I2cRtosDriver

File content as of revision 14:352609d395c1:

#include "I2CDriver.h"
#include "i2cRtos_api.h"
//#include "rt_System.h"
#include "error.h"

using namespace mbed;
using namespace rtos;

//DigitalOut I2CDriver::osci2(p7);

#define PREFIX i2cRtos
//#define PREFIX i2c // fallback to offical busy wait i2c c-api for performance testing 
#define PASTER(x,y) x ## _ ## y
#define EVALUATOR(x,y)  PASTER(x,y)
#define FUNCTION(fun) EVALUATOR(PREFIX, fun)

const PinName I2CDriver::c_sdas[] = {p9,p28};
const PinName I2CDriver::c_scls[] = {p10,p27};

I2CDriver::Channel* I2CDriver::s_channels[2] = {0,0};

I2CDriver::I2CDriver(PinName sda, PinName scl, int hz, int slaveAdr):m_freq(hz),m_slaveAdr(slaveAdr)
{
    // ensure exclusive access for initialization 
    static Mutex mtx;
    bool locked = false;
    if(osKernelRunning()) {  // but don't try to lock if rtos kernel is not running yet. (global/static definition) 
        mtx.lock();
        locked = true;
    }

    // check pins and determine i2c channel
    int channel=0;
#if defined(TARGET_LPC1768) || defined(TARGET_LPC2368)
    if(sda==c_sdas[0] && scl==c_scls[0]) channel=0; // I2C_1
    else
#endif
        if (sda==c_sdas[1] && scl==c_scls[1]) channel=1; //I2C_2 or I2C
        else error("I2CDriver: Invalid I2C pins selected\n");
    
    // initialize the selected i2c channel 
    if(s_channels[channel]==0) {
        s_channels[channel] = new I2CDriver::Channel;
        m_channel = s_channels[channel];
        m_channel->freq = 0;
        m_channel->slaveAdr = 0;
        m_channel->modeSlave = 0;
        m_channel->initialized=false; // defer i2c initialization util we are sure the rtos kernel is running (config() function)
    }
    m_channel = s_channels[channel];
    if(locked) mtx.unlock();
}

void I2CDriver::lock()
{
    //osci2.write(1);
    // One and the same thread can lock twice, but then it needs also to unlock twice.
    // exactly what we need here
    m_channel->mutex.lock(osWaitForever);
    m_channel->callerID = osThreadGetId();
    m_channel->callerPrio = osThreadGetPriority(m_channel->callerID);
    // maximize thread prio
    osThreadSetPriority(m_channel->callerID, c_drvPrio); // hopefully not interrupted since the lock in the line above
    // mutex code looks like that waiting threads are priority ordered
    // also priority inheritance seems to be provided
    //osci2.write(0);
}

void I2CDriver::unlock()
{
    //osci2.write(1);
    // free the mutex and restore original prio
    //rt_tsk_lock();  // just prevent beeing preempted after restoring prio before freeing the mutex 
    osThreadSetPriority(m_channel->callerID, m_channel->callerPrio);
    m_channel->mutex.unlock();   
    //rt_tsk_unlock();
    //osci2.write(0);
}

void I2CDriver::config()
{
    //osci2.write(1);
    // check and initialize driver
    if(!m_channel->initialized) {
        int channel = m_channel==s_channels[0] ? 0 : 1; // ...ugly
        FUNCTION(init)(&m_channel->i2c, c_sdas[channel], c_scls[channel]);
        m_channel->initialized=true;
    }
    // check and update frequency
    if(m_freq != m_channel->freq) {
        m_channel->freq = m_freq;
        i2c_frequency(&m_channel->i2c, m_freq);
    }
    // check and update slave/master mode
    if(m_modeSlave != m_channel->modeSlave) {
        m_channel->modeSlave = m_modeSlave;
        i2c_slave_mode(&m_channel->i2c, m_modeSlave);
    }
    // check and update slave address
    if(m_modeSlave && m_slaveAdr != m_channel->slaveAdr) {
        m_channel->slaveAdr = m_slaveAdr;
        i2c_slave_address(&m_channel->i2c, 0, m_slaveAdr, 0);
    }
    //osci2.write(0);
}

int I2CDriver::readMaster(int address, char *data, int length, bool repeated)
{
    m_modeSlave = false;
    lockNconfig();
    int ret = FUNCTION(read)(&m_channel->i2c, address, data, length, (repeated?0:1));
    unlock();
    return ret;
}
int I2CDriver::readMaster(int address, uint8_t _register, char *data, int length, bool repeated)
{
    m_modeSlave = false;
    lockNconfig();
    int ret = FUNCTION(write)(&m_channel->i2c, address,(const char*)&_register, 1, 0);
    if(!ret) ret = FUNCTION(read)(&m_channel->i2c, address, data, length, (repeated?0:1));
    unlock();
    return ret;
}
int I2CDriver::readMaster(int ack)
{
    m_modeSlave = false;
    lockNconfig();
    int ret = i2cRtos_byte_read(&m_channel->i2c, (ack?0:1));
    unlock();
    return ret;
}
int I2CDriver::writeMaster(int address, const char *data, int length, bool repeated)
{
    m_modeSlave = false;
    lockNconfig();
    int ret = FUNCTION(write)(&m_channel->i2c, address, data, length, (repeated?0:1));
    unlock();
    return ret;
}
int I2CDriver::writeMaster(int data)
{
    m_modeSlave = false;
    lockNconfig();
    int ret = i2cRtos_byte_write(&m_channel->i2c, data);
    unlock();
    return ret;
}
void I2CDriver::startMaster(void)
{
    m_modeSlave = false;
    lockNconfig();
    i2c_start(&m_channel->i2c);
    unlock();
}
bool I2CDriver::stopMaster(void)
{
    m_modeSlave = false;
    lockNconfig();
    bool ret=i2cRtos_stop(&m_channel->i2c);
    unlock();
    return ret;
}
void I2CDriver::stopSlave(void)
{
    m_modeSlave = true;
    lockNconfig();
    i2c_stop(&m_channel->i2c);
    unlock();
}
int I2CDriver::receiveSlave(uint32_t timeout_ms)
{
    m_modeSlave = true;
    lockNconfig();
    int ret = i2cRtos_slave_receive(&m_channel->i2c, timeout_ms);
    unlock();
    return ret;
}
int I2CDriver::readSlave(char* data, int length)
{
    m_modeSlave = true;
    lockNconfig();
    int ret = i2cRtos_slave_read(&m_channel->i2c, data, length);
    unlock();
    return ret;
}
int I2CDriver::readSlave(void)
{
    m_modeSlave = true;
    lockNconfig();
    int ret = i2cRtos_byte_read(&m_channel->i2c, 0);
    unlock();
    return ret;
}
int I2CDriver::writeSlave(const char *data, int length)
{
    m_modeSlave = true;
    lockNconfig();
    int ret = i2cRtos_slave_write(&m_channel->i2c, data, length);
    unlock();
    return ret;
}
int I2CDriver::writeSlave(int data)
{
    m_modeSlave = true;
    lockNconfig();
    int ret = i2cRtos_byte_write(&m_channel->i2c, data);
    unlock();
    return ret;
}