tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
20struct of_serial_info {
21 int type;
22 int line;
23};
24
25/*
26 * Fill a struct uart_port for a given device node
27 */
28static int __devinit of_platform_serial_setup(struct of_device *ofdev,
29 int type, struct uart_port *port)
30{
31 struct resource resource;
32 struct device_node *np = ofdev->node;
33 const unsigned int *clk, *spd;
34 int ret;
35
36 memset(port, 0, sizeof *port);
37 spd = of_get_property(np, "current-speed", NULL);
38 clk = of_get_property(np, "clock-frequency", NULL);
39 if (!clk) {
40 dev_warn(&ofdev->dev, "no clock-frequency property set\n");
41 return -ENODEV;
42 }
43
44 ret = of_address_to_resource(np, 0, &resource);
45 if (ret) {
46 dev_warn(&ofdev->dev, "invalid address\n");
47 return ret;
48 }
49
50 spin_lock_init(&port->lock);
51 port->mapbase = resource.start;
52 port->irq = irq_of_parse_and_map(np, 0);
53 port->iotype = UPIO_MEM;
54 port->type = type;
55 port->uartclk = *clk;
56 port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP
57 | UPF_FIXED_PORT;
58 port->dev = &ofdev->dev;
59 port->custom_divisor = *clk / (16 * (*spd));
60
61 return 0;
62}
63
64/*
65 * Try to register a serial port
66 */
67static int __devinit of_platform_serial_probe(struct of_device *ofdev,
68 const struct of_device_id *id)
69{
70 struct of_serial_info *info;
71 struct uart_port port;
72 int port_type;
73 int ret;
74
75 if (of_find_property(ofdev->node, "used-by-rtas", NULL))
76 return -EBUSY;
77
78 info = kmalloc(sizeof(*info), GFP_KERNEL);
79 if (info == NULL)
80 return -ENOMEM;
81
82 port_type = (unsigned long)id->data;
83 ret = of_platform_serial_setup(ofdev, port_type, &port);
84 if (ret)
85 goto out;
86
87 switch (port_type) {
88 case PORT_8250 ... PORT_MAX_8250:
89 ret = serial8250_register_port(&port);
90 break;
91 default:
92 /* need to add code for these */
93 case PORT_UNKNOWN:
94 dev_info(&ofdev->dev, "Unknown serial port found, ignored\n");
95 ret = -ENODEV;
96 break;
97 }
98 if (ret < 0)
99 goto out;
100
101 info->type = port_type;
102 info->line = ret;
103 ofdev->dev.driver_data = info;
104 return 0;
105out:
106 kfree(info);
107 irq_dispose_mapping(port.irq);
108 return ret;
109}
110
111/*
112 * Release a line
113 */
114static int of_platform_serial_remove(struct of_device *ofdev)
115{
116 struct of_serial_info *info = ofdev->dev.driver_data;
117 switch (info->type) {
118 case PORT_8250 ... PORT_MAX_8250:
119 serial8250_unregister_port(info->line);
120 break;
121 default:
122 /* need to add code for these */
123 break;
124 }
125 kfree(info);
126 return 0;
127}
128
129/*
130 * A few common types, add more as needed.
131 */
132static struct of_device_id __devinitdata of_platform_serial_table[] = {
133 { .type = "serial", .compatible = "ns8250", .data = (void *)PORT_8250, },
134 { .type = "serial", .compatible = "ns16450", .data = (void *)PORT_16450, },
135 { .type = "serial", .compatible = "ns16550", .data = (void *)PORT_16550, },
136 { .type = "serial", .compatible = "ns16750", .data = (void *)PORT_16750, },
137 { .type = "serial", .data = (void *)PORT_UNKNOWN, },
138 { /* end of list */ },
139};
140
141static struct of_platform_driver __devinitdata of_platform_serial_driver = {
142 .owner = THIS_MODULE,
143 .name = "of_serial",
144 .probe = of_platform_serial_probe,
145 .remove = of_platform_serial_remove,
146 .match_table = of_platform_serial_table,
147};
148
149static int __init of_platform_serial_init(void)
150{
151 return of_register_platform_driver(&of_platform_serial_driver);
152}
153module_init(of_platform_serial_init);
154
155static void __exit of_platform_serial_exit(void)
156{
157 return of_unregister_platform_driver(&of_platform_serial_driver);
158};
159module_exit(of_platform_serial_exit);
160
161MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
162MODULE_LICENSE("GPL");
163MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");