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         port->custom_divisor = *clk / (16 * (*spd));
  60
  61         return 0;
  62 }
  63
  64 /*
  65  * Try to register a serial port
  66  */
  67 static 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;
 105 out:
 106         kfree(info);
 107         irq_dispose_mapping(port.irq);
 108         return ret;
 109 }
 110
 111 /*
 112  * Release a line
 113  */
 114 static 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  */
 132 static 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
 141 static struct of_platform_driver 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
 149 static int __init of_platform_serial_init(void)
 150 {
 151         return of_register_platform_driver(&of_platform_serial_driver);
 152 }
 153 module_init(of_platform_serial_init);
 154
 155 static void __exit of_platform_serial_exit(void)
 156 {
 157         return of_unregister_platform_driver(&of_platform_serial_driver);
 158 };
 159 module_exit(of_platform_serial_exit);
 160
 161 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
 162 MODULE_LICENSE("GPL");
 163 MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");