//*****************************************************************************
//
// i2c.c - Driver for Inter-IC (I2C) bus block.
//
// Copyright (c) 2005,2006 Luminary Micro, Inc.  All rights reserved.
//
// Software License Agreement
//
// Luminary Micro, Inc. (LMI) is supplying this software for use solely and
// exclusively on LMI's Stellaris Family of microcontroller products.
//
// The software is owned by LMI and/or its suppliers, and is protected under
// applicable copyright laws.  All rights are reserved.  Any use in violation
// of the foregoing restrictions may subject the user to criminal sanctions
// under applicable laws, as well as to civil liability for the breach of the
// terms and conditions of this license.
//
// THIS SOFTWARE IS PROVIDED "AS IS".  NO WARRANTIES, WHETHER EXPRESS, IMPLIED
// OR STATUTORY, INCLUDING, BUT NOT LIMITED TO, IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE APPLY TO THIS SOFTWARE.
// LMI SHALL NOT, IN ANY CIRCUMSTANCES, BE LIABLE FOR SPECIAL, INCIDENTAL, OR
// CONSEQUENTIAL DAMAGES, FOR ANY REASON WHATSOEVER.
//
// This is part of revision 852 of the Stellaris Driver Library.
//
//*****************************************************************************

//*****************************************************************************
//
//! \addtogroup i2c_api
//! @{
//
//*****************************************************************************

#include "hw_i2c.h"
#include "hw_ints.h"
#include "hw_memmap.h"
#include "hw_types.h"
#include "debug.h"
#include "i2c.h"
#include "interrupt.h"
#include "sysctl.h"

//*****************************************************************************
//
//! Initializes the I2C Master block.
//!
//! \param ulBase base address of the I2C Master module
//! \param bFast set up for fast data transfers
//!
//! This function initializes operation of the I2C Master block. Upon
//! successful initialization of the I2C block, this function will have
//! set the bus speed for the master, and will have enabled the I2C Master
//! block.
//!
//! If the parameter \e bFast is \b true, then the master block will be
//! set up to transfer data at 400 kbps; otherwise, it will be set up to
//! transfer data at 100 kbps.
//!
//! The I2C clocking is dependent upon the system clock rate returned by
//! SysCtlClockGet(); if it does not return the correct system clock rate then
//! the I2C clock rate will be incorrect.
//!
//! \return None.
//
//*****************************************************************************
void
I2CMasterInit(unsigned long ulBase, tBoolean bFast)
{
    unsigned long ulSysClk;
    unsigned long ulSCLFreq;
    unsigned long ulTPR;

    //
    // Check the arguments.
    //
    ASSERT(ulBase == I2C_MASTER_BASE);

    //
    // Must enable the device before doing anything else.
    //
    I2CMasterEnable(ulBase);

    //
    // Get the system clock speed.
    //
    ulSysClk = SysCtlClockGet();

    //
    // Get the desired SCL speed.
    //
    if(bFast == true)
    {
        ulSCLFreq = I2C_SCL_FAST;
    }
    else
    {
        ulSCLFreq = I2C_SCL_STANDARD;
    }

    //
    // Compute the clock divider that achieves the fastest speed less than or
    // equal to the desired speed.  The numerator is biases to favor a larger
    // clock divider so that the resulting clock is always less than or equal
    // to the desired clock, never greater.
    //
    ulTPR = (((ulSysClk + (2 * I2C_MASTER_TPR_SCL * ulSCLFreq) - 1) /
              (2 * I2C_MASTER_TPR_SCL * ulSCLFreq)) - 1);
    HWREG(ulBase + I2C_MASTER_O_TPR) = ulTPR;
}

//*****************************************************************************
//
//! Initializes the I2C Slave block.
//!
//! \param ulBase base address of the I2C Slave module
//! \param ucSlaveAddr 7-bit slave address
//!
//! This function initializes operation of the I2C Slave block. Upon
//! successful initialization of the I2C blocks, this function will have
//! set the slave address and have enabled the I2C Slave block.
//!
//! The parameter \e ucSlaveAddr is the value that will be compared
//! against the slave address sent by an I2C master.
//!
//! \return None.
//
//*****************************************************************************
void
I2CSlaveInit(unsigned long ulBase, unsigned char ucSlaveAddr)
{
    //
    // Check the arguments.
    //
    ASSERT(ulBase == I2C_SLAVE_BASE);
    ASSERT(!(ucSlaveAddr & 0x80));

    //
    // Must enable the device before doing anything else.
    //
    I2CSlaveEnable(ulBase);

    //
    // Set up the slave address.
    //
    HWREG(ulBase + I2C_SLAVE_O_OAR) = ucSlaveAddr;
}

//*****************************************************************************
//
//! Enables the I2C Master block.
//!
//! \param ulBase base address of the I2C Master module
//!
//! This will enable operation of the I2C Master block.
//!
//! \return None.
//
//*****************************************************************************
void
I2CMasterEnable(unsigned long ulBase)
{
    //
    // Check the arguments.
    //
    ASSERT(ulBase == I2C_MASTER_BASE);

    //
    // Enable the master block.
    //
    HWREG(ulBase + I2C_MASTER_O_CR) |= I2C_MASTER_CR_MFE;
}

//*****************************************************************************
//
//! Enables the I2C Slave block.
//!
//! \param ulBase base address of the I2C Slave module
//!
//! This will enable operation of the I2C Slave block.
//!
//! \return None.
//
//*****************************************************************************
void
I2CSlaveEnable(unsigned long ulBase)
{
    //
    // Check the arguments.
    //
    ASSERT(ulBase == I2C_SLAVE_BASE);

    //
    // Enable the clock to the slave block.
    //
    HWREG(ulBase - I2C_O_SLAVE + I2C_MASTER_O_CR) |= I2C_MASTER_CR_SFE;

    //
    // Enable the slave.
    //
    HWREG(ulBase + I2C_SLAVE_O_CSR) = I2C_SLAVE_CSR_DA;
}

//*****************************************************************************
//
//! Disables the I2C master block.
//!
//! \param ulBase base address of the I2C Master module
//!
//! This will disable operation of the I2C master block.
//!
//! \return None.
//
//*****************************************************************************
void
I2CMasterDisable(unsigned long ulBase)
{
    //
    // Check the arguments.
    //
    ASSERT(ulBase == I2C_MASTER_BASE);

    //
    // Disable the master block.
    //
    HWREG(ulBase + I2C_MASTER_O_CR) &= ~(I2C_MASTER_CR_MFE);
}

//*****************************************************************************
//
//! Disables the I2C slave block.
//!
//! \param ulBase base address of the I2C Slave module
//!
//! This will disable operation of the I2C slave block.
//!
//! \return None.
//
//*****************************************************************************
void
I2CSlaveDisable(unsigned long ulBase)
{
    //
    // Check the arguments.
    //
    ASSERT(ulBase == I2C_SLAVE_BASE);

    //
    // Disable the slave.
    //
    HWREG(ulBase + I2C_SLAVE_O_CSR) = 0;

    //
    // Disable the clock to the slave block.
    //
    HWREG(ulBase - I2C_O_SLAVE + I2C_MASTER_O_CR) &= ~(I2C_MASTER_CR_SFE);
}

//*****************************************************************************
//
//! Registers an interrupt.handler for the I2C module
//!
//! \param ulBase base address of the I2C module
//! \param pfnHandler is a pointer to the function to be called when the
//! synchronous serial interface interrupt occurs.
//!
//! This sets the handler to be called when an I2C interrupt occurs.  This
//! will enable the global interrupt in the interrupt controller; specific I2C
//! interrupts must be enabled via I2CMasterIntEnable() and
//! I2CSlaveIntEnable().  If necessary, it is the interrupt.handler's
//! responsibility to clear the interrupt source via I2CMasterIntClear() and
//! I2CSlaveIntClear().
//!
//! \sa IntRegister() for important information about registering interrupt
//! handlers.
//!
//! \return None.
//
//*****************************************************************************
void
I2CIntRegister(unsigned long ulBase, void (*pfnHandler)(void))
{
    //
    // Check the arguments.
    //
    ASSERT(ulBase == I2C_MASTER_BASE);

    //
    // Register the interrupt.handler, returning an error if an error occurs.
    //
    IntRegister(INT_I2C, pfnHandler);

    //
    // Enable the I2C interrupt.
    //
    IntEnable(INT_I2C);
}

//*****************************************************************************
//
//! Unregisters an interrupt.handler for the I2C module.
//!
//! \param ulBase base address of the I2C module
//!
//! This function will clear the handler to be called when an I2C
//! interrupt occurs.  This will also mask off the interrupt in the interrupt
//! controller so that the interrupt.handler no longer is called.
//!
//! \sa IntRegister() for important information about registering interrupt
//! handlers.
//!
//! \return None.
//
//*****************************************************************************
void
I2CIntUnregister(unsigned long ulBase)
{
    //
    // Check the arguments.
    //
    ASSERT(ulBase == I2C_MASTER_BASE);

    //
    // Disable the interrupt.
    //
    IntDisable(INT_I2C);

    //
    // Unregister the interrupt.handler.
    //
    IntUnregister(INT_I2C);
}

//*****************************************************************************
//
//! Enables the I2C Master interrupt.
//!
//! \param ulBase base address of the I2C Master module
//!
//! Enables the I2C Master interrupt source.
//!
//! \return None.
//
//*****************************************************************************
void
I2CMasterIntEnable(unsigned long ulBase)
{
    //
    // Check the arguments.
    //
    ASSERT(ulBase == I2C_MASTER_BASE);

    //
    // Enable the master interrupt.
    //
    HWREG(ulBase + I2C_MASTER_O_IMR) = 1;
}

//*****************************************************************************
//
//! Enables the I2C Slave interrupt.
//!
//! \param ulBase base address of the I2C Slave module
//!
//! Enables the I2C Slave interrupt source.
//!
//! \return None.
//
//*****************************************************************************
void
I2CSlaveIntEnable(unsigned long ulBase)
{
    //
    // Check the arguments.
    //
    ASSERT(ulBase == I2C_SLAVE_BASE);

    //
    // Enable the slave interrupt.
    //
    HWREG(ulBase + I2C_SLAVE_O_IM) = 1;
}

//*****************************************************************************
//
//! Disables the I2C Master interrupt.
//!
//! \param ulBase base address of the I2C Master module
//!
//! Disables the I2C Master interrupt source.
//!
//! \return None.
//
//*****************************************************************************
void
I2CMasterIntDisable(unsigned long ulBase)
{
    //
    // Check the arguments.
    //
    ASSERT(ulBase == I2C_MASTER_BASE);

    //
    // Disable the master interrupt.
    //
    HWREG(ulBase + I2C_MASTER_O_IMR) = 0;
}

//*****************************************************************************
//
//! Disables the I2C Slave interrupt.
//!
//! \param ulBase base address of the I2C Slave module
//!
//! Disables the I2C Slave interrupt source.
//!
//! \return None.
//
//*****************************************************************************
void
I2CSlaveIntDisable(unsigned long ulBase)
{
    //
    // Check the arguments.
    //
    ASSERT(ulBase == I2C_SLAVE_BASE);

    //
    // Disable the slave interrupt.
    //
    HWREG(ulBase + I2C_SLAVE_O_IM) = 0;
}

//*****************************************************************************
//
//! Gets the current I2C Master interrupt status.
//!
//! \param ulBase base address of the I2C Master module
//! \param bMasked is false if the raw interrupt status is requested and
//! true if the masked interrupt status is requested.
//!
//! This returns the interrupt status for the I2C Master module.
//! Either the raw interrupt status or the status of interrupts that are
//! allowed to reflect to the processor can be returned.
//!
//! \return The current interrupt status, returned as \b true if active
//! or \b false if not active.
//
//*****************************************************************************
tBoolean
I2CMasterIntStatus(unsigned long ulBase, tBoolean bMasked)
{
    //
    // Check the arguments.
    //
    ASSERT(ulBase == I2C_MASTER_BASE);