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@xxxxxx>
Reviewed-by: Felipe Balbi <balbi@xxxxxx>
Acked-by: Felipe Balbi <balbi@xxxxxx>
> ---
> .../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@xxxxxx>
> + *
> + * 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@xxxxxx>");
> +MODULE_DESCRIPTION("USB GPIO extcon driver");
> +MODULE_LICENSE("GPL v2");
> --
> 2.1.0
>
--
balbi
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