LXR linux/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
  27MODULE_LICENSE("GPL");
  28MODULE_AUTHOR("Sébastien Hinderer <Sebastien.Hinderer@ens-lyon.org>");
  29MODULE_DESCRIPTION("A power_off handler for Iris devices from EuroBraille");
  30MODULE_SUPPORTED_DEVICE("Eurobraille/Iris");
  31
  32static bool force;
  33
  34module_param(force, bool, 0);
  35MODULE_PARM_DESC(force, "Set to one to force poweroff handler installation.");
  36
  37static void (*old_pm_power_off)(void);
  38
  39static 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 */
  52static 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
  66static 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
  73static struct platform_driver iris_driver = {
  74        .driver         = {
  75                .name   = "iris",
  76        },
  77        .probe          = iris_probe,
  78        .remove         = iris_remove,
  79};
  80
  81static 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
  90static struct platform_device *iris_device;
  91
  92static 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
 116static void iris_exit(void)
 117{
 118        platform_device_unregister(iris_device);
 119        platform_driver_unregister(&iris_driver);
 120}
 121
 122module_init(iris_init);
 123module_exit(iris_exit);
 124