drivers/staging/sm750fb/ddk750_hwi2c.c

#define USE_HW_I2C
#ifdef USE_HW_I2C
#include "ddk750_help.h"
#include "ddk750_reg.h"
#include "ddk750_hwi2c.h"
#include "ddk750_power.h"

#define MAX_HWI2C_FIFO                  16
#define HWI2C_WAIT_TIMEOUT              0xF0000


int hwI2CInit(
    unsigned char busSpeedMode
)
{
    unsigned int value;

    /* Enable GPIO 30 & 31 as IIC clock & data */
	value = PEEK32(GPIO_MUX);

    value = FIELD_SET(value, GPIO_MUX, 30, I2C) |
			FIELD_SET(0, GPIO_MUX, 31, I2C);
	POKE32(GPIO_MUX, value);

    /* Enable Hardware I2C power.
       TODO: Check if we need to enable GPIO power?
     */
    enableI2C(1);

    /* Enable the I2C Controller and set the bus speed mode */
    value = PEEK32(I2C_CTRL);
    if (busSpeedMode == 0)
        value = FIELD_SET(value, I2C_CTRL, MODE, STANDARD);
    else
        value = FIELD_SET(value, I2C_CTRL, MODE, FAST);
    value = FIELD_SET(value, I2C_CTRL, EN, ENABLE);
    POKE32(I2C_CTRL, value);

    return 0;
}


void hwI2CClose(void)
{
    unsigned int value;

    /* Disable I2C controller */
    value = PEEK32(I2C_CTRL);
    value = FIELD_SET(value, I2C_CTRL, EN, DISABLE);
    POKE32(I2C_CTRL, value);

    /* Disable I2C Power */
    enableI2C(0);

    /* Set GPIO 30 & 31 back as GPIO pins */
    value = PEEK32(GPIO_MUX);
    value = FIELD_SET(value, GPIO_MUX, 30, GPIO);
    value = FIELD_SET(value, GPIO_MUX, 31, GPIO);
    POKE32(GPIO_MUX, value);
}


static long hwI2CWaitTXDone(void)
{
    unsigned int timeout;

    /* Wait until the transfer is completed. */
    timeout = HWI2C_WAIT_TIMEOUT;
	while ((FIELD_GET(PEEK32(I2C_STATUS), I2C_STATUS, TX) != I2C_STATUS_TX_COMPLETED) &&
           (timeout != 0))
		timeout--;

	if (timeout == 0)
	    return (-1);

    return 0;
}



/*
 *  This function writes data to the i2c slave device registers.
 *
 *  Parameters:
 *      deviceAddress   - i2c Slave device address
 *      length          - Total number of bytes to be written to the device
 *      pBuffer         - The buffer that contains the data to be written to the
 *                     i2c device.
 *
 *  Return Value:
 *      Total number of bytes those are actually written.
 */
static unsigned int hwI2CWriteData(
    unsigned char deviceAddress,
    unsigned int length,
    unsigned char *pBuffer
)
{
    unsigned char count, i;
    unsigned int totalBytes = 0;

    /* Set the Device Address */
    POKE32(I2C_SLAVE_ADDRESS, deviceAddress & ~0x01);

    /* Write data.
     * Note:
     *      Only 16 byte can be accessed per i2c start instruction.
     */
    do
    {
        /* Reset I2C by writing 0 to I2C_RESET register to clear the previous status. */
        POKE32(I2C_RESET, 0);

        /* Set the number of bytes to be written */
        if (length < MAX_HWI2C_FIFO)
            count = length - 1;
        else
            count = MAX_HWI2C_FIFO - 1;
        POKE32(I2C_BYTE_COUNT, count);

        /* Move the data to the I2C data register */
	    for (i = 0; i <= count; i++)
            POKE32(I2C_DATA0 + i, *pBuffer++);

        /* Start the I2C */
        POKE32(I2C_CTRL, FIELD_SET(PEEK32(I2C_CTRL), I2C_CTRL, CTRL, START));

        /* Wait until the transfer is completed. */
        if (hwI2CWaitTXDone() != 0)
            break;

        /* Substract length */
        length -= (count + 1);

        /* Total byte written */
        totalBytes += (count + 1);

    } while (length > 0);

    return totalBytes;
}




/*
 *  This function reads data from the slave device and stores them
 *  in the given buffer
 *
 *  Parameters:
 *      deviceAddress   - i2c Slave device address
 *      length          - Total number of bytes to be read
 *      pBuffer         - Pointer to a buffer to be filled with the data read
 *                     from the slave device. It has to be the same size as the
 *                     length to make sure that it can keep all the data read.
 *
 *  Return Value:
 *      Total number of actual bytes read from the slave device
 */
static unsigned int hwI2CReadData(
    unsigned char deviceAddress,
    unsigned int length,
    unsigned char *pBuffer
)
{
    unsigned char count, i;
    unsigned int totalBytes = 0;

    /* Set the Device Address */
    POKE32(I2C_SLAVE_ADDRESS, deviceAddress | 0x01);

    /* Read data and save them to the buffer.
     * Note:
     *      Only 16 byte can be accessed per i2c start instruction.
     */
    do
    {
        /* Reset I2C by writing 0 to I2C_RESET register to clear all the status. */
        POKE32(I2C_RESET, 0);

        /* Set the number of bytes to be read */
        if (length <= MAX_HWI2C_FIFO)
            count = length - 1;
        else
            count = MAX_HWI2C_FIFO - 1;
        POKE32(I2C_BYTE_COUNT, count);

        /* Start the I2C */
        POKE32(I2C_CTRL, FIELD_SET(PEEK32(I2C_CTRL), I2C_CTRL, CTRL, START));

        /* Wait until transaction done. */
        if (hwI2CWaitTXDone() != 0)
            break;

        /* Save the data to the given buffer */
        for (i = 0; i <= count; i++)
		    *pBuffer++ = PEEK32(I2C_DATA0 + i);

        /* Substract length by 16 */
        length -= (count + 1);

        /* Number of bytes read. */
        totalBytes += (count + 1);

    } while (length > 0);

    return totalBytes;
}




/*
 *  This function reads the slave device's register
 *
 *  Parameters:
 *      deviceAddress   - i2c Slave device address which register
 *                        to be read from
 *      registerIndex   - Slave device's register to be read
 *
 *  Return Value:
 *      Register value
 */
unsigned char hwI2CReadReg(
    unsigned char deviceAddress,
    unsigned char registerIndex
)
{
    unsigned char value = (0xFF);

    if (hwI2CWriteData(deviceAddress, 1, &registerIndex) == 1)
        hwI2CReadData(deviceAddress, 1, &value);

    return value;
}





/*
 *  This function writes a value to the slave device's register
 *
 *  Parameters:
 *      deviceAddress   - i2c Slave device address which register
 *                        to be written
 *      registerIndex   - Slave device's register to be written
 *      data            - Data to be written to the register
 *
 *  Result:
 *          0   - Success
 *         -1   - Fail
 */
int hwI2CWriteReg(
    unsigned char deviceAddress,
    unsigned char registerIndex,
    unsigned char data
)
{
    unsigned char value[2];

    value[0] = registerIndex;
    value[1] = data;
    if (hwI2CWriteData(deviceAddress, 2, value) == 2)
        return 0;

    return (-1);
}


#endif