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(msecs: 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 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 | |
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(name: "iris" , id: (-1), |
106 | res: iris_resources, ARRAY_SIZE(iris_resources)); |
107 | if (IS_ERR(ptr: iris_device)) { |
108 | printk(KERN_ERR "Failed to register iris platform device\n" ); |
109 | platform_driver_unregister(&iris_driver); |
110 | return PTR_ERR(ptr: iris_device); |
111 | } |
112 | return 0; |
113 | } |
114 | |
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 | |