Commit ca530cfa authored by Christoph Niedermaier's avatar Christoph Niedermaier Committed by Greg Kroah-Hartman
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serial: imx: Add support for RS485 RX_DURING_TX output GPIO 



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: default avatarChristoph Niedermaier <cniedermaier@dh-electronics.com>
Link: https://lore.kernel.org/r/20221202104127.122761-3-cniedermaier@dh-electronics.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 163f080e

drivers/tty/serial/imx.c

+8 −2
Original line number Diff line number Diff line
@@ -476,6 +476,7 @@ static void imx_uart_stop_tx(struct uart_port *port) 
				imx_uart_rts_inactive(sport, &ucr2);

			imx_uart_writel(sport, ucr2, UCR2);



			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;
@@ -1956,6 +1958,10 @@ 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;

}