169 lines
4.1 KiB
C
169 lines
4.1 KiB
C
/* drivers/misc/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/slab.h>
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#include <linux/hrtimer.h>
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#include <linux/err.h>
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#include <linux/gpio.h>
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#include "timed_output.h"
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#include "timed_gpio.h"
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struct timed_gpio_data {
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struct timed_output_dev 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 *data =
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container_of(timer, struct timed_gpio_data, timer);
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gpio_direction_output(data->gpio, data->active_low ? 1 : 0);
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return HRTIMER_NORESTART;
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}
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static int gpio_get_time(struct timed_output_dev *dev)
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{
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struct timed_gpio_data *data;
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struct timeval t;
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data = container_of(dev, struct timed_gpio_data, dev);
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if (!hrtimer_active(&data->timer))
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return 0;
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t = ktime_to_timeval(hrtimer_get_remaining(&data->timer));
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return t.tv_sec * 1000 + t.tv_usec / 1000;
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}
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static void gpio_enable(struct timed_output_dev *dev, int value)
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{
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struct timed_gpio_data *data =
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container_of(dev, struct timed_gpio_data, dev);
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unsigned long flags;
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spin_lock_irqsave(&data->lock, flags);
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/* cancel previous timer and set GPIO according to value */
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hrtimer_cancel(&data->timer);
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gpio_direction_output(data->gpio, data->active_low ? !value : !!value);
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if (value > 0) {
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if (value > data->max_timeout)
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value = data->max_timeout;
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hrtimer_start(&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(&data->lock, flags);
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}
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static int 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;
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if (!pdata)
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return -EBUSY;
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gpio_data = devm_kzalloc(&pdev->dev,
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sizeof(struct timed_gpio_data) * pdata->num_gpios,
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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,
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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->dev.name = cur_gpio->name;
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gpio_dat->dev.get_time = gpio_get_time;
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gpio_dat->dev.enable = gpio_enable;
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ret = gpio_request(cur_gpio->gpio, cur_gpio->name);
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if (ret < 0)
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goto err_out;
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ret = timed_output_dev_register(&gpio_dat->dev);
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if (ret < 0) {
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gpio_free(cur_gpio->gpio);
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goto err_out;
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}
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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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}
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platform_set_drvdata(pdev, gpio_data);
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return 0;
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err_out:
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while (--i >= 0) {
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timed_output_dev_unregister(&gpio_data[i].dev);
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gpio_free(gpio_data[i].gpio);
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}
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return ret;
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}
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static int 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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timed_output_dev_unregister(&gpio_data[i].dev);
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gpio_free(gpio_data[i].gpio);
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}
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return 0;
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}
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static struct platform_driver timed_gpio_driver = {
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.probe = timed_gpio_probe,
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.remove = timed_gpio_remove,
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.driver = {
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.name = TIMED_GPIO_NAME,
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.owner = THIS_MODULE,
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},
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};
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module_platform_driver(timed_gpio_driver);
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MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>");
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MODULE_DESCRIPTION("timed gpio driver");
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MODULE_LICENSE("GPL");
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