usb: misc: Add driver for usb4604

diff --git a/Documentation/devicetree/bindings/usb/usb4604.txt b/Documentation/devicetree/bindings/usb/usb4604.txt
new file mode 100644
index 000000000000..82506d17712c
--- /dev/null
+++ b/Documentation/devicetree/bindings/usb/usb4604.txt
@@ -0,0 +1,19 @@ 
+SMSC USB4604 High-Speed Hub Controller
+
+Required properties:
+- compatible: Should be "smsc,usb4604"
+
+Optional properties:
+- reg: Specifies the i2c slave address, it is required and should be 0x2d
+       if I2C is used.
+- reset-gpios: Should specify GPIO for reset.
+- initial-mode: Should specify initial mode.
+                (1 for HUB mode, 2 for STANDBY mode)
+
+Examples:
+	usb-hub@2d {
+		compatible = "smsc,usb4604";
+		reg = <0x2d>;
+		reset-gpios = <&gpx3 5 1>;
+		initial-mode = <1>;
+	};
diff --git a/drivers/usb/misc/Kconfig b/drivers/usb/misc/Kconfig
index e9e5ae521fa6..ac9ca570b26d 100644
--- a/drivers/usb/misc/Kconfig
+++ b/drivers/usb/misc/Kconfig
@@ -249,6 +249,12 @@  config USB_HSIC_USB3503
        help
          This option enables support for SMSC USB3503 HSIC to USB 2.0 Driver.
 
+config USB_HSIC_USB4604
+       tristate "USB4604 HSIC to USB20 Driver"
+       depends on I2C
+       help
+         This option enables support for SMSC USB4604 HSIC to USB 2.0 Driver.
+
 config USB_LINK_LAYER_TEST
 	tristate "USB Link Layer Test driver"
 	help
diff --git a/drivers/usb/misc/Makefile b/drivers/usb/misc/Makefile
index 2769cf6351b4..95e897dff681 100644
--- a/drivers/usb/misc/Makefile
+++ b/drivers/usb/misc/Makefile
@@ -25,6 +25,7 @@  obj-$(CONFIG_USB_USS720)		+= uss720.o
 obj-$(CONFIG_USB_SEVSEG)		+= usbsevseg.o
 obj-$(CONFIG_USB_YUREX)			+= yurex.o
 obj-$(CONFIG_USB_HSIC_USB3503)		+= usb3503.o
+obj-$(CONFIG_USB_HSIC_USB4604)		+= usb4604.o
 obj-$(CONFIG_USB_CHAOSKEY)		+= chaoskey.o
 obj-$(CONFIG_UCSI)			+= ucsi.o
 
diff --git a/drivers/usb/misc/usb4604.c b/drivers/usb/misc/usb4604.c
new file mode 100644
index 000000000000..e9f37fb746ac
--- /dev/null
+++ b/drivers/usb/misc/usb4604.c
@@ -0,0 +1,175 @@ 
+/*
+ * Driver for SMSC USB4604 USB HSIC 4-port 2.0 hub controller driver
+ * Based on usb3503 driver
+ *
+ * Copyright (c) 2012-2013 Dongjin Kim (tobetter@gmail.com)
+ * Copyright (c) 2016 Linaro Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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/i2c.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/gpio/consumer.h>
+
+enum usb4604_mode {
+	USB4604_MODE_UNKNOWN,
+	USB4604_MODE_HUB,
+	USB4604_MODE_STANDBY,
+};
+
+struct usb4604 {
+	enum usb4604_mode	mode;
+	struct device		*dev;
+	struct gpio_desc	*gpio_reset;
+};
+
+static void usb4604_reset(struct usb4604 *hub, int state)
+{
+	gpiod_set_value_cansleep(hub->gpio_reset, state);
+
+	/* Wait for i2c logic to come up */
+	if (state)
+		msleep(250);
+}
+
+static int usb4604_connect(struct usb4604 *hub)
+{
+	struct device *dev = hub->dev;
+	struct i2c_client *client = to_i2c_client(dev);
+	int err;
+	u8 connect_cmd[] = { 0xaa, 0x55, 0x00 };
+
+	usb4604_reset(hub, 1);
+
+	err = i2c_master_send(client, connect_cmd, ARRAY_SIZE(connect_cmd));
+	if (err < 0) {
+		usb4604_reset(hub, 0);
+		return err;
+	}
+
+	hub->mode = USB4604_MODE_HUB;
+	dev_dbg(dev, "switched to HUB mode\n");
+
+	return 0;
+}
+
+static int usb4604_switch_mode(struct usb4604 *hub, enum usb4604_mode mode)
+{
+	struct device *dev = hub->dev;
+	int err = 0;
+
+	switch (mode) {
+	case USB4604_MODE_HUB:
+		err = usb4604_connect(hub);
+		break;
+
+	case USB4604_MODE_STANDBY:
+		usb4604_reset(hub, 0);
+		dev_dbg(dev, "switched to STANDBY mode\n");
+		break;
+
+	default:
+		dev_err(dev, "unknown mode is requested\n");
+		err = -EINVAL;
+		break;
+	}
+
+	return err;
+}
+
+static int usb4604_probe(struct usb4604 *hub)
+{
+	struct device *dev = hub->dev;
+	struct device_node *np = dev->of_node;
+	struct gpio_desc *gpio;
+	u32 mode = USB4604_MODE_HUB;
+
+	gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
+	if (IS_ERR(gpio))
+		return PTR_ERR(gpio);
+	hub->gpio_reset = gpio;
+
+	if (of_property_read_u32(np, "initial-mode", &hub->mode))
+		hub->mode = mode;
+
+	return usb4604_switch_mode(hub, hub->mode);
+}
+
+static int usb4604_i2c_probe(struct i2c_client *i2c,
+			     const struct i2c_device_id *id)
+{
+	struct usb4604 *hub;
+
+	hub = devm_kzalloc(&i2c->dev, sizeof(*hub), GFP_KERNEL);
+	if (!hub)
+		return -ENOMEM;
+
+	i2c_set_clientdata(i2c, hub);
+	hub->dev = &i2c->dev;
+
+	return usb4604_probe(hub);
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int usb4604_i2c_suspend(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct usb4604 *hub = i2c_get_clientdata(client);
+
+	usb4604_switch_mode(hub, USB4604_MODE_STANDBY);
+
+	return 0;
+}
+
+static int usb4604_i2c_resume(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct usb4604 *hub = i2c_get_clientdata(client);
+
+	usb4604_switch_mode(hub, hub->mode);
+
+	return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(usb4604_i2c_pm_ops, usb4604_i2c_suspend,
+		usb4604_i2c_resume);
+
+static const struct i2c_device_id usb4604_id[] = {
+	{ "usb4604", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, usb4604_id);
+
+#ifdef CONFIG_OF
+static const struct of_device_id usb4604_of_match[] = {
+	{ .compatible = "smsc,usb4604" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, usb4604_of_match);
+#endif
+
+static struct i2c_driver usb4604_i2c_driver = {
+	.driver = {
+		.name = "usb4604",
+		.pm = &usb4604_i2c_pm_ops,
+		.of_match_table = of_match_ptr(usb4604_of_match),
+	},
+	.probe		= usb4604_i2c_probe,
+	.id_table	= usb4604_id,
+};
+module_i2c_driver(usb4604_i2c_driver);
+
+MODULE_DESCRIPTION("USB4604 USB HUB driver");
+MODULE_LICENSE("GPL v2");