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/*
* (C) Copyright 2003
* Martin Krause, TQ-Systems GmbH, <martin.krause@tqs.de>
*
* Based on cpu/arm920t/serial.c, by Gary Jennejohn
* (C) Copyright 2002 Gary Jennejohn, DENX Software Engineering, <garyj@denx.de>
*
* 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
*
*/
#include <common.h>
#include <s3c2400.h>
#include "rs485.h"
static void rs485_setbrg (void);
static void rs485_cfgio (void);
static void set_rs485re(unsigned char rs485re_state);
static void set_rs485de(unsigned char rs485de_state);
static void rs485_setbrg (void);
#ifdef NOT_USED
static void trab_rs485_disable_tx(void);
static void trab_rs485_disable_rx(void);
#endif
#define UART_NR S3C24X0_UART1
/* CPLD-Register for controlling TRAB hardware functions */
#define CPLD_RS485_RE ((volatile unsigned long *)0x04028000)
static void rs485_setbrg (void)
{
struct s3c24x0_uart * const uart = s3c24x0_get_base_uart(UART_NR);
int i;
unsigned int reg = 0;
/* value is calculated so : (int)(PCLK/16./baudrate) -1 */
/* reg = (33000000 / (16 * gd->baudrate)) - 1; */
reg = (33000000 / (16 * 38400)) - 1;
/* FIFO enable, Tx/Rx FIFO clear */
uart->UFCON = 0x07;
uart->UMCON = 0x0;
/* Normal,No parity,1 stop,8 bit */
uart->ULCON = 0x3;
/*
* tx=level,rx=edge,disable timeout int.,enable rx error int.,
* normal,interrupt or polling
*/
uart->UCON = 0x245;
uart->UBRDIV = reg;
for (i = 0; i < 100; i++);
}
static void rs485_cfgio (void)
{
struct s3c24x0_gpio * const gpio = s3c24x0_get_base_gpio();
gpio->PFCON &= ~(0x3 << 2);
gpio->PFCON |= (0x2 << 2); /* configure GPF1 as RXD1 */
gpio->PFCON &= ~(0x3 << 6);
gpio->PFCON |= (0x2 << 6); /* configure GPF3 as TXD1 */
gpio->PFUP |= (1 << 1); /* disable pullup on GPF1 */
gpio->PFUP |= (1 << 3); /* disable pullup on GPF3 */
gpio->PACON &= ~(1 << 11); /* set GPA11 (RS485_DE) to output */
}
/*
* Initialise the rs485 port with the given baudrate. The settings
* are always 8 data bits, no parity, 1 stop bit, no start bits.
*
*/
int rs485_init (void)
{
rs485_cfgio ();
rs485_setbrg ();
return (0);
}
/*
* Read a single byte from the rs485 port. Returns 1 on success, 0
* otherwise. When the function is succesfull, the character read is
* written into its argument c.
*/
int rs485_getc (void)
{
struct s3c24x0_uart * const uart = s3c24x0_get_base_uart(UART_NR);
/* wait for character to arrive */
while (!(uart->UTRSTAT & 0x1));
return uart->URXH & 0xff;
}
/*
* Output a single byte to the rs485 port.
*/
void rs485_putc (const char c)
{
struct s3c24x0_uart * const uart = s3c24x0_get_base_uart(UART_NR);
/* wait for room in the tx FIFO */
while (!(uart->UTRSTAT & 0x2));
uart->UTXH = c;
/* If \n, also do \r */
if (c == '\n')
rs485_putc ('\r');
}
/*
* Test whether a character is in the RX buffer
*/
int rs485_tstc (void)
{
struct s3c24x0_uart * const uart = s3c24x0_get_base_uart(UART_NR);
return uart->UTRSTAT & 0x1;
}
void rs485_puts (const char *s)
{
while (*s) {
rs485_putc (*s++);
}
}
/*
* State table:
* RE DE Result
* 1 1 XMIT
* 0 0 RCV
* 1 0 Shutdown
*/
/* function that controls the receiver enable for the rs485 */
/* rs485re_state reflects the level (0/1) of the RE pin */
static void set_rs485re(unsigned char rs485re_state)
{
if(rs485re_state)
*CPLD_RS485_RE = 0x010000;
else
*CPLD_RS485_RE = 0x0;
}
/* function that controls the sender enable for the rs485 */
/* rs485de_state reflects the level (0/1) of the DE pin */
static void set_rs485de(unsigned char rs485de_state)
{
struct s3c24x0_gpio * const gpio = s3c24x0_get_base_gpio();
/* This is on PORT A bit 11 */
if(rs485de_state)
gpio->PADAT |= (1 << 11);
else
gpio->PADAT &= ~(1 << 11);
}
void trab_rs485_enable_tx(void)
{
set_rs485de(1);
set_rs485re(1);
}
void trab_rs485_enable_rx(void)
{
set_rs485re(0);
set_rs485de(0);
}
#ifdef NOT_USED
static void trab_rs485_disable_tx(void)
{
set_rs485de(0);
}
static void trab_rs485_disable_rx(void)
{
set_rs485re(1);
}
#endif
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