// SPDX-License-Identifier: GPL-2.0
  // ChromeOS Embedded Controller extcon
  //
  // Copyright (C) 2017 Google, Inc.
  // Author: Benson Leung <bleung@chromium.org>

  #include <linux/extcon-provider.h>

  #include <linux/kernel.h>

  #include <linux/module.h>
  #include <linux/notifier.h>
  #include <linux/of.h>

  #include <linux/platform_data/cros_ec_commands.h>
  #include <linux/platform_data/cros_ec_proto.h>

  #include <linux/platform_device.h>
  #include <linux/slab.h>
  #include <linux/sched.h>
  
  struct cros_ec_extcon_info {
  	struct device *dev;
  	struct extcon_dev *edev;
  
  	int port_id;
  
  	struct cros_ec_device *ec;
  
  	struct notifier_block notifier;

  	unsigned int dr; /* data role */
  	bool pr; /* power role (true if VBUS enabled) */

  	bool dp; /* DisplayPort enabled */
  	bool mux; /* SuperSpeed (usb3) enabled */
  	unsigned int power_type;
  };
  
  static const unsigned int usb_type_c_cable[] = {

  	EXTCON_USB,
  	EXTCON_USB_HOST,

  	EXTCON_DISP_DP,
  	EXTCON_NONE,
  };

  enum usb_data_roles {
  	DR_NONE,
  	DR_HOST,
  	DR_DEVICE,
  };

  /**
   * cros_ec_pd_command() - Send a command to the EC.
   * @info: pointer to struct cros_ec_extcon_info
   * @command: EC command
   * @version: EC command version
   * @outdata: EC command output data
   * @outsize: Size of outdata
   * @indata: EC command input data
   * @insize: Size of indata
   *
   * Return: 0 on success, <0 on failure.
   */
  static int cros_ec_pd_command(struct cros_ec_extcon_info *info,
  			      unsigned int command,
  			      unsigned int version,
  			      void *outdata,
  			      unsigned int outsize,
  			      void *indata,
  			      unsigned int insize)
  {
  	struct cros_ec_command *msg;
  	int ret;
  
  	msg = kzalloc(sizeof(*msg) + max(outsize, insize), GFP_KERNEL);

  	if (!msg)
  		return -ENOMEM;

  
  	msg->version = version;
  	msg->command = command;
  	msg->outsize = outsize;
  	msg->insize = insize;
  
  	if (outsize)
  		memcpy(msg->data, outdata, outsize);
  
  	ret = cros_ec_cmd_xfer_status(info->ec, msg);
  	if (ret >= 0 && insize)
  		memcpy(indata, msg->data, insize);
  
  	kfree(msg);
  	return ret;
  }
  
  /**
   * cros_ec_usb_get_power_type() - Get power type info about PD device attached
   * to given port.
   * @info: pointer to struct cros_ec_extcon_info
   *
   * Return: power type on success, <0 on failure.
   */
  static int cros_ec_usb_get_power_type(struct cros_ec_extcon_info *info)
  {
  	struct ec_params_usb_pd_power_info req;
  	struct ec_response_usb_pd_power_info resp;
  	int ret;
  
  	req.port = info->port_id;
  	ret = cros_ec_pd_command(info, EC_CMD_USB_PD_POWER_INFO, 0,
  				 &req, sizeof(req), &resp, sizeof(resp));
  	if (ret < 0)
  		return ret;
  
  	return resp.type;
  }
  
  /**
   * cros_ec_usb_get_pd_mux_state() - Get PD mux state for given port.
   * @info: pointer to struct cros_ec_extcon_info
   *
   * Return: PD mux state on success, <0 on failure.
   */
  static int cros_ec_usb_get_pd_mux_state(struct cros_ec_extcon_info *info)
  {
  	struct ec_params_usb_pd_mux_info req;
  	struct ec_response_usb_pd_mux_info resp;
  	int ret;
  
  	req.port = info->port_id;
  	ret = cros_ec_pd_command(info, EC_CMD_USB_PD_MUX_INFO, 0,
  				 &req, sizeof(req),
  				 &resp, sizeof(resp));
  	if (ret < 0)
  		return ret;
  
  	return resp.flags;
  }
  
  /**
   * cros_ec_usb_get_role() - Get role info about possible PD device attached to a
   * given port.
   * @info: pointer to struct cros_ec_extcon_info
   * @polarity: pointer to cable polarity (return value)
   *
   * Return: role info on success, -ENOTCONN if no cable is connected, <0 on
   * failure.
   */
  static int cros_ec_usb_get_role(struct cros_ec_extcon_info *info,
  				bool *polarity)
  {
  	struct ec_params_usb_pd_control pd_control;
  	struct ec_response_usb_pd_control_v1 resp;
  	int ret;
  
  	pd_control.port = info->port_id;
  	pd_control.role = USB_PD_CTRL_ROLE_NO_CHANGE;
  	pd_control.mux = USB_PD_CTRL_MUX_NO_CHANGE;

  	pd_control.swap = USB_PD_CTRL_SWAP_NONE;

  	ret = cros_ec_pd_command(info, EC_CMD_USB_PD_CONTROL, 1,
  				 &pd_control, sizeof(pd_control),
  				 &resp, sizeof(resp));
  	if (ret < 0)
  		return ret;
  
  	if (!(resp.enabled & PD_CTRL_RESP_ENABLED_CONNECTED))
  		return -ENOTCONN;
  
  	*polarity = resp.polarity;
  
  	return resp.role;
  }
  
  /**
   * cros_ec_pd_get_num_ports() - Get number of EC charge ports.
   * @info: pointer to struct cros_ec_extcon_info
   *
   * Return: number of ports on success, <0 on failure.
   */
  static int cros_ec_pd_get_num_ports(struct cros_ec_extcon_info *info)
  {
  	struct ec_response_usb_pd_ports resp;
  	int ret;
  
  	ret = cros_ec_pd_command(info, EC_CMD_USB_PD_PORTS,
  				 0, NULL, 0, &resp, sizeof(resp));
  	if (ret < 0)
  		return ret;
  
  	return resp.num_ports;
  }

  static const char *cros_ec_usb_role_string(unsigned int role)
  {
  	return role == DR_NONE ? "DISCONNECTED" :
  		(role == DR_HOST ? "DFP" : "UFP");
  }
  
  static const char *cros_ec_usb_power_type_string(unsigned int type)
  {
  	switch (type) {
  	case USB_CHG_TYPE_NONE:
  		return "USB_CHG_TYPE_NONE";
  	case USB_CHG_TYPE_PD:
  		return "USB_CHG_TYPE_PD";
  	case USB_CHG_TYPE_PROPRIETARY:
  		return "USB_CHG_TYPE_PROPRIETARY";
  	case USB_CHG_TYPE_C:
  		return "USB_CHG_TYPE_C";
  	case USB_CHG_TYPE_BC12_DCP:
  		return "USB_CHG_TYPE_BC12_DCP";
  	case USB_CHG_TYPE_BC12_CDP:
  		return "USB_CHG_TYPE_BC12_CDP";
  	case USB_CHG_TYPE_BC12_SDP:
  		return "USB_CHG_TYPE_BC12_SDP";
  	case USB_CHG_TYPE_OTHER:
  		return "USB_CHG_TYPE_OTHER";
  	case USB_CHG_TYPE_VBUS:
  		return "USB_CHG_TYPE_VBUS";
  	case USB_CHG_TYPE_UNKNOWN:
  		return "USB_CHG_TYPE_UNKNOWN";
  	default:
  		return "USB_CHG_TYPE_UNKNOWN";
  	}
  }
  
  static bool cros_ec_usb_power_type_is_wall_wart(unsigned int type,
  						unsigned int role)
  {
  	switch (type) {
  	/* FIXME : Guppy, Donnettes, and other chargers will be miscategorized
  	 * because they identify with USB_CHG_TYPE_C, but we can't return true
  	 * here from that code because that breaks Suzy-Q and other kinds of
  	 * USB Type-C cables and peripherals.
  	 */
  	case USB_CHG_TYPE_PROPRIETARY:
  	case USB_CHG_TYPE_BC12_DCP:
  		return true;
  	case USB_CHG_TYPE_PD:
  	case USB_CHG_TYPE_C:
  	case USB_CHG_TYPE_BC12_CDP:
  	case USB_CHG_TYPE_BC12_SDP:
  	case USB_CHG_TYPE_OTHER:
  	case USB_CHG_TYPE_VBUS:
  	case USB_CHG_TYPE_UNKNOWN:
  	case USB_CHG_TYPE_NONE:
  	default:
  		return false;
  	}
  }

  static int extcon_cros_ec_detect_cable(struct cros_ec_extcon_info *info,
  				       bool force)
  {
  	struct device *dev = info->dev;
  	int role, power_type;

  	unsigned int dr = DR_NONE;
  	bool pr = false;

  	bool polarity = false;
  	bool dp = false;
  	bool mux = false;
  	bool hpd = false;
  
  	power_type = cros_ec_usb_get_power_type(info);
  	if (power_type < 0) {
  		dev_err(dev, "failed getting power type err = %d
  ",
  			power_type);
  		return power_type;
  	}
  
  	role = cros_ec_usb_get_role(info, &polarity);
  	if (role < 0) {
  		if (role != -ENOTCONN) {
  			dev_err(dev, "failed getting role err = %d
  ", role);
  			return role;
  		}

  		dev_dbg(dev, "disconnected
  ");

  	} else {
  		int pd_mux_state;

  		dr = (role & PD_CTRL_RESP_ROLE_DATA) ? DR_HOST : DR_DEVICE;
  		pr = (role & PD_CTRL_RESP_ROLE_POWER);

  		pd_mux_state = cros_ec_usb_get_pd_mux_state(info);
  		if (pd_mux_state < 0)
  			pd_mux_state = USB_PD_MUX_USB_ENABLED;
  
  		dp = pd_mux_state & USB_PD_MUX_DP_ENABLED;
  		mux = pd_mux_state & USB_PD_MUX_USB_ENABLED;
  		hpd = pd_mux_state & USB_PD_MUX_HPD_IRQ;

  		dev_dbg(dev,
  			"connected role 0x%x pwr type %d dr %d pr %d pol %d mux %d dp %d hpd %d
  ",
  			role, power_type, dr, pr, polarity, mux, dp, hpd);
  	}

  	/*
  	 * When there is no USB host (e.g. USB PD charger),
  	 * we are not really a UFP for the AP.
  	 */
  	if (dr == DR_DEVICE &&
  	    cros_ec_usb_power_type_is_wall_wart(power_type, role))
  		dr = DR_NONE;
  
  	if (force || info->dr != dr || info->pr != pr || info->dp != dp ||
  	    info->mux != mux || info->power_type != power_type) {
  		bool host_connected = false, device_connected = false;
  
  		dev_dbg(dev, "Type/Role switch! type = %s role = %s
  ",
  			cros_ec_usb_power_type_string(power_type),
  			cros_ec_usb_role_string(dr));
  		info->dr = dr;
  		info->pr = pr;

  		info->dp = dp;
  		info->mux = mux;
  		info->power_type = power_type;

  		if (dr == DR_DEVICE)
  			device_connected = true;
  		else if (dr == DR_HOST)
  			host_connected = true;

  		extcon_set_state(info->edev, EXTCON_USB, device_connected);
  		extcon_set_state(info->edev, EXTCON_USB_HOST, host_connected);
  		extcon_set_state(info->edev, EXTCON_DISP_DP, dp);
  		extcon_set_property(info->edev, EXTCON_USB,
  				    EXTCON_PROP_USB_VBUS,
  				    (union extcon_property_value)(int)pr);
  		extcon_set_property(info->edev, EXTCON_USB_HOST,
  				    EXTCON_PROP_USB_VBUS,
  				    (union extcon_property_value)(int)pr);
  		extcon_set_property(info->edev, EXTCON_USB,
  				    EXTCON_PROP_USB_TYPEC_POLARITY,
  				    (union extcon_property_value)(int)polarity);
  		extcon_set_property(info->edev, EXTCON_USB_HOST,
  				    EXTCON_PROP_USB_TYPEC_POLARITY,
  				    (union extcon_property_value)(int)polarity);

  		extcon_set_property(info->edev, EXTCON_DISP_DP,
  				    EXTCON_PROP_USB_TYPEC_POLARITY,
  				    (union extcon_property_value)(int)polarity);

  		extcon_set_property(info->edev, EXTCON_USB,
  				    EXTCON_PROP_USB_SS,
  				    (union extcon_property_value)(int)mux);
  		extcon_set_property(info->edev, EXTCON_USB_HOST,
  				    EXTCON_PROP_USB_SS,
  				    (union extcon_property_value)(int)mux);

  		extcon_set_property(info->edev, EXTCON_DISP_DP,
  				    EXTCON_PROP_USB_SS,
  				    (union extcon_property_value)(int)mux);
  		extcon_set_property(info->edev, EXTCON_DISP_DP,
  				    EXTCON_PROP_DISP_HPD,
  				    (union extcon_property_value)(int)hpd);

  		extcon_sync(info->edev, EXTCON_USB);
  		extcon_sync(info->edev, EXTCON_USB_HOST);

  		extcon_sync(info->edev, EXTCON_DISP_DP);
  
  	} else if (hpd) {
  		extcon_set_property(info->edev, EXTCON_DISP_DP,
  				    EXTCON_PROP_DISP_HPD,
  				    (union extcon_property_value)(int)hpd);
  		extcon_sync(info->edev, EXTCON_DISP_DP);
  	}
  
  	return 0;
  }
  
  static int extcon_cros_ec_event(struct notifier_block *nb,
  				unsigned long queued_during_suspend,
  				void *_notify)
  {
  	struct cros_ec_extcon_info *info;
  	struct cros_ec_device *ec;
  	u32 host_event;
  
  	info = container_of(nb, struct cros_ec_extcon_info, notifier);
  	ec = info->ec;
  
  	host_event = cros_ec_get_host_event(ec);
  	if (host_event & (EC_HOST_EVENT_MASK(EC_HOST_EVENT_PD_MCU) |
  			  EC_HOST_EVENT_MASK(EC_HOST_EVENT_USB_MUX))) {
  		extcon_cros_ec_detect_cable(info, false);
  		return NOTIFY_OK;
  	}
  
  	return NOTIFY_DONE;
  }
  
  static int extcon_cros_ec_probe(struct platform_device *pdev)
  {
  	struct cros_ec_extcon_info *info;
  	struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
  	struct device *dev = &pdev->dev;
  	struct device_node *np = dev->of_node;
  	int numports, ret;
  
  	info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
  	if (!info)
  		return -ENOMEM;
  
  	info->dev = dev;
  	info->ec = ec;
  
  	if (np) {
  		u32 port;
  
  		ret = of_property_read_u32(np, "google,usb-port-id", &port);
  		if (ret < 0) {
  			dev_err(dev, "Missing google,usb-port-id property
  ");
  			return ret;
  		}
  		info->port_id = port;
  	} else {
  		info->port_id = pdev->id;
  	}
  
  	numports = cros_ec_pd_get_num_ports(info);
  	if (numports < 0) {
  		dev_err(dev, "failed getting number of ports! ret = %d
  ",
  			numports);
  		return numports;
  	}
  
  	if (info->port_id >= numports) {
  		dev_err(dev, "This system only supports %d ports
  ", numports);
  		return -ENODEV;
  	}
  
  	info->edev = devm_extcon_dev_allocate(dev, usb_type_c_cable);
  	if (IS_ERR(info->edev)) {
  		dev_err(dev, "failed to allocate extcon device
  ");
  		return -ENOMEM;
  	}
  
  	ret = devm_extcon_dev_register(dev, info->edev);
  	if (ret < 0) {
  		dev_err(dev, "failed to register extcon device
  ");
  		return ret;
  	}

  	extcon_set_property_capability(info->edev, EXTCON_USB,
  				       EXTCON_PROP_USB_VBUS);
  	extcon_set_property_capability(info->edev, EXTCON_USB_HOST,
  				       EXTCON_PROP_USB_VBUS);
  	extcon_set_property_capability(info->edev, EXTCON_USB,
  				       EXTCON_PROP_USB_TYPEC_POLARITY);
  	extcon_set_property_capability(info->edev, EXTCON_USB_HOST,
  				       EXTCON_PROP_USB_TYPEC_POLARITY);

  	extcon_set_property_capability(info->edev, EXTCON_DISP_DP,
  				       EXTCON_PROP_USB_TYPEC_POLARITY);

  	extcon_set_property_capability(info->edev, EXTCON_USB,
  				       EXTCON_PROP_USB_SS);
  	extcon_set_property_capability(info->edev, EXTCON_USB_HOST,
  				       EXTCON_PROP_USB_SS);

  	extcon_set_property_capability(info->edev, EXTCON_DISP_DP,
  				       EXTCON_PROP_USB_SS);
  	extcon_set_property_capability(info->edev, EXTCON_DISP_DP,
  				       EXTCON_PROP_DISP_HPD);

  	info->dr = DR_NONE;
  	info->pr = false;

  	platform_set_drvdata(pdev, info);
  
  	/* Get PD events from the EC */
  	info->notifier.notifier_call = extcon_cros_ec_event;
  	ret = blocking_notifier_chain_register(&info->ec->event_notifier,
  					       &info->notifier);
  	if (ret < 0) {
  		dev_err(dev, "failed to register notifier
  ");
  		return ret;
  	}
  
  	/* Perform initial detection */
  	ret = extcon_cros_ec_detect_cable(info, true);
  	if (ret < 0) {
  		dev_err(dev, "failed to detect initial cable state
  ");
  		goto unregister_notifier;
  	}
  
  	return 0;
  
  unregister_notifier:
  	blocking_notifier_chain_unregister(&info->ec->event_notifier,
  					   &info->notifier);
  	return ret;
  }
  
  static int extcon_cros_ec_remove(struct platform_device *pdev)
  {
  	struct cros_ec_extcon_info *info = platform_get_drvdata(pdev);
  
  	blocking_notifier_chain_unregister(&info->ec->event_notifier,
  					   &info->notifier);
  
  	return 0;
  }
  
  #ifdef CONFIG_PM_SLEEP
  static int extcon_cros_ec_suspend(struct device *dev)
  {
  	return 0;
  }
  
  static int extcon_cros_ec_resume(struct device *dev)
  {
  	int ret;
  	struct cros_ec_extcon_info *info = dev_get_drvdata(dev);
  
  	ret = extcon_cros_ec_detect_cable(info, true);
  	if (ret < 0)
  		dev_err(dev, "failed to detect cable state on resume
  ");
  
  	return 0;
  }
  
  static const struct dev_pm_ops extcon_cros_ec_dev_pm_ops = {
  	SET_SYSTEM_SLEEP_PM_OPS(extcon_cros_ec_suspend, extcon_cros_ec_resume)
  };
  
  #define DEV_PM_OPS	(&extcon_cros_ec_dev_pm_ops)
  #else
  #define DEV_PM_OPS	NULL
  #endif /* CONFIG_PM_SLEEP */
  
  #ifdef CONFIG_OF
  static const struct of_device_id extcon_cros_ec_of_match[] = {
  	{ .compatible = "google,extcon-usbc-cros-ec" },
  	{ /* sentinel */ }
  };
  MODULE_DEVICE_TABLE(of, extcon_cros_ec_of_match);
  #endif /* CONFIG_OF */
  
  static struct platform_driver extcon_cros_ec_driver = {
  	.driver = {
  		.name  = "extcon-usbc-cros-ec",
  		.of_match_table = of_match_ptr(extcon_cros_ec_of_match),
  		.pm = DEV_PM_OPS,
  	},
  	.remove  = extcon_cros_ec_remove,
  	.probe   = extcon_cros_ec_probe,
  };
  
  module_platform_driver(extcon_cros_ec_driver);
  
  MODULE_DESCRIPTION("ChromeOS Embedded Controller extcon driver");
  MODULE_AUTHOR("Benson Leung <bleung@chromium.org>");

  MODULE_LICENSE("GPL v2");