v4.19.13 snapshot.
diff --git a/include/linux/serdev.h b/include/linux/serdev.h
new file mode 100644
index 0000000..f153b2c
--- /dev/null
+++ b/include/linux/serdev.h
@@ -0,0 +1,338 @@
+/*
+ * 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.
+ */
+#ifndef _LINUX_SERDEV_H
+#define _LINUX_SERDEV_H
+
+#include <linux/types.h>
+#include <linux/device.h>
+#include <linux/termios.h>
+#include <linux/delay.h>
+
+struct serdev_controller;
+struct serdev_device;
+
+/*
+ * serdev device structures
+ */
+
+/**
+ * struct serdev_device_ops - Callback operations for a serdev device
+ * @receive_buf: Function called with data received from device;
+ * returns number of bytes accepted; may sleep.
+ * @write_wakeup: Function called when ready to transmit more data; must
+ * not sleep.
+ */
+struct serdev_device_ops {
+ int (*receive_buf)(struct serdev_device *, const unsigned char *, size_t);
+ void (*write_wakeup)(struct serdev_device *);
+};
+
+/**
+ * struct serdev_device - Basic representation of an serdev device
+ * @dev: Driver model representation of the device.
+ * @nr: Device number on serdev bus.
+ * @ctrl: serdev controller managing this device.
+ * @ops: Device operations.
+ * @write_comp Completion used by serdev_device_write() internally
+ * @write_lock Lock to serialize access when writing data
+ */
+struct serdev_device {
+ struct device dev;
+ int nr;
+ struct serdev_controller *ctrl;
+ const struct serdev_device_ops *ops;
+ struct completion write_comp;
+ struct mutex write_lock;
+};
+
+static inline struct serdev_device *to_serdev_device(struct device *d)
+{
+ return container_of(d, struct serdev_device, dev);
+}
+
+/**
+ * struct serdev_device_driver - serdev slave device driver
+ * @driver: serdev device drivers should initialize name field of this
+ * structure.
+ * @probe: binds this driver to a serdev device.
+ * @remove: unbinds this driver from the serdev device.
+ */
+struct serdev_device_driver {
+ struct device_driver driver;
+ int (*probe)(struct serdev_device *);
+ void (*remove)(struct serdev_device *);
+};
+
+static inline struct serdev_device_driver *to_serdev_device_driver(struct device_driver *d)
+{
+ return container_of(d, struct serdev_device_driver, driver);
+}
+
+enum serdev_parity {
+ SERDEV_PARITY_NONE,
+ SERDEV_PARITY_EVEN,
+ SERDEV_PARITY_ODD,
+};
+
+/*
+ * serdev controller structures
+ */
+struct serdev_controller_ops {
+ int (*write_buf)(struct serdev_controller *, const unsigned char *, size_t);
+ void (*write_flush)(struct serdev_controller *);
+ int (*write_room)(struct serdev_controller *);
+ int (*open)(struct serdev_controller *);
+ void (*close)(struct serdev_controller *);
+ void (*set_flow_control)(struct serdev_controller *, bool);
+ int (*set_parity)(struct serdev_controller *, enum serdev_parity);
+ unsigned int (*set_baudrate)(struct serdev_controller *, unsigned int);
+ void (*wait_until_sent)(struct serdev_controller *, long);
+ int (*get_tiocm)(struct serdev_controller *);
+ int (*set_tiocm)(struct serdev_controller *, unsigned int, unsigned int);
+};
+
+/**
+ * struct serdev_controller - interface to the serdev controller
+ * @dev: Driver model representation of the device.
+ * @nr: number identifier for this controller/bus.
+ * @serdev: Pointer to slave device for this controller.
+ * @ops: Controller operations.
+ */
+struct serdev_controller {
+ struct device dev;
+ unsigned int nr;
+ struct serdev_device *serdev;
+ const struct serdev_controller_ops *ops;
+};
+
+static inline struct serdev_controller *to_serdev_controller(struct device *d)
+{
+ return container_of(d, struct serdev_controller, dev);
+}
+
+static inline void *serdev_device_get_drvdata(const struct serdev_device *serdev)
+{
+ return dev_get_drvdata(&serdev->dev);
+}
+
+static inline void serdev_device_set_drvdata(struct serdev_device *serdev, void *data)
+{
+ dev_set_drvdata(&serdev->dev, data);
+}
+
+/**
+ * serdev_device_put() - decrement serdev device refcount
+ * @serdev serdev device.
+ */
+static inline void serdev_device_put(struct serdev_device *serdev)
+{
+ if (serdev)
+ put_device(&serdev->dev);
+}
+
+static inline void serdev_device_set_client_ops(struct serdev_device *serdev,
+ const struct serdev_device_ops *ops)
+{
+ serdev->ops = ops;
+}
+
+static inline
+void *serdev_controller_get_drvdata(const struct serdev_controller *ctrl)
+{
+ return ctrl ? dev_get_drvdata(&ctrl->dev) : NULL;
+}
+
+static inline void serdev_controller_set_drvdata(struct serdev_controller *ctrl,
+ void *data)
+{
+ dev_set_drvdata(&ctrl->dev, data);
+}
+
+/**
+ * serdev_controller_put() - decrement controller refcount
+ * @ctrl serdev controller.
+ */
+static inline void serdev_controller_put(struct serdev_controller *ctrl)
+{
+ if (ctrl)
+ put_device(&ctrl->dev);
+}
+
+struct serdev_device *serdev_device_alloc(struct serdev_controller *);
+int serdev_device_add(struct serdev_device *);
+void serdev_device_remove(struct serdev_device *);
+
+struct serdev_controller *serdev_controller_alloc(struct device *, size_t);
+int serdev_controller_add(struct serdev_controller *);
+void serdev_controller_remove(struct serdev_controller *);
+
+static inline void serdev_controller_write_wakeup(struct serdev_controller *ctrl)
+{
+ struct serdev_device *serdev = ctrl->serdev;
+
+ if (!serdev || !serdev->ops->write_wakeup)
+ return;
+
+ serdev->ops->write_wakeup(serdev);
+}
+
+static inline int serdev_controller_receive_buf(struct serdev_controller *ctrl,
+ const unsigned char *data,
+ size_t count)
+{
+ struct serdev_device *serdev = ctrl->serdev;
+
+ if (!serdev || !serdev->ops->receive_buf)
+ return 0;
+
+ return serdev->ops->receive_buf(serdev, data, count);
+}
+
+#if IS_ENABLED(CONFIG_SERIAL_DEV_BUS)
+
+int serdev_device_open(struct serdev_device *);
+void serdev_device_close(struct serdev_device *);
+int devm_serdev_device_open(struct device *, struct serdev_device *);
+unsigned int serdev_device_set_baudrate(struct serdev_device *, unsigned int);
+void serdev_device_set_flow_control(struct serdev_device *, bool);
+int serdev_device_write_buf(struct serdev_device *, const unsigned char *, size_t);
+void serdev_device_wait_until_sent(struct serdev_device *, long);
+int serdev_device_get_tiocm(struct serdev_device *);
+int serdev_device_set_tiocm(struct serdev_device *, int, int);
+void serdev_device_write_wakeup(struct serdev_device *);
+int serdev_device_write(struct serdev_device *, const unsigned char *, size_t, unsigned long);
+void serdev_device_write_flush(struct serdev_device *);
+int serdev_device_write_room(struct serdev_device *);
+
+/*
+ * serdev device driver functions
+ */
+int __serdev_device_driver_register(struct serdev_device_driver *, struct module *);
+#define serdev_device_driver_register(sdrv) \
+ __serdev_device_driver_register(sdrv, THIS_MODULE)
+
+/**
+ * serdev_device_driver_unregister() - unregister an serdev client driver
+ * @sdrv: the driver to unregister
+ */
+static inline void serdev_device_driver_unregister(struct serdev_device_driver *sdrv)
+{
+ if (sdrv)
+ driver_unregister(&sdrv->driver);
+}
+
+#define module_serdev_device_driver(__serdev_device_driver) \
+ module_driver(__serdev_device_driver, serdev_device_driver_register, \
+ serdev_device_driver_unregister)
+
+#else
+
+static inline int serdev_device_open(struct serdev_device *sdev)
+{
+ return -ENODEV;
+}
+static inline void serdev_device_close(struct serdev_device *sdev) {}
+static inline unsigned int serdev_device_set_baudrate(struct serdev_device *sdev, unsigned int baudrate)
+{
+ return 0;
+}
+static inline void serdev_device_set_flow_control(struct serdev_device *sdev, bool enable) {}
+static inline int serdev_device_write_buf(struct serdev_device *serdev,
+ const unsigned char *buf,
+ size_t count)
+{
+ return -ENODEV;
+}
+static inline void serdev_device_wait_until_sent(struct serdev_device *sdev, long timeout) {}
+static inline int serdev_device_get_tiocm(struct serdev_device *serdev)
+{
+ return -ENOTSUPP;
+}
+static inline int serdev_device_set_tiocm(struct serdev_device *serdev, int set, int clear)
+{
+ return -ENOTSUPP;
+}
+static inline int serdev_device_write(struct serdev_device *sdev, const unsigned char *buf,
+ size_t count, unsigned long timeout)
+{
+ return -ENODEV;
+}
+static inline void serdev_device_write_flush(struct serdev_device *sdev) {}
+static inline int serdev_device_write_room(struct serdev_device *sdev)
+{
+ return 0;
+}
+
+#define serdev_device_driver_register(x)
+#define serdev_device_driver_unregister(x)
+
+#endif /* CONFIG_SERIAL_DEV_BUS */
+
+static inline bool serdev_device_get_cts(struct serdev_device *serdev)
+{
+ int status = serdev_device_get_tiocm(serdev);
+ return !!(status & TIOCM_CTS);
+}
+
+static inline int serdev_device_wait_for_cts(struct serdev_device *serdev, bool state, int timeout_ms)
+{
+ unsigned long timeout;
+ bool signal;
+
+ timeout = jiffies + msecs_to_jiffies(timeout_ms);
+ while (time_is_after_jiffies(timeout)) {
+ signal = serdev_device_get_cts(serdev);
+ if (signal == state)
+ return 0;
+ usleep_range(1000, 2000);
+ }
+
+ return -ETIMEDOUT;
+}
+
+static inline int serdev_device_set_rts(struct serdev_device *serdev, bool enable)
+{
+ if (enable)
+ return serdev_device_set_tiocm(serdev, TIOCM_RTS, 0);
+ else
+ return serdev_device_set_tiocm(serdev, 0, TIOCM_RTS);
+}
+
+int serdev_device_set_parity(struct serdev_device *serdev,
+ enum serdev_parity parity);
+
+/*
+ * 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);
+int 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 int serdev_tty_port_unregister(struct tty_port *port)
+{
+ return -ENODEV;
+}
+#endif /* CONFIG_SERIAL_DEV_CTRL_TTYPORT */
+
+#endif /*_LINUX_SERDEV_H */