Commit 283e096f authored by Lukas Wunner's avatar Lukas Wunner Committed by Greg Kroah-Hartman
Browse files

serial: 8250: Deduplicate ->rs485_config() callback 



Commit e490c914 ("tty: Add software emulated RS485 support for 8250")
introduced support to use RTS as an rs485 Transmit Enable signal.
Drivers opt in to the feature by calling serial8250_em485_init() from
their ->rs485_config() callback.

So far there are two drivers doing that, 8250_omap.c and 8250_of.c.
Both use an identical callback.  We're about to add a third user of that
callback, therefore deduplicate it and move it to 8250_port.c.

Drivers now opt in to rs485 software emulation by assigning the generic
serial8250_rs485_config() callback introduced herein to their
.rs485_config struct member.  This change allows unexporting
serial8250_em485_init() and declaring it static.

Signed-off-by: default avatarLukas Wunner <lukas@wunner.de>
Cc: Matwey V. Kornilov <matwey@sai.msu.ru>
Cc: Heiko Schocher <hs@denx.de>
Link: https://lore.kernel.org/r/fcef63642dc4eae41ae7842d23747b2bf5d40285.1582895077.git.lukas@wunner.de


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent fe7f0fa4

drivers/tty/serial/8250/8250.h

+1 −1
Original line number Diff line number Diff line
@@ -156,7 +156,7 @@ void serial8250_rpm_put(struct uart_8250_port *p); 
void serial8250_rpm_get_tx(struct uart_8250_port *p);

void serial8250_rpm_put_tx(struct uart_8250_port *p);



int serial8250_em485_init(struct uart_8250_port *p);

int serial8250_em485_config(struct uart_port *port, struct serial_rs485 *rs485);

void serial8250_em485_destroy(struct uart_8250_port *p);



/* MCR <-> TIOCM conversion */

drivers/tty/serial/8250/8250_of.c

+1 −31
Original line number Diff line number Diff line
@@ -25,36 +25,6 @@ struct of_serial_info { 
	int line;

};



static int of_8250_rs485_config(struct uart_port *port,

				  struct serial_rs485 *rs485)

{

	struct uart_8250_port *up = up_to_u8250p(port);



	/* Clamp the delays to [0, 100ms] */

	rs485->delay_rts_before_send = min(rs485->delay_rts_before_send, 100U);

	rs485->delay_rts_after_send  = min(rs485->delay_rts_after_send, 100U);



	port->rs485 = *rs485;



	/*

	 * Both serial8250_em485_init and serial8250_em485_destroy

	 * are idempotent

	 */

	if (rs485->flags & SER_RS485_ENABLED) {

		int ret = serial8250_em485_init(up);



		if (ret) {

			rs485->flags &= ~SER_RS485_ENABLED;

			port->rs485.flags &= ~SER_RS485_ENABLED;

		}

		return ret;

	}



	serial8250_em485_destroy(up);



	return 0;

}



/*

 * Fill a struct uart_port for a given device node

 */
@@ -184,7 +154,7 @@ static int of_platform_serial_setup(struct platform_device *ofdev, 
		port->flags |= UPF_SKIP_TEST;



	port->dev = &ofdev->dev;

	port->rs485_config = of_8250_rs485_config;

	port->rs485_config = serial8250_em485_config;



	switch (type) {

	case PORT_RT2880:

drivers/tty/serial/8250/8250_omap.c

+1 −31
Original line number Diff line number Diff line
@@ -714,36 +714,6 @@ static void omap_8250_throttle(struct uart_port *port) 
	pm_runtime_put_autosuspend(port->dev);

}



static int omap_8250_rs485_config(struct uart_port *port,

				  struct serial_rs485 *rs485)

{

	struct uart_8250_port *up = up_to_u8250p(port);



	/* Clamp the delays to [0, 100ms] */

	rs485->delay_rts_before_send = min(rs485->delay_rts_before_send, 100U);

	rs485->delay_rts_after_send  = min(rs485->delay_rts_after_send, 100U);



	port->rs485 = *rs485;



	/*

	 * Both serial8250_em485_init and serial8250_em485_destroy

	 * are idempotent

	 */

	if (rs485->flags & SER_RS485_ENABLED) {

		int ret = serial8250_em485_init(up);



		if (ret) {

			rs485->flags &= ~SER_RS485_ENABLED;

			port->rs485.flags &= ~SER_RS485_ENABLED;

		}

		return ret;

	}



	serial8250_em485_destroy(up);



	return 0;

}



static void omap_8250_unthrottle(struct uart_port *port)

{

	struct omap8250_priv *priv = port->private_data;
@@ -1187,7 +1157,7 @@ static int omap8250_probe(struct platform_device *pdev) 
	up.port.shutdown = omap_8250_shutdown;

	up.port.throttle = omap_8250_throttle;

	up.port.unthrottle = omap_8250_unthrottle;

	up.port.rs485_config = omap_8250_rs485_config;

	up.port.rs485_config = serial8250_em485_config;

	up.port.has_sysrq = IS_ENABLED(CONFIG_SERIAL_8250_CONSOLE);



	ret = of_alias_get_id(np, "serial");

drivers/tty/serial/8250/8250_port.c

+39 −2
Original line number Diff line number Diff line
@@ -615,7 +615,7 @@ EXPORT_SYMBOL_GPL(serial8250_rpm_put); 
 *

 *	Return 0 - success, -errno - otherwise

 */

int serial8250_em485_init(struct uart_8250_port *p)

static int serial8250_em485_init(struct uart_8250_port *p)

{

	if (p->em485)

		return 0;
@@ -636,7 +636,6 @@ int serial8250_em485_init(struct uart_8250_port *p) 


	return 0;

}

EXPORT_SYMBOL_GPL(serial8250_em485_init);



/**

 *	serial8250_em485_destroy() - put uart_8250_port into normal state
@@ -664,6 +663,44 @@ void serial8250_em485_destroy(struct uart_8250_port *p) 
}

EXPORT_SYMBOL_GPL(serial8250_em485_destroy);



/**

 * serial8250_em485_config() - generic ->rs485_config() callback

 * @port: uart port

 * @rs485: rs485 settings

 *

 * Generic callback usable by 8250 uart drivers to activate rs485 settings

 * if the uart is incapable of driving RTS as a Transmit Enable signal in

 * hardware, relying on software emulation instead.

 */

int serial8250_em485_config(struct uart_port *port, struct serial_rs485 *rs485)

{

	struct uart_8250_port *up = up_to_u8250p(port);



	/* clamp the delays to [0, 100ms] */

	rs485->delay_rts_before_send = min(rs485->delay_rts_before_send, 100U);

	rs485->delay_rts_after_send  = min(rs485->delay_rts_after_send, 100U);



	port->rs485 = *rs485;



	/*

	 * Both serial8250_em485_init() and serial8250_em485_destroy()

	 * are idempotent.

	 */

	if (rs485->flags & SER_RS485_ENABLED) {

		int ret = serial8250_em485_init(up);



		if (ret) {

			rs485->flags &= ~SER_RS485_ENABLED;

			port->rs485.flags &= ~SER_RS485_ENABLED;

		}

		return ret;

	}



	serial8250_em485_destroy(up);

	return 0;

}

EXPORT_SYMBOL_GPL(serial8250_em485_config);



/*

 * These two wrappers ensure that enable_runtime_pm_tx() can be called more than

 * once and disable_runtime_pm_tx() will still disable RPM because the fifo is

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