1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * Eurobraille/Iris power off support.
5 * Eurobraille's Iris machine is a PC with no APM or ACPI support.
6 * It is shutdown by a special I/O sequence which this module provides.
8 * Copyright (C) Shérab <Sebastien.Hinderer@ens-lyon.org>
11 #include <linux/moduleparam.h>
12 #include <linux/module.h>
13 #include <linux/platform_device.h>
14 #include <linux/kernel.h>
15 #include <linux/errno.h>
16 #include <linux/delay.h>
20 #define IRIS_GIO_BASE 0x340
21 #define IRIS_GIO_INPUT IRIS_GIO_BASE
22 #define IRIS_GIO_OUTPUT (IRIS_GIO_BASE + 1)
23 #define IRIS_GIO_PULSE 0x80 /* First byte to send */
24 #define IRIS_GIO_REST 0x00 /* Second byte to send */
25 #define IRIS_GIO_NODEV 0xff /* Likely not an Iris */
27 MODULE_LICENSE("GPL");
28 MODULE_AUTHOR("Sébastien Hinderer <Sebastien.Hinderer@ens-lyon.org>");
29 MODULE_DESCRIPTION("A power_off handler for Iris devices from EuroBraille");
33 module_param(force, bool, 0);
34 MODULE_PARM_DESC(force, "Set to one to force poweroff handler installation.");
36 static void (*old_pm_power_off)(void);
38 static void iris_power_off(void)
40 outb(IRIS_GIO_PULSE, IRIS_GIO_OUTPUT);
42 outb(IRIS_GIO_REST, IRIS_GIO_OUTPUT);
46 * Before installing the power_off handler, try to make sure the OS is
47 * running on an Iris. Since Iris does not support DMI, this is done
48 * by reading its input port and seeing whether the read value is
51 static int iris_probe(struct platform_device *pdev)
53 unsigned char status = inb(IRIS_GIO_INPUT);
54 if (status == IRIS_GIO_NODEV) {
55 printk(KERN_ERR "This machine does not seem to be an Iris. "
56 "Power off handler not installed.\n");
59 old_pm_power_off = pm_power_off;
60 pm_power_off = &iris_power_off;
61 printk(KERN_INFO "Iris power_off handler installed.\n");
65 static int iris_remove(struct platform_device *pdev)
67 pm_power_off = old_pm_power_off;
68 printk(KERN_INFO "Iris power_off handler uninstalled.\n");
72 static struct platform_driver iris_driver = {
77 .remove = iris_remove,
80 static struct resource iris_resources[] = {
82 .start = IRIS_GIO_BASE,
83 .end = IRIS_GIO_OUTPUT,
84 .flags = IORESOURCE_IO,
89 static struct platform_device *iris_device;
91 static int iris_init(void)
95 printk(KERN_ERR "The force parameter has not been set to 1."
96 " The Iris poweroff handler will not be installed.\n");
99 ret = platform_driver_register(&iris_driver);
101 printk(KERN_ERR "Failed to register iris platform driver: %d\n",
105 iris_device = platform_device_register_simple("iris", (-1),
106 iris_resources, ARRAY_SIZE(iris_resources));
107 if (IS_ERR(iris_device)) {
108 printk(KERN_ERR "Failed to register iris platform device\n");
109 platform_driver_unregister(&iris_driver);
110 return PTR_ERR(iris_device);
115 static void iris_exit(void)
117 platform_device_unregister(iris_device);
118 platform_driver_unregister(&iris_driver);
121 module_init(iris_init);
122 module_exit(iris_exit);