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[3/4] serial: imx: Add support for rs485 RX_DURING_TX GPIO

Message ID 20221026165049.9541-4-cniedermaier@dh-electronics.com
State New
Headers show
Series tty: serial: Add ability to control rs485 RX_DURING_TX via a GPIO | expand

Commit Message

Christoph Niedermaier Oct. 26, 2022, 4:50 p.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: Fabio Estevam <festevam@denx.de>
Cc: Marek Vasut <marex@denx.de>
Cc: Linux Team <linux-imx@nxp.com>
To: linux-serial@vger.kernel.org
To: linux-arm-kernel@lists.infradead.org
---
 drivers/tty/serial/imx.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 05b432dc7a85..16f8baaf4f12 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;
 		}
@@ -697,7 +698,8 @@  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;
@@ -1931,6 +1933,13 @@  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) {
+		if (rs485conf->flags & SER_RS485_RX_DURING_TX)
+			gpiod_set_value_cansleep(port->rs485_rx_during_tx_gpio, 1);
+		else
+			gpiod_set_value_cansleep(port->rs485_rx_during_tx_gpio, 0);
+	}
+
 	return 0;
 }