2.3-InternetRadio/nutos/nut/dev/spibus_gpio.c

/*
 * Copyright (C) 2009 by egnite GmbH
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 * 2. Redistributions in binary form must reproduce the above copyright
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 *    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
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/*!
 * \file arch/avr/dev/spibus_gpio.c
 * \brief General GPIO SPI bus driver rotuines.
 *
 * \verbatim
 * $Id: spibus_gpio.c 4163 2012-05-15 12:09:43Z olereinhardt $
 * \endverbatim
 */

#include <sys/timer.h>
#include <sys/nutdebug.h>

#include <dev/spibus_gpio.h>

/*!
 * \brief Set clock rate of a specified SPI device.
 *
 * The new clock rate will be used for the next transfer. If the given
 * rate is beyond the capabilities of the bus controller, it will
 * automatically adjusted before the transfer starts.
 *
 * \param node Specifies the SPI bus node.
 * \param rate New clock rate, given in bits per second. If the value is
 *             SPI_CURRENT_RATE, then the current rate is kept.
 *
 * \return Previous rate.
 */
uint_fast32_t GpioSpiBusSetRate(NUTSPINODE * node, uint_fast32_t rate)
{
    uint32_t rc;
    GSPIREG *gspi;

    /* Sanity check. */
    NUTASSERT(node != NULL);
    NUTASSERT(node->node_stat != NULL);
    gspi = (GSPIREG *)node->node_stat;

    if(gspi->gspi_dly_rate)
        rc = 500000/ gspi->gspi_dly_rate;
    else
        rc = 500000;

    if (rate != SPI_CURRENT_RATE) {
        gspi->gspi_dly_rate = 500000 / rate;
        node->node_rate = (gspi->gspi_dly_rate)?
            (500000 /gspi->gspi_dly_rate):500000;
        node->node_mode |= SPI_MODE_UPDATE;
    }
    return rc;
}

/*!
 * \brief Update SPI settings.
 */
int GpioSpiSetup(NUTSPINODE * node)
{
    /* We support 8 bit only. */
    node->node_bits = 8;
    /* Calculate rate at the cost of a division*/
    GpioSpiBusSetRate(node, node->node_rate);
    /* Update done. */
    node->node_mode &= ~SPI_MODE_UPDATE;

    return 0;
}