i2c.h

Linux下比较早的基于命令行的DVD播放器

//
// Copyright (c) 2004 by Istv醤 V醨adi
//
// This file is part of dxr3Player, a DVD player written specifically 
// for the DXR3 (aka Hollywood+) decoder card, but now handles other
// hardware as well. These files contain a (mostly) user-space driver 
// for the Unichrome board found on Via's EPIA motherboards.
//
// The information for implementing this driver has been gathered
// from the following sources:
//
// - The DirectFB Unichrome driver
//   Copyright (c) 2003 Andreas Robinson, All rights reserved.
//
// - Andreas Robinson's MPEG-2 decoder for the Unichrome board.
//   Copyright (c) 2003 Andreas Robinson, All rights reserved.
//
// - Via's Unichrome Framebuffer driver
//   Copyright 1998-2003 VIA Technologies, Inc. All Rights Reserved.
//   Copyright 2001-2003 S3 Graphics, Inc. All Rights Reserved.

// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

#ifndef DXR3PLAYER_UNICHROME_I2C_H
#define DXR3PLAYER_UNICHROME_I2C_H
//------------------------------------------------------------------------------

#include <cstdlib>
#include <inttypes.h>

//------------------------------------------------------------------------------

namespace unichrome {

//------------------------------------------------------------------------------

class IO;

//------------------------------------------------------------------------------

/**
 * Handler for I2C communication.
 */
class I2C
{
private:
    /**
     * The I2C port.
     */
    static const uint8_t I2C_PORT_INDEX = 0x31;

    /**
     * Bit to enable the I2C port.
     */
    static const uint8_t BIT_I2C_ENABLE = 0;

    /**
     * Mask for the bit to enable the I2C port.
     */
    static const uint8_t MASK_I2C_ENABLE = 1<<BIT_I2C_ENABLE;

    /**
     * Bit for the I2C data input
     */
    static const uint8_t BIT_I2C_DATA_IN = 2;

    /**
     * Mask for the bit for the I2C data input
     */
    static const uint8_t MASK_I2C_DATA_IN = 1<<BIT_I2C_DATA_IN;

    /**
     * Bit for the I2C data output
     */
    static const uint8_t BIT_I2C_DATA_OUT = 4;

    /**
     * Mask for the bit for the I2C data output
     */
    static const uint8_t MASK_I2C_DATA_OUT = 1<<BIT_I2C_DATA_OUT;

    /**
     * Bit for the I2C clock
     */
    static const uint8_t BIT_I2C_CLOCK = 5;

    /**
     * Mask for the bit for the I2C clock
     */
    static const uint8_t MASK_I2C_CLOCK = 1<<BIT_I2C_CLOCK;

    /**
     * Reference to the I/O subsystem.
     */
    IO& io;

    /**
     * The last data bit that has been written to the I2C port.
     */
    unsigned currentData;

public:
    /**
     * Construct the I2C handler.
     */
    I2C(IO& io);

    /**
     * Destroy the I2C handler.
     */
    ~I2C();

    /**
     * Enable the I2C port of the Unichrome device.
     */
    void enable();

    /**
     * Write a byte to the slave.
     *
     * @return if the slave has acknowledged the data
     */
    unsigned write(unsigned address, unsigned subAddress, unsigned data);
    
    /**
     * Write a buffer to the slave. 
     *
     * @return the number of bytes the slave has acknowledged
     */
    unsigned write(unsigned address, const void* from, size_t size);
    
    /**
     * Read a byte from the slave.
     *
     * @return the byte read, or -1 on error
     */
    int read(unsigned address, unsigned subAddress);

private:
    /**
     * Write the SCL bit.
     */
    void writeSCL(unsigned on);

    /**
     * Write the SDA bit.
     */
    void writeSDA(unsigned on);

    /**
     * Read the SDA bit.
     */
    unsigned readSDA();

    /**
     * Get an acknowledgement from the slave device.
     */
    unsigned getAcknowledgement();

    /**
     * Send a start sequence.
     */
    void sendStart();

    /**
     * Send a stop sequence.
     */
    void sendStop();

    /**
     * Write a data byte to the slave.
     */
    unsigned writeData(unsigned data);
};

//------------------------------------------------------------------------------

} /* namespace unichrome */

//------------------------------------------------------------------------------
#endif // DXR3PLAYER_UNICHROME_I2C_H

// Local variables:
// mode: c++
// End: