| b.liu | e958203 | 2025-04-17 19:18:16 +0800 | [diff] [blame^] | 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 | MODULE_SUPPORTED_DEVICE("Eurobraille/Iris"); |
| 31 | |
| 32 | static bool force; |
| 33 | |
| 34 | module_param(force, bool, 0); |
| 35 | MODULE_PARM_DESC(force, "Set to one to force poweroff handler installation."); |
| 36 | |
| 37 | static void (*old_pm_power_off)(void); |
| 38 | |
| 39 | static void iris_power_off(void) |
| 40 | { |
| 41 | outb(IRIS_GIO_PULSE, IRIS_GIO_OUTPUT); |
| 42 | msleep(850); |
| 43 | outb(IRIS_GIO_REST, IRIS_GIO_OUTPUT); |
| 44 | } |
| 45 | |
| 46 | /* |
| 47 | * Before installing the power_off handler, try to make sure the OS is |
| 48 | * running on an Iris. Since Iris does not support DMI, this is done |
| 49 | * by reading its input port and seeing whether the read value is |
| 50 | * meaningful. |
| 51 | */ |
| 52 | static int iris_probe(struct platform_device *pdev) |
| 53 | { |
| 54 | unsigned char status = inb(IRIS_GIO_INPUT); |
| 55 | if (status == IRIS_GIO_NODEV) { |
| 56 | printk(KERN_ERR "This machine does not seem to be an Iris. " |
| 57 | "Power off handler not installed.\n"); |
| 58 | return -ENODEV; |
| 59 | } |
| 60 | old_pm_power_off = pm_power_off; |
| 61 | pm_power_off = &iris_power_off; |
| 62 | printk(KERN_INFO "Iris power_off handler installed.\n"); |
| 63 | return 0; |
| 64 | } |
| 65 | |
| 66 | static int iris_remove(struct platform_device *pdev) |
| 67 | { |
| 68 | pm_power_off = old_pm_power_off; |
| 69 | printk(KERN_INFO "Iris power_off handler uninstalled.\n"); |
| 70 | return 0; |
| 71 | } |
| 72 | |
| 73 | static struct platform_driver iris_driver = { |
| 74 | .driver = { |
| 75 | .name = "iris", |
| 76 | }, |
| 77 | .probe = iris_probe, |
| 78 | .remove = iris_remove, |
| 79 | }; |
| 80 | |
| 81 | static struct resource iris_resources[] = { |
| 82 | { |
| 83 | .start = IRIS_GIO_BASE, |
| 84 | .end = IRIS_GIO_OUTPUT, |
| 85 | .flags = IORESOURCE_IO, |
| 86 | .name = "address" |
| 87 | } |
| 88 | }; |
| 89 | |
| 90 | static struct platform_device *iris_device; |
| 91 | |
| 92 | static int iris_init(void) |
| 93 | { |
| 94 | int ret; |
| 95 | if (force != 1) { |
| 96 | printk(KERN_ERR "The force parameter has not been set to 1." |
| 97 | " The Iris poweroff handler will not be installed.\n"); |
| 98 | return -ENODEV; |
| 99 | } |
| 100 | ret = platform_driver_register(&iris_driver); |
| 101 | if (ret < 0) { |
| 102 | printk(KERN_ERR "Failed to register iris platform driver: %d\n", |
| 103 | ret); |
| 104 | return ret; |
| 105 | } |
| 106 | iris_device = platform_device_register_simple("iris", (-1), |
| 107 | iris_resources, ARRAY_SIZE(iris_resources)); |
| 108 | if (IS_ERR(iris_device)) { |
| 109 | printk(KERN_ERR "Failed to register iris platform device\n"); |
| 110 | platform_driver_unregister(&iris_driver); |
| 111 | return PTR_ERR(iris_device); |
| 112 | } |
| 113 | return 0; |
| 114 | } |
| 115 | |
| 116 | static void iris_exit(void) |
| 117 | { |
| 118 | platform_device_unregister(iris_device); |
| 119 | platform_driver_unregister(&iris_driver); |
| 120 | } |
| 121 | |
| 122 | module_init(iris_init); |
| 123 | module_exit(iris_exit); |