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serial: imx: Add support for RS485 RX_DURING_TX output GPIO

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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>
Link: https://lore.kernel.org/r/20221202104127.122761-3-cniedermaier@dh-electronics.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Christoph Niedermaier 2022-12-02 11:41:26 +01:00 committed by Greg Kroah-Hartman
parent 163f080eb7
commit ca530cfa96
1 changed files with 8 additions and 2 deletions
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10
drivers/tty/serial/imx.c
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@ -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;
@ -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;
}