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From:   Chunfeng Yun <chunfeng.yun@mediatek.com>
To:     Rob Herring <robh+dt@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Heikki Krogerus <heikki.krogerus@linux.intel.com>
CC:     Mark Rutland <mark.rutland@arm.com>,
        Chunfeng Yun <chunfeng.yun@mediatek.com>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Adam Thomson <Adam.Thomson.Opensource@diasemi.com>,
        Li Jun <jun.li@nxp.com>,
        Badhri Jagan Sridharan <badhri@google.com>,
        Hans de Goede <hdegoede@redhat.com>,
        Andy Shevchenko <andy.shevchenko@gmail.com>,
        Min Guo <min.guo@mediatek.com>, <devicetree@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <linux-usb@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-mediatek@lists.infradead.org>
Subject: [PATCH 4/5] usb: roles: add USB Type-B connector driver
Date:   Fri, 8 Mar 2019 14:13:41 +0800
Message-ID: <1552025622-15582-5-git-send-email-chunfeng.yun@mediatek.com>
In-Reply-To: <1552025622-15582-1-git-send-email-chunfeng.yun@mediatek.com>
References: <1552025622-15582-1-git-send-email-chunfeng.yun@mediatek.com>
MIME-Version: 1.0
Content-Type: text/plain
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

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 introduce a Type-B connector driver and try to replace
the function provided by extcon-usb-gpio driver

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
---
 drivers/usb/roles/Kconfig           |  14 ++
 drivers/usb/roles/Makefile          |   1 +
 drivers/usb/roles/usb-b-connector.c | 285 ++++++++++++++++++++++++++++
 3 files changed, 300 insertions(+)
 create mode 100644 drivers/usb/roles/usb-b-connector.c

diff --git a/drivers/usb/roles/Kconfig b/drivers/usb/roles/Kconfig
index e4194ac94510..e267132917c2 100644
--- a/drivers/usb/roles/Kconfig
+++ b/drivers/usb/roles/Kconfig
@@ -24,4 +24,18 @@ 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 USB_B_CONNECTOR
+	tristate "USB Type-B Connector"
+	depends on GPIOLIB
+	help
+	  The driver supports USB role switch between host and device by GPIO
+	  based USB cable detection, used typically if GPIO is used for USB ID
+	  pin detection. And it's used to replace the function provided by
+	  drivers/extcon/extcon-usb-gpio.c driver due to the requirement by
+	  connector/usb-connector.txt
+
+	  Say Y here if your USB Type-B Connector supports Dual-Role mode.
+	  To compile the driver as a module, choose M here: the module will
+	  be called usb-b-connector.ko
+
 endif # USB_ROLE_SWITCH
diff --git a/drivers/usb/roles/Makefile b/drivers/usb/roles/Makefile
index c02873206fc1..ff8be33253a4 100644
--- a/drivers/usb/roles/Makefile
+++ b/drivers/usb/roles/Makefile
@@ -1,3 +1,4 @@
 obj-$(CONFIG_USB_ROLE_SWITCH)		+= roles.o
 roles-y					:= class.o
+obj-$(CONFIG_USB_B_CONNECTOR)		+= usb-b-connector.o
 obj-$(CONFIG_USB_ROLES_INTEL_XHCI)	+= intel-xhci-usb-role-switch.o
diff --git a/drivers/usb/roles/usb-b-connector.c b/drivers/usb/roles/usb-b-connector.c
new file mode 100644
index 000000000000..debd0c6500cf
--- /dev/null
+++ b/drivers/usb/roles/usb-b-connector.c
@@ -0,0 +1,285 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * USB Type-B Connector Driver
+ *
+ * Copyright (C) 2019 MediaTek Inc.
+ *
+ * Author: Chunfeng Yun <chunfeng.yun@mediatek.com>
+ *
+ * Some code borrowed from drivers/extcon/extcon-usb-gpio.c
+ */
+
+#include <linux/device.h>
+#include <linux/gpio.h>
+#include <linux/gpio/consumer.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/module.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 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;
+	info->id_gpiod = devm_gpiod_get_optional(dev, "id", GPIOD_IN);
+	if (IS_ERR(info->id_gpiod))
+		return PTR_ERR(info->id_gpiod);
+
+	info->vbus_gpiod = devm_gpiod_get_optional(dev, "vbus", GPIOD_IN);
+	if (IS_ERR(info->vbus_gpiod))
+		return PTR_ERR(info->vbus_gpiod);
+
+	if (!info->id_gpiod && !info->vbus_gpiod) {
+		dev_err(dev, "failed to get gpios\n");
+		return -ENODEV;
+	}
+
+	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);
+	}
+
+	parent = of_get_parent(np);
+	info->role_sw = usb_role_switch_get_by_node(parent);
+	if (IS_ERR_OR_NULL(info->role_sw)) {
+		dev_err(dev, "failed to get role switch\n");
+		return PTR_ERR(info->role_sw);
+	}
+
+	of_node_put(parent);
+
+	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");
+			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");
+			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");
+			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");
+			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 = "usb-b-connector", },
+	{ }
+};
+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	= "usb_b_conn",
+		.pm	= DEV_PMS_OPS,
+		.of_match_table = usb_conn_dt_match,
+	},
+};
+
+module_platform_driver(usb_conn_driver);
+
+MODULE_AUTHOR("Chunfeng Yun <chunfeng.yun@mediatek.com>");
+MODULE_DESCRIPTION("USB GPIO conn driver");
+MODULE_LICENSE("GPL v2");
-- 
2.20.1