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 */ 23static 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 = of_get_property(np, "current-speed", NULL); 33 clk = of_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 | UPF_FIXED_PORT; 53 port->dev = &ofdev->dev; 54 port->custom_divisor = *clk / (16 * (*spd)); 55 56 return 0; 57} 58 59/* 60 * Try to register a serial port 61 */ 62static int __devinit of_platform_serial_probe(struct of_device *ofdev, 63 const struct of_device_id *id) 64{ 65 struct uart_port port; 66 int port_type; 67 int ret; 68 69 if (of_find_property(ofdev->node, "used-by-rtas", NULL)) 70 return -EBUSY; 71 72 port_type = (unsigned long)id->data; 73 ret = of_platform_serial_setup(ofdev, port_type, &port); 74 if (ret) 75 goto out; 76 77 switch (port_type) { 78 case PORT_UNKNOWN: 79 dev_info(&ofdev->dev, "Unknown serial port found, " 80 "attempting to use 8250 driver\n"); 81 /* fallthrough */ 82 case PORT_8250 ... PORT_MAX_8250: 83 ret = serial8250_register_port(&port); 84 break; 85 default: 86 /* need to add code for these */ 87 ret = -ENODEV; 88 break; 89 } 90 if (ret < 0) 91 goto out; 92 93 ofdev->dev.driver_data = (void *)(unsigned long)ret; 94 return 0; 95out: 96 irq_dispose_mapping(port.irq); 97 return ret; 98} 99 100/* 101 * Release a line 102 */ 103static int of_platform_serial_remove(struct of_device *ofdev) 104{ 105 int line = (unsigned long)ofdev->dev.driver_data; 106 serial8250_unregister_port(line); 107 return 0; 108} 109 110/* 111 * A few common types, add more as needed. 112 */ 113static struct of_device_id __devinitdata of_platform_serial_table[] = { 114 { .type = "serial", .compatible = "ns8250", .data = (void *)PORT_8250, }, 115 { .type = "serial", .compatible = "ns16450", .data = (void *)PORT_16450, }, 116 { .type = "serial", .compatible = "ns16550", .data = (void *)PORT_16550, }, 117 { .type = "serial", .compatible = "ns16750", .data = (void *)PORT_16750, }, 118 { .type = "serial", .data = (void *)PORT_UNKNOWN, }, 119 { /* end of list */ }, 120}; 121 122static struct of_platform_driver __devinitdata of_platform_serial_driver = { 123 .owner = THIS_MODULE, 124 .name = "of_serial", 125 .probe = of_platform_serial_probe, 126 .remove = of_platform_serial_remove, 127 .match_table = of_platform_serial_table, 128}; 129 130static int __init of_platform_serial_init(void) 131{ 132 return of_register_platform_driver(&of_platform_serial_driver); 133} 134module_init(of_platform_serial_init); 135 136static void __exit of_platform_serial_exit(void) 137{ 138 return of_unregister_platform_driver(&of_platform_serial_driver); 139}; 140module_exit(of_platform_serial_exit); 141 142MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>"); 143MODULE_LICENSE("GPL"); 144MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices"); 145