diff options
| -rw-r--r-- | drivers/extcon/Kconfig | 7 | ||||
| -rw-r--r-- | drivers/extcon/Makefile | 1 | ||||
| -rw-r--r-- | drivers/extcon/extcon_gpio.c | 169 | ||||
| -rw-r--r-- | include/linux/extcon/extcon_gpio.h | 52 |
4 files changed, 229 insertions, 0 deletions
diff --git a/drivers/extcon/Kconfig b/drivers/extcon/Kconfig index 7932e1bd9b02..85cecff36db3 100644 --- a/drivers/extcon/Kconfig +++ b/drivers/extcon/Kconfig @@ -14,4 +14,11 @@ if EXTCON comment "Extcon Device Drivers" +config EXTCON_GPIO + tristate "GPIO extcon support" + depends on GENERIC_GPIO + help + Say Y here to enable GPIO based extcon support. Note that GPIO + extcon supports single state per extcon instance. + endif # MULTISTATE_SWITCH diff --git a/drivers/extcon/Makefile b/drivers/extcon/Makefile index 6bc69214fcd7..2c46d4176d18 100644 --- a/drivers/extcon/Makefile +++ b/drivers/extcon/Makefile @@ -3,3 +3,4 @@ # obj-$(CONFIG_EXTCON) += extcon_class.o +obj-$(CONFIG_EXTCON_GPIO) += extcon_gpio.o diff --git a/drivers/extcon/extcon_gpio.c b/drivers/extcon/extcon_gpio.c new file mode 100644 index 000000000000..5c0f08506f93 --- /dev/null +++ b/drivers/extcon/extcon_gpio.c @@ -0,0 +1,169 @@ +/* + * 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/module.h> +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/interrupt.h> +#include <linux/platform_device.h> +#include <linux/slab.h> +#include <linux/extcon.h> +#include <linux/workqueue.h> +#include <linux/gpio.h> +#include <linux/extcon.h> +#include <linux/extcon/extcon_gpio.h> + +struct gpio_extcon_data { + struct extcon_dev edev; + unsigned gpio; + const char *state_on; + const char *state_off; + int irq; + struct delayed_work work; + unsigned long debounce_jiffies; +}; + +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); + 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; + + schedule_delayed_work(&extcon_data->work, + extcon_data->debounce_jiffies); + return IRQ_HANDLED; +} + +static ssize_t extcon_gpio_print_state(struct extcon_dev *edev, char *buf) +{ + struct gpio_extcon_data *extcon_data = + container_of(edev, struct gpio_extcon_data, edev); + 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 __devinit gpio_extcon_probe(struct platform_device *pdev) +{ + struct gpio_extcon_platform_data *pdata = pdev->dev.platform_data; + struct gpio_extcon_data *extcon_data; + int ret = 0; + + 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.name = pdata->name; + extcon_data->gpio = pdata->gpio; + extcon_data->state_on = pdata->state_on; + extcon_data->state_off = pdata->state_off; + if (pdata->state_on && pdata->state_off) + extcon_data->edev.print_state = extcon_gpio_print_state; + extcon_data->debounce_jiffies = msecs_to_jiffies(pdata->debounce); + + ret = extcon_dev_register(&extcon_data->edev, &pdev->dev); + if (ret < 0) + goto err_extcon_dev_register; + + ret = gpio_request_one(extcon_data->gpio, GPIOF_DIR_IN, pdev->name); + if (ret < 0) + goto err_request_gpio; + + INIT_DELAYED_WORK(&extcon_data->work, gpio_extcon_work); + + extcon_data->irq = gpio_to_irq(extcon_data->gpio); + if (extcon_data->irq < 0) { + ret = extcon_data->irq; + goto err_detect_irq_num_failed; + } + + ret = request_any_context_irq(extcon_data->irq, gpio_irq_handler, + pdata->irq_flags, pdev->name, + extcon_data); + if (ret < 0) + goto err_request_irq; + + /* Perform initial detection */ + gpio_extcon_work(&extcon_data->work.work); + + return 0; + +err_request_irq: +err_detect_irq_num_failed: + gpio_free(extcon_data->gpio); +err_request_gpio: + extcon_dev_unregister(&extcon_data->edev); +err_extcon_dev_register: + devm_kfree(&pdev->dev, extcon_data); + + return ret; +} + +static int __devexit gpio_extcon_remove(struct platform_device *pdev) +{ + struct gpio_extcon_data *extcon_data = platform_get_drvdata(pdev); + + cancel_delayed_work_sync(&extcon_data->work); + gpio_free(extcon_data->gpio); + extcon_dev_unregister(&extcon_data->edev); + devm_kfree(&pdev->dev, extcon_data); + + return 0; +} + +static struct platform_driver gpio_extcon = { + .probe = gpio_extcon_probe, + .remove = __devexit_p(gpio_extcon_remove), + .driver = { + .name = "extcon-gpio", + .owner = THIS_MODULE, + }, +}; + +module_platform_driver(gpio_extcon); + +MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>"); +MODULE_DESCRIPTION("GPIO extcon driver"); +MODULE_LICENSE("GPL"); diff --git a/include/linux/extcon/extcon_gpio.h b/include/linux/extcon/extcon_gpio.h new file mode 100644 index 000000000000..a2129b73dcb1 --- /dev/null +++ b/include/linux/extcon/extcon_gpio.h @@ -0,0 +1,52 @@ +/* + * External connector (extcon) class generic GPIO driver + * + * Copyright (C) 2012 Samsung Electronics + * Author: MyungJoo Ham <myungjoo.ham@samsung.com> + * + * based on switch class driver + * 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. + * +*/ +#ifndef __EXTCON_GPIO_H__ +#define __EXTCON_GPIO_H__ __FILE__ + +#include <linux/extcon.h> + +/** + * struct gpio_extcon_platform_data - A simple GPIO-controlled extcon device. + * @name The name of this GPIO extcon device. + * @gpio Corresponding GPIO. + * @debounce Debounce time for GPIO IRQ in ms. + * @irq_flags IRQ Flags (e.g., IRQF_TRIGGER_LOW). + * @state_on print_state is overriden with state_on if attached. If Null, + * default method of extcon class is used. + * @state_off print_state is overriden with state_on if dettached. If Null, + * default method of extcon class is used. + * + * Note that in order for state_on or state_off to be valid, both state_on + * and state_off should be not NULL. If at least one of them is NULL, + * the print_state is not overriden. + */ +struct gpio_extcon_platform_data { + const char *name; + unsigned gpio; + unsigned long debounce; + unsigned long irq_flags; + + /* if NULL, "0" or "1" will be printed */ + const char *state_on; + const char *state_off; +}; + +#endif /* __EXTCON_GPIO_H__ */ |