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/*
* Copyright 2012 Ettus Research LLC
* Copyright 2007,2008 Free Software Foundation, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "spi.h"
#include "memory_map.h"
#include "nonstdio.h"
#include "mdelay.h"
void spi_init(void)
{
spi_core->divider = 100;
}
void spi_wait(void)
{
//assumption that divider is reasonably small
mdelay(1);
}
uint32_t spi_transact(bool readback, int slave, uint32_t data, int length, uint32_t flags)
{
uint32_t control_word = 0;
control_word |= (slave << SPI_CORE_SLAVE_SELECT_SHIFT);
control_word |= (length << SPI_CORE_NUM_BITS_SHIFT);
if ((flags & SPI_PUSH_RISE) != 0) control_word |= (1 << SPI_CORE_DATA_IN_EDGE_SHIFT);
if ((flags & SPI_PUSH_FALL) != 0) control_word |= (0 << SPI_CORE_DATA_IN_EDGE_SHIFT);
if ((flags & SPI_LATCH_RISE) != 0) control_word |= (1 << SPI_CORE_DATA_OUT_EDGE_SHIFT);
if ((flags & SPI_LATCH_FALL) != 0) control_word |= (0 << SPI_CORE_DATA_OUT_EDGE_SHIFT);
uint32_t data_out_rev = 0;
for (size_t i = 0; i < length; i++){
const int bit = ((data >> i) & 0x1);
data_out_rev |= (bit << (length - i - 1));
}
spi_wait();
spi_core->control = control_word;
spi_core->data = data_out_rev;
if (readback) spi_wait();
return readback_mux->spi;
}
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