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Commit f1e5b618 authored by Lukas Wunner's avatar Lukas Wunner Committed by Greg Kroah-Hartman
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serial: core: Support common rs485 binding for RTS polarity 



When a driver invokes the uart_get_rs485_mode() helper, set the RTS
polarity to active high by default unless the newly introduced
"rs485-rts-active-low" property was specified.

imx contains a line to set the default RTS polarity to active high,
it is now superfluous and hence deleted.

omap-serial historically defaults to active low and supports an
"rs485-rts-active-high" property to inverse the polarity.
Retain that behavior for compatibility.

Cc: Mark Jackson <mpfj@newflow.co.uk>
Cc: Michał Oleszczyk <oleszczyk.m@gmail.com>
Cc: Rafael Gago Castano <rgc@hms.se>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: default avatarLukas Wunner <lukas@wunner.de>
Acked-by: default avatarUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 6abe9ea8

drivers/tty/serial/imx.c

+0 −1
Original line number Diff line number Diff line
@@ -2060,7 +2060,6 @@ static int serial_imx_probe(struct platform_device *pdev) 
	sport->port.fifosize = 32;

	sport->port.ops = &imx_pops;

	sport->port.rs485_config = imx_rs485_config;

	sport->port.rs485.flags |= SER_RS485_RTS_ON_SEND;

	sport->port.flags = UPF_BOOT_AUTOCONF;

	timer_setup(&sport->timer, imx_timeout, 0);

drivers/tty/serial/omap-serial.c

+5 −2
Original line number Diff line number Diff line
@@ -1613,10 +1613,13 @@ static int serial_omap_probe_rs485(struct uart_omap_port *up, 


	uart_get_rs485_mode(up->dev, rs485conf);



	if (of_property_read_bool(np, "rs485-rts-active-high"))

	if (of_property_read_bool(np, "rs485-rts-active-high")) {

		rs485conf->flags |= SER_RS485_RTS_ON_SEND;

	else

		rs485conf->flags &= ~SER_RS485_RTS_AFTER_SEND;

	} else {

		rs485conf->flags &= ~SER_RS485_RTS_ON_SEND;

		rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;

	}



	/* check for tx enable gpio */

	up->rts_gpio = of_get_named_gpio_flags(np, "rts-gpio", 0, &flags);

drivers/tty/serial/serial_core.c

+10 −3
Original line number Diff line number Diff line
@@ -3036,16 +3036,23 @@ void uart_get_rs485_mode(struct device *dev, struct serial_rs485 *rs485conf) 
	}



	/*

	 * clear full-duplex and enabled flags to get to a defined state with

	 * the two following properties.

	 * Clear full-duplex and enabled flags, set RTS polarity to active high

	 * to get to a defined state with the following properties:

	 */

	rs485conf->flags &= ~(SER_RS485_RX_DURING_TX | SER_RS485_ENABLED);

	rs485conf->flags &= ~(SER_RS485_RX_DURING_TX | SER_RS485_ENABLED |

			      SER_RS485_RTS_AFTER_SEND);

	rs485conf->flags |= SER_RS485_RTS_ON_SEND;



	if (device_property_read_bool(dev, "rs485-rx-during-tx"))

		rs485conf->flags |= SER_RS485_RX_DURING_TX;



	if (device_property_read_bool(dev, "linux,rs485-enabled-at-boot-time"))

		rs485conf->flags |= SER_RS485_ENABLED;



	if (device_property_read_bool(dev, "rs485-rts-active-low")) {

		rs485conf->flags &= ~SER_RS485_RTS_ON_SEND;

		rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;

	}

}

EXPORT_SYMBOL_GPL(uart_get_rs485_mode);