drivers/staging/greybus/arche-platform.c - kernel/msm-4.9 - Gitiles

 /*
  * Arche Platform driver to enable Unipro link.
  *
  * Copyright 2014-2015 Google Inc.
  * Copyright 2014-2015 Linaro Ltd.
  *
  * Released under the GPLv2 only.
  */

 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/gpio.h>
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/of_gpio.h>
 #include <linux/of_platform.h>
 #include <linux/pinctrl/consumer.h>
 #include <linux/platform_device.h>
 #include <linux/pm.h>
 #include "arche_platform.h"

 #include <linux/usb/usb3613.h>

 struct arche_platform_drvdata {
 	/* Control GPIO signals to and from AP <=> SVC */
 	int svc_reset_gpio;
 	bool is_reset_act_hi;
 	int svc_sysboot_gpio;
 	int wake_detect_gpio; /* bi-dir,maps to WAKE_MOD & WAKE_FRAME signals */

 	enum arche_platform_state state;

 	unsigned int svc_refclk_req;
 	struct clk *svc_ref_clk;

 	struct pinctrl *pinctrl;
 	struct pinctrl_state *pin_default;

 	int num_apbs;

 	struct delayed_work delayed_work;
 	struct device *dev;
 };

 static inline void svc_reset_onoff(unsigned int gpio, bool onoff)
 {
 	gpio_set_value(gpio, onoff);
 }

 static int apb_cold_boot(struct device *dev, void *data)
 {
 	int ret;

 	ret = apb_ctrl_coldboot(dev);
 	if (ret)
 		dev_warn(dev, "failed to coldboot\n");

 	/*Child nodes are independent, so do not exit coldboot operation */
 	return 0;
 }

 static int apb_fw_flashing_state(struct device *dev, void *data)
 {
 	int ret;

 	ret = apb_ctrl_fw_flashing(dev);
 	if (ret)
 		dev_warn(dev, "failed to switch to fw flashing state\n");

 	/*Child nodes are independent, so do not exit coldboot operation */
 	return 0;
 }

 static int apb_poweroff(struct device *dev, void *data)
 {
 	apb_ctrl_poweroff(dev);

 	return 0;
 }

 /**
  * svc_delayed_work - Time to give SVC to boot.
  */
 static void svc_delayed_work(struct work_struct *work)
 {
 	struct arche_platform_drvdata *arche_pdata =
 		container_of(work, struct arche_platform_drvdata, delayed_work.work);
 	int timeout = 50;

 	/*
 	 * 1.   SVC and AP boot independently, with AP<-->SVC wake/detect pin
 	 *      deasserted (LOW in this case)
 	 * 2.1. SVC allows 360 milliseconds to elapse after switch boots to work
 	 *      around bug described in ENG-330.
 	 * 2.2. AP asserts wake/detect pin (HIGH) (this can proceed in parallel with 2.1)
 	 * 3.   SVC detects assertion of wake/detect pin, and sends "wake out" signal to AP
 	 * 4.   AP receives "wake out" signal, takes AP Bridges through their power
 	 *      on reset sequence as defined in the bridge ASIC reference manuals
 	 * 5. AP takes USB3613 through its power on reset sequence
 	 * 6. AP enumerates AP Bridges
 	 */
 	gpio_set_value(arche_pdata->wake_detect_gpio, 1);
 	gpio_direction_input(arche_pdata->wake_detect_gpio);
 	do {
 		/* Read the wake_detect GPIO, for WAKE_OUT event from SVC */
 		if (gpio_get_value(arche_pdata->wake_detect_gpio) == 0)
 			break;

 		msleep(100);
 	} while(timeout--);

 	if (timeout < 0) {
 		/* FIXME: We may want to limit retries here */
 		dev_warn(arche_pdata->dev,
 			"Timed out on wake/detect, rescheduling handshake\n");
 		gpio_direction_output(arche_pdata->wake_detect_gpio, 0);
 		schedule_delayed_work(&arche_pdata->delayed_work, msecs_to_jiffies(2000));
 		return;
 	}

 	/* Bring APB out of reset: cold boot sequence */
 	device_for_each_child(arche_pdata->dev, NULL, apb_cold_boot);

 	/* re-assert wake_detect to confirm SVC WAKE_OUT */
 	gpio_direction_output(arche_pdata->wake_detect_gpio, 1);

 	/* Enable HUB3613 into HUB mode. */
 	if (usb3613_hub_mode_ctrl(true))
 		dev_warn(arche_pdata->dev, "failed to control hub device\n");
 }

 static int arche_platform_coldboot_seq(struct arche_platform_drvdata *arche_pdata)
 {
 	int ret;

 	dev_info(arche_pdata->dev, "Booting from cold boot state\n");

 	svc_reset_onoff(arche_pdata->svc_reset_gpio,
 			arche_pdata->is_reset_act_hi);

 	gpio_set_value(arche_pdata->svc_sysboot_gpio, 0);
 	usleep_range(100, 200);

 	ret = clk_prepare_enable(arche_pdata->svc_ref_clk);
 	if (ret) {
 		dev_err(arche_pdata->dev, "failed to enable svc_ref_clk: %d\n",
 				ret);
 		return ret;
 	}

 	/* bring SVC out of reset */
 	svc_reset_onoff(arche_pdata->svc_reset_gpio,
 			!arche_pdata->is_reset_act_hi);

 	arche_pdata->state = ARCHE_PLATFORM_STATE_ACTIVE;

 	return 0;
 }

 static void arche_platform_fw_flashing_seq(struct arche_platform_drvdata *arche_pdata)
 {
 	dev_info(arche_pdata->dev, "Switching to FW flashing state\n");

 	svc_reset_onoff(arche_pdata->svc_reset_gpio,
 			arche_pdata->is_reset_act_hi);

 	gpio_set_value(arche_pdata->svc_sysboot_gpio, 1);

 	usleep_range(100, 200);
 	svc_reset_onoff(arche_pdata->svc_reset_gpio,
 			!arche_pdata->is_reset_act_hi);

 	arche_pdata->state = ARCHE_PLATFORM_STATE_FW_FLASHING;

 }

 static void arche_platform_poweroff_seq(struct arche_platform_drvdata *arche_pdata)
 {
 	/* Send disconnect/detach event to SVC */
 	gpio_set_value(arche_pdata->wake_detect_gpio, 0);
 	usleep_range(100, 200);

 	clk_disable_unprepare(arche_pdata->svc_ref_clk);
 	/* As part of exit, put APB back in reset state */
 	svc_reset_onoff(arche_pdata->svc_reset_gpio,
 			arche_pdata->is_reset_act_hi);

 	arche_pdata->state = ARCHE_PLATFORM_STATE_OFF;
 }

 static ssize_t state_store(struct device *dev,
 		struct device_attribute *attr, const char *buf, size_t count)
 {
 	struct platform_device *pdev = to_platform_device(dev);
 	struct arche_platform_drvdata *arche_pdata = platform_get_drvdata(pdev);
 	int ret = 0;

 	if (sysfs_streq(buf, "off")) {
 		if (arche_pdata->state == ARCHE_PLATFORM_STATE_OFF)
 			return count;

 		/*  If SVC goes down, bring down APB's as well */
 		device_for_each_child(arche_pdata->dev, NULL, apb_poweroff);

 		arche_platform_poweroff_seq(arche_pdata);

 		ret = usb3613_hub_mode_ctrl(false);
 		if (ret)
 			dev_warn(arche_pdata->dev, "failed to control hub device\n");
 			/* TODO: Should we do anything more here ?? */
 	} else if (sysfs_streq(buf, "active")) {
 		if (arche_pdata->state == ARCHE_PLATFORM_STATE_ACTIVE)
 			return count;

 		ret = arche_platform_coldboot_seq(arche_pdata);
 		/* Give enough time for SVC to boot and then handshake with SVC */
 		schedule_delayed_work(&arche_pdata->delayed_work, msecs_to_jiffies(2000));
 	} else if (sysfs_streq(buf, "standby")) {
 		if (arche_pdata->state == ARCHE_PLATFORM_STATE_STANDBY)
 			return count;

 		dev_warn(arche_pdata->dev, "standby state not supported\n");
 	} else if (sysfs_streq(buf, "fw_flashing")) {
 		if (arche_pdata->state == ARCHE_PLATFORM_STATE_FW_FLASHING)
 			return count;

 		/* First we want to make sure we power off everything
 		 * and then enter FW flashing state */
 		device_for_each_child(arche_pdata->dev, NULL, apb_poweroff);

 		arche_platform_poweroff_seq(arche_pdata);

 		ret = usb3613_hub_mode_ctrl(false);
 		if (ret)
 			dev_warn(arche_pdata->dev, "failed to control hub device\n");
 			/* TODO: Should we do anything more here ?? */

 		arche_platform_fw_flashing_seq(arche_pdata);

 		device_for_each_child(arche_pdata->dev, NULL, apb_fw_flashing_state);
 	} else {
 		dev_err(arche_pdata->dev, "unknown state\n");
 		ret = -EINVAL;
 	}

 	return ret ? ret : count;
 }

 static ssize_t state_show(struct device *dev,
 		struct device_attribute *attr, char *buf)
 {
 	struct arche_platform_drvdata *arche_pdata = dev_get_drvdata(dev);

 	switch (arche_pdata->state) {
 	case ARCHE_PLATFORM_STATE_OFF:
 		return sprintf(buf, "off\n");
 	case ARCHE_PLATFORM_STATE_ACTIVE:
 		return sprintf(buf, "active\n");
 	case ARCHE_PLATFORM_STATE_STANDBY:
 		return sprintf(buf, "standby\n");
 	case ARCHE_PLATFORM_STATE_FW_FLASHING:
 		return sprintf(buf, "fw_flashing\n");
 	default:
 		return sprintf(buf, "unknown state\n");
 	}
 }

 static DEVICE_ATTR_RW(state);

 static int arche_platform_probe(struct platform_device *pdev)
 {
 	struct arche_platform_drvdata *arche_pdata;
 	struct device *dev = &pdev->dev;
 	struct device_node *np = dev->of_node;
 	int ret;

 	arche_pdata = devm_kzalloc(&pdev->dev, sizeof(*arche_pdata), GFP_KERNEL);
 	if (!arche_pdata)
 		return -ENOMEM;

 	/* setup svc reset gpio */
 	arche_pdata->is_reset_act_hi = of_property_read_bool(np,
 					"svc,reset-active-high");
 	arche_pdata->svc_reset_gpio = of_get_named_gpio(np, "svc,reset-gpio", 0);
 	if (arche_pdata->svc_reset_gpio < 0) {
 		dev_err(dev, "failed to get reset-gpio\n");
 		return arche_pdata->svc_reset_gpio;
 	}
 	ret = devm_gpio_request(dev, arche_pdata->svc_reset_gpio, "svc-reset");
 	if (ret) {
 		dev_err(dev, "failed to request svc-reset gpio:%d\n", ret);
 		return ret;
 	}
 	ret = gpio_direction_output(arche_pdata->svc_reset_gpio,
 					arche_pdata->is_reset_act_hi);
 	if (ret) {
 		dev_err(dev, "failed to set svc-reset gpio dir:%d\n", ret);
 		return ret;
 	}
 	arche_pdata->state = ARCHE_PLATFORM_STATE_OFF;

 	arche_pdata->svc_sysboot_gpio = of_get_named_gpio(np,
 					"svc,sysboot-gpio", 0);
 	if (arche_pdata->svc_sysboot_gpio < 0) {
 		dev_err(dev, "failed to get sysboot gpio\n");
 		return arche_pdata->svc_sysboot_gpio;
 	}
 	ret = devm_gpio_request(dev, arche_pdata->svc_sysboot_gpio, "sysboot0");
 	if (ret) {
 		dev_err(dev, "failed to request sysboot0 gpio:%d\n", ret);
 		return ret;
 	}
 	ret = gpio_direction_output(arche_pdata->svc_sysboot_gpio, 0);
 	if (ret) {
 		dev_err(dev, "failed to set svc-reset gpio dir:%d\n", ret);
 		return ret;
 	}

 	/* setup the clock request gpio first */
 	arche_pdata->svc_refclk_req = of_get_named_gpio(np,
 					"svc,refclk-req-gpio", 0);
 	if (arche_pdata->svc_refclk_req < 0) {
 		dev_err(dev, "failed to get svc clock-req gpio\n");
 		return arche_pdata->svc_refclk_req;
 	}
 	ret = devm_gpio_request(dev, arche_pdata->svc_refclk_req, "svc-clk-req");
 	if (ret) {
 		dev_err(dev, "failed to request svc-clk-req gpio: %d\n", ret);
 		return ret;
 	}
 	ret = gpio_direction_input(arche_pdata->svc_refclk_req);
 	if (ret) {
 		dev_err(dev, "failed to set svc-clk-req gpio dir :%d\n", ret);
 		return ret;
 	}

 	/* setup refclk2 to follow the pin */
 	arche_pdata->svc_ref_clk = devm_clk_get(dev, "svc_ref_clk");
 	if (IS_ERR(arche_pdata->svc_ref_clk)) {
 		ret = PTR_ERR(arche_pdata->svc_ref_clk);
 		dev_err(dev, "failed to get svc_ref_clk: %d\n", ret);
 		return ret;
 	}

 	platform_set_drvdata(pdev, arche_pdata);

 	arche_pdata->num_apbs = of_get_child_count(np);
 	dev_dbg(dev, "Number of APB's available - %d\n", arche_pdata->num_apbs);

 	arche_pdata->wake_detect_gpio = of_get_named_gpio(np, "svc,wake-detect-gpio", 0);
 	if (arche_pdata->wake_detect_gpio < 0) {
 		dev_err(dev, "failed to get wake detect gpio\n");
 		ret = arche_pdata->wake_detect_gpio;
 		return ret;
 	}

 	ret = devm_gpio_request(dev, arche_pdata->wake_detect_gpio, "wake detect");
 	if (ret) {
 		dev_err(dev, "Failed requesting wake_detect gpio %d\n",
 				arche_pdata->wake_detect_gpio);
 		return ret;
 	}
 	/* deassert wake detect */
 	gpio_direction_output(arche_pdata->wake_detect_gpio, 0);

 	arche_pdata->dev = &pdev->dev;

 	ret = device_create_file(dev, &dev_attr_state);
 	if (ret) {
 		dev_err(dev, "failed to create state file in sysfs\n");
 		return ret;
 	}

 	ret = arche_platform_coldboot_seq(arche_pdata);
 	if (ret) {
 		dev_err(dev, "Failed to cold boot svc %d\n", ret);
 		return ret;
 	}

 	ret = of_platform_populate(np, NULL, NULL, dev);
 	if (ret) {
 		dev_err(dev, "failed to populate child nodes %d\n", ret);
 		return ret;
 	}

 	INIT_DELAYED_WORK(&arche_pdata->delayed_work, svc_delayed_work);
 	schedule_delayed_work(&arche_pdata->delayed_work, msecs_to_jiffies(2000));

 	dev_info(dev, "Device registered successfully\n");
 	return 0;
 }

 static int arche_remove_child(struct device *dev, void *unused)
 {
 	struct platform_device *pdev = to_platform_device(dev);

 	platform_device_unregister(pdev);

 	return 0;
 }

 static int arche_platform_remove(struct platform_device *pdev)
 {
 	struct arche_platform_drvdata *arche_pdata = platform_get_drvdata(pdev);

 	device_remove_file(&pdev->dev, &dev_attr_state);
 	cancel_delayed_work_sync(&arche_pdata->delayed_work);
 	device_for_each_child(&pdev->dev, NULL, arche_remove_child);
 	arche_platform_poweroff_seq(arche_pdata);
 	platform_set_drvdata(pdev, NULL);

 	if (usb3613_hub_mode_ctrl(false))
 		dev_warn(arche_pdata->dev, "failed to control hub device\n");
 		/* TODO: Should we do anything more here ?? */
 	return 0;
 }

 static int arche_platform_suspend(struct device *dev)
 {
 	/*
 	 * If timing profile premits, we may shutdown bridge
 	 * completely
 	 *
 	 * TODO: sequence ??
 	 *
 	 * Also, need to make sure we meet precondition for unipro suspend
 	 * Precondition: Definition ???
 	 */
 	return 0;
 }

 static int arche_platform_resume(struct device *dev)
 {
 	/*
 	 * Atleast for ES2 we have to meet the delay requirement between
 	 * unipro switch and AP bridge init, depending on whether bridge is in
 	 * OFF state or standby state.
 	 *
 	 * Based on whether bridge is in standby or OFF state we may have to
 	 * assert multiple signals. Please refer to WDM spec, for more info.
 	 *
 	 */
 	return 0;
 }

 static SIMPLE_DEV_PM_OPS(arche_platform_pm_ops,
 			arche_platform_suspend,
 			arche_platform_resume);

 static struct of_device_id arche_platform_of_match[] = {
 	{ .compatible = "google,arche-platform", }, /* Use PID/VID of SVC device */
 	{ },
 };

 static struct of_device_id arche_apb_ctrl_of_match[] = {
 	{ .compatible = "usbffff,2", },
 	{ },
 };

 static struct of_device_id arche_combined_id[] = {
 	{ .compatible = "google,arche-platform", }, /* Use PID/VID of SVC device */
 	{ .compatible = "usbffff,2", },
 	{ },
 };
 MODULE_DEVICE_TABLE(of, arche_combined_id);

 static struct platform_driver arche_platform_device_driver = {
 	.probe		= arche_platform_probe,
 	.remove		= arche_platform_remove,
 	.driver		= {
 		.name	= "arche-platform-ctrl",
 		.pm	= &arche_platform_pm_ops,
 		.of_match_table = arche_platform_of_match,
 	}
 };

 static struct platform_driver arche_apb_ctrl_device_driver = {
 	.probe		= arche_apb_ctrl_probe,
 	.remove		= arche_apb_ctrl_remove,
 	.driver		= {
 		.name	= "arche-apb-ctrl",
 		.pm	= &arche_apb_ctrl_pm_ops,
 		.of_match_table = arche_apb_ctrl_of_match,
 	}
 };

 static int __init arche_init(void)
 {
 	int retval;

 	retval = platform_driver_register(&arche_platform_device_driver);
 	if (retval)
 		return retval;

 	retval = platform_driver_register(&arche_apb_ctrl_device_driver);
 	if (retval)
 		platform_driver_unregister(&arche_platform_device_driver);

 	return retval;
 }
 module_init(arche_init);

 static void __exit arche_exit(void)
 {
 	platform_driver_unregister(&arche_apb_ctrl_device_driver);
 	platform_driver_unregister(&arche_platform_device_driver);
 }
 module_exit(arche_exit);

 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Vaibhav Hiremath <vaibhav.hiremath@linaro.org>");
 MODULE_DESCRIPTION("Arche Platform Driver");
	/*
	* Arche Platform driver to enable Unipro link.
	*
	* Copyright 2014-2015 Google Inc.
	* Copyright 2014-2015 Linaro Ltd.
	*
	* Released under the GPLv2 only.
	*/

	#include <linux/clk.h>
	#include <linux/delay.h>
	#include <linux/gpio.h>
	#include <linux/init.h>
	#include <linux/module.h>
	#include <linux/of_gpio.h>
	#include <linux/of_platform.h>
	#include <linux/pinctrl/consumer.h>
	#include <linux/platform_device.h>
	#include <linux/pm.h>
	#include "arche_platform.h"

	#include <linux/usb/usb3613.h>

	struct arche_platform_drvdata {
	/* Control GPIO signals to and from AP <=> SVC */
	int svc_reset_gpio;
	bool is_reset_act_hi;
	int svc_sysboot_gpio;
	int wake_detect_gpio; /* bi-dir,maps to WAKE_MOD & WAKE_FRAME signals */

	enum arche_platform_state state;

	unsigned int svc_refclk_req;
	struct clk *svc_ref_clk;

	struct pinctrl *pinctrl;
	struct pinctrl_state *pin_default;

	int num_apbs;

	struct delayed_work delayed_work;
	struct device *dev;
	};

	static inline void svc_reset_onoff(unsigned int gpio, bool onoff)
	{
	gpio_set_value(gpio, onoff);
	}

	static int apb_cold_boot(struct device dev, void data)
	{
	int ret;

	ret = apb_ctrl_coldboot(dev);
	if (ret)
	dev_warn(dev, "failed to coldboot\n");

	/Child nodes are independent, so do not exit coldboot operation /
	return 0;
	}

	static int apb_fw_flashing_state(struct device dev, void data)
	{
	int ret;

	ret = apb_ctrl_fw_flashing(dev);
	if (ret)
	dev_warn(dev, "failed to switch to fw flashing state\n");

	/Child nodes are independent, so do not exit coldboot operation /
	return 0;
	}

	static int apb_poweroff(struct device dev, void data)
	{
	apb_ctrl_poweroff(dev);

	return 0;
	}

	/**
	* svc_delayed_work - Time to give SVC to boot.
	*/
	static void svc_delayed_work(struct work_struct *work)
	{
	struct arche_platform_drvdata *arche_pdata =
	container_of(work, struct arche_platform_drvdata, delayed_work.work);
	int timeout = 50;

	/*
	* 1. SVC and AP boot independently, with AP<-->SVC wake/detect pin
	* deasserted (LOW in this case)
	* 2.1. SVC allows 360 milliseconds to elapse after switch boots to work
	* around bug described in ENG-330.
	* 2.2. AP asserts wake/detect pin (HIGH) (this can proceed in parallel with 2.1)
	* 3. SVC detects assertion of wake/detect pin, and sends "wake out" signal to AP
	* 4. AP receives "wake out" signal, takes AP Bridges through their power
	* on reset sequence as defined in the bridge ASIC reference manuals
	* 5. AP takes USB3613 through its power on reset sequence
	* 6. AP enumerates AP Bridges
	*/
	gpio_set_value(arche_pdata->wake_detect_gpio, 1);
	gpio_direction_input(arche_pdata->wake_detect_gpio);
	do {
	/* Read the wake_detect GPIO, for WAKE_OUT event from SVC */
	if (gpio_get_value(arche_pdata->wake_detect_gpio) == 0)
	break;

	msleep(100);
	} while(timeout--);

	if (timeout < 0) {
	/* FIXME: We may want to limit retries here */
	dev_warn(arche_pdata->dev,
	"Timed out on wake/detect, rescheduling handshake\n");
	gpio_direction_output(arche_pdata->wake_detect_gpio, 0);
	schedule_delayed_work(&arche_pdata->delayed_work, msecs_to_jiffies(2000));
	return;
	}

	/* Bring APB out of reset: cold boot sequence */
	device_for_each_child(arche_pdata->dev, NULL, apb_cold_boot);

	/* re-assert wake_detect to confirm SVC WAKE_OUT */
	gpio_direction_output(arche_pdata->wake_detect_gpio, 1);

	/* Enable HUB3613 into HUB mode. */
	if (usb3613_hub_mode_ctrl(true))
	dev_warn(arche_pdata->dev, "failed to control hub device\n");
	}

	static int arche_platform_coldboot_seq(struct arche_platform_drvdata *arche_pdata)
	{
	int ret;

	dev_info(arche_pdata->dev, "Booting from cold boot state\n");

	svc_reset_onoff(arche_pdata->svc_reset_gpio,
	arche_pdata->is_reset_act_hi);

	gpio_set_value(arche_pdata->svc_sysboot_gpio, 0);
	usleep_range(100, 200);

	ret = clk_prepare_enable(arche_pdata->svc_ref_clk);
	if (ret) {
	dev_err(arche_pdata->dev, "failed to enable svc_ref_clk: %d\n",
	ret);
	return ret;
	}

	/* bring SVC out of reset */
	svc_reset_onoff(arche_pdata->svc_reset_gpio,
	!arche_pdata->is_reset_act_hi);

	arche_pdata->state = ARCHE_PLATFORM_STATE_ACTIVE;

	return 0;
	}

	static void arche_platform_fw_flashing_seq(struct arche_platform_drvdata *arche_pdata)
	{
	dev_info(arche_pdata->dev, "Switching to FW flashing state\n");

	svc_reset_onoff(arche_pdata->svc_reset_gpio,
	arche_pdata->is_reset_act_hi);

	gpio_set_value(arche_pdata->svc_sysboot_gpio, 1);

	usleep_range(100, 200);
	svc_reset_onoff(arche_pdata->svc_reset_gpio,
	!arche_pdata->is_reset_act_hi);

	arche_pdata->state = ARCHE_PLATFORM_STATE_FW_FLASHING;

	}

	static void arche_platform_poweroff_seq(struct arche_platform_drvdata *arche_pdata)
	{
	/* Send disconnect/detach event to SVC */
	gpio_set_value(arche_pdata->wake_detect_gpio, 0);
	usleep_range(100, 200);

	clk_disable_unprepare(arche_pdata->svc_ref_clk);
	/* As part of exit, put APB back in reset state */
	svc_reset_onoff(arche_pdata->svc_reset_gpio,
	arche_pdata->is_reset_act_hi);

	arche_pdata->state = ARCHE_PLATFORM_STATE_OFF;
	}

	static ssize_t state_store(struct device *dev,
	struct device_attribute attr, const char buf, size_t count)
	{
	struct platform_device *pdev = to_platform_device(dev);
	struct arche_platform_drvdata *arche_pdata = platform_get_drvdata(pdev);
	int ret = 0;

	if (sysfs_streq(buf, "off")) {
	if (arche_pdata->state == ARCHE_PLATFORM_STATE_OFF)
	return count;

	/* If SVC goes down, bring down APB's as well */
	device_for_each_child(arche_pdata->dev, NULL, apb_poweroff);

	arche_platform_poweroff_seq(arche_pdata);

	ret = usb3613_hub_mode_ctrl(false);
	if (ret)
	dev_warn(arche_pdata->dev, "failed to control hub device\n");
	/* TODO: Should we do anything more here ?? */
	} else if (sysfs_streq(buf, "active")) {
	if (arche_pdata->state == ARCHE_PLATFORM_STATE_ACTIVE)
	return count;

	ret = arche_platform_coldboot_seq(arche_pdata);
	/* Give enough time for SVC to boot and then handshake with SVC */
	schedule_delayed_work(&arche_pdata->delayed_work, msecs_to_jiffies(2000));
	} else if (sysfs_streq(buf, "standby")) {
	if (arche_pdata->state == ARCHE_PLATFORM_STATE_STANDBY)
	return count;

	dev_warn(arche_pdata->dev, "standby state not supported\n");
	} else if (sysfs_streq(buf, "fw_flashing")) {
	if (arche_pdata->state == ARCHE_PLATFORM_STATE_FW_FLASHING)
	return count;

	/* First we want to make sure we power off everything
	* and then enter FW flashing state */
	device_for_each_child(arche_pdata->dev, NULL, apb_poweroff);

	arche_platform_poweroff_seq(arche_pdata);

	ret = usb3613_hub_mode_ctrl(false);
	if (ret)
	dev_warn(arche_pdata->dev, "failed to control hub device\n");
	/* TODO: Should we do anything more here ?? */

	arche_platform_fw_flashing_seq(arche_pdata);

	device_for_each_child(arche_pdata->dev, NULL, apb_fw_flashing_state);
	} else {
	dev_err(arche_pdata->dev, "unknown state\n");
	ret = -EINVAL;
	}

	return ret ? ret : count;
	}

	static ssize_t state_show(struct device *dev,
	struct device_attribute attr, char buf)
	{
	struct arche_platform_drvdata *arche_pdata = dev_get_drvdata(dev);

	switch (arche_pdata->state) {
	case ARCHE_PLATFORM_STATE_OFF:
	return sprintf(buf, "off\n");
	case ARCHE_PLATFORM_STATE_ACTIVE:
	return sprintf(buf, "active\n");
	case ARCHE_PLATFORM_STATE_STANDBY:
	return sprintf(buf, "standby\n");
	case ARCHE_PLATFORM_STATE_FW_FLASHING:
	return sprintf(buf, "fw_flashing\n");
	default:
	return sprintf(buf, "unknown state\n");
	}
	}

	static DEVICE_ATTR_RW(state);

	static int arche_platform_probe(struct platform_device *pdev)
	{
	struct arche_platform_drvdata *arche_pdata;
	struct device *dev = &pdev->dev;
	struct device_node *np = dev->of_node;
	int ret;

	arche_pdata = devm_kzalloc(&pdev->dev, sizeof(*arche_pdata), GFP_KERNEL);
	if (!arche_pdata)
	return -ENOMEM;

	/* setup svc reset gpio */
	arche_pdata->is_reset_act_hi = of_property_read_bool(np,
	"svc,reset-active-high");
	arche_pdata->svc_reset_gpio = of_get_named_gpio(np, "svc,reset-gpio", 0);
	if (arche_pdata->svc_reset_gpio < 0) {
	dev_err(dev, "failed to get reset-gpio\n");
	return arche_pdata->svc_reset_gpio;
	}
	ret = devm_gpio_request(dev, arche_pdata->svc_reset_gpio, "svc-reset");
	if (ret) {
	dev_err(dev, "failed to request svc-reset gpio:%d\n", ret);
	return ret;
	}
	ret = gpio_direction_output(arche_pdata->svc_reset_gpio,
	arche_pdata->is_reset_act_hi);
	if (ret) {
	dev_err(dev, "failed to set svc-reset gpio dir:%d\n", ret);
	return ret;
	}
	arche_pdata->state = ARCHE_PLATFORM_STATE_OFF;

	arche_pdata->svc_sysboot_gpio = of_get_named_gpio(np,
	"svc,sysboot-gpio", 0);
	if (arche_pdata->svc_sysboot_gpio < 0) {
	dev_err(dev, "failed to get sysboot gpio\n");
	return arche_pdata->svc_sysboot_gpio;
	}
	ret = devm_gpio_request(dev, arche_pdata->svc_sysboot_gpio, "sysboot0");
	if (ret) {
	dev_err(dev, "failed to request sysboot0 gpio:%d\n", ret);
	return ret;
	}
	ret = gpio_direction_output(arche_pdata->svc_sysboot_gpio, 0);
	if (ret) {
	dev_err(dev, "failed to set svc-reset gpio dir:%d\n", ret);
	return ret;
	}

	/* setup the clock request gpio first */
	arche_pdata->svc_refclk_req = of_get_named_gpio(np,
	"svc,refclk-req-gpio", 0);
	if (arche_pdata->svc_refclk_req < 0) {
	dev_err(dev, "failed to get svc clock-req gpio\n");
	return arche_pdata->svc_refclk_req;
	}
	ret = devm_gpio_request(dev, arche_pdata->svc_refclk_req, "svc-clk-req");
	if (ret) {
	dev_err(dev, "failed to request svc-clk-req gpio: %d\n", ret);
	return ret;
	}
	ret = gpio_direction_input(arche_pdata->svc_refclk_req);
	if (ret) {
	dev_err(dev, "failed to set svc-clk-req gpio dir :%d\n", ret);
	return ret;
	}

	/* setup refclk2 to follow the pin */
	arche_pdata->svc_ref_clk = devm_clk_get(dev, "svc_ref_clk");
	if (IS_ERR(arche_pdata->svc_ref_clk)) {
	ret = PTR_ERR(arche_pdata->svc_ref_clk);
	dev_err(dev, "failed to get svc_ref_clk: %d\n", ret);
	return ret;
	}

	platform_set_drvdata(pdev, arche_pdata);

	arche_pdata->num_apbs = of_get_child_count(np);
	dev_dbg(dev, "Number of APB's available - %d\n", arche_pdata->num_apbs);

	arche_pdata->wake_detect_gpio = of_get_named_gpio(np, "svc,wake-detect-gpio", 0);
	if (arche_pdata->wake_detect_gpio < 0) {
	dev_err(dev, "failed to get wake detect gpio\n");
	ret = arche_pdata->wake_detect_gpio;
	return ret;
	}

	ret = devm_gpio_request(dev, arche_pdata->wake_detect_gpio, "wake detect");
	if (ret) {
	dev_err(dev, "Failed requesting wake_detect gpio %d\n",
	arche_pdata->wake_detect_gpio);
	return ret;
	}
	/* deassert wake detect */
	gpio_direction_output(arche_pdata->wake_detect_gpio, 0);

	arche_pdata->dev = &pdev->dev;

	ret = device_create_file(dev, &dev_attr_state);
	if (ret) {
	dev_err(dev, "failed to create state file in sysfs\n");
	return ret;
	}

	ret = arche_platform_coldboot_seq(arche_pdata);
	if (ret) {
	dev_err(dev, "Failed to cold boot svc %d\n", ret);
	return ret;
	}

	ret = of_platform_populate(np, NULL, NULL, dev);
	if (ret) {
	dev_err(dev, "failed to populate child nodes %d\n", ret);
	return ret;
	}

	INIT_DELAYED_WORK(&arche_pdata->delayed_work, svc_delayed_work);
	schedule_delayed_work(&arche_pdata->delayed_work, msecs_to_jiffies(2000));

	dev_info(dev, "Device registered successfully\n");
	return 0;
	}

	static int arche_remove_child(struct device dev, void unused)
	{
	struct platform_device *pdev = to_platform_device(dev);

	platform_device_unregister(pdev);

	return 0;
	}

	static int arche_platform_remove(struct platform_device *pdev)
	{
	struct arche_platform_drvdata *arche_pdata = platform_get_drvdata(pdev);

	device_remove_file(&pdev->dev, &dev_attr_state);
	cancel_delayed_work_sync(&arche_pdata->delayed_work);
	device_for_each_child(&pdev->dev, NULL, arche_remove_child);
	arche_platform_poweroff_seq(arche_pdata);
	platform_set_drvdata(pdev, NULL);

	if (usb3613_hub_mode_ctrl(false))
	dev_warn(arche_pdata->dev, "failed to control hub device\n");
	/* TODO: Should we do anything more here ?? */
	return 0;
	}

	static int arche_platform_suspend(struct device *dev)
	{
	/*
	* If timing profile premits, we may shutdown bridge
	* completely
	*
	* TODO: sequence ??
	*
	* Also, need to make sure we meet precondition for unipro suspend
	* Precondition: Definition ???
	*/
	return 0;
	}

	static int arche_platform_resume(struct device *dev)
	{
	/*
	* Atleast for ES2 we have to meet the delay requirement between
	* unipro switch and AP bridge init, depending on whether bridge is in
	* OFF state or standby state.
	*
	* Based on whether bridge is in standby or OFF state we may have to
	* assert multiple signals. Please refer to WDM spec, for more info.
	*
	*/
	return 0;
	}

	static SIMPLE_DEV_PM_OPS(arche_platform_pm_ops,
	arche_platform_suspend,
	arche_platform_resume);

	static struct of_device_id arche_platform_of_match[] = {
	{ .compatible = "google,arche-platform", }, /* Use PID/VID of SVC device */
	{ },
	};

	static struct of_device_id arche_apb_ctrl_of_match[] = {
	{ .compatible = "usbffff,2", },
	{ },
	};

	static struct of_device_id arche_combined_id[] = {
	{ .compatible = "google,arche-platform", }, /* Use PID/VID of SVC device */
	{ .compatible = "usbffff,2", },
	{ },
	};
	MODULE_DEVICE_TABLE(of, arche_combined_id);

	static struct platform_driver arche_platform_device_driver = {
	.probe = arche_platform_probe,
	.remove = arche_platform_remove,
	.driver = {
	.name = "arche-platform-ctrl",
	.pm = &arche_platform_pm_ops,
	.of_match_table = arche_platform_of_match,
	}
	};

	static struct platform_driver arche_apb_ctrl_device_driver = {
	.probe = arche_apb_ctrl_probe,
	.remove = arche_apb_ctrl_remove,
	.driver = {
	.name = "arche-apb-ctrl",
	.pm = &arche_apb_ctrl_pm_ops,
	.of_match_table = arche_apb_ctrl_of_match,
	}
	};

	static int __init arche_init(void)
	{
	int retval;

	retval = platform_driver_register(&arche_platform_device_driver);
	if (retval)
	return retval;

	retval = platform_driver_register(&arche_apb_ctrl_device_driver);
	if (retval)
	platform_driver_unregister(&arche_platform_device_driver);

	return retval;
	}
	module_init(arche_init);

	static void __exit arche_exit(void)
	{
	platform_driver_unregister(&arche_apb_ctrl_device_driver);
	platform_driver_unregister(&arche_platform_device_driver);
	}
	module_exit(arche_exit);

	MODULE_LICENSE("GPL");
	MODULE_AUTHOR("Vaibhav Hiremath <vaibhav.hiremath@linaro.org>");
	MODULE_DESCRIPTION("Arche Platform Driver");