RE: [PATCH v4 5/6] usb: roles: add USB Type-B GPIO connector driver

[Biju Das]

Hi Chunfeng Yun,

Thanks for the patch.

> Subject: [PATCH v4 5/6] usb: roles: add USB Type-B GPIO connector driver
> 
> Due to the requirement of usb-connector.txt binding, the old way using
> extcon to support USB Dual-Role switch is now deprecated when use Type-B
> connector.
> This patch introduces a driver of Type-B connector which typically uses an
> input GPIO to detect USB ID pin, and try to replace the function provided by
> extcon-usb-gpio driver
> 
> Signed-off-by: Chunfeng Yun <chunfeng.yun@xxxxxxxxxxxx>
> ---
> v4 changes:
>   1. remove linux/gpio.h suggested by Linus
>   2. put node when error happens
> 
> v3 changes:
>   1. treat bype-B connector as a virtual device;
>   2. change file name again
> 
> v2 changes:
>   1. file name is changed
>   2. use new compatible
> ---
>  drivers/usb/roles/Kconfig           |  11 +
>  drivers/usb/roles/Makefile          |   1 +
>  drivers/usb/roles/typeb-conn-gpio.c | 305
> ++++++++++++++++++++++++++++
>  3 files changed, 317 insertions(+)
>  create mode 100644 drivers/usb/roles/typeb-conn-gpio.c
> 
> diff --git a/drivers/usb/roles/Kconfig b/drivers/usb/roles/Kconfig index
> f8b31aa67526..d1156e18a81a 100644
> --- a/drivers/usb/roles/Kconfig
> +++ b/drivers/usb/roles/Kconfig
> @@ -26,4 +26,15 @@ config USB_ROLES_INTEL_XHCI
>  	  To compile the driver as a module, choose M here: the module will
>  	  be called intel-xhci-usb-role-switch.
> 
> +config TYPEB_CONN_GPIO
> +	tristate "USB Type-B GPIO Connector"
> +	depends on GPIOLIB
> +	help
> +	  The driver supports USB role switch between host and device via
> GPIO
> +	  based USB cable detection, used typically if an input GPIO is used
> +	  to detect USB ID pin.
> +
> +	  To compile the driver as a module, choose M here: the module will
> +	  be called typeb-conn-gpio.ko
> +
>  endif # USB_ROLE_SWITCH
> diff --git a/drivers/usb/roles/Makefile b/drivers/usb/roles/Makefile index
> 757a7d2797eb..5d5620d9d113 100644
> --- a/drivers/usb/roles/Makefile
> +++ b/drivers/usb/roles/Makefile
> @@ -3,3 +3,4 @@
>  obj-$(CONFIG_USB_ROLE_SWITCH)		+= roles.o
>  roles-y					:= class.o
>  obj-$(CONFIG_USB_ROLES_INTEL_XHCI)	+= intel-xhci-usb-role-
> switch.o
> +obj-$(CONFIG_TYPEB_CONN_GPIO)		+= typeb-conn-gpio.o
> diff --git a/drivers/usb/roles/typeb-conn-gpio.c b/drivers/usb/roles/typeb-
> conn-gpio.c
> new file mode 100644
> index 000000000000..097d2ca12a12
> --- /dev/null
> +++ b/drivers/usb/roles/typeb-conn-gpio.c
> @@ -0,0 +1,305 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * USB Type-B GPIO Connector Driver
> + *
> + * Copyright (C) 2019 MediaTek Inc.
> + *
> + * Author: Chunfeng Yun <chunfeng.yun@xxxxxxxxxxxx>
> + *
> + * Some code borrowed from drivers/extcon/extcon-usb-gpio.c  */
> +
> +#include <linux/device.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/interrupt.h>
> +#include <linux/irq.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_graph.h>
> +#include <linux/pinctrl/consumer.h>
> +#include <linux/platform_device.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/usb/role.h>
> +
> +#define USB_GPIO_DEB_MS		20	/* ms */
> +#define USB_GPIO_DEB_US		((USB_GPIO_DEB_MS) * 1000)	/* us
> */
> +
> +#define USB_CONN_IRQF	\
> +	(IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING |
> IRQF_ONESHOT)
> +
> +struct usb_conn_info {
> +	struct device *dev;
> +	struct usb_role_switch *role_sw;
> +	enum usb_role last_role;
> +	struct regulator *vbus;
> +	struct delayed_work dw_det;
> +	unsigned long debounce_jiffies;
> +
> +	struct gpio_desc *id_gpiod;
> +	struct gpio_desc *vbus_gpiod;
> +	int id_irq;
> +	int vbus_irq;
> +};
> +
> +/**
> + * "DEVICE" = VBUS and "HOST" = !ID, so we have:
> + * Both "DEVICE" and "HOST" can't be set as active at the same time
> + * so if "HOST" is active (i.e. ID is 0)  we keep "DEVICE" inactive
> + * even if VBUS is on.
> + *
> + *  Role          |   ID  |  VBUS
> + * ------------------------------------
> + *  [1] DEVICE    |   H   |   H
> + *  [2] NONE      |   H   |   L
> + *  [3] HOST      |   L   |   H
> + *  [4] HOST      |   L   |   L
> + *
> + * In case we have only one of these signals:
> + * - VBUS only - we want to distinguish between [1] and [2], so ID is
> +always 1
> + * - ID only - we want to distinguish between [1] and [4], so VBUS = ID
> +*/ static void usb_conn_detect_cable(struct work_struct *work) {
> +	struct usb_conn_info *info;
> +	enum usb_role role;
> +	int id, vbus, ret;
> +
> +	info = container_of(to_delayed_work(work),
> +			    struct usb_conn_info, dw_det);
> +
> +	/* check ID and VBUS */
> +	id = info->id_gpiod ?
> +		gpiod_get_value_cansleep(info->id_gpiod) : 1;
> +	vbus = info->vbus_gpiod ?
> +		gpiod_get_value_cansleep(info->vbus_gpiod) : id;
> +
> +	if (!id)
> +		role = USB_ROLE_HOST;
> +	else if (vbus)
> +		role = USB_ROLE_DEVICE;
> +	else
> +		role = USB_ROLE_NONE;
> +
> +	dev_dbg(info->dev, "role %d/%d, gpios: id %d, vbus %d\n",
> +		info->last_role, role, id, vbus);
> +
> +	if (info->last_role == role) {
> +		dev_warn(info->dev, "repeated role: %d\n", role);
> +		return;
> +	}
> +
> +	if (info->last_role == USB_ROLE_HOST)
> +		regulator_disable(info->vbus);
> +
> +	ret = usb_role_switch_set_role(info->role_sw, role);
> +	if (ret)
> +		dev_err(info->dev, "failed to set role: %d\n", ret);
> +
> +	if (role == USB_ROLE_HOST) {
> +		ret = regulator_enable(info->vbus);
> +		if (ret)
> +			dev_err(info->dev, "enable vbus regulator failed\n");
> +	}
> +
> +	info->last_role = role;
> +
> +	dev_dbg(info->dev, "vbus regulator is %s\n",
> +		regulator_is_enabled(info->vbus) ? "enabled" : "disabled"); }
> +
> +static void usb_conn_queue_dwork(struct usb_conn_info *info,
> +				 unsigned long delay)
> +{
> +	queue_delayed_work(system_power_efficient_wq, &info-
> >dw_det, delay); }
> +
> +static irqreturn_t usb_conn_isr(int irq, void *dev_id) {
> +	struct usb_conn_info *info = dev_id;
> +
> +	usb_conn_queue_dwork(info, info->debounce_jiffies);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int usb_conn_probe(struct platform_device *pdev) {
> +	struct device *dev = &pdev->dev;
> +	struct device_node *np = dev->of_node;
> +	struct device_node *parent;
> +	struct device_node *child;
> +	struct usb_conn_info *info;
> +	int ret = 0;
> +
> +	if (!np)
> +		return -EINVAL;
> +
> +	info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
> +	if (!info)
> +		return -ENOMEM;
> +
> +	info->dev = dev;
> +
> +	child = of_get_child_by_name(np, "connector");
> +	if (!child) {
> +		dev_err(dev, "failed to find connector node\n");
> +		return -ENODEV;
> +	}
> +
> +	info->id_gpiod = devm_gpiod_get_from_of_node(
> +				dev, child, "id-gpios", 0, GPIOD_IN, "idpin");
> +	if (IS_ERR(info->id_gpiod)) {
> +		of_node_put(child);
> +		return PTR_ERR(info->id_gpiod);
> +	}
> +
> +	info->vbus_gpiod = devm_gpiod_get_from_of_node(
> +				dev, child, "vbus-gpios", 0, GPIOD_IN,
> +				"vbuspin");
> +	if (IS_ERR(info->vbus_gpiod)) {
> +		of_node_put(child);
> +		return PTR_ERR(info->vbus_gpiod);
> +	}
> +
> +	if (!info->id_gpiod && !info->vbus_gpiod) {
> +		dev_err(dev, "failed to get gpios\n");
> +		return -ENODEV;
> +	}
> +
> +	of_node_put(child);
> +
> +	if (info->id_gpiod)
> +		ret = gpiod_set_debounce(info->id_gpiod,
> USB_GPIO_DEB_US);
> +	if (!ret && info->vbus_gpiod)
> +		ret = gpiod_set_debounce(info->vbus_gpiod,
> USB_GPIO_DEB_US);
> +	if (ret < 0)
> +		info->debounce_jiffies =
> msecs_to_jiffies(USB_GPIO_DEB_MS);
> +
> +	INIT_DELAYED_WORK(&info->dw_det, usb_conn_detect_cable);
> +
> +	info->vbus = devm_regulator_get(dev, "vbus");
> +	if (IS_ERR(info->vbus)) {
> +		dev_err(dev, "failed to get vbus\n");
> +		return PTR_ERR(info->vbus);
> +	}
> +
> +	child = of_graph_get_endpoint_by_regs(np, -1, 0);
> +	parent = of_graph_get_remote_port_parent(child);
> +	info->role_sw =
> fwnode_usb_role_switch_get(of_fwnode_handle(parent));
> +	of_node_put(child);
> +	of_node_put(parent);
> +	if (IS_ERR(info->role_sw)) {
> +		dev_err(dev, "failed to get role switch\n");
> +		return PTR_ERR(info->role_sw);
> +	}
> +
> +	if (info->id_gpiod) {
> +		info->id_irq = gpiod_to_irq(info->id_gpiod);
> +		if (info->id_irq < 0) {
> +			dev_err(dev, "failed to get ID IRQ\n");
May be usb_role_switch_put(info->role_sw); ??
> +			return info->id_irq;
> +		}
> +
> +		ret = devm_request_threaded_irq(dev, info->id_irq, NULL,
> +						usb_conn_isr,
> USB_CONN_IRQF,
> +						pdev->name, info);
> +		if (ret < 0) {
> +			dev_err(dev, "failed to request ID IRQ\n");
May be usb_role_switch_put(info->role_sw); ??
> +			return ret;
> +		}
> +	}
> +
> +	if (info->vbus_gpiod) {
> +		info->vbus_irq = gpiod_to_irq(info->vbus_gpiod);
> +		if (info->vbus_irq < 0) {
> +			dev_err(dev, "failed to get VBUS IRQ\n");
May be usb_role_switch_put(info->role_sw);
> +			return info->vbus_irq;
> +		}
> +
> +		ret = devm_request_threaded_irq(dev, info->vbus_irq,
> NULL,
> +						usb_conn_isr,
> USB_CONN_IRQF,
> +						pdev->name, info);
> +		if (ret < 0) {
> +			dev_err(dev, "failed to request VBUS IRQ\n");
May be usb_role_switch_put(info->role_sw); ??
> +			return ret;
> +		}
> +	}
> +
> +	platform_set_drvdata(pdev, info);
> +
> +	/* Perform initial detection */
> +	usb_conn_queue_dwork(info, 0);
> +
> +	return 0;
> +}
> +
> +static int usb_conn_remove(struct platform_device *pdev) {
> +	struct usb_conn_info *info = platform_get_drvdata(pdev);
> +
> +	cancel_delayed_work_sync(&info->dw_det);
> +
> +	if (info->last_role == USB_ROLE_HOST)
> +		regulator_disable(info->vbus);
> +
> +	usb_role_switch_put(info->role_sw);
> +
> +	return 0;
> +}
> +
> +static int __maybe_unused usb_conn_suspend(struct device *dev) {
> +	struct usb_conn_info *info = dev_get_drvdata(dev);
> +
> +	if (info->id_gpiod)
> +		disable_irq(info->id_irq);
> +	if (info->vbus_gpiod)
> +		disable_irq(info->vbus_irq);
> +
> +	pinctrl_pm_select_sleep_state(dev);
> +
> +	return 0;
> +}
> +
> +static int __maybe_unused usb_conn_resume(struct device *dev) {
> +	struct usb_conn_info *info = dev_get_drvdata(dev);
> +
> +	pinctrl_pm_select_default_state(dev);
> +
> +	if (info->id_gpiod)
> +		enable_irq(info->id_irq);
> +	if (info->vbus_gpiod)
> +		enable_irq(info->vbus_irq);
> +
> +	usb_conn_queue_dwork(info, 0);
> +
> +	return 0;
> +}
> +
> +static SIMPLE_DEV_PM_OPS(usb_conn_pm_ops,
> +			 usb_conn_suspend, usb_conn_resume);
> +
> +#define DEV_PMS_OPS (IS_ENABLED(CONFIG_PM_SLEEP) ?
> &usb_conn_pm_ops :
> +NULL)
> +
> +static const struct of_device_id usb_conn_dt_match[] = {
> +	{ .compatible = "linux,typeb-conn-gpio", },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, usb_conn_dt_match);
> +
> +static struct platform_driver usb_conn_driver = {
> +	.probe		= usb_conn_probe,
> +	.remove		= usb_conn_remove,
> +	.driver		= {
> +		.name	= "typeb-conn-gpio",
> +		.pm	= DEV_PMS_OPS,
> +		.of_match_table = usb_conn_dt_match,
> +	},
> +};
> +
> +module_platform_driver(usb_conn_driver);
> +
> +MODULE_AUTHOR("Chunfeng Yun <chunfeng.yun@xxxxxxxxxxxx>");
> +MODULE_DESCRIPTION("USB Type-B GPIO connector driver");
> +MODULE_LICENSE("GPL v2");
> --
> 2.21.0