linux/drivers/tty/serial/serial_port.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * Serial core port device driver
 *
 * Copyright (C) 2023 Texas Instruments Incorporated - https://www.ti.com/
 * Author: Tony Lindgren <[email protected]>
 */

#include <linux/device.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/pnp.h>
#include <linux/property.h>
#include <linux/serial_core.h>
#include <linux/spinlock.h>

#include "serial_base.h"

#define SERIAL_PORT_AUTOSUSPEND_DELAY_MS …

/* Only considers pending TX for now. Caller must take care of locking */
static int __serial_port_busy(struct uart_port *port)
{ … }

static int serial_port_runtime_resume(struct device *dev)
{ … }

static int serial_port_runtime_suspend(struct device *dev)
{ … }

static void serial_base_port_set_tx(struct uart_port *port,
				    struct serial_port_device *port_dev,
				    bool enabled)
{ … }

void serial_base_port_startup(struct uart_port *port)
{ … }

void serial_base_port_shutdown(struct uart_port *port)
{ … }

static DEFINE_RUNTIME_DEV_PM_OPS(serial_port_pm,
				 serial_port_runtime_suspend,
				 serial_port_runtime_resume, NULL);

static int serial_port_probe(struct device *dev)
{ … }

static int serial_port_remove(struct device *dev)
{ … }

/*
 * Serial core port device init functions. Note that the physical serial
 * port device driver may not have completed probe at this point.
 */
int uart_add_one_port(struct uart_driver *drv, struct uart_port *port)
{ … }
EXPORT_SYMBOL(…);

void uart_remove_one_port(struct uart_driver *drv, struct uart_port *port)
{ … }
EXPORT_SYMBOL(…);

/**
 * __uart_read_properties - read firmware properties of the given UART port
 * @port: corresponding port
 * @use_defaults: apply defaults (when %true) or validate the values (when %false)
 *
 * The following device properties are supported:
 *   - clock-frequency (optional)
 *   - fifo-size (optional)
 *   - no-loopback-test (optional)
 *   - reg-shift (defaults may apply)
 *   - reg-offset (value may be validated)
 *   - reg-io-width (defaults may apply or value may be validated)
 *   - interrupts (OF only)
 *   - serial [alias ID] (OF only)
 *
 * If the port->dev is of struct platform_device type the interrupt line
 * will be retrieved via platform_get_irq() call against that device.
 * Otherwise it will be assigned by fwnode_irq_get() call. In both cases
 * the index 0 of the resource is used.
 *
 * The caller is responsible to initialize the following fields of the @port
 *   ->dev (must be valid)
 *   ->flags
 *   ->mapbase
 *   ->mapsize
 *   ->regshift (if @use_defaults is false)
 * before calling this function. Alternatively the above mentioned fields
 * may be zeroed, in such case the only ones, that have associated properties
 * found, will be set to the respective values.
 *
 * If no error happened, the ->irq, ->mapbase, ->mapsize will be altered.
 * The ->iotype is always altered.
 *
 * When @use_defaults is true and the respective property is not found
 * the following values will be applied:
 *   ->regshift = 0
 * In this case IRQ must be provided, otherwise an error will be returned.
 *
 * When @use_defaults is false and the respective property is found
 * the following values will be validated:
 *   - reg-io-width (->iotype)
 *   - reg-offset (->mapsize against ->mapbase)
 *
 * Returns: 0 on success or negative errno on failure
 */
static int __uart_read_properties(struct uart_port *port, bool use_defaults)
{ … }

int uart_read_port_properties(struct uart_port *port)
{ … }
EXPORT_SYMBOL_GPL(…);

int uart_read_and_validate_port_properties(struct uart_port *port)
{ … }
EXPORT_SYMBOL_GPL(…);

static struct device_driver serial_port_driver = …;

int serial_base_port_init(void)
{ … }

void serial_base_port_exit(void)
{ … }

MODULE_AUTHOR(…) …;
MODULE_DESCRIPTION(…) …;
MODULE_LICENSE(…) …;