diff options
Diffstat (limited to 'drivers/extcon/extcon-gpio.c')
| -rw-r--r-- | drivers/extcon/extcon-gpio.c | 165 |
1 files changed, 165 insertions, 0 deletions
diff --git a/drivers/extcon/extcon-gpio.c b/drivers/extcon/extcon-gpio.c new file mode 100644 index 000000000..4105df74f --- /dev/null +++ b/drivers/extcon/extcon-gpio.c @@ -0,0 +1,165 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * 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) + */ + +#include <linux/devm-helpers.h> +#include <linux/extcon-provider.h> +#include <linux/gpio/consumer.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 - A simple GPIO-controlled extcon device state container. + * @edev: Extcon device. + * @work: Work fired by the interrupt. + * @debounce_jiffies: Number of jiffies to wait for the GPIO to stabilize, from the debounce + * value. + * @gpiod: GPIO descriptor for this external connector. + * @extcon_id: The unique id of specific external connector. + * @debounce: Debounce time for GPIO IRQ in ms. + * @check_on_resume: Boolean describing whether to check the state of gpio + * while resuming from sleep. + */ +struct gpio_extcon_data { + struct extcon_dev *edev; + struct delayed_work work; + unsigned long debounce_jiffies; + struct gpio_desc *gpiod; + unsigned int extcon_id; + unsigned long debounce; + 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 = gpiod_get_value_cansleep(data->gpiod); + extcon_set_state_sync(data->edev, data->extcon_id, state); +} + +static irqreturn_t gpio_irq_handler(int irq, void *dev_id) +{ + struct gpio_extcon_data *data = dev_id; + + queue_delayed_work(system_power_efficient_wq, &data->work, + data->debounce_jiffies); + return IRQ_HANDLED; +} + +static int gpio_extcon_probe(struct platform_device *pdev) +{ + struct gpio_extcon_data *data; + struct device *dev = &pdev->dev; + unsigned long irq_flags; + int irq; + int ret; + + data = devm_kzalloc(dev, sizeof(struct gpio_extcon_data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + /* + * FIXME: extcon_id represents the unique identifier of external + * connectors such as EXTCON_USB, EXTCON_DISP_HDMI and so on. extcon_id + * is necessary to register the extcon device. But, it's not yet + * developed to get the extcon id from device-tree or others. + * On later, it have to be solved. + */ + if (data->extcon_id > EXTCON_NONE) + return -EINVAL; + + data->gpiod = devm_gpiod_get(dev, "extcon", GPIOD_IN); + if (IS_ERR(data->gpiod)) + return PTR_ERR(data->gpiod); + irq = gpiod_to_irq(data->gpiod); + if (irq <= 0) + return irq; + + /* + * It is unlikely that this is an acknowledged interrupt that goes + * away after handling, what we are looking for are falling edges + * if the signal is active low, and rising edges if the signal is + * active high. + */ + if (gpiod_is_active_low(data->gpiod)) + irq_flags = IRQF_TRIGGER_FALLING; + else + irq_flags = IRQF_TRIGGER_RISING; + + /* Allocate the memory of extcon devie and register extcon device */ + data->edev = devm_extcon_dev_allocate(dev, &data->extcon_id); + if (IS_ERR(data->edev)) { + dev_err(dev, "failed to allocate extcon device\n"); + return -ENOMEM; + } + + ret = devm_extcon_dev_register(dev, data->edev); + if (ret < 0) + return ret; + + ret = devm_delayed_work_autocancel(dev, &data->work, gpio_extcon_work); + if (ret) + return ret; + + /* + * Request the interrupt of gpio to detect whether external connector + * is attached or detached. + */ + ret = devm_request_any_context_irq(dev, irq, + gpio_irq_handler, irq_flags, + pdev->name, data); + if (ret < 0) + return ret; + + platform_set_drvdata(pdev, data); + /* Perform initial detection */ + gpio_extcon_work(&data->work.work); + + return 0; +} + +#ifdef CONFIG_PM_SLEEP +static int gpio_extcon_resume(struct device *dev) +{ + struct gpio_extcon_data *data; + + data = dev_get_drvdata(dev); + if (data->check_on_resume) + queue_delayed_work(system_power_efficient_wq, + &data->work, 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, + .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"); |