diff options
Diffstat (limited to 'kernel/drivers/extcon/extcon-gpio.c')
| -rw-r--r-- | kernel/drivers/extcon/extcon-gpio.c | 192 |
1 files changed, 192 insertions, 0 deletions
diff --git a/kernel/drivers/extcon/extcon-gpio.c b/kernel/drivers/extcon/extcon-gpio.c new file mode 100644 index 000000000..7af33fc43 --- /dev/null +++ b/kernel/drivers/extcon/extcon-gpio.c @@ -0,0 +1,192 @@ +/* + * drivers/extcon/extcon_gpio.c + * + * Single-state GPIO extcon driver based on extcon class + * + * Copyright (C) 2008 Google, Inc. + * Author: Mike Lockwood <lockwood@android.com> + * + * Modified by MyungJoo Ham <myungjoo.ham@samsung.com> to support extcon + * (originally switch class is supported) + * + * 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/extcon.h> +#include <linux/extcon/extcon-gpio.h> +#include <linux/gpio.h> +#include <linux/init.h> +#include <linux/interrupt.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/slab.h> +#include <linux/workqueue.h> + +struct gpio_extcon_data { + struct extcon_dev *edev; + unsigned gpio; + bool gpio_active_low; + const char *state_on; + const char *state_off; + int irq; + struct delayed_work work; + unsigned long debounce_jiffies; + bool check_on_resume; +}; + +static void gpio_extcon_work(struct work_struct *work) +{ + int state; + struct gpio_extcon_data *data = + container_of(to_delayed_work(work), struct gpio_extcon_data, + work); + + state = gpio_get_value(data->gpio); + if (data->gpio_active_low) + state = !state; + extcon_set_state(data->edev, state); +} + +static irqreturn_t gpio_irq_handler(int irq, void *dev_id) +{ + struct gpio_extcon_data *extcon_data = dev_id; + + queue_delayed_work(system_power_efficient_wq, &extcon_data->work, + extcon_data->debounce_jiffies); + return IRQ_HANDLED; +} + +static ssize_t extcon_gpio_print_state(struct extcon_dev *edev, char *buf) +{ + struct device *dev = edev->dev.parent; + struct gpio_extcon_data *extcon_data = dev_get_drvdata(dev); + const char *state; + + if (extcon_get_state(edev)) + state = extcon_data->state_on; + else + state = extcon_data->state_off; + + if (state) + return sprintf(buf, "%s\n", state); + return -EINVAL; +} + +static int gpio_extcon_probe(struct platform_device *pdev) +{ + struct gpio_extcon_platform_data *pdata = dev_get_platdata(&pdev->dev); + struct gpio_extcon_data *extcon_data; + int ret; + + if (!pdata) + return -EBUSY; + if (!pdata->irq_flags) { + dev_err(&pdev->dev, "IRQ flag is not specified.\n"); + return -EINVAL; + } + + extcon_data = devm_kzalloc(&pdev->dev, sizeof(struct gpio_extcon_data), + GFP_KERNEL); + if (!extcon_data) + return -ENOMEM; + + extcon_data->edev = devm_extcon_dev_allocate(&pdev->dev, NULL); + if (IS_ERR(extcon_data->edev)) { + dev_err(&pdev->dev, "failed to allocate extcon device\n"); + return -ENOMEM; + } + extcon_data->edev->name = pdata->name; + + extcon_data->gpio = pdata->gpio; + extcon_data->gpio_active_low = pdata->gpio_active_low; + extcon_data->state_on = pdata->state_on; + extcon_data->state_off = pdata->state_off; + extcon_data->check_on_resume = pdata->check_on_resume; + if (pdata->state_on && pdata->state_off) + extcon_data->edev->print_state = extcon_gpio_print_state; + + ret = devm_gpio_request_one(&pdev->dev, extcon_data->gpio, GPIOF_DIR_IN, + pdev->name); + if (ret < 0) + return ret; + + if (pdata->debounce) { + ret = gpio_set_debounce(extcon_data->gpio, + pdata->debounce * 1000); + if (ret < 0) + extcon_data->debounce_jiffies = + msecs_to_jiffies(pdata->debounce); + } + + ret = devm_extcon_dev_register(&pdev->dev, extcon_data->edev); + if (ret < 0) + return ret; + + INIT_DELAYED_WORK(&extcon_data->work, gpio_extcon_work); + + extcon_data->irq = gpio_to_irq(extcon_data->gpio); + if (extcon_data->irq < 0) + return extcon_data->irq; + + ret = request_any_context_irq(extcon_data->irq, gpio_irq_handler, + pdata->irq_flags, pdev->name, + extcon_data); + if (ret < 0) + return ret; + + platform_set_drvdata(pdev, extcon_data); + /* Perform initial detection */ + gpio_extcon_work(&extcon_data->work.work); + + return 0; +} + +static int gpio_extcon_remove(struct platform_device *pdev) +{ + struct gpio_extcon_data *extcon_data = platform_get_drvdata(pdev); + + cancel_delayed_work_sync(&extcon_data->work); + free_irq(extcon_data->irq, extcon_data); + + return 0; +} + +#ifdef CONFIG_PM_SLEEP +static int gpio_extcon_resume(struct device *dev) +{ + struct gpio_extcon_data *extcon_data; + + extcon_data = dev_get_drvdata(dev); + if (extcon_data->check_on_resume) + queue_delayed_work(system_power_efficient_wq, + &extcon_data->work, extcon_data->debounce_jiffies); + + return 0; +} +#endif + +static SIMPLE_DEV_PM_OPS(gpio_extcon_pm_ops, NULL, gpio_extcon_resume); + +static struct platform_driver gpio_extcon_driver = { + .probe = gpio_extcon_probe, + .remove = gpio_extcon_remove, + .driver = { + .name = "extcon-gpio", + .pm = &gpio_extcon_pm_ops, + }, +}; + +module_platform_driver(gpio_extcon_driver); + +MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>"); +MODULE_DESCRIPTION("GPIO extcon driver"); +MODULE_LICENSE("GPL"); |