58 lines
2.0 KiB
C
58 lines
2.0 KiB
C
/*
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* Copyright (c) 2012, The Linux Foundation. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/types.h>
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#include <platform/timer.h>
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#include <dev/gpio.h>
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void spi_bit_bang_write(uint8_t spi_sclk, uint8_t spi_mosi, uint8_t dc, uint8_t data)
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{
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uint8_t bit;
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uint8_t bnum;
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gpio_set(spi_sclk, 0); /* clk low */
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/* dc: 0 for command, 1 for parameter */
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gpio_set(spi_mosi, dc);
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udelay(1); /* at least 20 ns */
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gpio_set(spi_sclk, 1); /* clk high */
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udelay(1); /* at least 20 ns */
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bnum = 8; /* 8 data bits */
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bit = 0x80;
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while(bnum){
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gpio_set(spi_sclk, 0); /* clk low */
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if (data & bit)
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gpio_set(spi_mosi, 1);
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else
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gpio_set(spi_mosi, 0);
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udelay(1);
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gpio_set(spi_sclk, 1); /* clk high */
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udelay(1);
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bit >>= 1;
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bnum--;
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}
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}
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