09b0b736a751e6e4bbe9ff5537b1a143b6cbd06a
[linux-2.6.git] / drivers / serial / of_serial.c
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  */
23 static 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 = get_property(np, "current-speed", NULL);
33         clk = 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         port->dev = &ofdev->dev;
53         port->custom_divisor = *clk / (16 * (*spd));
54
55         return 0;
56 }
57
58 /*
59  * Try to register a serial port
60  */
61 static int __devinit of_platform_serial_probe(struct of_device *ofdev,
62                                                 const struct of_device_id *id)
63 {
64         struct uart_port port;
65         int port_type;
66         int ret;
67
68         if (of_find_property(ofdev->node, "used-by-rtas", NULL))
69                 return -EBUSY;
70
71         port_type = (unsigned long)id->data;
72         ret = of_platform_serial_setup(ofdev, port_type, &port);
73         if (ret)
74                 goto out;
75
76         switch (port_type) {
77         case PORT_UNKNOWN:
78                 dev_info(&ofdev->dev, "Unknown serial port found, "
79                         "attempting to use 8250 driver\n");
80                 /* fallthrough */
81         case PORT_8250 ... PORT_MAX_8250:
82                 ret = serial8250_register_port(&port);
83                 break;
84         default:
85                 /* need to add code for these */
86                 ret = -ENODEV;
87                 break;
88         }
89         if (ret < 0)
90                 goto out;
91
92         ofdev->dev.driver_data = (void *)(unsigned long)ret;
93         return 0;
94 out:
95         irq_dispose_mapping(port.irq);
96         return ret;
97 }
98
99 /*
100  * Release a line
101  */
102 static int of_platform_serial_remove(struct of_device *ofdev)
103 {
104         int line = (unsigned long)ofdev->dev.driver_data;
105         serial8250_unregister_port(line);
106         return 0;
107 }
108
109 /*
110  * A few common types, add more as needed.
111  */
112 static struct of_device_id __devinitdata of_platform_serial_table[] = {
113         { .type = "serial", .compatible = "ns8250",   .data = (void *)PORT_8250, },
114         { .type = "serial", .compatible = "ns16450",  .data = (void *)PORT_16450, },
115         { .type = "serial", .compatible = "ns16550",  .data = (void *)PORT_16550, },
116         { .type = "serial", .compatible = "ns16750",  .data = (void *)PORT_16750, },
117         { .type = "serial",                           .data = (void *)PORT_UNKNOWN, },
118         { /* end of list */ },
119 };
120
121 static struct of_platform_driver __devinitdata of_platform_serial_driver = {
122         .owner = THIS_MODULE,
123         .name = "of_serial",
124         .probe = of_platform_serial_probe,
125         .remove = of_platform_serial_remove,
126         .match_table = of_platform_serial_table,
127 };
128
129 static int __init of_platform_serial_init(void)
130 {
131         return of_register_platform_driver(&of_platform_serial_driver);
132 }
133 module_init(of_platform_serial_init);
134
135 static void __exit of_platform_serial_exit(void)
136 {
137         return of_unregister_platform_driver(&of_platform_serial_driver);
138 };
139 module_exit(of_platform_serial_exit);
140
141 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
142 MODULE_LICENSE("GPL");
143 MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");