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serial: mcf: Add support RS485 in ColdFire serial driver 

Signed-off-by: Quoc-Viet Nguyen <afelion@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Quoc-Viet Nguyen 2013-01-15 09:32:53 +10:00 committed by Greg Kroah-Hartman
parent b81273a132
commit 496c907740
1 changed files with 71 additions and 0 deletions
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71
drivers/tty/serial/mcf.c
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@ -23,6 +23,7 @@
#include <linux/serial.h>
#include <linux/serial_core.h>
#include <linux/io.h>
#include <linux/uaccess.h>
#include <asm/coldfire.h>
#include <asm/mcfsim.h>
#include <asm/mcfuart.h>
@ -55,6 +56,7 @@ struct mcf_uart {
struct uart_port port;
unsigned int sigs; /* Local copy of line sigs */
unsigned char imr; /* Local IMR mirror */
struct serial_rs485 rs485; /* RS485 settings */
};
/****************************************************************************/
@ -101,6 +103,12 @@ static void mcf_start_tx(struct uart_port *port)
{
struct mcf_uart *pp = container_of(port, struct mcf_uart, port);
if (pp->rs485.flags & SER_RS485_ENABLED) {
/* Enable Transmitter */
writeb(MCFUART_UCR_TXENABLE, port->membase + MCFUART_UCR);
/* Manually assert RTS */
writeb(MCFUART_UOP_RTS, port->membase + MCFUART_UOP1);
}
pp->imr |= MCFUART_UIR_TXREADY;
writeb(pp->imr, port->membase + MCFUART_UIMR);
}
@ -196,6 +204,7 @@ static void mcf_shutdown(struct uart_port *port)
static void mcf_set_termios(struct uart_port *port, struct ktermios *termios,
struct ktermios *old)
{
struct mcf_uart *pp = container_of(port, struct mcf_uart, port);
unsigned long flags;
unsigned int baud, baudclk;
#if defined(CONFIG_M5272)
@ -248,6 +257,11 @@ static void mcf_set_termios(struct uart_port *port, struct ktermios *termios,
mr2 |= MCFUART_MR2_TXCTS;
}
if (pp->rs485.flags & SER_RS485_ENABLED) {
dev_dbg(port->dev, "Setting UART to RS485\n");
mr2 |= MCFUART_MR2_TXRTS;
}
spin_lock_irqsave(&port->lock, flags);
uart_update_timeout(port, termios->c_cflag, baud);
writeb(MCFUART_UCR_CMDRESETRX, port->membase + MCFUART_UCR);
@ -342,6 +356,10 @@ static void mcf_tx_chars(struct mcf_uart *pp)
if (xmit->head == xmit->tail) {
pp->imr &= ~MCFUART_UIR_TXREADY;
writeb(pp->imr, port->membase + MCFUART_UIMR);
/* Disable TX to negate RTS automatically */
if (pp->rs485.flags & SER_RS485_ENABLED)
writeb(MCFUART_UCR_TXDISABLE,
port->membase + MCFUART_UCR);
}
}
@ -418,6 +436,58 @@ static int mcf_verify_port(struct uart_port *port, struct serial_struct *ser)
/****************************************************************************/
/* Enable or disable the RS485 support */
static void mcf_config_rs485(struct uart_port *port, struct serial_rs485 *rs485)
{
struct mcf_uart *pp = container_of(port, struct mcf_uart, port);
unsigned long flags;
unsigned char mr1, mr2;
spin_lock_irqsave(&port->lock, flags);
/* Get mode registers */
mr1 = readb(port->membase + MCFUART_UMR);
mr2 = readb(port->membase + MCFUART_UMR);
if (rs485->flags & SER_RS485_ENABLED) {
dev_dbg(port->dev, "Setting UART to RS485\n");
/* Automatically negate RTS after TX completes */
mr2 |= MCFUART_MR2_TXRTS;
} else {
dev_dbg(port->dev, "Setting UART to RS232\n");
mr2 &= ~MCFUART_MR2_TXRTS;
}
writeb(mr1, port->membase + MCFUART_UMR);
writeb(mr2, port->membase + MCFUART_UMR);
pp->rs485 = *rs485;
spin_unlock_irqrestore(&port->lock, flags);
}
static int mcf_ioctl(struct uart_port *port, unsigned int cmd,
unsigned long arg)
{
switch (cmd) {
case TIOCSRS485: {
struct serial_rs485 rs485;
if (copy_from_user(&rs485, (struct serial_rs485 *)arg,
sizeof(struct serial_rs485)))
return -EFAULT;
mcf_config_rs485(port, &rs485);
break;
}
case TIOCGRS485: {
struct mcf_uart *pp = container_of(port, struct mcf_uart, port);
if (copy_to_user((struct serial_rs485 *)arg, &pp->rs485,
sizeof(struct serial_rs485)))
return -EFAULT;
break;
}
default:
return -ENOIOCTLCMD;
}
return 0;
}
/****************************************************************************/
/*
* Define the basic serial functions we support.
*/
@ -438,6 +508,7 @@ static const struct uart_ops mcf_uart_ops = {
.release_port = mcf_release_port,
.config_port = mcf_config_port,
.verify_port = mcf_verify_port,
.ioctl = mcf_ioctl,
};
static struct mcf_uart mcf_ports[4];