arch/x86/platform/iris/iris.c

   1 /*
   2  * Eurobraille/Iris power off support.
   3  *
   4  * Eurobraille's Iris machine is a PC with no APM or ACPI support.
   5  * It is shutdown by a special I/O sequence which this module provides.
   6  *
   7  *  Copyright (C) Shérab <Sebastien.Hinderer@ens-lyon.org>
   8  *
   9  * This program is free software ; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation ; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY ; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with the program ; if not, write to the Free Software
  21  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  22  */
  23
  24 #include <linux/moduleparam.h>
  25 #include <linux/module.h>
  26 #include <linux/platform_device.h>
  27 #include <linux/kernel.h>
  28 #include <linux/errno.h>
  29 #include <linux/delay.h>
  30 #include <linux/init.h>
  31 #include <linux/pm.h>
  32 #include <asm/io.h>
  33
  34 #define IRIS_GIO_BASE           0x340
  35 #define IRIS_GIO_INPUT          IRIS_GIO_BASE
  36 #define IRIS_GIO_OUTPUT         (IRIS_GIO_BASE + 1)
  37 #define IRIS_GIO_PULSE          0x80 /* First byte to send */
  38 #define IRIS_GIO_REST           0x00 /* Second byte to send */
  39 #define IRIS_GIO_NODEV          0xff /* Likely not an Iris */
  40
  41 MODULE_LICENSE("GPL");
  42 MODULE_AUTHOR("Sébastien Hinderer <Sebastien.Hinderer@ens-lyon.org>");
  43 MODULE_DESCRIPTION("A power_off handler for Iris devices from EuroBraille");
  44 MODULE_SUPPORTED_DEVICE("Eurobraille/Iris");
  45
  46 static int force;
  47
  48 module_param(force, bool, 0);
  49 MODULE_PARM_DESC(force, "Set to one to force poweroff handler installation.");
  50
  51 static void (*old_pm_power_off)(void);
  52
  53 static void iris_power_off(void)
  54 {
  55         outb(IRIS_GIO_PULSE, IRIS_GIO_OUTPUT);
  56         msleep(850);
  57         outb(IRIS_GIO_REST, IRIS_GIO_OUTPUT);
  58 }
  59
  60 /*
  61  * Before installing the power_off handler, try to make sure the OS is
  62  * running on an Iris.  Since Iris does not support DMI, this is done
  63  * by reading its input port and seeing whether the read value is
  64  * meaningful.
  65  */
  66 static int iris_probe(struct platform_device *pdev)
  67 {
  68         unsigned char status = inb(IRIS_GIO_INPUT);
  69         if (status == IRIS_GIO_NODEV) {
  70                 printk(KERN_ERR "This machine does not seem to be an Iris. "
  71                         "Power off handler not installed.\n");
  72                 return -ENODEV;
  73         }
  74         old_pm_power_off = pm_power_off;
  75         pm_power_off = &iris_power_off;
  76         printk(KERN_INFO "Iris power_off handler installed.\n");
  77         return 0;
  78 }
  79
  80 static int iris_remove(struct platform_device *pdev)
  81 {
  82         pm_power_off = old_pm_power_off;
  83         printk(KERN_INFO "Iris power_off handler uninstalled.\n");
  84         return 0;
  85 }
  86
  87 static struct platform_driver iris_driver = {
  88         .driver         = {
  89                 .name   = "iris",
  90                 .owner  = THIS_MODULE,
  91         },
  92         .probe          = iris_probe,
  93         .remove         = iris_remove,
  94 };
  95
  96 static struct resource iris_resources[] = {
  97         {
  98                 .start  = IRIS_GIO_BASE,
  99                 .end    = IRIS_GIO_OUTPUT,
 100                 .flags  = IORESOURCE_IO,
 101                 .name   = "address"
 102         }
 103 };
 104
 105 static struct platform_device *iris_device;
 106
 107 static int iris_init(void)
 108 {
 109         int ret;
 110         if (force != 1) {
 111                 printk(KERN_ERR "The force parameter has not been set to 1."
 112                         " The Iris poweroff handler will not be installed.\n");
 113                 return -ENODEV;
 114         }
 115         ret = platform_driver_register(&iris_driver);
 116         if (ret < 0) {
 117                 printk(KERN_ERR "Failed to register iris platform driver: %d\n",
 118                         ret);
 119                 return ret;
 120         }
 121         iris_device = platform_device_register_simple("iris", (-1),
 122                                 iris_resources, ARRAY_SIZE(iris_resources));
 123         if (IS_ERR(iris_device)) {
 124                 printk(KERN_ERR "Failed to register iris platform device\n");
 125                 platform_driver_unregister(&iris_driver);
 126                 return PTR_ERR(iris_device);
 127         }
 128         return 0;
 129 }
 130
 131 static void iris_exit(void)
 132 {
 133         platform_device_unregister(iris_device);
 134         platform_driver_unregister(&iris_driver);
 135 }
 136
 137 module_init(iris_init);
 138 module_exit(iris_exit);