xref: /openbmc/linux/arch/x86/platform/iris/iris.c (revision 6417f031)
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