Staging: android: add timed_gpio driver
driver for GPIOs that turn back off after a delay From: Mike Lockwood <lockwood@android.com> Signed-off-by: Brian Swetland <swetland@google.com> Cc: Robert Love <rlove@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Mike Lockwood
Greg Kroah-Hartman
parent
adc567e8a9
commit
99f41131b8
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@ -72,4 +72,9 @@ config ANDROID_RAM_CONSOLE_EARLY_SIZE
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default 0
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depends on ANDROID_RAM_CONSOLE_EARLY_INIT
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config ANDROID_TIMED_GPIO
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tristate "Android timed gpio driver"
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depends on GENERIC_GPIO
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default n
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endmenu
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@ -2,3 +2,4 @@ obj-$(CONFIG_ANDROID) += android.o
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obj-$(CONFIG_ANDROID_BINDER_IPC) += binder.o
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obj-$(CONFIG_ANDROID_LOGGER) += logger.o
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obj-$(CONFIG_ANDROID_RAM_CONSOLE) += ram_console.o
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obj-$(CONFIG_ANDROID_TIMED_GPIO) += timed_gpio.o
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@ -0,0 +1,31 @@
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/* include/linux/android_timed_gpio.h
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*
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* Copyright (C) 2008 Google, Inc.
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*
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* This software is licensed under the terms of the GNU General Public
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* License version 2, as published by the Free Software Foundation, and
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* may be copied, distributed, and modified under those terms.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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*/
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#ifndef _LINUX_ANDROID_TIMED_GPIO_H
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#define _LINUX_ANDROID_TIMED_GPIO_H
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struct timed_gpio {
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const char *name;
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unsigned gpio;
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int max_timeout;
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u8 active_low;
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};
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struct timed_gpio_platform_data {
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int num_gpios;
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struct timed_gpio *gpios;
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};
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#endif
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@ -0,0 +1,177 @@
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/* drivers/android/timed_gpio.c
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*
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* Copyright (C) 2008 Google, Inc.
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* Author: Mike Lockwood <lockwood@android.com>
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*
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* This software is licensed under the terms of the GNU General Public
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* License version 2, as published by the Free Software Foundation, and
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* may be copied, distributed, and modified under those terms.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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*/
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/hrtimer.h>
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#include <linux/err.h>
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#include <asm/arch/gpio.h>
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#include "android_timed_gpio.h"
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static struct class *timed_gpio_class;
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struct timed_gpio_data {
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struct device *dev;
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struct hrtimer timer;
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spinlock_t lock;
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unsigned gpio;
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int max_timeout;
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u8 active_low;
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};
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static enum hrtimer_restart gpio_timer_func(struct hrtimer *timer)
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{
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struct timed_gpio_data *gpio_data = container_of(timer, struct timed_gpio_data, timer);
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gpio_direction_output(gpio_data->gpio, gpio_data->active_low ? 1 : 0);
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return HRTIMER_NORESTART;
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}
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static ssize_t gpio_enable_show(struct device *dev, struct device_attribute *attr, char *buf)
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{
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struct timed_gpio_data *gpio_data = dev_get_drvdata(dev);
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int remaining;
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if (hrtimer_active(&gpio_data->timer)) {
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ktime_t r = hrtimer_get_remaining(&gpio_data->timer);
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remaining = r.tv.sec * 1000 + r.tv.nsec / 1000000;
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} else
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remaining = 0;
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return sprintf(buf, "%d\n", remaining);
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}
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static ssize_t gpio_enable_store(
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struct device *dev, struct device_attribute *attr,
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const char *buf, size_t size)
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{
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struct timed_gpio_data *gpio_data = dev_get_drvdata(dev);
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int value;
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unsigned long flags;
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sscanf(buf, "%d", &value);
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spin_lock_irqsave(&gpio_data->lock, flags);
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/* cancel previous timer and set GPIO according to value */
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hrtimer_cancel(&gpio_data->timer);
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gpio_direction_output(gpio_data->gpio, gpio_data->active_low ? !value : !!value);
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if (value > 0) {
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if (value > gpio_data->max_timeout)
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value = gpio_data->max_timeout;
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hrtimer_start(&gpio_data->timer,
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ktime_set(value / 1000, (value % 1000) * 1000000),
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HRTIMER_MODE_REL);
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}
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spin_unlock_irqrestore(&gpio_data->lock, flags);
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return size;
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}
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static DEVICE_ATTR(enable, S_IRUGO | S_IWUSR, gpio_enable_show, gpio_enable_store);
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static int android_timed_gpio_probe(struct platform_device *pdev)
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{
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struct timed_gpio_platform_data *pdata = pdev->dev.platform_data;
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struct timed_gpio *cur_gpio;
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struct timed_gpio_data *gpio_data, *gpio_dat;
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int i, ret = 0;
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if (!pdata)
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return -EBUSY;
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gpio_data = kzalloc(sizeof(struct timed_gpio_data) * pdata->num_gpios, GFP_KERNEL);
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if (!gpio_data)
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return -ENOMEM;
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for (i = 0; i < pdata->num_gpios; i++) {
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cur_gpio = &pdata->gpios[i];
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gpio_dat = &gpio_data[i];
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hrtimer_init(&gpio_dat->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
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gpio_dat->timer.function = gpio_timer_func;
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spin_lock_init(&gpio_dat->lock);
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gpio_dat->gpio = cur_gpio->gpio;
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gpio_dat->max_timeout = cur_gpio->max_timeout;
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gpio_dat->active_low = cur_gpio->active_low;
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gpio_direction_output(gpio_dat->gpio, gpio_dat->active_low);
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gpio_dat->dev = device_create(timed_gpio_class, &pdev->dev, 0, "%s", cur_gpio->name);
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if (unlikely(IS_ERR(gpio_dat->dev)))
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return PTR_ERR(gpio_dat->dev);
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dev_set_drvdata(gpio_dat->dev, gpio_dat);
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ret = device_create_file(gpio_dat->dev, &dev_attr_enable);
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if (ret)
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return ret;
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}
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platform_set_drvdata(pdev, gpio_data);
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return 0;
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}
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static int android_timed_gpio_remove(struct platform_device *pdev)
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{
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struct timed_gpio_platform_data *pdata = pdev->dev.platform_data;
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struct timed_gpio_data *gpio_data = platform_get_drvdata(pdev);
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int i;
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for (i = 0; i < pdata->num_gpios; i++) {
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device_remove_file(gpio_data[i].dev, &dev_attr_enable);
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device_unregister(gpio_data[i].dev);
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}
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kfree(gpio_data);
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return 0;
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}
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static struct platform_driver android_timed_gpio_driver = {
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.probe = android_timed_gpio_probe,
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.remove = android_timed_gpio_remove,
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.driver = {
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.name = "android-timed-gpio",
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.owner = THIS_MODULE,
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},
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};
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static int __init android_timed_gpio_init(void)
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{
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timed_gpio_class = class_create(THIS_MODULE, "timed_output");
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if (IS_ERR(timed_gpio_class))
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return PTR_ERR(timed_gpio_class);
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return platform_driver_register(&android_timed_gpio_driver);
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}
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static void __exit android_timed_gpio_exit(void)
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{
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class_destroy(timed_gpio_class);
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platform_driver_unregister(&android_timed_gpio_driver);
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}
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module_init(android_timed_gpio_init);
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module_exit(android_timed_gpio_exit);
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MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>");
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MODULE_DESCRIPTION("Android timed gpio driver");
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MODULE_LICENSE("GPL");
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