M7350/bootable/bootloader/lk/platform/msm_shared/spi.c

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2024-09-09 08:52:07 +00:00
/*
* 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--;
}
}