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    SubjectRe: [PATCH 1/5] extcon: gpio-usb: Introduce gpio usb extcon driver
    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 <rogerq@ti.com>

    Reviewed-by: Felipe Balbi <balbi@ti.com>
    Acked-by: Felipe Balbi <balbi@ti.com>

    > ---
    > .../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 <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/extcon/extcon-gpio.h>
    > +#include <linux/gpio.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;
    > + 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 <rogerq@ti.com>");
    > +MODULE_DESCRIPTION("USB GPIO extcon driver");
    > +MODULE_LICENSE("GPL v2");
    > --
    > 2.1.0
    >

    --
    balbi
    [unhandled content-type:application/pgp-signature]
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