1/*
2 * Eurobraille/Iris power off support.
3 *
4 * Eurobraille's Iris machine is a PC with no APM or ACPI support.
5 * It is shutdown by a special I/O sequence which this module provides.
6 *
7 *  Copyright (C) Shérab <Sebastien.Hinderer@ens-lyon.org>
8 *
9 * This program is free software ; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation ; either version 2 of the License, or
12 * (at your option) any later version.
13 *
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY ; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License
20 * along with the program ; if not, write to the Free Software
21 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
22 */
23
24#include <linux/moduleparam.h>
25#include <linux/module.h>
26#include <linux/platform_device.h>
27#include <linux/kernel.h>
28#include <linux/errno.h>
29#include <linux/delay.h>
30#include <linux/pm.h>
31#include <asm/io.h>
32
33#define IRIS_GIO_BASE		0x340
34#define IRIS_GIO_INPUT		IRIS_GIO_BASE
35#define IRIS_GIO_OUTPUT		(IRIS_GIO_BASE + 1)
36#define IRIS_GIO_PULSE		0x80 /* First byte to send */
37#define IRIS_GIO_REST		0x00 /* Second byte to send */
38#define IRIS_GIO_NODEV		0xff /* Likely not an Iris */
39
40MODULE_LICENSE("GPL");
41MODULE_AUTHOR("Sébastien Hinderer <Sebastien.Hinderer@ens-lyon.org>");
42MODULE_DESCRIPTION("A power_off handler for Iris devices from EuroBraille");
43MODULE_SUPPORTED_DEVICE("Eurobraille/Iris");
44
45static bool force;
46
47module_param(force, bool, 0);
48MODULE_PARM_DESC(force, "Set to one to force poweroff handler installation.");
49
50static void (*old_pm_power_off)(void);
51
52static void iris_power_off(void)
53{
54	outb(IRIS_GIO_PULSE, IRIS_GIO_OUTPUT);
55	msleep(850);
56	outb(IRIS_GIO_REST, IRIS_GIO_OUTPUT);
57}
58
59/*
60 * Before installing the power_off handler, try to make sure the OS is
61 * running on an Iris.  Since Iris does not support DMI, this is done
62 * by reading its input port and seeing whether the read value is
63 * meaningful.
64 */
65static int iris_probe(struct platform_device *pdev)
66{
67	unsigned char status = inb(IRIS_GIO_INPUT);
68	if (status == IRIS_GIO_NODEV) {
69		printk(KERN_ERR "This machine does not seem to be an Iris. "
70			"Power off handler not installed.\n");
71		return -ENODEV;
72	}
73	old_pm_power_off = pm_power_off;
74	pm_power_off = &iris_power_off;
75	printk(KERN_INFO "Iris power_off handler installed.\n");
76	return 0;
77}
78
79static int iris_remove(struct platform_device *pdev)
80{
81	pm_power_off = old_pm_power_off;
82	printk(KERN_INFO "Iris power_off handler uninstalled.\n");
83	return 0;
84}
85
86static struct platform_driver iris_driver = {
87	.driver		= {
88		.name   = "iris",
89	},
90	.probe          = iris_probe,
91	.remove         = iris_remove,
92};
93
94static struct resource iris_resources[] = {
95	{
96		.start  = IRIS_GIO_BASE,
97		.end    = IRIS_GIO_OUTPUT,
98		.flags  = IORESOURCE_IO,
99		.name   = "address"
100	}
101};
102
103static struct platform_device *iris_device;
104
105static int iris_init(void)
106{
107	int ret;
108	if (force != 1) {
109		printk(KERN_ERR "The force parameter has not been set to 1."
110			" The Iris poweroff handler will not be installed.\n");
111		return -ENODEV;
112	}
113	ret = platform_driver_register(&iris_driver);
114	if (ret < 0) {
115		printk(KERN_ERR "Failed to register iris platform driver: %d\n",
116			ret);
117		return ret;
118	}
119	iris_device = platform_device_register_simple("iris", (-1),
120				iris_resources, ARRAY_SIZE(iris_resources));
121	if (IS_ERR(iris_device)) {
122		printk(KERN_ERR "Failed to register iris platform device\n");
123		platform_driver_unregister(&iris_driver);
124		return PTR_ERR(iris_device);
125	}
126	return 0;
127}
128
129static void iris_exit(void)
130{
131	platform_device_unregister(iris_device);
132	platform_driver_unregister(&iris_driver);
133}
134
135module_init(iris_init);
136module_exit(iris_exit);
137