1/*
2 *  Serial Port driver for Open Firmware platform devices
3 *
4 *    Copyright (C) 2006 Arnd Bergmann <arnd@arndb.de>, IBM Corp.
5 *
6 *  This program is free software; you can redistribute it and/or
7 *  modify it under the terms of the GNU General Public License
8 *  as published by the Free Software Foundation; either version
9 *  2 of the License, or (at your option) any later version.
10 *
11 */
12#include <linux/init.h>
13#include <linux/module.h>
14#include <linux/serial_core.h>
15#include <linux/serial_8250.h>
16
17#include <asm/of_platform.h>
18#include <asm/prom.h>
19
20/*
21 * Fill a struct uart_port for a given device node
22 */
23static int __devinit of_platform_serial_setup(struct of_device *ofdev,
24					int type, struct uart_port *port)
25{
26	struct resource resource;
27	struct device_node *np = ofdev->node;
28	const unsigned int *clk, *spd;
29	int ret;
30
31	memset(port, 0, sizeof *port);
32	spd = of_get_property(np, "current-speed", NULL);
33	clk = of_get_property(np, "clock-frequency", NULL);
34	if (!clk) {
35		dev_warn(&ofdev->dev, "no clock-frequency property set\n");
36		return -ENODEV;
37	}
38
39	ret = of_address_to_resource(np, 0, &resource);
40	if (ret) {
41		dev_warn(&ofdev->dev, "invalid address\n");
42		return ret;
43	}
44
45	spin_lock_init(&port->lock);
46	port->mapbase = resource.start;
47	port->irq = irq_of_parse_and_map(np, 0);
48	port->iotype = UPIO_MEM;
49	port->type = type;
50	port->uartclk = *clk;
51	port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP
52		| UPF_FIXED_PORT;
53	port->dev = &ofdev->dev;
54	port->custom_divisor = *clk / (16 * (*spd));
55
56	return 0;
57}
58
59/*
60 * Try to register a serial port
61 */
62static int __devinit of_platform_serial_probe(struct of_device *ofdev,
63						const struct of_device_id *id)
64{
65	struct uart_port port;
66	int port_type;
67	int ret;
68
69	if (of_find_property(ofdev->node, "used-by-rtas", NULL))
70		return -EBUSY;
71
72	port_type = (unsigned long)id->data;
73	ret = of_platform_serial_setup(ofdev, port_type, &port);
74	if (ret)
75		goto out;
76
77	switch (port_type) {
78	case PORT_UNKNOWN:
79		dev_info(&ofdev->dev, "Unknown serial port found, "
80			"attempting to use 8250 driver\n");
81		/* fallthrough */
82	case PORT_8250 ... PORT_MAX_8250:
83		ret = serial8250_register_port(&port);
84		break;
85	default:
86		/* need to add code for these */
87		ret = -ENODEV;
88		break;
89	}
90	if (ret < 0)
91		goto out;
92
93	ofdev->dev.driver_data = (void *)(unsigned long)ret;
94	return 0;
95out:
96	irq_dispose_mapping(port.irq);
97	return ret;
98}
99
100/*
101 * Release a line
102 */
103static int of_platform_serial_remove(struct of_device *ofdev)
104{
105	int line = (unsigned long)ofdev->dev.driver_data;
106	serial8250_unregister_port(line);
107	return 0;
108}
109
110/*
111 * A few common types, add more as needed.
112 */
113static struct of_device_id __devinitdata of_platform_serial_table[] = {
114	{ .type = "serial", .compatible = "ns8250",   .data = (void *)PORT_8250, },
115	{ .type = "serial", .compatible = "ns16450",  .data = (void *)PORT_16450, },
116	{ .type = "serial", .compatible = "ns16550",  .data = (void *)PORT_16550, },
117	{ .type = "serial", .compatible = "ns16750",  .data = (void *)PORT_16750, },
118	{ .type = "serial",			      .data = (void *)PORT_UNKNOWN, },
119	{ /* end of list */ },
120};
121
122static struct of_platform_driver __devinitdata of_platform_serial_driver = {
123	.owner = THIS_MODULE,
124	.name = "of_serial",
125	.probe = of_platform_serial_probe,
126	.remove = of_platform_serial_remove,
127	.match_table = of_platform_serial_table,
128};
129
130static int __init of_platform_serial_init(void)
131{
132	return of_register_platform_driver(&of_platform_serial_driver);
133}
134module_init(of_platform_serial_init);
135
136static void __exit of_platform_serial_exit(void)
137{
138	return of_unregister_platform_driver(&of_platform_serial_driver);
139};
140module_exit(of_platform_serial_exit);
141
142MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
143MODULE_LICENSE("GPL");
144MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");
145