diff mbox series

[V4,3/4] serial: imx: Add support for RS485 RX_DURING_TX output GPIO

Message ID 20221202104127.122761-3-cniedermaier@dh-electronics.com
State New
Headers show
Series [V4,1/4] dt-bindings: serial: rs485: Add GPIO controlling RX enable during TX | expand

Commit Message

Christoph Niedermaier Dec. 2, 2022, 10:41 a.m. UTC 
If a RX_DURING_TX GPIO is defined by the DT property "rs485-rx-during-tx-gpios"
this patch switches this GPIO accordingly to the RS485 flag RX_DURING_TX in user
space. In addition, the i.MX UART receiver is no longer turned on and off during
sending, because now the hardware is responsible for connecting or disconnecting
RX during TX controlled by this GPIO.

Signed-off-by: Christoph Niedermaier <cniedermaier@dh-electronics.com>
---
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Pengutronix Kernel Team <kernel@pengutronix.de>
Cc: Alexander Dahl <ada@thorsis.com>
Cc: Fabio Estevam <festevam@denx.de>
Cc: Marek Vasut <marex@denx.de>
Cc: kernel@dh-electronics.com
Cc: Linux Team <linux-imx@nxp.com>
To: linux-serial@vger.kernel.org
To: linux-arm-kernel@lists.infradead.org
---
V2: - Rework of the commit message
V3: - No changes
V4: - Direct call of gpiod_set_value_cansleep() without if statement
---
 drivers/tty/serial/imx.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 757825edb0cd..a2aea88128af 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -476,7 +476,8 @@  static void imx_uart_stop_tx(struct uart_port *port)
 				imx_uart_rts_inactive(sport, &ucr2);
 			imx_uart_writel(sport, ucr2, UCR2);
 
-			imx_uart_start_rx(port);
+			if (!port->rs485_rx_during_tx_gpio)
+				imx_uart_start_rx(port);
 
 			sport->tx_state = OFF;
 		}
@@ -705,7 +706,8 @@  static void imx_uart_start_tx(struct uart_port *port)
 				imx_uart_rts_inactive(sport, &ucr2);
 			imx_uart_writel(sport, ucr2, UCR2);
 
-			if (!(port->rs485.flags & SER_RS485_RX_DURING_TX))
+			if (!(port->rs485.flags & SER_RS485_RX_DURING_TX) &&
+			    !port->rs485_rx_during_tx_gpio)
 				imx_uart_stop_rx(port);
 
 			sport->tx_state = WAIT_AFTER_RTS;
@@ -1955,6 +1957,10 @@  static int imx_uart_rs485_config(struct uart_port *port, struct ktermios *termio
 	    rs485conf->flags & SER_RS485_RX_DURING_TX)
 		imx_uart_start_rx(port);
 
+	if (port->rs485_rx_during_tx_gpio)
+		gpiod_set_value_cansleep(port->rs485_rx_during_tx_gpio,
+					 !!(rs485conf->flags & SER_RS485_RX_DURING_TX));
+
 	return 0;
 }