LXR linux/drivers/serial/of

   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");
 164