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 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         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         /* If current-speed was set, then try not to change it. */
  60         if (spd)
  61                 port->custom_divisor = *clk / (16 * (*spd));
  62
  63         return 0;
  64 }
  65
  66 /*
  67  * Try to register a serial port
  68  */
  69 static int __devinit of_platform_serial_probe(struct of_device *ofdev,
  70                                                 const struct of_device_id *id)
  71 {
  72         struct of_serial_info *info;
  73         struct uart_port port;
  74         int port_type;
  75         int ret;
  76
  77         if (of_find_property(ofdev->node, "used-by-rtas", NULL))
  78                 return -EBUSY;
  79
  80         info = kmalloc(sizeof(*info), GFP_KERNEL);
  81         if (info == NULL)
  82                 return -ENOMEM;
  83
  84         port_type = (unsigned long)id->data;
  85         ret = of_platform_serial_setup(ofdev, port_type, &port);
  86         if (ret)
  87                 goto out;
  88
  89         switch (port_type) {
  90         case PORT_8250 ... PORT_MAX_8250:
  91                 ret = serial8250_register_port(&port);
  92                 break;
  93         default:
  94                 /* need to add code for these */
  95         case PORT_UNKNOWN:
  96                 dev_info(&ofdev->dev, "Unknown serial port found, ignored\n");
  97                 ret = -ENODEV;
  98                 break;
  99         }
 100         if (ret < 0)
 101                 goto out;
 102
 103         info->type = port_type;
 104         info->line = ret;
 105         ofdev->dev.driver_data = info;
 106         return 0;
 107 out:
 108         kfree(info);
 109         irq_dispose_mapping(port.irq);
 110         return ret;
 111 }
 112
 113 /*
 114  * Release a line
 115  */
 116 static int of_platform_serial_remove(struct of_device *ofdev)
 117 {
 118         struct of_serial_info *info = ofdev->dev.driver_data;
 119         switch (info->type) {
 120         case PORT_8250 ... PORT_MAX_8250:
 121                 serial8250_unregister_port(info->line);
 122                 break;
 123         default:
 124                 /* need to add code for these */
 125                 break;
 126         }
 127         kfree(info);
 128         return 0;
 129 }
 130
 131 /*
 132  * A few common types, add more as needed.
 133  */
 134 static struct of_device_id __devinitdata of_platform_serial_table[] = {
 135         { .type = "serial", .compatible = "ns8250",   .data = (void *)PORT_8250, },
 136         { .type = "serial", .compatible = "ns16450",  .data = (void *)PORT_16450, },
 137         { .type = "serial", .compatible = "ns16550",  .data = (void *)PORT_16550, },
 138         { .type = "serial", .compatible = "ns16750",  .data = (void *)PORT_16750, },
 139         { .type = "serial",                           .data = (void *)PORT_UNKNOWN, },
 140         { /* end of list */ },
 141 };
 142
 143 static struct of_platform_driver of_platform_serial_driver = {
 144         .owner = THIS_MODULE,
 145         .name = "of_serial",
 146         .probe = of_platform_serial_probe,
 147         .remove = of_platform_serial_remove,
 148         .match_table = of_platform_serial_table,
 149 };
 150
 151 static int __init of_platform_serial_init(void)
 152 {
 153         return of_register_platform_driver(&of_platform_serial_driver);
 154 }
 155 module_init(of_platform_serial_init);
 156
 157 static void __exit of_platform_serial_exit(void)
 158 {
 159         return of_unregister_platform_driver(&of_platform_serial_driver);
 160 };
 161 module_exit(of_platform_serial_exit);
 162
 163 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
 164 MODULE_LICENSE("GPL");
 165 MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");