arch/x86/platform/iris/iris.c

   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);