diff options
Diffstat (limited to 'drivers/serial/of_serial.c')
| -rw-r--r-- | drivers/serial/of_serial.c | 143 |
1 files changed, 143 insertions, 0 deletions
diff --git a/drivers/serial/of_serial.c b/drivers/serial/of_serial.c new file mode 100644 index 00000000000..09b0b736a75 --- /dev/null +++ b/drivers/serial/of_serial.c @@ -0,0 +1,143 @@ +/* + * Serial Port driver for Open Firmware platform devices + * + * Copyright (C) 2006 Arnd Bergmann <arnd@arndb.de>, IBM Corp. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + * + */ +#include <linux/init.h> +#include <linux/module.h> +#include <linux/serial_core.h> +#include <linux/serial_8250.h> + +#include <asm/of_platform.h> +#include <asm/prom.h> + +/* + * Fill a struct uart_port for a given device node + */ +static int __devinit of_platform_serial_setup(struct of_device *ofdev, + int type, struct uart_port *port) +{ + struct resource resource; + struct device_node *np = ofdev->node; + const unsigned int *clk, *spd; + int ret; + + memset(port, 0, sizeof *port); + spd = get_property(np, "current-speed", NULL); + clk = get_property(np, "clock-frequency", NULL); + if (!clk) { + dev_warn(&ofdev->dev, "no clock-frequency property set\n"); + return -ENODEV; + } + + ret = of_address_to_resource(np, 0, &resource); + if (ret) { + dev_warn(&ofdev->dev, "invalid address\n"); + return ret; + } + + spin_lock_init(&port->lock); + port->mapbase = resource.start; + port->irq = irq_of_parse_and_map(np, 0); + port->iotype = UPIO_MEM; + port->type = type; + port->uartclk = *clk; + port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP; + port->dev = &ofdev->dev; + port->custom_divisor = *clk / (16 * (*spd)); + + return 0; +} + +/* + * Try to register a serial port + */ +static int __devinit of_platform_serial_probe(struct of_device *ofdev, + const struct of_device_id *id) +{ + struct uart_port port; + int port_type; + int ret; + + if (of_find_property(ofdev->node, "used-by-rtas", NULL)) + return -EBUSY; + + port_type = (unsigned long)id->data; + ret = of_platform_serial_setup(ofdev, port_type, &port); + if (ret) + goto out; + + switch (port_type) { + case PORT_UNKNOWN: + dev_info(&ofdev->dev, "Unknown serial port found, " + "attempting to use 8250 driver\n"); + /* fallthrough */ + case PORT_8250 ... PORT_MAX_8250: + ret = serial8250_register_port(&port); + break; + default: + /* need to add code for these */ + ret = -ENODEV; + break; + } + if (ret < 0) + goto out; + + ofdev->dev.driver_data = (void *)(unsigned long)ret; + return 0; +out: + irq_dispose_mapping(port.irq); + return ret; +} + +/* + * Release a line + */ +static int of_platform_serial_remove(struct of_device *ofdev) +{ + int line = (unsigned long)ofdev->dev.driver_data; + serial8250_unregister_port(line); + return 0; +} + +/* + * A few common types, add more as needed. + */ +static struct of_device_id __devinitdata of_platform_serial_table[] = { + { .type = "serial", .compatible = "ns8250", .data = (void *)PORT_8250, }, + { .type = "serial", .compatible = "ns16450", .data = (void *)PORT_16450, }, + { .type = "serial", .compatible = "ns16550", .data = (void *)PORT_16550, }, + { .type = "serial", .compatible = "ns16750", .data = (void *)PORT_16750, }, + { .type = "serial", .data = (void *)PORT_UNKNOWN, }, + { /* end of list */ }, +}; + +static struct of_platform_driver __devinitdata of_platform_serial_driver = { + .owner = THIS_MODULE, + .name = "of_serial", + .probe = of_platform_serial_probe, + .remove = of_platform_serial_remove, + .match_table = of_platform_serial_table, +}; + +static int __init of_platform_serial_init(void) +{ + return of_register_platform_driver(&of_platform_serial_driver); +} +module_init(of_platform_serial_init); + +static void __exit of_platform_serial_exit(void) +{ + return of_unregister_platform_driver(&of_platform_serial_driver); +}; +module_exit(of_platform_serial_exit); + +MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>"); +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices"); |