gpiocontrol.c

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#include <xinu.h>

/*------------------------------------------------------------------------
 *  gpiocontrol  -  Control a gpio device pin settings
 *------------------------------------------------------------------------
 */
devcall gpiocontrol(
    struct dentry *devptr, /* Entry in device switch table  */
    int32 func,            /* Function to perform       */
    int32 arg1,            /* Argument 1 for request    */
    int32 arg2             /* Argument 2 for request    */
)
{
    struct gpio_csreg *csrptr; /* Pointer ot the CSR for GPIO   */
    struct gpiocblk *gpioptr;  /* Pointer to the control block  */

    csrptr = (struct gpio_csreg *)(devptr->dvcsr);
    gpioptr = &gpiotab[devptr->dvminor];

    /* Process the request */

    switch (func)
    {

        /* Enable output capability for pins in arg1 */

    case GPIO_OUTPUT_ENABLE:
        csrptr->oe &= (~arg1);
        return (devcall)OK;

        /* Disable output capability for pins in arg1 */

    case GPIO_OUTPUT_DISABLE:
        csrptr->oe |= arg1;
        return (devcall)OK;

        /* Register arg1 function pointer to be called from interrupt */

    case GPIO_REG_INT_HANDLER:
        gpioptr->gphookfn = (gpiointhook)arg1;
        return (devcall)OK;

        /* Configure debounce capability for pins in arg2 */

    case GPIO_DEB_SET_TIME:
        if (arg1 > 0)
        {
            csrptr->deb_time = (arg1 - 1) & 0xFF;
            csrptr->deb_ena |= arg2;
        }
        else
        {
            csrptr->deb_ena &= (~arg2);
        }
        return (devcall)OK;

        /* Configure interrupt capability for pins in arg2 */

    case GPIO_INTERRUPT_CTL:

        /* No lines affected */

        if ((arg1 & GPIO_INT_ALL_LINES) == 0)
        {
            return (devcall)SYSERR;
        }

        /* Disable lines and triggers */

        if ((arg1 & GPIO_INT_ALL_TRIG) == 0)
        {

            /* Flags affect line 0 */

            if ((arg1 & GPIO_INT_LINE0_EN) != 0)
            {
                csrptr->irqclear0 = arg2;
            }

            /* Flags affect line 1 */

            if ((arg1 & GPIO_INT_LINE1_EN) != 0)
            {
                csrptr->irqclear1 = arg2;
            }

            /* Disable all triggers */

            csrptr->rising &= (~arg2);
            csrptr->falling &= (~arg2);
            csrptr->level0 &= (~arg2);
            csrptr->level1 &= (~arg2);

            return (devcall)OK;
        }

        /* Enable lines and triggers */

        if ((arg1 & GPIO_INT_LINE0_EN) != 0)
        {
            csrptr->irqset0 = arg2;
        }
        if ((arg1 & GPIO_INT_LINE1_EN) != 0)
        {
            csrptr->irqset1 = arg2;
        }
        if ((arg1 & GPIO_INT_RISE_TRIG) != 0)
        {
            csrptr->rising |= arg2;
        }
        if ((arg1 & GPIO_INT_FALL_TRIG) != 0)
        {
            csrptr->falling |= arg2;
        }
        if ((arg1 & GPIO_INT_LVL0_TRIG) != 0)
        {
            csrptr->level0 |= arg2;
        }
        if ((arg1 & GPIO_INT_LVL1_TRIG) != 0)
        {
            csrptr->level1 |= arg2;
        }

        return (devcall)OK;

        /* Read input from a single pin arg1 */

    case GPIO_READ_PIN:
        arg2 = csrptr->datain & PIN_MASK(arg1);
        return (arg2 > 0);

        /* Write value arg2 to a single output pin arg1 */

    case GPIO_WRITE_PIN:
        if (arg2)
        {
            csrptr->set_data = PIN_MASK(arg1);
        }
        else
        {
            csrptr->clear_data = PIN_MASK(arg1);
        }
        return (devcall)OK;

    default:
        return (devcall)SYSERR;
    }
}