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robherringgregkh
robherring
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gregkh
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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: Rob Herring <[email protected]> Reviewed-By: Sebastian Reichel <[email protected]> Tested-By: Sebastian Reichel <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
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‎drivers/tty/serdev/Kconfig‎

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@@ -6,3 +6,11 @@ menuconfig SERIAL_DEV_BUS
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help
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Core support for devices connected via a serial port.
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if SERIAL_DEV_BUS
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config SERIAL_DEV_CTRL_TTYPORT
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bool "Serial device TTY port controller"
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depends on TTY
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depends on SERIAL_DEV_BUS != m
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endif

‎drivers/tty/serdev/Makefile‎

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@@ -1,3 +1,5 @@
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serdev-objs := core.o
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obj-$(CONFIG_SERIAL_DEV_BUS) += serdev.o
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obj-$(CONFIG_SERIAL_DEV_CTRL_TTYPORT) += serdev-ttyport.o

‎drivers/tty/serdev/serdev-ttyport.c‎

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@@ -0,0 +1,224 @@
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/*
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* Copyright (C) 2016-2017 Linaro Ltd., Rob Herring <[email protected]>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 and
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* only version 2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/kernel.h>
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#include <linux/serdev.h>
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#include <linux/tty.h>
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#include <linux/tty_driver.h>
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#define SERPORT_ACTIVE 1
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struct serport {
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struct tty_port *port;
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struct tty_struct *tty;
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struct tty_driver *tty_drv;
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int tty_idx;
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unsigned long flags;
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};
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/*
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* Callback functions from the tty port.
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*/
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static int ttyport_receive_buf(struct tty_port *port, const unsigned char *cp,
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const unsigned char *fp, size_t count)
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{
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struct serdev_controller *ctrl = port->client_data;
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struct serport *serport = serdev_controller_get_drvdata(ctrl);
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if (!test_bit(SERPORT_ACTIVE, &serport->flags))
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return 0;
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return serdev_controller_receive_buf(ctrl, cp, count);
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}
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static void ttyport_write_wakeup(struct tty_port *port)
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{
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struct serdev_controller *ctrl = port->client_data;
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struct serport *serport = serdev_controller_get_drvdata(ctrl);
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if (!test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &port->tty->flags))
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return;
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if (test_bit(SERPORT_ACTIVE, &serport->flags))
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serdev_controller_write_wakeup(ctrl);
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}
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static const struct tty_port_client_operations client_ops = {
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.receive_buf = ttyport_receive_buf,
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.write_wakeup = ttyport_write_wakeup,
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};
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/*
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* Callback functions from the serdev core.
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*/
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static int ttyport_write_buf(struct serdev_controller *ctrl, const unsigned char *data, size_t len)
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{
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struct serport *serport = serdev_controller_get_drvdata(ctrl);
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struct tty_struct *tty = serport->tty;
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if (!test_bit(SERPORT_ACTIVE, &serport->flags))
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return 0;
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set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
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return tty->ops->write(serport->tty, data, len);
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}
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static void ttyport_write_flush(struct serdev_controller *ctrl)
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{
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struct serport *serport = serdev_controller_get_drvdata(ctrl);
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struct tty_struct *tty = serport->tty;
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tty_driver_flush_buffer(tty);
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}
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static int ttyport_write_room(struct serdev_controller *ctrl)
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{
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struct serport *serport = serdev_controller_get_drvdata(ctrl);
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struct tty_struct *tty = serport->tty;
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return tty_write_room(tty);
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}
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static int ttyport_open(struct serdev_controller *ctrl)
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{
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struct serport *serport = serdev_controller_get_drvdata(ctrl);
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struct tty_struct *tty;
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struct ktermios ktermios;
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tty = tty_init_dev(serport->tty_drv, serport->tty_idx);
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serport->tty = tty;
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serport->port->client_ops = &client_ops;
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serport->port->client_data = ctrl;
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if (tty->ops->open)
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tty->ops->open(serport->tty, NULL);
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else
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tty_port_open(serport->port, tty, NULL);
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/* Bring the UART into a known 8 bits no parity hw fc state */
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ktermios = tty->termios;
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ktermios.c_iflag &= ~(IGNBRK | BRKINT | PARMRK | ISTRIP |
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INLCR | IGNCR | ICRNL | IXON);
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ktermios.c_oflag &= ~OPOST;
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ktermios.c_lflag &= ~(ECHO | ECHONL | ICANON | ISIG | IEXTEN);
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ktermios.c_cflag &= ~(CSIZE | PARENB);
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ktermios.c_cflag |= CS8;
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ktermios.c_cflag |= CRTSCTS;
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tty_set_termios(tty, &ktermios);
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set_bit(SERPORT_ACTIVE, &serport->flags);
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tty_unlock(serport->tty);
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return 0;
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}
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static void ttyport_close(struct serdev_controller *ctrl)
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{
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struct serport *serport = serdev_controller_get_drvdata(ctrl);
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struct tty_struct *tty = serport->tty;
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clear_bit(SERPORT_ACTIVE, &serport->flags);
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if (tty->ops->close)
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tty->ops->close(tty, NULL);
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tty_release_struct(tty, serport->tty_idx);
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}
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static unsigned int ttyport_set_baudrate(struct serdev_controller *ctrl, unsigned int speed)
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{
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struct serport *serport = serdev_controller_get_drvdata(ctrl);
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struct tty_struct *tty = serport->tty;
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struct ktermios ktermios = tty->termios;
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ktermios.c_cflag &= ~CBAUD;
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tty_termios_encode_baud_rate(&ktermios, speed, speed);
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/* tty_set_termios() return not checked as it is always 0 */
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tty_set_termios(tty, &ktermios);
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return speed;
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}
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static void ttyport_set_flow_control(struct serdev_controller *ctrl, bool enable)
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{
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struct serport *serport = serdev_controller_get_drvdata(ctrl);
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struct tty_struct *tty = serport->tty;
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struct ktermios ktermios = tty->termios;
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if (enable)
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ktermios.c_cflag |= CRTSCTS;
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else
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ktermios.c_cflag &= ~CRTSCTS;
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tty_set_termios(tty, &ktermios);
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}
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static const struct serdev_controller_ops ctrl_ops = {
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.write_buf = ttyport_write_buf,
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.write_flush = ttyport_write_flush,
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.write_room = ttyport_write_room,
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.open = ttyport_open,
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.close = ttyport_close,
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.set_flow_control = ttyport_set_flow_control,
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.set_baudrate = ttyport_set_baudrate,
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};
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struct device *serdev_tty_port_register(struct tty_port *port,
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struct device *parent,
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struct tty_driver *drv, int idx)
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{
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struct serdev_controller *ctrl;
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struct serport *serport;
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int ret;
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if (!port || !drv || !parent)
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return ERR_PTR(-ENODEV);
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ctrl = serdev_controller_alloc(parent, sizeof(struct serport));
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if (!ctrl)
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return ERR_PTR(-ENOMEM);
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serport = serdev_controller_get_drvdata(ctrl);
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serport->port = port;
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serport->tty_idx = idx;
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serport->tty_drv = drv;
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ctrl->ops = &ctrl_ops;
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ret = serdev_controller_add(ctrl);
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if (ret)
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goto err_controller_put;
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dev_info(&ctrl->dev, "tty port %s%d registered\n", drv->name, idx);
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return &ctrl->dev;
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err_controller_put:
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serdev_controller_put(ctrl);
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return ERR_PTR(ret);
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}
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void serdev_tty_port_unregister(struct tty_port *port)
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{
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struct serdev_controller *ctrl = port->client_data;
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struct serport *serport = serdev_controller_get_drvdata(ctrl);
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if (!serport)
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return;
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serdev_controller_remove(ctrl);
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port->client_ops = NULL;
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port->client_data = NULL;
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serdev_controller_put(ctrl);
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}

‎include/linux/serdev.h‎

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Original file line numberDiff line numberDiff line change
@@ -238,4 +238,25 @@ static inline int serdev_device_write_room(struct serdev_device *sdev)
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#endif /* CONFIG_SERIAL_DEV_BUS */
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/*
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* serdev hooks into TTY core
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*/
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struct tty_port;
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struct tty_driver;
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#ifdef CONFIG_SERIAL_DEV_CTRL_TTYPORT
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struct device *serdev_tty_port_register(struct tty_port *port,
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struct device *parent,
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struct tty_driver *drv, int idx);
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void serdev_tty_port_unregister(struct tty_port *port);
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#else
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static inline struct device *serdev_tty_port_register(struct tty_port *port,
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struct device *parent,
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struct tty_driver *drv, int idx)
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{
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return ERR_PTR(-ENODEV);
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}
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static inline void serdev_tty_port_unregister(struct tty_port *port) {}
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#endif /* CONFIG_SERIAL_DEV_CTRL_TTYPORT */
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#endif /*_LINUX_SERDEV_H */

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