2.3-InternetRadio/nutos/nut/arch/avr/dev/ih_twi.c

/*
 * Copyright (C) 2001-2005 by egnite Software GmbH. All rights reserved.
 *
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 * modification, are permitted provided that the following conditions
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 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holders nor the names of
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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/*!
 * \file arch/avr/dev/ih_twi.c
 * \brief Two wire serial transfer complete interrupt.
 *
 * \verbatim
 * $Id: ih_twi.c 4937 2013-01-22 11:38:42Z haraldkipp $
 * \endverbatim
 */

#include <dev/irqreg.h>

/*!
 * \addtogroup xgIrqReg
 */
/*@{*/

#if defined(TWI_vect) || defined(iv_TWI)

static int AvrTwiIrqCtl(int cmd, void *param);

IRQ_HANDLER sig_2WIRE_SERIAL = {
#ifdef NUT_PERFMON
    0,                          /* Interrupt counter, ir_count. */
#endif
    NULL,                       /* Passed argument, ir_arg. */
    NULL,                       /* Handler subroutine, ir_handler. */
    AvrTwiIrqCtl                /* Interrupt control, ir_ctl. */
};

/*!
 * \brief Two wire serial transfer complete interrupt control.
 *
 * \param cmd   Control command.
 *              - NUT_IRQCTL_INIT Initialize and disable interrupt.
 *              - NUT_IRQCTL_CLEAR Clear interrupt.
 *              - NUT_IRQCTL_STATUS Query interrupt status.
 *              - NUT_IRQCTL_ENABLE Enable interrupt.
 *              - NUT_IRQCTL_DISABLE Disable interrupt.
 *              - NUT_IRQCTL_GETPRIO Query interrupt priority.
 *              - NUT_IRQCTL_GETCOUNT Query and clear interrupt counter.
 * \param param Pointer to optional parameter.
 *
 * \return 0 on success, -1 otherwise.
 */
static int AvrTwiIrqCtl(int cmd, void *param)
{
    int rc = 0;
    unsigned int *ival = (unsigned int *) param;
    int_fast8_t enabled = bit_is_set(TWCR, TWIE);

    /* Disable interrupt. */
    cbi(TWCR, TWIE);

    switch (cmd) {
    case NUT_IRQCTL_INIT:
        enabled = 0;
    case NUT_IRQCTL_CLEAR:
        /* Clear any pending interrupt. */
        if (bit_is_set(SPSR, SPIF)) {
            inb(SPDR);
        }
        break;
    case NUT_IRQCTL_STATUS:
        if (bit_is_set(TWCR, TWINT)) {
            *ival = 1;
        } else {
            *ival = 0;
        }
        if (enabled) {
            *ival |= 0x80;
        }
        break;
    case NUT_IRQCTL_ENABLE:
        enabled = 1;
        break;
    case NUT_IRQCTL_DISABLE:
        enabled = 0;
        break;
    case NUT_IRQCTL_GETPRIO:
        *ival = 16;
        break;
#ifdef NUT_PERFMON
    case NUT_IRQCTL_GETCOUNT:
        *ival = (unsigned int) sig_2WIRE_SERIAL.ir_count;
        sig_2WIRE_SERIAL.ir_count = 0;
        break;
#endif
    default:
        rc = -1;
        break;
    }

    /* Enable interrupt. */
    if (enabled) {
        sbi(TWCR, TWIE);
    }
    return rc;
}

/*! \fn TWI_vect(void)
 * \brief Two-wire serial interface interrupt entry.
 */
#ifdef __IMAGECRAFT__
#pragma interrupt_handler TWI_vect:iv_TWI
#endif
NUTSIGNAL(TWI_vect, sig_2WIRE_SERIAL)
#endif
/*@}*/