Commit 99f41131 authored by Mike Lockwood's avatar Mike Lockwood Committed by Greg Kroah-Hartman
Browse files

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: default avatarBrian Swetland <swetland@google.com>
Cc: Robert Love <rlove@google.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent adc567e8

drivers/staging/android/Kconfig

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@@ -72,4 +72,9 @@ config ANDROID_RAM_CONSOLE_EARLY_SIZE 
	default 0

	depends on ANDROID_RAM_CONSOLE_EARLY_INIT



config ANDROID_TIMED_GPIO

	tristate "Android timed gpio driver"

	depends on GENERIC_GPIO

	default n



endmenu

drivers/staging/android/Makefile

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@@ -2,3 +2,4 @@ obj-$(CONFIG_ANDROID) += android.o 
obj-$(CONFIG_ANDROID_BINDER_IPC)	+= binder.o

obj-$(CONFIG_ANDROID_LOGGER)		+= logger.o

obj-$(CONFIG_ANDROID_RAM_CONSOLE)	+= ram_console.o

obj-$(CONFIG_ANDROID_TIMED_GPIO)	+= timed_gpio.o

drivers/staging/android/android_timed_gpio.h

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/* include/linux/android_timed_gpio.h

 *

 * Copyright (C) 2008 Google, Inc.

 *

 * This software is licensed under the terms of the GNU General Public

 * License version 2, as published by the Free Software Foundation, and

 * may be copied, distributed, and modified under those terms.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

*/



#ifndef _LINUX_ANDROID_TIMED_GPIO_H

#define _LINUX_ANDROID_TIMED_GPIO_H



struct timed_gpio {

	const char *name;

	unsigned 	gpio;

	int     max_timeout;

	u8 		active_low;

};



struct timed_gpio_platform_data {

	int 		num_gpios;

	struct timed_gpio *gpios;

};



#endif

drivers/staging/android/timed_gpio.c

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Original line number Diff line number Diff line 
/* drivers/android/timed_gpio.c

 *

 * Copyright (C) 2008 Google, Inc.

 * Author: Mike Lockwood <lockwood@android.com>

 *

 * This software is licensed under the terms of the GNU General Public

 * License version 2, as published by the Free Software Foundation, and

 * may be copied, distributed, and modified under those terms.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 */



#include <linux/module.h>

#include <linux/platform_device.h>

#include <linux/hrtimer.h>

#include <linux/err.h>

#include <asm/arch/gpio.h>



#include "android_timed_gpio.h"





static struct class *timed_gpio_class;



struct timed_gpio_data {

	struct device *dev;

	struct hrtimer timer;

	spinlock_t lock;

	unsigned 	gpio;

	int 		max_timeout;

	u8 		active_low;

};



static enum hrtimer_restart gpio_timer_func(struct hrtimer *timer)

{

	struct timed_gpio_data *gpio_data = container_of(timer, struct timed_gpio_data, timer);



	gpio_direction_output(gpio_data->gpio, gpio_data->active_low ? 1 : 0);

	return HRTIMER_NORESTART;

}



static ssize_t gpio_enable_show(struct device *dev, struct device_attribute *attr, char *buf)

{

	struct timed_gpio_data *gpio_data = dev_get_drvdata(dev);

	int remaining;



	if (hrtimer_active(&gpio_data->timer)) {

		ktime_t r = hrtimer_get_remaining(&gpio_data->timer);

		remaining = r.tv.sec * 1000 + r.tv.nsec / 1000000;

	} else

		remaining = 0;



	return sprintf(buf, "%d\n", remaining);

}



static ssize_t gpio_enable_store(

		struct device *dev, struct device_attribute *attr,

		const char *buf, size_t size)

{

	struct timed_gpio_data *gpio_data = dev_get_drvdata(dev);

	int value;

	unsigned long	flags;



	sscanf(buf, "%d", &value);



	spin_lock_irqsave(&gpio_data->lock, flags);



	/* cancel previous timer and set GPIO according to value */

	hrtimer_cancel(&gpio_data->timer);

	gpio_direction_output(gpio_data->gpio, gpio_data->active_low ? !value : !!value);



	if (value > 0) {

		if (value > gpio_data->max_timeout)

			value = gpio_data->max_timeout;



		hrtimer_start(&gpio_data->timer,

						ktime_set(value / 1000, (value % 1000) * 1000000),

						HRTIMER_MODE_REL);

	}



	spin_unlock_irqrestore(&gpio_data->lock, flags);



	return size;

}



static DEVICE_ATTR(enable, S_IRUGO | S_IWUSR, gpio_enable_show, gpio_enable_store);



static int android_timed_gpio_probe(struct platform_device *pdev)

{

	struct timed_gpio_platform_data *pdata = pdev->dev.platform_data;

	struct timed_gpio *cur_gpio;

	struct timed_gpio_data *gpio_data, *gpio_dat;

	int i, ret = 0;



	if (!pdata)

		return -EBUSY;



	gpio_data = kzalloc(sizeof(struct timed_gpio_data) * pdata->num_gpios, GFP_KERNEL);

	if (!gpio_data)

		return -ENOMEM;



	for (i = 0; i < pdata->num_gpios; i++) {

		cur_gpio = &pdata->gpios[i];

		gpio_dat = &gpio_data[i];



		hrtimer_init(&gpio_dat->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);

		gpio_dat->timer.function = gpio_timer_func;

		spin_lock_init(&gpio_dat->lock);



		gpio_dat->gpio = cur_gpio->gpio;

		gpio_dat->max_timeout = cur_gpio->max_timeout;

		gpio_dat->active_low = cur_gpio->active_low;

		gpio_direction_output(gpio_dat->gpio, gpio_dat->active_low);



		gpio_dat->dev = device_create(timed_gpio_class, &pdev->dev, 0, "%s", cur_gpio->name);

		if (unlikely(IS_ERR(gpio_dat->dev)))

			return PTR_ERR(gpio_dat->dev);



		dev_set_drvdata(gpio_dat->dev, gpio_dat);

		ret = device_create_file(gpio_dat->dev, &dev_attr_enable);

		if (ret)

			return ret;

	}



	platform_set_drvdata(pdev, gpio_data);



	return 0;

}



static int android_timed_gpio_remove(struct platform_device *pdev)

{

	struct timed_gpio_platform_data *pdata = pdev->dev.platform_data;

	struct timed_gpio_data *gpio_data = platform_get_drvdata(pdev);

	int i;



	for (i = 0; i < pdata->num_gpios; i++) {

		device_remove_file(gpio_data[i].dev, &dev_attr_enable);

		device_unregister(gpio_data[i].dev);

	}



	kfree(gpio_data);



	return 0;

}



static struct platform_driver android_timed_gpio_driver = {

	.probe		= android_timed_gpio_probe,

	.remove		= android_timed_gpio_remove,

	.driver		= {

		.name		= "android-timed-gpio",

		.owner		= THIS_MODULE,

	},

};



static int __init android_timed_gpio_init(void)

{

	timed_gpio_class = class_create(THIS_MODULE, "timed_output");

	if (IS_ERR(timed_gpio_class))

		return PTR_ERR(timed_gpio_class);

	return platform_driver_register(&android_timed_gpio_driver);

}



static void __exit android_timed_gpio_exit(void)

{

	class_destroy(timed_gpio_class);

	platform_driver_unregister(&android_timed_gpio_driver);

}



module_init(android_timed_gpio_init);

module_exit(android_timed_gpio_exit);



MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>");

MODULE_DESCRIPTION("Android timed gpio driver");

MODULE_LICENSE("GPL");

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