I2C.cxx

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#include <cstdint>
#include <fcntl.h>
#include "Devtab.hxx"
#include "I2C.hxx"
 
ssize_t I2C::read(File *file, void *buf, size_t count)
{
    int result;
 
    if ((file->flags & O_ACCMODE) == O_WRONLY)
    {
        return -EBADF;
    }
 
    struct i2c_msg msg;
    msg.addr = (uintptr_t)file->priv;
    msg.flags = I2C_M_RD;
    msg.len = count;
    msg.buf = (uint8_t*)buf;
 
    lock_.lock();
    result = transfer(&msg, true);
    lock_.unlock();
 
    return result;
}
 
ssize_t I2C::write(File *file, const void *buf, size_t count)
{
    int result;
 
    if ((file->flags & O_ACCMODE) == O_RDONLY)
    {
        return -EBADF;
    }
 
    struct i2c_msg msg;
    msg.addr = (uintptr_t)file->priv;
    msg.flags = 0;
    msg.len = count;
    msg.buf = (uint8_t*)buf;
 
    lock_.lock();
    result = transfer(&msg, true);
    lock_.unlock();
 
    return result;
}
 
int I2C::ioctl(File *file, unsigned long int key, unsigned long data)
{
    HASSERT(IOC_TYPE(key) == I2C_MAGIC);
 
    switch (key)
    {
        default:
            return -EINVAL;
        case I2C_SLAVE:
            file->priv = (void*)data;
            break;
        case I2C_RDWR:
        {
            struct i2c_rdwr_ioctl_data *rdwr_data = (struct i2c_rdwr_ioctl_data*)data;
            return transfer_messages(rdwr_data->msgs, rdwr_data->nmsgs);
        }
        case I2C_SMBUS:
            return smbus(file, data);
    }
    return 0;
}
 
int I2C::transfer_messages(struct i2c_msg *msgs, int num)
{
    HASSERT(num > 0);
 
    int count = 0;
    int result;
 
    lock_.lock();
    for (int i = 0; i < num; ++i)
    {
        count += msgs[i].len;
        result = transfer(msgs + i, (num == (i + 1)));
        if (result < 0)
        {
            lock_.unlock();
            return result;
        }
    }
    lock_.unlock();
 
    return  count;
}
 
int I2C::smbus(File *file, unsigned long data)
{
    struct i2c_smbus_ioctl_data *sm_data = (struct i2c_smbus_ioctl_data *)data;
 
    /* check that we have a valid transaction type */
    if ((sm_data->size != I2C_SMBUS_QUICK) &&
        (sm_data->size != I2C_SMBUS_BYTE) &&
        (sm_data->size != I2C_SMBUS_BYTE_DATA) &&
        (sm_data->size != I2C_SMBUS_WORD_DATA) &&
        (sm_data->size != I2C_SMBUS_PROC_CALL) &&
        (sm_data->size != I2C_SMBUS_BLOCK_DATA) &&
        (sm_data->size != I2C_SMBUS_I2C_BLOCK_BROKEN) &&
        (sm_data->size != I2C_SMBUS_BLOCK_PROC_CALL) &&
        (sm_data->size != I2C_SMBUS_I2C_BLOCK_DATA))
    {
        return -EINVAL;
    }
 
    /* check that we have a read or write */
    if ((sm_data->read_write != I2C_SMBUS_READ) &&
        (sm_data->read_write != I2C_SMBUS_WRITE))
    {
        return -EINVAL;
    }
 
    return 0;
}