drivers/usb/common/common.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Provides code common for host and device side USB.
  *
  * If either host side (ie. CONFIG_USB=y) or device side USB stack
  * (ie. CONFIG_USB_GADGET=y) is compiled in the kernel, this module is
  * compiled-in as well.  Otherwise, if either of the two stacks is
  * compiled as module, this file is compiled as module as well.
  */

 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/usb/ch9.h>
 #include <linux/usb/of.h>
 #include <linux/usb/otg.h>
 #include <linux/of_platform.h>
 #include <linux/debugfs.h>
 #include "common.h"

 static const char *const ep_type_names[] = {
 	[USB_ENDPOINT_XFER_CONTROL] = "ctrl",
 	[USB_ENDPOINT_XFER_ISOC] = "isoc",
 	[USB_ENDPOINT_XFER_BULK] = "bulk",
 	[USB_ENDPOINT_XFER_INT] = "intr",
 };

 /**
  * usb_ep_type_string() - Returns human readable-name of the endpoint type.
  * @ep_type: The endpoint type to return human-readable name for.  If it's not
  *   any of the types: USB_ENDPOINT_XFER_{CONTROL, ISOC, BULK, INT},
  *   usually got by usb_endpoint_type(), the string 'unknown' will be returned.
  */
 const char *usb_ep_type_string(int ep_type)
 {
 	if (ep_type < 0 || ep_type >= ARRAY_SIZE(ep_type_names))
 		return "unknown";

 	return ep_type_names[ep_type];
 }
 EXPORT_SYMBOL_GPL(usb_ep_type_string);

 const char *usb_otg_state_string(enum usb_otg_state state)
 {
 	static const char *const names[] = {
 		[OTG_STATE_A_IDLE] = "a_idle",
 		[OTG_STATE_A_WAIT_VRISE] = "a_wait_vrise",
 		[OTG_STATE_A_WAIT_BCON] = "a_wait_bcon",
 		[OTG_STATE_A_HOST] = "a_host",
 		[OTG_STATE_A_SUSPEND] = "a_suspend",
 		[OTG_STATE_A_PERIPHERAL] = "a_peripheral",
 		[OTG_STATE_A_WAIT_VFALL] = "a_wait_vfall",
 		[OTG_STATE_A_VBUS_ERR] = "a_vbus_err",
 		[OTG_STATE_B_IDLE] = "b_idle",
 		[OTG_STATE_B_SRP_INIT] = "b_srp_init",
 		[OTG_STATE_B_PERIPHERAL] = "b_peripheral",
 		[OTG_STATE_B_WAIT_ACON] = "b_wait_acon",
 		[OTG_STATE_B_HOST] = "b_host",
 	};

 	if (state < 0 || state >= ARRAY_SIZE(names))
 		return "UNDEFINED";

 	return names[state];
 }
 EXPORT_SYMBOL_GPL(usb_otg_state_string);

 static const char *const speed_names[] = {
 	[USB_SPEED_UNKNOWN] = "UNKNOWN",
 	[USB_SPEED_LOW] = "low-speed",
 	[USB_SPEED_FULL] = "full-speed",
 	[USB_SPEED_HIGH] = "high-speed",
 	[USB_SPEED_WIRELESS] = "wireless",
 	[USB_SPEED_SUPER] = "super-speed",
 	[USB_SPEED_SUPER_PLUS] = "super-speed-plus",
 };

 static const char *const ssp_rate[] = {
 	[USB_SSP_GEN_UNKNOWN] = "UNKNOWN",
 	[USB_SSP_GEN_2x1] = "super-speed-plus-gen2x1",
 	[USB_SSP_GEN_1x2] = "super-speed-plus-gen1x2",
 	[USB_SSP_GEN_2x2] = "super-speed-plus-gen2x2",
 };

 /**
  * usb_speed_string() - Returns human readable-name of the speed.
  * @speed: The speed to return human-readable name for.  If it's not
  *   any of the speeds defined in usb_device_speed enum, string for
  *   USB_SPEED_UNKNOWN will be returned.
  */
 const char *usb_speed_string(enum usb_device_speed speed)
 {
 	if (speed < 0 || speed >= ARRAY_SIZE(speed_names))
 		speed = USB_SPEED_UNKNOWN;
 	return speed_names[speed];
 }
 EXPORT_SYMBOL_GPL(usb_speed_string);

 /**
  * usb_get_maximum_speed - Get maximum requested speed for a given USB
  * controller.
  * @dev: Pointer to the given USB controller device
  *
  * The function gets the maximum speed string from property "maximum-speed",
  * and returns the corresponding enum usb_device_speed.
  */
 enum usb_device_speed usb_get_maximum_speed(struct device *dev)
 {
 	const char *maximum_speed;
 	int ret;

 	ret = device_property_read_string(dev, "maximum-speed", &maximum_speed);
 	if (ret < 0)
 		return USB_SPEED_UNKNOWN;

 	ret = match_string(ssp_rate, ARRAY_SIZE(ssp_rate), maximum_speed);
 	if (ret > 0)
 		return USB_SPEED_SUPER_PLUS;

 	ret = match_string(speed_names, ARRAY_SIZE(speed_names), maximum_speed);
 	return (ret < 0) ? USB_SPEED_UNKNOWN : ret;
 }
 EXPORT_SYMBOL_GPL(usb_get_maximum_speed);

 /**
  * usb_get_maximum_ssp_rate - Get the signaling rate generation and lane count
  *	of a SuperSpeed Plus capable device.
  * @dev: Pointer to the given USB controller device
  *
  * If the string from "maximum-speed" property is super-speed-plus-genXxY where
  * 'X' is the generation number and 'Y' is the number of lanes, then this
  * function returns the corresponding enum usb_ssp_rate.
  */
 enum usb_ssp_rate usb_get_maximum_ssp_rate(struct device *dev)
 {
 	const char *maximum_speed;
 	int ret;

 	ret = device_property_read_string(dev, "maximum-speed", &maximum_speed);
 	if (ret < 0)
 		return USB_SSP_GEN_UNKNOWN;

 	ret = match_string(ssp_rate, ARRAY_SIZE(ssp_rate), maximum_speed);
 	return (ret < 0) ? USB_SSP_GEN_UNKNOWN : ret;
 }
 EXPORT_SYMBOL_GPL(usb_get_maximum_ssp_rate);

 /**
  * usb_state_string - Returns human readable name for the state.
  * @state: The state to return a human-readable name for. If it's not
  *	any of the states devices in usb_device_state_string enum,
  *	the string UNKNOWN will be returned.
  */
 const char *usb_state_string(enum usb_device_state state)
 {
 	static const char *const names[] = {
 		[USB_STATE_NOTATTACHED] = "not attached",
 		[USB_STATE_ATTACHED] = "attached",
 		[USB_STATE_POWERED] = "powered",
 		[USB_STATE_RECONNECTING] = "reconnecting",
 		[USB_STATE_UNAUTHENTICATED] = "unauthenticated",
 		[USB_STATE_DEFAULT] = "default",
 		[USB_STATE_ADDRESS] = "addressed",
 		[USB_STATE_CONFIGURED] = "configured",
 		[USB_STATE_SUSPENDED] = "suspended",
 	};

 	if (state < 0 || state >= ARRAY_SIZE(names))
 		return "UNKNOWN";

 	return names[state];
 }
 EXPORT_SYMBOL_GPL(usb_state_string);

 static const char *const usb_dr_modes[] = {
 	[USB_DR_MODE_UNKNOWN]		= "",
 	[USB_DR_MODE_HOST]		= "host",
 	[USB_DR_MODE_PERIPHERAL]	= "peripheral",
 	[USB_DR_MODE_OTG]		= "otg",
 };

 static enum usb_dr_mode usb_get_dr_mode_from_string(const char *str)
 {
 	int ret;

 	ret = match_string(usb_dr_modes, ARRAY_SIZE(usb_dr_modes), str);
 	return (ret < 0) ? USB_DR_MODE_UNKNOWN : ret;
 }

 enum usb_dr_mode usb_get_dr_mode(struct device *dev)
 {
 	const char *dr_mode;
 	int err;

 	err = device_property_read_string(dev, "dr_mode", &dr_mode);
 	if (err < 0)
 		return USB_DR_MODE_UNKNOWN;

 	return usb_get_dr_mode_from_string(dr_mode);
 }
 EXPORT_SYMBOL_GPL(usb_get_dr_mode);

 /**
  * usb_get_role_switch_default_mode - Get default mode for given device
  * @dev: Pointer to the given device
  *
  * The function gets string from property 'role-switch-default-mode',
  * and returns the corresponding enum usb_dr_mode.
  */
 enum usb_dr_mode usb_get_role_switch_default_mode(struct device *dev)
 {
 	const char *str;
 	int ret;

 	ret = device_property_read_string(dev, "role-switch-default-mode", &str);
 	if (ret < 0)
 		return USB_DR_MODE_UNKNOWN;

 	return usb_get_dr_mode_from_string(str);
 }
 EXPORT_SYMBOL_GPL(usb_get_role_switch_default_mode);

 /**
  * usb_decode_interval - Decode bInterval into the time expressed in 1us unit
  * @epd: The descriptor of the endpoint
  * @speed: The speed that the endpoint works as
  *
  * Function returns the interval expressed in 1us unit for servicing
  * endpoint for data transfers.
  */
 unsigned int usb_decode_interval(const struct usb_endpoint_descriptor *epd,
 				 enum usb_device_speed speed)
 {
 	unsigned int interval = 0;

 	switch (usb_endpoint_type(epd)) {
 	case USB_ENDPOINT_XFER_CONTROL:
 		/* uframes per NAK */
 		if (speed == USB_SPEED_HIGH)
 			interval = epd->bInterval;
 		break;
 	case USB_ENDPOINT_XFER_ISOC:
 		interval = 1 << (epd->bInterval - 1);
 		break;
 	case USB_ENDPOINT_XFER_BULK:
 		/* uframes per NAK */
 		if (speed == USB_SPEED_HIGH && usb_endpoint_dir_out(epd))
 			interval = epd->bInterval;
 		break;
 	case USB_ENDPOINT_XFER_INT:
 		if (speed >= USB_SPEED_HIGH)
 			interval = 1 << (epd->bInterval - 1);
 		else
 			interval = epd->bInterval;
 		break;
 	}

 	interval *= (speed >= USB_SPEED_HIGH) ? 125 : 1000;

 	return interval;
 }
 EXPORT_SYMBOL_GPL(usb_decode_interval);

 #ifdef CONFIG_OF
 /**
  * of_usb_get_dr_mode_by_phy - Get dual role mode for the controller device
  * which is associated with the given phy device_node
  * @np:	Pointer to the given phy device_node
  * @arg0: phandle args[0] for phy's with #phy-cells >= 1, or -1 for
  *        phys which do not have phy-cells
  *
  * In dts a usb controller associates with phy devices.  The function gets
  * the string from property 'dr_mode' of the controller associated with the
  * given phy device node, and returns the correspondig enum usb_dr_mode.
  */
 enum usb_dr_mode of_usb_get_dr_mode_by_phy(struct device_node *np, int arg0)
 {
 	struct device_node *controller = NULL;
 	struct of_phandle_args args;
 	const char *dr_mode;
 	int index;
 	int err;

 	do {
 		controller = of_find_node_with_property(controller, "phys");
 		if (!of_device_is_available(controller))
 			continue;
 		index = 0;
 		do {
 			if (arg0 == -1) {
 				args.np = of_parse_phandle(controller, "phys",
 							index);
 				args.args_count = 0;
 			} else {
 				err = of_parse_phandle_with_args(controller,
 							"phys", "#phy-cells",
 							index, &args);
 				if (err)
 					break;
 			}

 			of_node_put(args.np);
 			if (args.np == np && (args.args_count == 0 ||
 					      args.args[0] == arg0))
 				goto finish;
 			index++;
 		} while (args.np);
 	} while (controller);

 finish:
 	err = of_property_read_string(controller, "dr_mode", &dr_mode);
 	of_node_put(controller);

 	if (err < 0)
 		return USB_DR_MODE_UNKNOWN;

 	return usb_get_dr_mode_from_string(dr_mode);
 }
 EXPORT_SYMBOL_GPL(of_usb_get_dr_mode_by_phy);

 /**
  * of_usb_host_tpl_support - to get if Targeted Peripheral List is supported
  * for given targeted hosts (non-PC hosts)
  * @np: Pointer to the given device_node
  *
  * The function gets if the targeted hosts support TPL or not
  */
 bool of_usb_host_tpl_support(struct device_node *np)
 {
 	return of_property_read_bool(np, "tpl-support");
 }
 EXPORT_SYMBOL_GPL(of_usb_host_tpl_support);

 /**
  * of_usb_update_otg_caps - to update usb otg capabilities according to
  * the passed properties in DT.
  * @np: Pointer to the given device_node
  * @otg_caps: Pointer to the target usb_otg_caps to be set
  *
  * The function updates the otg capabilities
  */
 int of_usb_update_otg_caps(struct device_node *np,
 			struct usb_otg_caps *otg_caps)
 {
 	u32 otg_rev;

 	if (!otg_caps)
 		return -EINVAL;

 	if (!of_property_read_u32(np, "otg-rev", &otg_rev)) {
 		switch (otg_rev) {
 		case 0x0100:
 		case 0x0120:
 		case 0x0130:
 		case 0x0200:
 			/* Choose the lesser one if it's already been set */
 			if (otg_caps->otg_rev)
 				otg_caps->otg_rev = min_t(u16, otg_rev,
 							otg_caps->otg_rev);
 			else
 				otg_caps->otg_rev = otg_rev;
 			break;
 		default:
 			pr_err("%pOF: unsupported otg-rev: 0x%x\n",
 						np, otg_rev);
 			return -EINVAL;
 		}
 	} else {
 		/*
 		 * otg-rev is mandatory for otg properties, if not passed
 		 * we set it to be 0 and assume it's a legacy otg device.
 		 * Non-dt platform can set it afterwards.
 		 */
 		otg_caps->otg_rev = 0;
 	}

 	if (of_property_read_bool(np, "hnp-disable"))
 		otg_caps->hnp_support = false;
 	if (of_property_read_bool(np, "srp-disable"))
 		otg_caps->srp_support = false;
 	if (of_property_read_bool(np, "adp-disable") ||
 				(otg_caps->otg_rev < 0x0200))
 		otg_caps->adp_support = false;

 	return 0;
 }
 EXPORT_SYMBOL_GPL(of_usb_update_otg_caps);

 /**
  * usb_of_get_companion_dev - Find the companion device
  * @dev: the device pointer to find a companion
  *
  * Find the companion device from platform bus.
  *
  * Takes a reference to the returned struct device which needs to be dropped
  * after use.
  *
  * Return: On success, a pointer to the companion device, %NULL on failure.
  */
 struct device *usb_of_get_companion_dev(struct device *dev)
 {
 	struct device_node *node;
 	struct platform_device *pdev = NULL;

 	node = of_parse_phandle(dev->of_node, "companion", 0);
 	if (node)
 		pdev = of_find_device_by_node(node);

 	of_node_put(node);

 	return pdev ? &pdev->dev : NULL;
 }
 EXPORT_SYMBOL_GPL(usb_of_get_companion_dev);
 #endif

 struct dentry *usb_debug_root;
 EXPORT_SYMBOL_GPL(usb_debug_root);

 static int __init usb_common_init(void)
 {
 	usb_debug_root = debugfs_create_dir("usb", NULL);
 	ledtrig_usb_init();
 	return 0;
 }

 static void __exit usb_common_exit(void)
 {
 	ledtrig_usb_exit();
 	debugfs_remove_recursive(usb_debug_root);
 }

 subsys_initcall(usb_common_init);
 module_exit(usb_common_exit);

 MODULE_DESCRIPTION("Common code for host and device side USB");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0
	/*
	* Provides code common for host and device side USB.
	*
	* If either host side (ie. CONFIG_USB=y) or device side USB stack
	* (ie. CONFIG_USB_GADGET=y) is compiled in the kernel, this module is
	* compiled-in as well. Otherwise, if either of the two stacks is
	* compiled as module, this file is compiled as module as well.
	*/

	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/platform_device.h>
	#include <linux/usb/ch9.h>
	#include <linux/usb/of.h>
	#include <linux/usb/otg.h>
	#include <linux/of_platform.h>
	#include <linux/debugfs.h>
	#include "common.h"

	static const char *const ep_type_names[] = {
	[USB_ENDPOINT_XFER_CONTROL] = "ctrl",
	[USB_ENDPOINT_XFER_ISOC] = "isoc",
	[USB_ENDPOINT_XFER_BULK] = "bulk",
	[USB_ENDPOINT_XFER_INT] = "intr",
	};

	/**
	* usb_ep_type_string() - Returns human readable-name of the endpoint type.
	* @ep_type: The endpoint type to return human-readable name for. If it's not
	* any of the types: USB_ENDPOINT_XFER_{CONTROL, ISOC, BULK, INT},
	* usually got by usb_endpoint_type(), the string 'unknown' will be returned.
	*/
	const char *usb_ep_type_string(int ep_type)
	{
	if (ep_type < 0 \|\| ep_type >= ARRAY_SIZE(ep_type_names))
	return "unknown";

	return ep_type_names[ep_type];
	}
	EXPORT_SYMBOL_GPL(usb_ep_type_string);

	const char *usb_otg_state_string(enum usb_otg_state state)
	{
	static const char *const names[] = {
	[OTG_STATE_A_IDLE] = "a_idle",
	[OTG_STATE_A_WAIT_VRISE] = "a_wait_vrise",
	[OTG_STATE_A_WAIT_BCON] = "a_wait_bcon",
	[OTG_STATE_A_HOST] = "a_host",
	[OTG_STATE_A_SUSPEND] = "a_suspend",
	[OTG_STATE_A_PERIPHERAL] = "a_peripheral",
	[OTG_STATE_A_WAIT_VFALL] = "a_wait_vfall",
	[OTG_STATE_A_VBUS_ERR] = "a_vbus_err",
	[OTG_STATE_B_IDLE] = "b_idle",
	[OTG_STATE_B_SRP_INIT] = "b_srp_init",
	[OTG_STATE_B_PERIPHERAL] = "b_peripheral",
	[OTG_STATE_B_WAIT_ACON] = "b_wait_acon",
	[OTG_STATE_B_HOST] = "b_host",
	};

	if (state < 0 \|\| state >= ARRAY_SIZE(names))
	return "UNDEFINED";

	return names[state];
	}
	EXPORT_SYMBOL_GPL(usb_otg_state_string);

	static const char *const speed_names[] = {
	[USB_SPEED_UNKNOWN] = "UNKNOWN",
	[USB_SPEED_LOW] = "low-speed",
	[USB_SPEED_FULL] = "full-speed",
	[USB_SPEED_HIGH] = "high-speed",
	[USB_SPEED_WIRELESS] = "wireless",
	[USB_SPEED_SUPER] = "super-speed",
	[USB_SPEED_SUPER_PLUS] = "super-speed-plus",
	};

	static const char *const ssp_rate[] = {
	[USB_SSP_GEN_UNKNOWN] = "UNKNOWN",
	[USB_SSP_GEN_2x1] = "super-speed-plus-gen2x1",
	[USB_SSP_GEN_1x2] = "super-speed-plus-gen1x2",
	[USB_SSP_GEN_2x2] = "super-speed-plus-gen2x2",
	};

	/**
	* usb_speed_string() - Returns human readable-name of the speed.
	* @speed: The speed to return human-readable name for. If it's not
	* any of the speeds defined in usb_device_speed enum, string for
	* USB_SPEED_UNKNOWN will be returned.
	*/
	const char *usb_speed_string(enum usb_device_speed speed)
	{
	if (speed < 0 \|\| speed >= ARRAY_SIZE(speed_names))
	speed = USB_SPEED_UNKNOWN;
	return speed_names[speed];
	}
	EXPORT_SYMBOL_GPL(usb_speed_string);

	/**
	* usb_get_maximum_speed - Get maximum requested speed for a given USB
	* controller.
	* @dev: Pointer to the given USB controller device
	*
	* The function gets the maximum speed string from property "maximum-speed",
	* and returns the corresponding enum usb_device_speed.
	*/
	enum usb_device_speed usb_get_maximum_speed(struct device *dev)
	{
	const char *maximum_speed;
	int ret;

	ret = device_property_read_string(dev, "maximum-speed", &maximum_speed);
	if (ret < 0)
	return USB_SPEED_UNKNOWN;

	ret = match_string(ssp_rate, ARRAY_SIZE(ssp_rate), maximum_speed);
	if (ret > 0)
	return USB_SPEED_SUPER_PLUS;

	ret = match_string(speed_names, ARRAY_SIZE(speed_names), maximum_speed);
	return (ret < 0) ? USB_SPEED_UNKNOWN : ret;
	}
	EXPORT_SYMBOL_GPL(usb_get_maximum_speed);

	/**
	* usb_get_maximum_ssp_rate - Get the signaling rate generation and lane count
	* of a SuperSpeed Plus capable device.
	* @dev: Pointer to the given USB controller device
	*
	* If the string from "maximum-speed" property is super-speed-plus-genXxY where
	* 'X' is the generation number and 'Y' is the number of lanes, then this
	* function returns the corresponding enum usb_ssp_rate.
	*/
	enum usb_ssp_rate usb_get_maximum_ssp_rate(struct device *dev)
	{
	const char *maximum_speed;
	int ret;

	ret = device_property_read_string(dev, "maximum-speed", &maximum_speed);
	if (ret < 0)
	return USB_SSP_GEN_UNKNOWN;

	ret = match_string(ssp_rate, ARRAY_SIZE(ssp_rate), maximum_speed);
	return (ret < 0) ? USB_SSP_GEN_UNKNOWN : ret;
	}
	EXPORT_SYMBOL_GPL(usb_get_maximum_ssp_rate);

	/**
	* usb_state_string - Returns human readable name for the state.
	* @state: The state to return a human-readable name for. If it's not
	* any of the states devices in usb_device_state_string enum,
	* the string UNKNOWN will be returned.
	*/
	const char *usb_state_string(enum usb_device_state state)
	{
	static const char *const names[] = {
	[USB_STATE_NOTATTACHED] = "not attached",
	[USB_STATE_ATTACHED] = "attached",
	[USB_STATE_POWERED] = "powered",
	[USB_STATE_RECONNECTING] = "reconnecting",
	[USB_STATE_UNAUTHENTICATED] = "unauthenticated",
	[USB_STATE_DEFAULT] = "default",
	[USB_STATE_ADDRESS] = "addressed",
	[USB_STATE_CONFIGURED] = "configured",
	[USB_STATE_SUSPENDED] = "suspended",
	};

	if (state < 0 \|\| state >= ARRAY_SIZE(names))
	return "UNKNOWN";

	return names[state];
	}
	EXPORT_SYMBOL_GPL(usb_state_string);

	static const char *const usb_dr_modes[] = {
	[USB_DR_MODE_UNKNOWN] = "",
	[USB_DR_MODE_HOST] = "host",
	[USB_DR_MODE_PERIPHERAL] = "peripheral",
	[USB_DR_MODE_OTG] = "otg",
	};

	static enum usb_dr_mode usb_get_dr_mode_from_string(const char *str)
	{
	int ret;

	ret = match_string(usb_dr_modes, ARRAY_SIZE(usb_dr_modes), str);
	return (ret < 0) ? USB_DR_MODE_UNKNOWN : ret;
	}

	enum usb_dr_mode usb_get_dr_mode(struct device *dev)
	{
	const char *dr_mode;
	int err;

	err = device_property_read_string(dev, "dr_mode", &dr_mode);
	if (err < 0)
	return USB_DR_MODE_UNKNOWN;

	return usb_get_dr_mode_from_string(dr_mode);
	}
	EXPORT_SYMBOL_GPL(usb_get_dr_mode);

	/**
	* usb_get_role_switch_default_mode - Get default mode for given device
	* @dev: Pointer to the given device
	*
	* The function gets string from property 'role-switch-default-mode',
	* and returns the corresponding enum usb_dr_mode.
	*/
	enum usb_dr_mode usb_get_role_switch_default_mode(struct device *dev)
	{
	const char *str;
	int ret;

	ret = device_property_read_string(dev, "role-switch-default-mode", &str);
	if (ret < 0)
	return USB_DR_MODE_UNKNOWN;

	return usb_get_dr_mode_from_string(str);
	}
	EXPORT_SYMBOL_GPL(usb_get_role_switch_default_mode);

	/**
	* usb_decode_interval - Decode bInterval into the time expressed in 1us unit
	* @epd: The descriptor of the endpoint
	* @speed: The speed that the endpoint works as
	*
	* Function returns the interval expressed in 1us unit for servicing
	* endpoint for data transfers.
	*/
	unsigned int usb_decode_interval(const struct usb_endpoint_descriptor *epd,
	enum usb_device_speed speed)
	{
	unsigned int interval = 0;

	switch (usb_endpoint_type(epd)) {
	case USB_ENDPOINT_XFER_CONTROL:
	/* uframes per NAK */
	if (speed == USB_SPEED_HIGH)
	interval = epd->bInterval;
	break;
	case USB_ENDPOINT_XFER_ISOC:
	interval = 1 << (epd->bInterval - 1);
	break;
	case USB_ENDPOINT_XFER_BULK:
	/* uframes per NAK */
	if (speed == USB_SPEED_HIGH && usb_endpoint_dir_out(epd))
	interval = epd->bInterval;
	break;
	case USB_ENDPOINT_XFER_INT:
	if (speed >= USB_SPEED_HIGH)
	interval = 1 << (epd->bInterval - 1);
	else
	interval = epd->bInterval;
	break;
	}

	interval *= (speed >= USB_SPEED_HIGH) ? 125 : 1000;

	return interval;
	}
	EXPORT_SYMBOL_GPL(usb_decode_interval);

	#ifdef CONFIG_OF
	/**
	* of_usb_get_dr_mode_by_phy - Get dual role mode for the controller device
	* which is associated with the given phy device_node
	* @np: Pointer to the given phy device_node
	* @arg0: phandle args[0] for phy's with #phy-cells >= 1, or -1 for
	* phys which do not have phy-cells
	*
	* In dts a usb controller associates with phy devices. The function gets
	* the string from property 'dr_mode' of the controller associated with the
	* given phy device node, and returns the correspondig enum usb_dr_mode.
	*/
	enum usb_dr_mode of_usb_get_dr_mode_by_phy(struct device_node *np, int arg0)
	{
	struct device_node *controller = NULL;
	struct of_phandle_args args;
	const char *dr_mode;
	int index;
	int err;

	do {
	controller = of_find_node_with_property(controller, "phys");
	if (!of_device_is_available(controller))
	continue;
	index = 0;
	do {
	if (arg0 == -1) {
	args.np = of_parse_phandle(controller, "phys",
	index);
	args.args_count = 0;
	} else {
	err = of_parse_phandle_with_args(controller,
	"phys", "#phy-cells",
	index, &args);
	if (err)
	break;
	}

	of_node_put(args.np);
	if (args.np == np && (args.args_count == 0 \|\|
	args.args[0] == arg0))
	goto finish;
	index++;
	} while (args.np);
	} while (controller);

	finish:
	err = of_property_read_string(controller, "dr_mode", &dr_mode);
	of_node_put(controller);

	if (err < 0)
	return USB_DR_MODE_UNKNOWN;

	return usb_get_dr_mode_from_string(dr_mode);
	}
	EXPORT_SYMBOL_GPL(of_usb_get_dr_mode_by_phy);

	/**
	* of_usb_host_tpl_support - to get if Targeted Peripheral List is supported
	* for given targeted hosts (non-PC hosts)
	* @np: Pointer to the given device_node
	*
	* The function gets if the targeted hosts support TPL or not
	*/
	bool of_usb_host_tpl_support(struct device_node *np)
	{
	return of_property_read_bool(np, "tpl-support");
	}
	EXPORT_SYMBOL_GPL(of_usb_host_tpl_support);

	/**
	* of_usb_update_otg_caps - to update usb otg capabilities according to
	* the passed properties in DT.
	* @np: Pointer to the given device_node
	* @otg_caps: Pointer to the target usb_otg_caps to be set
	*
	* The function updates the otg capabilities
	*/
	int of_usb_update_otg_caps(struct device_node *np,
	struct usb_otg_caps *otg_caps)
	{
	u32 otg_rev;

	if (!otg_caps)
	return -EINVAL;

	if (!of_property_read_u32(np, "otg-rev", &otg_rev)) {
	switch (otg_rev) {
	case 0x0100:
	case 0x0120:
	case 0x0130:
	case 0x0200:
	/* Choose the lesser one if it's already been set */
	if (otg_caps->otg_rev)
	otg_caps->otg_rev = min_t(u16, otg_rev,
	otg_caps->otg_rev);
	else
	otg_caps->otg_rev = otg_rev;
	break;
	default:
	pr_err("%pOF: unsupported otg-rev: 0x%x\n",
	np, otg_rev);
	return -EINVAL;
	}
	} else {
	/*
	* otg-rev is mandatory for otg properties, if not passed
	* we set it to be 0 and assume it's a legacy otg device.
	* Non-dt platform can set it afterwards.
	*/
	otg_caps->otg_rev = 0;
	}

	if (of_property_read_bool(np, "hnp-disable"))
	otg_caps->hnp_support = false;
	if (of_property_read_bool(np, "srp-disable"))
	otg_caps->srp_support = false;
	if (of_property_read_bool(np, "adp-disable") \|\|
	(otg_caps->otg_rev < 0x0200))
	otg_caps->adp_support = false;

	return 0;
	}
	EXPORT_SYMBOL_GPL(of_usb_update_otg_caps);

	/**
	* usb_of_get_companion_dev - Find the companion device
	* @dev: the device pointer to find a companion
	*
	* Find the companion device from platform bus.
	*
	* Takes a reference to the returned struct device which needs to be dropped
	* after use.
	*
	* Return: On success, a pointer to the companion device, %NULL on failure.
	*/
	struct device usb_of_get_companion_dev(struct device dev)
	{
	struct device_node *node;
	struct platform_device *pdev = NULL;

	node = of_parse_phandle(dev->of_node, "companion", 0);
	if (node)
	pdev = of_find_device_by_node(node);

	of_node_put(node);

	return pdev ? &pdev->dev : NULL;
	}
	EXPORT_SYMBOL_GPL(usb_of_get_companion_dev);
	#endif

	struct dentry *usb_debug_root;
	EXPORT_SYMBOL_GPL(usb_debug_root);

	static int __init usb_common_init(void)
	{
	usb_debug_root = debugfs_create_dir("usb", NULL);
	ledtrig_usb_init();
	return 0;
	}

	static void __exit usb_common_exit(void)
	{
	ledtrig_usb_exit();
	debugfs_remove_recursive(usb_debug_root);
	}

	subsys_initcall(usb_common_init);
	module_exit(usb_common_exit);

	MODULE_DESCRIPTION("Common code for host and device side USB");
	MODULE_LICENSE("GPL");