soft_tws.c
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/*
* (C) Copyright 2009
* Detlev Zundel, DENX Software Engineering, dzu@denx.de.
*
* SPDX-License-Identifier: GPL-2.0+
*/
#define TWS_IMPLEMENTATION
#include <common.h>
/*=====================================================================*/
/* Public Functions */
/*=====================================================================*/
/*-----------------------------------------------------------------------
* Read bits
*/
int tws_read(uchar *buffer, int len)
{
int rem = len;
uchar accu, shift;
debug("tws_read: buffer %p len %d\n", buffer, len);
/* Configure the data pin for input */
tws_data_config_output(0);
/* Disable WR, i.e. setup a read */
tws_wr(0);
udelay(1);
/* Rise CE */
tws_ce(1);
udelay(1);
for (; rem > 0; ) {
for (shift = 0, accu = 0;
(rem > 0) && (shift < 8);
rem--, shift++) {
tws_clk(1);
udelay(10);
accu |= (tws_data_read() << shift); /* LSB first */
tws_clk(0);
udelay(10);
}
*buffer++ = accu;
}
/* Lower CE */
tws_ce(0);
return len - rem;
}
/*-----------------------------------------------------------------------
* Write bits
*/
int tws_write(uchar *buffer, int len)
{
int rem = len;
uchar accu, shift;
debug("tws_write: buffer %p len %d\n", buffer, len);
/* Configure the data pin for output */
tws_data_config_output(1);
/* Enable WR, i.e. setup a write */
tws_wr(1);
udelay(1);
/* Rise CE */
tws_ce(1);
udelay(1);
for (; rem > 0; ) {
for (shift = 0, accu = *buffer++;
(rem > 0) && (shift < 8);
rem--, shift++) {
tws_data(accu & 0x01); /* LSB first */
tws_clk(1);
udelay(10);
tws_clk(0);
udelay(10);
accu >>= 1;
}
}
/* Lower CE */
tws_ce(0);
return len - rem;
}