructor from derived only
spi_i (const type&) = delete; //!< No copies
type& operator= (const type&) = delete;
public:
virtual ~spi_i () = default; //!< Virtual default destructor
//!@}
/*!
* \name Implementation requirements
*/
//! @{
private:
virtual uint32_t _clock () const =0; //!< Read the clock frequency of the bus
virtual void _clock (uint32_t) =0; //!< Set the clock frequency of the bus
virtual byte_t _tx_data (byte_t) =0; //!< Transmit a byte on the bus and return the response
//! @}
/*!
* \name Get/Set functions provided by the interface
*/
//!@{
public:
uint32_t clock () const { return _clock (); } //!< \return clock frequency of the bus
void clock (uint32_t c) { _clock (c); } //!< \brief set clock frequency of the bus
//!@}
/*!
* \name I/O functions provided by the interface
*/
//!@{
public:
/*!
* Transmit a byte to spi bus and return the response
*/
byte_t tx_data (byte_t out) {
return _tx_data (out);
}
/*!
* \brief
* Transmit a number of bytes to the spi bus and read the response.
* \param out Pointer to data to send to the bus
* \param in Pointer to buffer to store the data from the bus
* \param n The number of bytes to transmit/receive
* \return The number of bytes.
*/
size_t tx_data (const byte_t *out, byte_t *in, size_t n);
/*!
* Receive a byte from spi bus while transmitting 0xFF
*/
byte_t rx_data () {
return _tx_data (0xFF);
}
/*!
* \brief
* Receive a number of bytes from the spi bus while transmitting 0xFFs.
* \param in Pointer to buffer to store the data
* \param n The number of bytes to read
* \return The number of received bytes.
*/
size_t rx_data (byte_t *in, size_t n);
//!@}
};
/*!
* \brief
* Transmit a number of bytes to the spi bus and read the response.
* \param out Pointer to data to send to the bus
* \param in Pointer to buffer to store the data from the bus
* \param n The number of bytes to transmit/receive
* \return The number of bytes.
*/
size_t spi_i::tx_data (const byte_t *out, byte_t *in, size_t n) {
for (size_t nn {n} ; nn ; --nn)
*in++ = _tx_data (*out++);
return n;
}
/*!
* \brief
* Receive a number of bytes from the spi bus while transmitting 0xFFs.
* \param in Pointer to buffer to store the data
* \param n The number of bytes to read
* \return The number of received bytes.
*/
size_t spi_i::rx_data (byte_t *in, size_t n) {
for (size_t nn {n} ; nn ; --nn)
*in++ = _tx_data (0xFF);
return n;
}
#if defined _utl_have_concepts
/*!
* i2c interface concept
*/
template
concept bool spi_c = requires (T t, const T ct, typename T::Sequence s) {
// Object type
requires not_::value>::value;
requires not_::value>::value;
// Methods
{ct.clock()} -> uint32_t;
{t.clock(0)} -> void;
{t.tx_data(1)} -> byte_t;
{t.rx_data()} -> byte_t;
};
#else
namespace spi_i_details {
using std::declval;
template using try_cclock_t= decltype (declval().clock());
template using try_clock_t = decltype (declval<_Tp>().clock(declval()));
template using try_tx_t = decltype (declval<_Tp>().tx_data(declval()));
template using try_rx_t = decltype (declval<_Tp>().rx_data());
//! Primary template to catch any non SPI interface types
template
struct is_spi_ : false_ {};
//! template to catch a proper SPI interface type
template
struct is_spi_ <
_Tp,
void_t <
use_if_same_t , uint32_t>,
use_if_same_t , void>,
use_if_same_t , byte_t>,
use_if_same_t , byte_t>
>
> : true_ {};
}
/*!
* Value meta-programming function for SPI interface checking
* \param _Tp Type to check
* \return True if _Tp is a spi interface
*/
template
constexpr bool spi_c = spi_i_details::is_spi_<_Tp>::value;
#endif
//!@}
} // namespace utl
#endif /* #ifndef _utl_com_spi_h__ */