Hi,
please see my patch for enabling the RS485 half-duplex control below.
Please note that I am using this on a PowerPC platform. So I needed to
add the ioctl to the PowerPC header. As Wolfgang stated, it is
already in the x86 header. I am not sure if I have to post the modification
on the powerpc header to the PowerPC list or if it will be accepted here
as well. .... But first I will have to see what you think of this patch :-)
Matthias
Some Exar UARTs support a auto rs485 mode. In this mode
the UART's RTS# pin is activated during transmitting and
can be used to enable a rs485 line driver. This has nothing
to do with attempts to do this by manually by asserting/
deasserting handshake lines.
Signed-off-by: Matthias Fuchs <mfuchs@xxxxxxxx>
---
arch/powerpc/include/asm/ioctls.h | 2 +
drivers/serial/8250.c | 59 +++++++++++++++++++++++++++++++++++++
2 files changed, 61 insertions(+), 0 deletions(-)
diff --git a/arch/powerpc/include/asm/ioctls.h b/arch/powerpc/include/asm/ioctls.h
index 279a622..1842186 100644
--- a/arch/powerpc/include/asm/ioctls.h
+++ b/arch/powerpc/include/asm/ioctls.h
@@ -89,6 +89,8 @@
#define TIOCSBRK 0x5427 /* BSD compatibility */
#define TIOCCBRK 0x5428 /* BSD compatibility */
#define TIOCGSID 0x5429 /* Return the session ID of FD */
+#define TIOCGRS485 0x542e
+#define TIOCSRS485 0x542f
#define TIOCGPTN _IOR('T',0x30, unsigned int) /* Get Pty Number (of pty-mux device) */
#define TIOCSPTLCK _IOW('T',0x31, int) /* Lock/unlock Pty */
diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index 303272a..e6df50f 100644
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -2511,6 +2511,64 @@ serial8250_type(struct uart_port *port)
return uart_config[type].name;
}
+static int
+serial8250_ioctl_port(struct uart_port *port, unsigned int cmd, unsigned long arg)
+{
+ struct uart_8250_port *up = (struct uart_8250_port *)port;
+
+ switch (cmd) {
+ case TIOCSRS485:
+ {
+ struct serial_rs485 rs485ctrl;
+ unsigned char fctr;
+
+ if (port->type != PORT_16850)
+ return -ENODEV;
+
+ if (copy_from_user(&rs485ctrl,
+ (struct serial_rs485 *)arg,
+ sizeof(rs485ctrl)))
+ return -EFAULT;
+
+ serial_outp(up, UART_LCR, 0xbf);
+ fctr = serial_inp(up, UART_FCTR);
+ if (rs485ctrl.flags & SER_RS485_ENABLED)
+ fctr |= 0x08;
+ else
+ fctr &= ~0x08;
+ serial_outp(up, UART_FCTR, fctr);
+ serial_outp(up, UART_LCR, 0);
+ return 0;
+ }
+
+ case TIOCGRS485:
+ {
+ struct serial_rs485 rs485ctrl;
+
+ if (port->type != PORT_16850)
+ return -ENODEV;
+
+ serial_outp(up, UART_LCR, 0xbf);
+ if (serial_inp(up, UART_FCTR) & 0x08)
+ rs485ctrl.flags = SER_RS485_ENABLED;
+ else
+ rs485ctrl.flags = 0;
+ serial_outp(up, UART_LCR, 0);
+
+ if (copy_to_user((struct serial_rs485 *)arg,
+ &rs485ctrl,
+ sizeof(rs485ctrl)))
+ return -EFAULT;
+ return 0;
+ }
+
+ default:
+ return -ENOIOCTLCMD;
+ }
+
+ return 0;
+}
+
static struct uart_ops serial8250_pops = {
.tx_empty = serial8250_tx_empty,
.set_mctrl = serial8250_set_mctrl,
@@ -2529,6 +2587,7 @@ static struct uart_ops serial8250_pops = {
.request_port = serial8250_request_port,
.config_port = serial8250_config_port,
.verify_port = serial8250_verify_port,
+ .ioctl = serial8250_ioctl_port,
#ifdef CONFIG_CONSOLE_POLL
.poll_get_char = serial8250_get_poll_char,
.poll_put_char = serial8250_put_poll_char,
--
1.5.6.3
--
To unsubscribe from this list: send the line "unsubscribe linux-serial" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
