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serial: fsl_lpuart: RS485 RTS polariy is inverse

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The setting of RS485 RTS polarity is inverse in the current driver.

When the property of 'rs485-rts-active-low' is enabled in the dts node,
the RTS signal should be LOW during sending. Otherwise, if there is no
such a property, the RTS should be HIGH during sending.

Fixes: 03895cf41d ("tty: serial: fsl_lpuart: Add support for RS-485")
Cc: stable <stable@kernel.org>
Signed-off-by: Nicolas Diaz <nicolas.diaz@nxp.com>
Signed-off-by: Shenwei Wang <shenwei.wang@nxp.com>
Link: https://lore.kernel.org/r/20220805144529.604856-1-shenwei.wang@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Shenwei Wang 2022-08-05 09:45:29 -05:00 committed by Greg Kroah-Hartman
parent 566f9c9f89
commit 846651eca0
1 changed files with 2 additions and 2 deletions
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4
drivers/tty/serial/fsl_lpuart.c
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@ -1394,9 +1394,9 @@ static int lpuart_config_rs485(struct uart_port *port, struct ktermios *termios,
* Note: UART is assumed to be active high.
*/
if (rs485->flags & SER_RS485_RTS_ON_SEND)
modem &= ~UARTMODEM_TXRTSPOL;
else if (rs485->flags & SER_RS485_RTS_AFTER_SEND)
modem |= UARTMODEM_TXRTSPOL;
else if (rs485->flags & SER_RS485_RTS_AFTER_SEND)
modem &= ~UARTMODEM_TXRTSPOL;
}
writeb(modem, sport->port.membase + UARTMODEM);