diff options
Diffstat (limited to 'drivers/extcon/extcon-usb-gpio.c')
| -rw-r--r-- | drivers/extcon/extcon-usb-gpio.c | 237 |
1 files changed, 237 insertions, 0 deletions
diff --git a/drivers/extcon/extcon-usb-gpio.c b/drivers/extcon/extcon-usb-gpio.c new file mode 100644 index 000000000..e45d1f13f --- /dev/null +++ b/drivers/extcon/extcon-usb-gpio.c @@ -0,0 +1,237 @@ +/** + * drivers/extcon/extcon-usb-gpio.c - USB GPIO extcon driver + * + * Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com + * Author: Roger Quadros <rogerq@ti.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * 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/init.h> +#include <linux/interrupt.h> +#include <linux/irq.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/of_gpio.h> +#include <linux/platform_device.h> +#include <linux/slab.h> +#include <linux/workqueue.h> + +#define USB_GPIO_DEBOUNCE_MS 20 /* ms */ + +struct usb_extcon_info { + struct device *dev; + struct extcon_dev *edev; + + struct gpio_desc *id_gpiod; + int id_irq; + + unsigned long debounce_jiffies; + struct delayed_work wq_detcable; +}; + +/* List of detectable cables */ +enum { + EXTCON_CABLE_USB = 0, + EXTCON_CABLE_USB_HOST, + + EXTCON_CABLE_END, +}; + +static const char *usb_extcon_cable[] = { + [EXTCON_CABLE_USB] = "USB", + [EXTCON_CABLE_USB_HOST] = "USB-HOST", + NULL, +}; + +static void usb_extcon_detect_cable(struct work_struct *work) +{ + int id; + struct usb_extcon_info *info = container_of(to_delayed_work(work), + struct usb_extcon_info, + wq_detcable); + + /* check ID and update cable state */ + id = gpiod_get_value_cansleep(info->id_gpiod); + if (id) { + /* + * ID = 1 means USB HOST cable detached. + * As we don't have event for USB peripheral cable attached, + * we simulate USB peripheral attach here. + */ + extcon_set_cable_state(info->edev, + usb_extcon_cable[EXTCON_CABLE_USB_HOST], + false); + extcon_set_cable_state(info->edev, + usb_extcon_cable[EXTCON_CABLE_USB], + true); + } else { + /* + * ID = 0 means USB HOST cable attached. + * As we don't have event for USB peripheral cable detached, + * we simulate USB peripheral detach here. + */ + extcon_set_cable_state(info->edev, + usb_extcon_cable[EXTCON_CABLE_USB], + false); + extcon_set_cable_state(info->edev, + usb_extcon_cable[EXTCON_CABLE_USB_HOST], + true); + } +} + +static irqreturn_t usb_irq_handler(int irq, void *dev_id) +{ + struct usb_extcon_info *info = dev_id; + + queue_delayed_work(system_power_efficient_wq, &info->wq_detcable, + info->debounce_jiffies); + + return IRQ_HANDLED; +} + +static int usb_extcon_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct device_node *np = dev->of_node; + struct usb_extcon_info *info; + int ret; + + if (!np) + return -EINVAL; + + info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL); + if (!info) + return -ENOMEM; + + info->dev = dev; + info->id_gpiod = devm_gpiod_get(&pdev->dev, "id"); + if (IS_ERR(info->id_gpiod)) { + dev_err(dev, "failed to get ID GPIO\n"); + return PTR_ERR(info->id_gpiod); + } + + info->edev = devm_extcon_dev_allocate(dev, usb_extcon_cable); + if (IS_ERR(info->edev)) { + dev_err(dev, "failed to allocate extcon device\n"); + return -ENOMEM; + } + + ret = devm_extcon_dev_register(dev, info->edev); + if (ret < 0) { + dev_err(dev, "failed to register extcon device\n"); + return ret; + } + + ret = gpiod_set_debounce(info->id_gpiod, + USB_GPIO_DEBOUNCE_MS * 1000); + if (ret < 0) + info->debounce_jiffies = msecs_to_jiffies(USB_GPIO_DEBOUNCE_MS); + + INIT_DELAYED_WORK(&info->wq_detcable, usb_extcon_detect_cable); + + info->id_irq = gpiod_to_irq(info->id_gpiod); + if (info->id_irq < 0) { + dev_err(dev, "failed to get ID IRQ\n"); + return info->id_irq; + } + + ret = devm_request_threaded_irq(dev, info->id_irq, NULL, + usb_irq_handler, + IRQF_TRIGGER_RISING | + IRQF_TRIGGER_FALLING | IRQF_ONESHOT, + pdev->name, info); + if (ret < 0) { + dev_err(dev, "failed to request handler for ID IRQ\n"); + return ret; + } + + platform_set_drvdata(pdev, info); + device_init_wakeup(dev, 1); + + /* Perform initial detection */ + usb_extcon_detect_cable(&info->wq_detcable.work); + + return 0; +} + +static int usb_extcon_remove(struct platform_device *pdev) +{ + struct usb_extcon_info *info = platform_get_drvdata(pdev); + + cancel_delayed_work_sync(&info->wq_detcable); + + return 0; +} + +#ifdef CONFIG_PM_SLEEP +static int usb_extcon_suspend(struct device *dev) +{ + struct usb_extcon_info *info = dev_get_drvdata(dev); + int ret = 0; + + if (device_may_wakeup(dev)) { + ret = enable_irq_wake(info->id_irq); + if (ret) + return ret; + } + + /* + * We don't want to process any IRQs after this point + * as GPIOs used behind I2C subsystem might not be + * accessible until resume completes. So disable IRQ. + */ + disable_irq(info->id_irq); + + return ret; +} + +static int usb_extcon_resume(struct device *dev) +{ + struct usb_extcon_info *info = dev_get_drvdata(dev); + int ret = 0; + + if (device_may_wakeup(dev)) { + ret = disable_irq_wake(info->id_irq); + if (ret) + return ret; + } + + enable_irq(info->id_irq); + + return ret; +} +#endif + +static SIMPLE_DEV_PM_OPS(usb_extcon_pm_ops, + usb_extcon_suspend, usb_extcon_resume); + +static const struct of_device_id usb_extcon_dt_match[] = { + { .compatible = "linux,extcon-usb-gpio", }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, usb_extcon_dt_match); + +static struct platform_driver usb_extcon_driver = { + .probe = usb_extcon_probe, + .remove = usb_extcon_remove, + .driver = { + .name = "extcon-usb-gpio", + .pm = &usb_extcon_pm_ops, + .of_match_table = usb_extcon_dt_match, + }, +}; + +module_platform_driver(usb_extcon_driver); + +MODULE_AUTHOR("Roger Quadros <rogerq@ti.com>"); +MODULE_DESCRIPTION("USB GPIO extcon driver"); +MODULE_LICENSE("GPL v2"); |