u-boot/cpu/i386/sc520/sc520_ssi.c

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/*
* (C) Copyright 2002
* Daniel Engstr<EFBFBD>m, Omicron Ceti AB <daniel@omicron.se>.
*
* See file CREDITS for list of people who contributed to this
* project.
*
* 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 2 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, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/
/* stuff specific for the sc520, but independent of implementation */
#include <common.h>
#include <asm/ic/ssi.h>
#include <asm/ic/sc520.h>
int ssi_set_interface(int freq, int lsb_first, int inv_clock, int inv_phase)
{
u8 temp=0;
if (freq >= 8192) {
temp |= CTL_CLK_SEL_4;
} else if (freq >= 4096) {
temp |= CTL_CLK_SEL_8;
} else if (freq >= 2048) {
temp |= CTL_CLK_SEL_16;
} else if (freq >= 1024) {
temp |= CTL_CLK_SEL_32;
} else if (freq >= 512) {
temp |= CTL_CLK_SEL_64;
} else if (freq >= 256) {
temp |= CTL_CLK_SEL_128;
} else if (freq >= 128) {
temp |= CTL_CLK_SEL_256;
} else {
temp |= CTL_CLK_SEL_512;
}
if (!lsb_first) {
temp |= MSBF_ENB;
}
if (inv_clock) {
temp |= CLK_INV_ENB;
}
if (inv_phase) {
temp |= PHS_INV_ENB;
}
write_mmcr_byte(SC520_SSICTL, temp);
return 0;
}
u8 ssi_txrx_byte(u8 data)
{
write_mmcr_byte(SC520_SSIXMIT, data);
while ((read_mmcr_byte(SC520_SSISTA)) & SSISTA_BSY);
write_mmcr_byte(SC520_SSICMD, SSICMD_CMD_SEL_XMITRCV);
while ((read_mmcr_byte(SC520_SSISTA)) & SSISTA_BSY);
return read_mmcr_byte(SC520_SSIRCV);
}
void ssi_tx_byte(u8 data)
{
write_mmcr_byte(SC520_SSIXMIT, data);
while ((read_mmcr_byte(SC520_SSISTA)) & SSISTA_BSY);
write_mmcr_byte(SC520_SSICMD, SSICMD_CMD_SEL_XMIT);
}
u8 ssi_rx_byte(void)
{
while ((read_mmcr_byte(SC520_SSISTA)) & SSISTA_BSY);
write_mmcr_byte(SC520_SSICMD, SSICMD_CMD_SEL_RCV);
while ((read_mmcr_byte(SC520_SSISTA)) & SSISTA_BSY);
return read_mmcr_byte(SC520_SSIRCV);
}