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>
diff --git a/drivers/tty/serial/mcf.c b/drivers/tty/serial/mcf.c
index 7ed9927..e956377 100644
--- a/drivers/tty/serial/mcf.c
+++ b/drivers/tty/serial/mcf.c
@@ -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 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 @@
{
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_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 @@
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 @@
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 @@
/****************************************************************************/
+/* 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 @@
.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];