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[linux-2.6] / 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 #include <linux/of_platform.h>
17
18 #include <asm/prom.h>
19
20 struct of_serial_info {
21         int type;
22         int line;
23 };
24
25 /*
26  * Fill a struct uart_port for a given device node
27  */
28 static 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         const u32 *prop;
35         int ret, prop_size;
36
37         memset(port, 0, sizeof *port);
38         spd = of_get_property(np, "current-speed", NULL);
39         clk = of_get_property(np, "clock-frequency", NULL);
40         if (!clk) {
41                 dev_warn(&ofdev->dev, "no clock-frequency property set\n");
42                 return -ENODEV;
43         }
44
45         ret = of_address_to_resource(np, 0, &resource);
46         if (ret) {
47                 dev_warn(&ofdev->dev, "invalid address\n");
48                 return ret;
49         }
50
51         spin_lock_init(&port->lock);
52         port->mapbase = resource.start;
53
54         /* Check for shifted address mapping */
55         prop = of_get_property(np, "reg-offset", &prop_size);
56         if (prop && (prop_size == sizeof(u32)))
57                 port->mapbase += *prop;
58
59         /* Check for registers offset within the devices address range */
60         prop = of_get_property(np, "reg-shift", &prop_size);
61         if (prop && (prop_size == sizeof(u32)))
62                 port->regshift = *prop;
63
64         port->irq = irq_of_parse_and_map(np, 0);
65         port->iotype = UPIO_MEM;
66         port->type = type;
67         port->uartclk = *clk;
68         port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP
69                 | UPF_FIXED_PORT;
70         port->dev = &ofdev->dev;
71         /* If current-speed was set, then try not to change it. */
72         if (spd)
73                 port->custom_divisor = *clk / (16 * (*spd));
74
75         return 0;
76 }
77
78 /*
79  * Try to register a serial port
80  */
81 static int __devinit of_platform_serial_probe(struct of_device *ofdev,
82                                                 const struct of_device_id *id)
83 {
84         struct of_serial_info *info;
85         struct uart_port port;
86         int port_type;
87         int ret;
88
89         if (of_find_property(ofdev->node, "used-by-rtas", NULL))
90                 return -EBUSY;
91
92         info = kmalloc(sizeof(*info), GFP_KERNEL);
93         if (info == NULL)
94                 return -ENOMEM;
95
96         port_type = (unsigned long)id->data;
97         ret = of_platform_serial_setup(ofdev, port_type, &port);
98         if (ret)
99                 goto out;
100
101         switch (port_type) {
102         case PORT_8250 ... PORT_MAX_8250:
103                 ret = serial8250_register_port(&port);
104                 break;
105         default:
106                 /* need to add code for these */
107         case PORT_UNKNOWN:
108                 dev_info(&ofdev->dev, "Unknown serial port found, ignored\n");
109                 ret = -ENODEV;
110                 break;
111         }
112         if (ret < 0)
113                 goto out;
114
115         info->type = port_type;
116         info->line = ret;
117         ofdev->dev.driver_data = info;
118         return 0;
119 out:
120         kfree(info);
121         irq_dispose_mapping(port.irq);
122         return ret;
123 }
124
125 /*
126  * Release a line
127  */
128 static int of_platform_serial_remove(struct of_device *ofdev)
129 {
130         struct of_serial_info *info = ofdev->dev.driver_data;
131         switch (info->type) {
132         case PORT_8250 ... PORT_MAX_8250:
133                 serial8250_unregister_port(info->line);
134                 break;
135         default:
136                 /* need to add code for these */
137                 break;
138         }
139         kfree(info);
140         return 0;
141 }
142
143 /*
144  * A few common types, add more as needed.
145  */
146 static struct of_device_id __devinitdata of_platform_serial_table[] = {
147         { .type = "serial", .compatible = "ns8250",   .data = (void *)PORT_8250, },
148         { .type = "serial", .compatible = "ns16450",  .data = (void *)PORT_16450, },
149         { .type = "serial", .compatible = "ns16550",  .data = (void *)PORT_16550, },
150         { .type = "serial", .compatible = "ns16750",  .data = (void *)PORT_16750, },
151         { .type = "serial",                           .data = (void *)PORT_UNKNOWN, },
152         { /* end of list */ },
153 };
154
155 static struct of_platform_driver of_platform_serial_driver = {
156         .owner = THIS_MODULE,
157         .name = "of_serial",
158         .probe = of_platform_serial_probe,
159         .remove = of_platform_serial_remove,
160         .match_table = of_platform_serial_table,
161 };
162
163 static int __init of_platform_serial_init(void)
164 {
165         return of_register_platform_driver(&of_platform_serial_driver);
166 }
167 module_init(of_platform_serial_init);
168
169 static void __exit of_platform_serial_exit(void)
170 {
171         return of_unregister_platform_driver(&of_platform_serial_driver);
172 };
173 module_exit(of_platform_serial_exit);
174
175 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
176 MODULE_LICENSE("GPL");
177 MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");