diff options
author | Mike Lockwood <lockwood@android.com> | 2008-12-19 18:18:16 -0800 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@suse.de> | 2009-01-06 13:52:42 -0800 |
commit | 99f41131b8d82cde1a84fec5b93ce31632552f0b (patch) | |
tree | aad7856ee5dd07d21fd14edb4a06fca2c4b5a201 /drivers/staging/android/timed_gpio.c | |
parent | adc567e8a9c25f08e91eb18b83bdaa5ff9705919 (diff) |
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>
Diffstat (limited to 'drivers/staging/android/timed_gpio.c')
-rw-r--r-- | drivers/staging/android/timed_gpio.c | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/drivers/staging/android/timed_gpio.c b/drivers/staging/android/timed_gpio.c new file mode 100644 index 00000000000..faaead1a712 --- /dev/null +++ b/drivers/staging/android/timed_gpio.c @@ -0,0 +1,177 @@ +/* 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"); |