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