diff options
Diffstat (limited to 'drivers/staging/android/timed_gpio.c')
| -rw-r--r-- | drivers/staging/android/timed_gpio.c | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/drivers/staging/android/timed_gpio.c b/drivers/staging/android/timed_gpio.c new file mode 100644 index 000000000000..a64481c3e86d --- /dev/null +++ b/drivers/staging/android/timed_gpio.c @@ -0,0 +1,176 @@ +/* drivers/misc/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/slab.h> +#include <linux/hrtimer.h> +#include <linux/err.h> +#include <linux/gpio.h> + +#include "timed_output.h" +#include "timed_gpio.h" + + +struct timed_gpio_data { + struct timed_output_dev 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 *data = + container_of(timer, struct timed_gpio_data, timer); + + gpio_direction_output(data->gpio, data->active_low ? 1 : 0); + return HRTIMER_NORESTART; +} + +static int gpio_get_time(struct timed_output_dev *dev) +{ + struct timed_gpio_data *data = + container_of(dev, struct timed_gpio_data, dev); + + if (hrtimer_active(&data->timer)) { + ktime_t r = hrtimer_get_remaining(&data->timer); + struct timeval t = ktime_to_timeval(r); + return t.tv_sec * 1000 + t.tv_usec / 1000; + } else + return 0; +} + +static void gpio_enable(struct timed_output_dev *dev, int value) +{ + struct timed_gpio_data *data = + container_of(dev, struct timed_gpio_data, dev); + unsigned long flags; + + spin_lock_irqsave(&data->lock, flags); + + /* cancel previous timer and set GPIO according to value */ + hrtimer_cancel(&data->timer); + gpio_direction_output(data->gpio, data->active_low ? !value : !!value); + + if (value > 0) { + if (value > data->max_timeout) + value = data->max_timeout; + + hrtimer_start(&data->timer, + ktime_set(value / 1000, (value % 1000) * 1000000), + HRTIMER_MODE_REL); + } + + spin_unlock_irqrestore(&data->lock, flags); +} + +static int 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, j, 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->dev.name = cur_gpio->name; + gpio_dat->dev.get_time = gpio_get_time; + gpio_dat->dev.enable = gpio_enable; + ret = gpio_request(cur_gpio->gpio, cur_gpio->name); + if (ret >= 0) { + ret = timed_output_dev_register(&gpio_dat->dev); + if (ret < 0) + gpio_free(cur_gpio->gpio); + } + if (ret < 0) { + for (j = 0; j < i; j++) { + timed_output_dev_unregister(&gpio_data[i].dev); + gpio_free(gpio_data[i].gpio); + } + kfree(gpio_data); + return ret; + } + + 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); + } + + platform_set_drvdata(pdev, gpio_data); + + return 0; +} + +static int 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++) { + timed_output_dev_unregister(&gpio_data[i].dev); + gpio_free(gpio_data[i].gpio); + } + + kfree(gpio_data); + + return 0; +} + +static struct platform_driver timed_gpio_driver = { + .probe = timed_gpio_probe, + .remove = timed_gpio_remove, + .driver = { + .name = TIMED_GPIO_NAME, + .owner = THIS_MODULE, + }, +}; + +static int __init timed_gpio_init(void) +{ + return platform_driver_register(&timed_gpio_driver); +} + +static void __exit timed_gpio_exit(void) +{ + platform_driver_unregister(&timed_gpio_driver); +} + +module_init(timed_gpio_init); +module_exit(timed_gpio_exit); + +MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>"); +MODULE_DESCRIPTION("timed gpio driver"); +MODULE_LICENSE("GPL"); |