On Mon, Jan 19, 2015 at 07:52:18PM +0200, Roger Quadros wrote: > This driver observes the USB ID pin connected over a GPIO and > updates the USB cable extcon states accordingly. > > The existing GPIO extcon driver is not suitable for this purpose > as it needs to be taught to understand USB cable states and it > can't handle more than one cable per instance. > > For the USB case we need to handle 2 cable states. > 1) USB (attach/detach) > 2) USB-Host (attach/detach) > > This driver can be easily updated in the future to handle VBUS > events in case it happens to be available on GPIO for any platform. > > Signed-off-by: Roger Quadros Reviewed-by: Felipe Balbi Acked-by: Felipe Balbi > --- > .../devicetree/bindings/extcon/extcon-usb.txt | 20 ++ > drivers/extcon/Kconfig | 7 + > drivers/extcon/Makefile | 1 + > drivers/extcon/extcon-gpio-usb.c | 225 +++++++++++++++++++++ > 4 files changed, 253 insertions(+) > create mode 100644 Documentation/devicetree/bindings/extcon/extcon-usb.txt > create mode 100644 drivers/extcon/extcon-gpio-usb.c > > diff --git a/Documentation/devicetree/bindings/extcon/extcon-usb.txt b/Documentation/devicetree/bindings/extcon/extcon-usb.txt > new file mode 100644 > index 0000000..171c5a4 > --- /dev/null > +++ b/Documentation/devicetree/bindings/extcon/extcon-usb.txt > @@ -0,0 +1,20 @@ > +USB Extcon device > + > +This is a virtual device used to generate USB cable states from the USB ID pin > +connected to a GPIO pin. > + > +Required properties: > +- compatible: Should be "linux,extcon-usb" > +- id-gpio: gpio for USB ID pin. See gpio binding. > + > +Example: > + extcon_usb1 { > + compatible = "linux,extcon-usb"; > + id-gpio = <&gpio6 1 GPIO_ACTIVE_HIGH>; > + } > + > + usb@1 { > + ... > + extcon = <&extcon_usb1>; > + ... > + }; > diff --git a/drivers/extcon/Kconfig b/drivers/extcon/Kconfig > index 6a1f7de..8106a83 100644 > --- a/drivers/extcon/Kconfig > +++ b/drivers/extcon/Kconfig > @@ -35,6 +35,13 @@ config EXTCON_GPIO > Say Y here to enable GPIO based extcon support. Note that GPIO > extcon supports single state per extcon instance. > > +config EXTCON_GPIO_USB > + tristate "USB GPIO extcon support" > + depends on GPIOLIB > + help > + Say Y here to enable GPIO based USB cable detection extcon support. > + Used typically if GPIO is used for USB ID pin detection. > + > config EXTCON_MAX14577 > tristate "MAX14577/77836 EXTCON Support" > depends on MFD_MAX14577 > diff --git a/drivers/extcon/Makefile b/drivers/extcon/Makefile > index 0370b42..bae594b 100644 > --- a/drivers/extcon/Makefile > +++ b/drivers/extcon/Makefile > @@ -12,3 +12,4 @@ obj-$(CONFIG_EXTCON_MAX8997) += extcon-max8997.o > obj-$(CONFIG_EXTCON_PALMAS) += extcon-palmas.o > obj-$(CONFIG_EXTCON_RT8973A) += extcon-rt8973a.o > obj-$(CONFIG_EXTCON_SM5502) += extcon-sm5502.o > +obj-$(CONFIG_EXTCON_GPIO_USB) += extcon-gpio-usb.o > diff --git a/drivers/extcon/extcon-gpio-usb.c b/drivers/extcon/extcon-gpio-usb.c > new file mode 100644 > index 0000000..aeb2298 > --- /dev/null > +++ b/drivers/extcon/extcon-gpio-usb.c > @@ -0,0 +1,225 @@ > +/** > + * drivers/extcon/extcon_gpio_usb.c - USB GPIO extcon driver > + * > + * Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com > + * > + * Author: Roger Quadros > + * > + * 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 > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +#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; > + const char **cable_names; > + > + info = container_of(to_delayed_work(work), struct usb_extcon_info, > + wq_detcable); > + cable_names = info->edev->supported_cable; > + > + /* 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, > + cable_names[EXTCON_CABLE_USB_HOST], > + false); > + extcon_set_cable_state(info->edev, > + cable_names[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, > + cable_names[EXTCON_CABLE_USB], false); > + extcon_set_cable_state(info->edev, > + cable_names[EXTCON_CABLE_USB_HOST], > + true); > + } > +} > + > +static irqreturn_t usb_irq_handler(int irq, void *dev_id) > +{ > + struct usb_extcon_info *info = dev_id; > + > + /* debounce the GPIO via delayed work */ > + 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(struct usb_extcon_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); > + } > + > + 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_SHARED | IRQF_ONESHOT, > + pdev->name, info); > + if (ret < 0) { > + dev_err(dev, "failed to request handler for ID IRQ\n"); > + return ret; > + } > + > + 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 allocate extcon device\n"); > + return ret; > + } > + > + platform_set_drvdata(pdev, info); > + /* 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; > + > + info = dev_get_drvdata(dev); > + > + if (!IS_ERR(info->id_gpiod)) > + enable_irq_wake(info->id_irq); > + > + return 0; > +} > + > +static int usb_extcon_resume(struct device *dev) > +{ > + struct usb_extcon_info *info; > + > + info = dev_get_drvdata(dev); > + > + if (!IS_ERR(info->id_gpiod)) > + disable_irq_wake(info->id_irq); > + > + return 0; > +} > +#endif > + > +static SIMPLE_DEV_PM_OPS(usb_extcon_pm_ops, > + usb_extcon_suspend, usb_extcon_resume); > + > +static struct of_device_id usb_extcon_dt_match[] = { > + { .compatible = "linux,extcon-usb", }, > + { /* end */ } > +}; > + > +static struct platform_driver usb_extcon_driver = { > + .probe = usb_extcon_probe, > + .remove = usb_extcon_remove, > + .driver = { > + .name = "extcon-usb", > + .pm = &usb_extcon_pm_ops, > + .of_match_table = usb_extcon_dt_match, > + }, > +}; > + > +module_platform_driver(usb_extcon_driver); > + > +MODULE_AUTHOR("Roger Quadros "); > +MODULE_DESCRIPTION("USB GPIO extcon driver"); > +MODULE_LICENSE("GPL v2"); > -- > 2.1.0 > -- balbi