Commit bed35c6d authored by Rob Herring's avatar Rob Herring Committed by Greg Kroah-Hartman
Browse files

serdev: add a tty port controller driver 



Add a serdev controller driver for tty ports.

The controller is registered with serdev when tty ports are registered
with the TTY core. As the TTY core is built-in only, this has the side
effect of making serdev built-in as well.

Signed-off-by: default avatarRob Herring <robh@kernel.org>
Reviewed-By: default avatarSebastian Reichel <sre@kernel.org>
Tested-By: default avatarSebastian Reichel <sre@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent cd6484e1

drivers/tty/serdev/Kconfig

+8 −0
Original line number Diff line number Diff line
@@ -6,3 +6,11 @@ menuconfig SERIAL_DEV_BUS 
	help

	  Core support for devices connected via a serial port.



if SERIAL_DEV_BUS



config SERIAL_DEV_CTRL_TTYPORT

	bool "Serial device TTY port controller"

	depends on TTY

	depends on SERIAL_DEV_BUS != m



endif

drivers/tty/serdev/Makefile

+2 −0
Original line number Diff line number Diff line 
serdev-objs := core.o



obj-$(CONFIG_SERIAL_DEV_BUS) += serdev.o



obj-$(CONFIG_SERIAL_DEV_CTRL_TTYPORT) += serdev-ttyport.o

drivers/tty/serdev/serdev-ttyport.c

0 → 100644
+224 −0
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2016-2017 Linaro Ltd., Rob Herring <robh@kernel.org>

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 and

 * only version 2 as published by the Free Software Foundation.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 */

#include <linux/kernel.h>

#include <linux/serdev.h>

#include <linux/tty.h>

#include <linux/tty_driver.h>



#define SERPORT_ACTIVE		1



struct serport {

	struct tty_port *port;

	struct tty_struct *tty;

	struct tty_driver *tty_drv;

	int tty_idx;

	unsigned long flags;

};



/*

 * Callback functions from the tty port.

 */



static int ttyport_receive_buf(struct tty_port *port, const unsigned char *cp,

				const unsigned char *fp, size_t count)

{

	struct serdev_controller *ctrl = port->client_data;

	struct serport *serport = serdev_controller_get_drvdata(ctrl);



	if (!test_bit(SERPORT_ACTIVE, &serport->flags))

		return 0;



	return serdev_controller_receive_buf(ctrl, cp, count);

}



static void ttyport_write_wakeup(struct tty_port *port)

{

	struct serdev_controller *ctrl = port->client_data;

	struct serport *serport = serdev_controller_get_drvdata(ctrl);



	if (!test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &port->tty->flags))

		return;



	if (test_bit(SERPORT_ACTIVE, &serport->flags))

		serdev_controller_write_wakeup(ctrl);

}



static const struct tty_port_client_operations client_ops = {

	.receive_buf = ttyport_receive_buf,

	.write_wakeup = ttyport_write_wakeup,

};



/*

 * Callback functions from the serdev core.

 */



static int ttyport_write_buf(struct serdev_controller *ctrl, const unsigned char *data, size_t len)

{

	struct serport *serport = serdev_controller_get_drvdata(ctrl);

	struct tty_struct *tty = serport->tty;



	if (!test_bit(SERPORT_ACTIVE, &serport->flags))

		return 0;



	set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);

	return tty->ops->write(serport->tty, data, len);

}



static void ttyport_write_flush(struct serdev_controller *ctrl)

{

	struct serport *serport = serdev_controller_get_drvdata(ctrl);

	struct tty_struct *tty = serport->tty;



	tty_driver_flush_buffer(tty);

}



static int ttyport_write_room(struct serdev_controller *ctrl)

{

	struct serport *serport = serdev_controller_get_drvdata(ctrl);

	struct tty_struct *tty = serport->tty;



	return tty_write_room(tty);

}



static int ttyport_open(struct serdev_controller *ctrl)

{

	struct serport *serport = serdev_controller_get_drvdata(ctrl);

	struct tty_struct *tty;

	struct ktermios ktermios;



	tty = tty_init_dev(serport->tty_drv, serport->tty_idx);

	serport->tty = tty;



	serport->port->client_ops = &client_ops;

	serport->port->client_data = ctrl;



	if (tty->ops->open)

		tty->ops->open(serport->tty, NULL);

	else

		tty_port_open(serport->port, tty, NULL);



	/* Bring the UART into a known 8 bits no parity hw fc state */

	ktermios = tty->termios;

	ktermios.c_iflag &= ~(IGNBRK | BRKINT | PARMRK | ISTRIP |

			      INLCR | IGNCR | ICRNL | IXON);

	ktermios.c_oflag &= ~OPOST;

	ktermios.c_lflag &= ~(ECHO | ECHONL | ICANON | ISIG | IEXTEN);

	ktermios.c_cflag &= ~(CSIZE | PARENB);

	ktermios.c_cflag |= CS8;

	ktermios.c_cflag |= CRTSCTS;

	tty_set_termios(tty, &ktermios);



	set_bit(SERPORT_ACTIVE, &serport->flags);



	tty_unlock(serport->tty);

	return 0;

}



static void ttyport_close(struct serdev_controller *ctrl)

{

	struct serport *serport = serdev_controller_get_drvdata(ctrl);

	struct tty_struct *tty = serport->tty;



	clear_bit(SERPORT_ACTIVE, &serport->flags);



	if (tty->ops->close)

		tty->ops->close(tty, NULL);



	tty_release_struct(tty, serport->tty_idx);

}



static unsigned int ttyport_set_baudrate(struct serdev_controller *ctrl, unsigned int speed)

{

	struct serport *serport = serdev_controller_get_drvdata(ctrl);

	struct tty_struct *tty = serport->tty;

	struct ktermios ktermios = tty->termios;



	ktermios.c_cflag &= ~CBAUD;

	tty_termios_encode_baud_rate(&ktermios, speed, speed);



	/* tty_set_termios() return not checked as it is always 0 */

	tty_set_termios(tty, &ktermios);

	return speed;

}



static void ttyport_set_flow_control(struct serdev_controller *ctrl, bool enable)

{

	struct serport *serport = serdev_controller_get_drvdata(ctrl);

	struct tty_struct *tty = serport->tty;

	struct ktermios ktermios = tty->termios;



	if (enable)

		ktermios.c_cflag |= CRTSCTS;

	else

		ktermios.c_cflag &= ~CRTSCTS;



	tty_set_termios(tty, &ktermios);

}



static const struct serdev_controller_ops ctrl_ops = {

	.write_buf = ttyport_write_buf,

	.write_flush = ttyport_write_flush,

	.write_room = ttyport_write_room,

	.open = ttyport_open,

	.close = ttyport_close,

	.set_flow_control = ttyport_set_flow_control,

	.set_baudrate = ttyport_set_baudrate,

};



struct device *serdev_tty_port_register(struct tty_port *port,

					struct device *parent,

					struct tty_driver *drv, int idx)

{

	struct serdev_controller *ctrl;

	struct serport *serport;

	int ret;



	if (!port || !drv || !parent)

		return ERR_PTR(-ENODEV);



	ctrl = serdev_controller_alloc(parent, sizeof(struct serport));

	if (!ctrl)

		return ERR_PTR(-ENOMEM);

	serport = serdev_controller_get_drvdata(ctrl);



	serport->port = port;

	serport->tty_idx = idx;

	serport->tty_drv = drv;



	ctrl->ops = &ctrl_ops;



	ret = serdev_controller_add(ctrl);

	if (ret)

		goto err_controller_put;



	dev_info(&ctrl->dev, "tty port %s%d registered\n", drv->name, idx);

	return &ctrl->dev;



err_controller_put:

	serdev_controller_put(ctrl);

	return ERR_PTR(ret);

}



void serdev_tty_port_unregister(struct tty_port *port)

{

	struct serdev_controller *ctrl = port->client_data;

	struct serport *serport = serdev_controller_get_drvdata(ctrl);



	if (!serport)

		return;



	serdev_controller_remove(ctrl);

	port->client_ops = NULL;

	port->client_data = NULL;

	serdev_controller_put(ctrl);

}

include/linux/serdev.h

+21 −0
Original line number Diff line number Diff line
@@ -238,4 +238,25 @@ static inline int serdev_device_write_room(struct serdev_device *sdev) 


#endif /* CONFIG_SERIAL_DEV_BUS */



/*

 * serdev hooks into TTY core

 */

struct tty_port;

struct tty_driver;



#ifdef CONFIG_SERIAL_DEV_CTRL_TTYPORT

struct device *serdev_tty_port_register(struct tty_port *port,

					struct device *parent,

					struct tty_driver *drv, int idx);

void serdev_tty_port_unregister(struct tty_port *port);

#else

static inline struct device *serdev_tty_port_register(struct tty_port *port,

					   struct device *parent,

					   struct tty_driver *drv, int idx)

{

	return ERR_PTR(-ENODEV);

}

static inline void serdev_tty_port_unregister(struct tty_port *port) {}

#endif /* CONFIG_SERIAL_DEV_CTRL_TTYPORT */



#endif /*_LINUX_SERDEV_H */

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