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
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 */
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
65 static void 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 }
70
71 static struct platform_driver iris_driver = {
72 .driver = {
73 .name = "iris",
74 },
75 .probe = iris_probe,
76 .remove_new = iris_remove,
77 };
78
79 static struct resource iris_resources[] = {
80 {
81 .start = IRIS_GIO_BASE,
82 .end = IRIS_GIO_OUTPUT,
83 .flags = IORESOURCE_IO,
84 .name = "address"
85 }
86 };
87
88 static struct platform_device *iris_device;
89
90 static int iris_init(void)
91 {
92 int ret;
93 if (force != 1) {
94 printk(KERN_ERR "The force parameter has not been set to 1."
95 " The Iris poweroff handler will not be installed.\n");
96 return -ENODEV;
97 }
98 ret = platform_driver_register(&iris_driver);
99 if (ret < 0) {
100 printk(KERN_ERR "Failed to register iris platform driver: %d\n",
101 ret);
102 return ret;
103 }
104 iris_device = platform_device_register_simple("iris", (-1),
105 iris_resources, ARRAY_SIZE(iris_resources));
106 if (IS_ERR(iris_device)) {
107 printk(KERN_ERR "Failed to register iris platform device\n");
108 platform_driver_unregister(&iris_driver);
109 return PTR_ERR(iris_device);
110 }
111 return 0;
112 }
113
114 static void iris_exit(void)
115 {
116 platform_device_unregister(iris_device);
117 platform_driver_unregister(&iris_driver);
118 }
119
120 module_init(iris_init);
121 module_exit(iris_exit);
122
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