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/kernel.h>
  27 #include <linux/errno.h>
  28 #include <linux/delay.h>
  29 #include <linux/init.h>
  30 #include <linux/pm.h>
  31 #include <asm/io.h>
  32
  33 #define IRIS_GIO_BASE           0x340
  34 #define IRIS_GIO_INPUT          IRIS_GIO_BASE
  35 #define IRIS_GIO_OUTPUT         (IRIS_GIO_BASE + 1)
  36 #define IRIS_GIO_PULSE          0x80 /* First byte to send */
  37 #define IRIS_GIO_REST           0x00 /* Second byte to send */
  38 #define IRIS_GIO_NODEV          0xff /* Likely not an Iris */
  39
  40 MODULE_LICENSE("GPL");
  41 MODULE_AUTHOR("Sébastien Hinderer <Sebastien.Hinderer@ens-lyon.org>");
  42 MODULE_DESCRIPTION("A power_off handler for Iris devices from EuroBraille");
  43 MODULE_SUPPORTED_DEVICE("Eurobraille/Iris");
  44
  45 static bool force;
  46
  47 module_param(force, bool, 0);
  48 MODULE_PARM_DESC(force, "Set to one to force poweroff handler installation.");
  49
  50 static void (*old_pm_power_off)(void);
  51
  52 static void iris_power_off(void)
  53 {
  54         outb(IRIS_GIO_PULSE, IRIS_GIO_OUTPUT);
  55         msleep(850);
  56         outb(IRIS_GIO_REST, IRIS_GIO_OUTPUT);
  57 }
  58
  59 /*
  60  * Before installing the power_off handler, try to make sure the OS is
  61  * running on an Iris.  Since Iris does not support DMI, this is done
  62  * by reading its input port and seeing whether the read value is
  63  * meaningful.
  64  */
  65 static int iris_init(void)
  66 {
  67         unsigned char status;
  68         if (force != 1) {
  69                 printk(KERN_ERR "The force parameter has not been set to 1 so the Iris poweroff handler will not be installed.\n");
  70                 return -ENODEV;
  71         }
  72         status = inb(IRIS_GIO_INPUT);
  73         if (status == IRIS_GIO_NODEV) {
  74                 printk(KERN_ERR "This machine does not seem to be an Iris. Power_off handler not installed.\n");
  75                 return -ENODEV;
  76         }
  77         old_pm_power_off = pm_power_off;
  78         pm_power_off = &iris_power_off;
  79         printk(KERN_INFO "Iris power_off handler installed.\n");
  80
  81         return 0;
  82 }
  83
  84 static void iris_exit(void)
  85 {
  86         pm_power_off = old_pm_power_off;
  87         printk(KERN_INFO "Iris power_off handler uninstalled.\n");
  88 }
  89
  90 module_init(iris_init);
  91 module_exit(iris_exit);