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