blob: 1ac8578258afb872996d63d27d3a9676155c1c44 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Eurobraille/Iris power off support.
*
* Eurobraille's Iris machine is a PC with no APM or ACPI support.
* It is shutdown by a special I/O sequence which this module provides.
*
* Copyright (C) Shérab <Sebastien.Hinderer@ens-lyon.org>
*/
#include <linux/moduleparam.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/delay.h>
#include <linux/pm.h>
#include <asm/io.h>
#define IRIS_GIO_BASE 0x340
#define IRIS_GIO_INPUT IRIS_GIO_BASE
#define IRIS_GIO_OUTPUT (IRIS_GIO_BASE + 1)
#define IRIS_GIO_PULSE 0x80 /* First byte to send */
#define IRIS_GIO_REST 0x00 /* Second byte to send */
#define IRIS_GIO_NODEV 0xff /* Likely not an Iris */
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Sébastien Hinderer <Sebastien.Hinderer@ens-lyon.org>");
MODULE_DESCRIPTION("A power_off handler for Iris devices from EuroBraille");
MODULE_SUPPORTED_DEVICE("Eurobraille/Iris");
static bool force;
module_param(force, bool, 0);
MODULE_PARM_DESC(force, "Set to one to force poweroff handler installation.");
static void (*old_pm_power_off)(void);
static void iris_power_off(void)
{
outb(IRIS_GIO_PULSE, IRIS_GIO_OUTPUT);
msleep(850);
outb(IRIS_GIO_REST, IRIS_GIO_OUTPUT);
}
/*
* Before installing the power_off handler, try to make sure the OS is
* running on an Iris. Since Iris does not support DMI, this is done
* by reading its input port and seeing whether the read value is
* meaningful.
*/
static int iris_probe(struct platform_device *pdev)
{
unsigned char status = inb(IRIS_GIO_INPUT);
if (status == IRIS_GIO_NODEV) {
printk(KERN_ERR "This machine does not seem to be an Iris. "
"Power off handler not installed.\n");
return -ENODEV;
}
old_pm_power_off = pm_power_off;
pm_power_off = &iris_power_off;
printk(KERN_INFO "Iris power_off handler installed.\n");
return 0;
}
static int iris_remove(struct platform_device *pdev)
{
pm_power_off = old_pm_power_off;
printk(KERN_INFO "Iris power_off handler uninstalled.\n");
return 0;
}
static struct platform_driver iris_driver = {
.driver = {
.name = "iris",
},
.probe = iris_probe,
.remove = iris_remove,
};
static struct resource iris_resources[] = {
{
.start = IRIS_GIO_BASE,
.end = IRIS_GIO_OUTPUT,
.flags = IORESOURCE_IO,
.name = "address"
}
};
static struct platform_device *iris_device;
static int iris_init(void)
{
int ret;
if (force != 1) {
printk(KERN_ERR "The force parameter has not been set to 1."
" The Iris poweroff handler will not be installed.\n");
return -ENODEV;
}
ret = platform_driver_register(&iris_driver);
if (ret < 0) {
printk(KERN_ERR "Failed to register iris platform driver: %d\n",
ret);
return ret;
}
iris_device = platform_device_register_simple("iris", (-1),
iris_resources, ARRAY_SIZE(iris_resources));
if (IS_ERR(iris_device)) {
printk(KERN_ERR "Failed to register iris platform device\n");
platform_driver_unregister(&iris_driver);
return PTR_ERR(iris_device);
}
return 0;
}
static void iris_exit(void)
{
platform_device_unregister(iris_device);
platform_driver_unregister(&iris_driver);
}
module_init(iris_init);
module_exit(iris_exit);