sipo.c

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#include "sipo.h"

#include "hw/hw_sipo.h"

#include <cfg/compiler.h>
#include <cfg/log.h>

#include <kern/kfile.h>

#include <string.h>


#define SIPO_DATAORDER_START(order)          (order ? SIPO_DATAORDER_START_LSB : SIPO_DATAORDER_START_MSB)
#define SIPO_DATAORDER_SHIFT(shift, order)   (order ?  ((shift) <<= 1) : ((shift) >>= 1))

INLINE void sipo_putchar(uint8_t c, uint8_t bit_order, uint8_t clock_pol)
{
    uint8_t shift = SIPO_DATAORDER_START(bit_order);

    for(int i = 0; i < 8; i++)
    {
        if((c & shift) == 0)
            SIPO_SI_LOW();
        else
            SIPO_SI_HIGH();

        SIPO_SI_CLOCK(clock_pol);

        SIPO_DATAORDER_SHIFT(shift, bit_order);
    }
}

static size_t sipo_write(struct KFile *_fd, const void *_buf, size_t size)
{
    const uint8_t *buf = (const uint8_t *)_buf;
    Sipo *fd = SIPO_CAST(_fd);
    size_t write_len = size;

    ASSERT(buf);

    SIPO_SET_SI_LEVEL();
    SIPO_SET_CLK_LEVEL(fd->clock_pol);
    SIPO_SET_LD_LEVEL(fd->load_device, fd->load_pol);

    // Load into the shift register all the buffer bytes
    while(size--)
        sipo_putchar(*buf++, fd->bit_order, fd->clock_pol);

    // We finsh to load bytes, so load it.
    SIPO_LOAD(fd->load_device, fd->load_pol);

    return write_len;
}

void sipo_init(Sipo *fd)
{
    ASSERT(fd);

    memset(fd, 0, sizeof(Sipo));

    //Set kfile struct type as a generic kfile structure.
    DB(fd->fd._type = KFT_SIPO);

    // Set up SIPO writing functions.
    fd->fd.write = sipo_write;

    SIPO_INIT_PIN();

    /* Enable sipo output */
    SIPO_ENABLE();
}