1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Eurobraille/Iris power off support.
4 *
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.
7 *
8 * Copyright (C) Shérab <Sebastien.Hinderer@ens-lyon.org>
9 */
10
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>
17 #include <linux/pm.h>
18 #include <asm/io.h>
19
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 */
26
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");
30
31 static bool force;
32
33 module_param(force, bool, 0);
34 MODULE_PARM_DESC(force, "Set to one to force poweroff handler installation.");
35
36 static void (*old_pm_power_off)(void);
37
iris_power_off(void)38 static void iris_power_off(void)
39 {
40 outb(IRIS_GIO_PULSE, IRIS_GIO_OUTPUT);
41 msleep(850);
42 outb(IRIS_GIO_REST, IRIS_GIO_OUTPUT);
43 }
44
45 /*
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
49 * meaningful.
50 */
iris_probe(struct platform_device * pdev)51 static int iris_probe(struct platform_device *pdev)
52 {
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");
57 return -ENODEV;
58 }
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");
62 return 0;
63 }
64
iris_remove(struct platform_device * pdev)65 static int iris_remove(struct platform_device *pdev)
66 {
67 pm_power_off = old_pm_power_off;
68 printk(KERN_INFO "Iris power_off handler uninstalled.\n");
69 return 0;
70 }
71
72 static struct platform_driver iris_driver = {
73 .driver = {
74 .name = "iris",
75 },
76 .probe = iris_probe,
77 .remove = iris_remove,
78 };
79
80 static struct resource iris_resources[] = {
81 {
82 .start = IRIS_GIO_BASE,
83 .end = IRIS_GIO_OUTPUT,
84 .flags = IORESOURCE_IO,
85 .name = "address"
86 }
87 };
88
89 static struct platform_device *iris_device;
90
iris_init(void)91 static int iris_init(void)
92 {
93 int ret;
94 if (force != 1) {
95 printk(KERN_ERR "The force parameter has not been set to 1."
96 " The Iris poweroff handler will not be installed.\n");
97 return -ENODEV;
98 }
99 ret = platform_driver_register(&iris_driver);
100 if (ret < 0) {
101 printk(KERN_ERR "Failed to register iris platform driver: %d\n",
102 ret);
103 return ret;
104 }
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);
111 }
112 return 0;
113 }
114
iris_exit(void)115 static void iris_exit(void)
116 {
117 platform_device_unregister(iris_device);
118 platform_driver_unregister(&iris_driver);
119 }
120
121 module_init(iris_init);
122 module_exit(iris_exit);
123