diff mbox series

serial: omap: don't disable rs485 if rts gpio is missing

Message ID 20210411085743.510-1-dariobin@libero.it
State Superseded
Headers show
Series serial: omap: don't disable rs485 if rts gpio is missing | expand

Commit Message

Dario Binacchi April 11, 2021, 8:57 a.m. UTC 
There are rs485 transceivers (e.g. MAX13487E/MAX13488E) which
automatically disable or enable the driver and receiver to keep the bus
in the correct state.
In these cases we don't need a GPIO for flow control.

Signed-off-by: Dario Binacchi <dariobin@libero.it>
---

 drivers/tty/serial/omap-serial.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

Comments

Greg Kroah-Hartman April 15, 2021, 8:14 a.m. UTC | #1 
On Sun, Apr 11, 2021 at 10:57:43AM +0200, Dario Binacchi wrote:
> There are rs485 transceivers (e.g. MAX13487E/MAX13488E) which

> automatically disable or enable the driver and receiver to keep the bus

> in the correct state.

> In these cases we don't need a GPIO for flow control.

> 

> Signed-off-by: Dario Binacchi <dariobin@libero.it>

> ---


Same here, what commit id does this "fix"?  Please add that and resend.

thanks,

greg k-h
diff mbox series

Patch

diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
index 76b94d0ff586..1583e93b2202 100644
--- a/drivers/tty/serial/omap-serial.c
+++ b/drivers/tty/serial/omap-serial.c
@@ -302,7 +302,8 @@  static void serial_omap_stop_tx(struct uart_port *port)
 			serial_out(up, UART_OMAP_SCR, up->scr);
 			res = (port->rs485.flags & SER_RS485_RTS_AFTER_SEND) ?
 				1 : 0;
-			if (gpiod_get_value(up->rts_gpiod) != res) {
+			if (up->rts_gpiod &&
+			    gpiod_get_value(up->rts_gpiod) != res) {
 				if (port->rs485.delay_rts_after_send > 0)
 					mdelay(
 					port->rs485.delay_rts_after_send);
@@ -411,7 +412,7 @@  static void serial_omap_start_tx(struct uart_port *port)
 
 		/* if rts not already enabled */
 		res = (port->rs485.flags & SER_RS485_RTS_ON_SEND) ? 1 : 0;
-		if (gpiod_get_value(up->rts_gpiod) != res) {
+		if (up->rts_gpiod && gpiod_get_value(up->rts_gpiod) != res) {
 			gpiod_set_value(up->rts_gpiod, res);
 			if (port->rs485.delay_rts_before_send > 0)
 				mdelay(port->rs485.delay_rts_before_send);
@@ -1407,18 +1408,13 @@  serial_omap_config_rs485(struct uart_port *port, struct serial_rs485 *rs485)
 	/* store new config */
 	port->rs485 = *rs485;
 
-	/*
-	 * Just as a precaution, only allow rs485
-	 * to be enabled if the gpio pin is valid
-	 */
 	if (up->rts_gpiod) {
 		/* enable / disable rts */
 		val = (port->rs485.flags & SER_RS485_ENABLED) ?
 			SER_RS485_RTS_AFTER_SEND : SER_RS485_RTS_ON_SEND;
 		val = (port->rs485.flags & val) ? 1 : 0;
 		gpiod_set_value(up->rts_gpiod, val);
-	} else
-		port->rs485.flags &= ~SER_RS485_ENABLED;
+	}
 
 	/* Enable interrupts */
 	up->ier = mode;