Commit ef838a81 authored by Uwe Kleine-König's avatar Uwe Kleine-König Committed by Greg Kroah-Hartman
Browse files

serial: Add common rs485 device tree parsing function 



Several drivers have the same device tree parsing code. Create
a common helper function for it.

This patch bases on work done by Sascha Hauer.

Signed-off-by: default avatarUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent c45e2d25

drivers/tty/serial/serial_core.c

+36 −0
Original line number Diff line number Diff line
@@ -3026,5 +3026,41 @@ EXPORT_SYMBOL(uart_resume_port); 
EXPORT_SYMBOL(uart_add_one_port);

EXPORT_SYMBOL(uart_remove_one_port);



/**

 * of_get_rs485_mode() - Implement parsing rs485 properties

 * @np: uart node

 * @rs485conf: output parameter

 *

 * This function implements the device tree binding described in

 * Documentation/devicetree/bindings/serial/rs485.txt.

 */

void of_get_rs485_mode(struct device_node *np, struct serial_rs485 *rs485conf)

{

	u32 rs485_delay[2];

	int ret;



	ret = of_property_read_u32_array(np, "rs485-rts-delay", rs485_delay, 2);

	if (!ret) {

		rs485conf->delay_rts_before_send = rs485_delay[0];

		rs485conf->delay_rts_after_send = rs485_delay[1];

	} else {

		rs485conf->delay_rts_before_send = 0;

		rs485conf->delay_rts_after_send = 0;

	}



	/*

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

	 * the two following properties.

	 */

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



	if (of_property_read_bool(np, "rs485-rx-during-tx"))

		rs485conf->flags |= SER_RS485_RX_DURING_TX;



	if (of_property_read_bool(np, "linux,rs485-enabled-at-boot-time"))

		rs485conf->flags |= SER_RS485_ENABLED;

}

EXPORT_SYMBOL_GPL(of_get_rs485_mode);



MODULE_DESCRIPTION("Serial driver core");

MODULE_LICENSE("GPL");

include/linux/serial_core.h

+5 −0
Original line number Diff line number Diff line
@@ -501,4 +501,9 @@ static inline int uart_handle_break(struct uart_port *port) 
					 (cflag) & CRTSCTS || \

					 !((cflag) & CLOCAL))



/*

 * Common device tree parsing helpers

 */

void of_get_rs485_mode(struct device_node *np, struct serial_rs485 *rs485conf);



#endif /* LINUX_SERIAL_CORE_H */

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