projects / linux-block.git / blame
| Commit | Line | Data |
|---|---|---|
| 84a9582f TL |
1 | // SPDX-License-Identifier: GPL-2.0+ |
| 2 | /* | |
| 3 | * Serial core port device driver | |
| 4 | * | |
| 5 | * Copyright (C) 2023 Texas Instruments Incorporated - https://www.ti.com/ | |
| 6 | * Author: Tony Lindgren <tony@atomide.com> | |
| 7 | */ | |
| 8 | ||
| 9 | #include <linux/device.h> | |
| 10 | #include <linux/module.h> | |
| 11 | #include <linux/pm_runtime.h> | |
| 12 | #include <linux/serial_core.h> | |
| 13 | #include <linux/spinlock.h> | |
| 14 | ||
| 15 | #include "serial_base.h" | |
| 16 | ||
| 17 | #define SERIAL_PORT_AUTOSUSPEND_DELAY_MS 500 | |
| 18 | ||
| 19 | /* Only considers pending TX for now. Caller must take care of locking */ | |
| 20 | static int __serial_port_busy(struct uart_port *port) | |
| 21 | { | |
| 22 | return !uart_tx_stopped(port) && | |
| 23 | uart_circ_chars_pending(&port->state->xmit); | |
| 24 | } | |
| 25 | ||
| 26 | static int serial_port_runtime_resume(struct device *dev) | |
| 27 | { | |
| 28 | struct serial_port_device *port_dev = to_serial_base_port_device(dev); | |
| 29 | struct uart_port *port; | |
| 30 | unsigned long flags; | |
| 31 | ||
| 32 | port = port_dev->port; | |
| 33 | ||
| 34 | if (port->flags & UPF_DEAD) | |
| 35 | goto out; | |
| 36 | ||
| 37 | /* Flush any pending TX for the port */ | |
| 559c7ff4 | 38 | uart_port_lock_irqsave(port, &flags); |
| 84a9582f TL |
39 | if (__serial_port_busy(port)) |
| 40 | port->ops->start_tx(port); | |
| 559c7ff4 | 41 | uart_port_unlock_irqrestore(port, flags); |
| 84a9582f TL |
42 | |
| 43 | out: | |
| 44 | pm_runtime_mark_last_busy(dev); | |
| 45 | ||
| 46 | return 0; | |
| 47 | } | |
| 48 | ||
| 43066e32 YY |
49 | static int serial_port_runtime_suspend(struct device *dev) |
| 50 | { | |
| 51 | struct serial_port_device *port_dev = to_serial_base_port_device(dev); | |
| 52 | struct uart_port *port = port_dev->port; | |
| 53 | unsigned long flags; | |
| 54 | bool busy; | |
| 55 | ||
| 56 | if (port->flags & UPF_DEAD) | |
| 57 | return 0; | |
| 58 | ||
| 59 | uart_port_lock_irqsave(port, &flags); | |
| 60 | busy = __serial_port_busy(port); | |
| 61 | if (busy) | |
| 62 | port->ops->start_tx(port); | |
| 63 | uart_port_unlock_irqrestore(port, flags); | |
| 64 | ||
| 65 | if (busy) | |
| 66 | pm_runtime_mark_last_busy(dev); | |
| 67 | ||
| 68 | return busy ? -EBUSY : 0; | |
| 69 | } | |
| 70 | ||
| 84a9582f | 71 | static DEFINE_RUNTIME_DEV_PM_OPS(serial_port_pm, |
| 43066e32 YY |
72 | serial_port_runtime_suspend, |
| 73 | serial_port_runtime_resume, NULL); | |
| 84a9582f TL |
74 | |
| 75 | static int serial_port_probe(struct device *dev) | |
| 76 | { | |
| 77 | pm_runtime_enable(dev); | |
| 78 | pm_runtime_set_autosuspend_delay(dev, SERIAL_PORT_AUTOSUSPEND_DELAY_MS); | |
| 79 | pm_runtime_use_autosuspend(dev); | |
| 80 | ||
| 81 | return 0; | |
| 82 | } | |
| 83 | ||
| 84 | static int serial_port_remove(struct device *dev) | |
| 85 | { | |
| 86 | pm_runtime_dont_use_autosuspend(dev); | |
| 87 | pm_runtime_disable(dev); | |
| 88 | ||
| 89 | return 0; | |
| 90 | } | |
| 91 | ||
| 92 | /* | |
| 93 | * Serial core port device init functions. Note that the physical serial | |
| 94 | * port device driver may not have completed probe at this point. | |
| 95 | */ | |
| 96 | int uart_add_one_port(struct uart_driver *drv, struct uart_port *port) | |
| 97 | { | |
| 98 | return serial_ctrl_register_port(drv, port); | |
| 99 | } | |
| 100 | EXPORT_SYMBOL(uart_add_one_port); | |
| 101 | ||
| 102 | void uart_remove_one_port(struct uart_driver *drv, struct uart_port *port) | |
| 103 | { | |
| 104 | serial_ctrl_unregister_port(drv, port); | |
| 105 | } | |
| 106 | EXPORT_SYMBOL(uart_remove_one_port); | |
| 107 | ||
| 108 | static struct device_driver serial_port_driver = { | |
| 109 | .name = "port", | |
| 110 | .suppress_bind_attrs = true, | |
| 111 | .probe = serial_port_probe, | |
| 112 | .remove = serial_port_remove, | |
| 113 | .pm = pm_ptr(&serial_port_pm), | |
| 114 | }; | |
| 115 | ||
| 116 | int serial_base_port_init(void) | |
| 117 | { | |
| 118 | return serial_base_driver_register(&serial_port_driver); | |
| 119 | } | |
| 120 | ||
| 121 | void serial_base_port_exit(void) | |
| 122 | { | |
| 123 | serial_base_driver_unregister(&serial_port_driver); | |
| 124 | } | |
| 125 | ||
| 126 | MODULE_AUTHOR("Tony Lindgren <tony@atomide.com>"); | |
| 127 | MODULE_DESCRIPTION("Serial controller port driver"); | |
| 128 | MODULE_LICENSE("GPL"); |