/*
   * HID driver for ELO usb touchscreen 4000/4500
   *
   * Copyright (c) 2013 Jiri Slaby
   *
   * Data parsing taken from elousb driver by Vojtech Pavlik.
   *
   * This driver is licensed under the terms of GPLv2.
   */
  
  #include <linux/hid.h>
  #include <linux/input.h>
  #include <linux/module.h>
  #include <linux/usb.h>
  #include <linux/workqueue.h>
  
  #include "hid-ids.h"
  
  #define ELO_PERIODIC_READ_INTERVAL	HZ
  #define ELO_SMARTSET_CMD_TIMEOUT	2000 /* msec */
  
  /* Elo SmartSet commands */
  #define ELO_FLUSH_SMARTSET_RESPONSES	0x02 /* Flush all pending smartset responses */
  #define ELO_SEND_SMARTSET_COMMAND	0x05 /* Send a smartset command */
  #define ELO_GET_SMARTSET_RESPONSE	0x06 /* Get a smartset response */
  #define ELO_DIAG			0x64 /* Diagnostics command */
  #define ELO_SMARTSET_PACKET_SIZE	8
  
  struct elo_priv {
  	struct usb_device *usbdev;
  	struct delayed_work work;
  	unsigned char buffer[ELO_SMARTSET_PACKET_SIZE];
  };
  
  static struct workqueue_struct *wq;
  static bool use_fw_quirk = true;
  module_param(use_fw_quirk, bool, S_IRUGO);
  MODULE_PARM_DESC(use_fw_quirk, "Do periodic pokes for broken M firmwares (default = true)");
  
  static void elo_input_configured(struct hid_device *hdev,
  		struct hid_input *hidinput)
  {
  	struct input_dev *input = hidinput->input;
  
  	set_bit(BTN_TOUCH, input->keybit);
  	set_bit(ABS_PRESSURE, input->absbit);
  	input_set_abs_params(input, ABS_PRESSURE, 0, 256, 0, 0);
  }
  
  static void elo_process_data(struct input_dev *input, const u8 *data, int size)
  {
  	int press;
  
  	input_report_abs(input, ABS_X, (data[3] << 8) | data[2]);
  	input_report_abs(input, ABS_Y, (data[5] << 8) | data[4]);
  
  	press = 0;
  	if (data[1] & 0x80)
  		press = (data[7] << 8) | data[6];
  	input_report_abs(input, ABS_PRESSURE, press);
  
  	if (data[1] & 0x03) {
  		input_report_key(input, BTN_TOUCH, 1);
  		input_sync(input);
  	}
  
  	if (data[1] & 0x04)
  		input_report_key(input, BTN_TOUCH, 0);
  
  	input_sync(input);
  }
  
  static int elo_raw_event(struct hid_device *hdev, struct hid_report *report,
  	 u8 *data, int size)
  {
  	struct hid_input *hidinput;
  
  	if (!(hdev->claimed & HID_CLAIMED_INPUT) || list_empty(&hdev->inputs))
  		return 0;
  
  	hidinput = list_first_entry(&hdev->inputs, struct hid_input, list);
  
  	switch (report->id) {
  	case 0:
  		if (data[0] == 'T') {	/* Mandatory ELO packet marker */
  			elo_process_data(hidinput->input, data, size);
  			return 1;
  		}
  		break;
  	default:	/* unknown report */
  		/* Unknown report type; pass upstream */
  		hid_info(hdev, "unknown report type %d
  ", report->id);
  		break;
  	}
  
  	return 0;
  }
  
  static int elo_smartset_send_get(struct usb_device *dev, u8 command,
  		void *data)
  {
  	unsigned int pipe;
  	u8 dir;
  
  	if (command == ELO_SEND_SMARTSET_COMMAND) {
  		pipe = usb_sndctrlpipe(dev, 0);
  		dir = USB_DIR_OUT;
  	} else if (command == ELO_GET_SMARTSET_RESPONSE) {
  		pipe = usb_rcvctrlpipe(dev, 0);
  		dir = USB_DIR_IN;
  	} else
  		return -EINVAL;
  
  	return usb_control_msg(dev, pipe, command,
  			dir | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
  			0, 0, data, ELO_SMARTSET_PACKET_SIZE,
  			ELO_SMARTSET_CMD_TIMEOUT);
  }
  
  static int elo_flush_smartset_responses(struct usb_device *dev)
  {
  	return usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
  			ELO_FLUSH_SMARTSET_RESPONSES,
  			USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
  			0, 0, NULL, 0, USB_CTRL_SET_TIMEOUT);
  }
  
  static void elo_work(struct work_struct *work)
  {
  	struct elo_priv *priv = container_of(work, struct elo_priv, work.work);
  	struct usb_device *dev = priv->usbdev;
  	unsigned char *buffer = priv->buffer;
  	int ret;
  
  	ret = elo_flush_smartset_responses(dev);
  	if (ret < 0) {
  		dev_err(&dev->dev, "initial FLUSH_SMARTSET_RESPONSES failed, error %d
  ",
  				ret);
  		goto fail;
  	}
  
  	/* send Diagnostics command */
  	*buffer = ELO_DIAG;
  	ret = elo_smartset_send_get(dev, ELO_SEND_SMARTSET_COMMAND, buffer);
  	if (ret < 0) {
  		dev_err(&dev->dev, "send Diagnostics Command failed, error %d
  ",
  				ret);
  		goto fail;
  	}
  
  	/* get the result */
  	ret = elo_smartset_send_get(dev, ELO_GET_SMARTSET_RESPONSE, buffer);
  	if (ret < 0) {
  		dev_err(&dev->dev, "get Diagnostics Command response failed, error %d
  ",
  				ret);
  		goto fail;
  	}
  
  	/* read the ack */
  	if (*buffer != 'A') {
  		ret = elo_smartset_send_get(dev, ELO_GET_SMARTSET_RESPONSE,
  				buffer);
  		if (ret < 0) {
  			dev_err(&dev->dev, "get acknowledge response failed, error %d
  ",
  					ret);
  			goto fail;
  		}
  	}
  
  fail:
  	ret = elo_flush_smartset_responses(dev);
  	if (ret < 0)
  		dev_err(&dev->dev, "final FLUSH_SMARTSET_RESPONSES failed, error %d
  ",
  				ret);
  	queue_delayed_work(wq, &priv->work, ELO_PERIODIC_READ_INTERVAL);
  }
  
  /*
   * Not all Elo devices need the periodic HID descriptor reads.
   * Only firmware version M needs this.
   */
  static bool elo_broken_firmware(struct usb_device *dev)
  {
  	struct usb_device *hub = dev->parent;
  	struct usb_device *child = NULL;
  	u16 fw_lvl = le16_to_cpu(dev->descriptor.bcdDevice);
  	u16 child_vid, child_pid;
  	int i;
      
  	if (!use_fw_quirk)
  		return false;
  	if (fw_lvl != 0x10d)
  		return false;
  
  	/* iterate sibling devices of the touch controller */
  	usb_hub_for_each_child(hub, i, child) {
  		child_vid = le16_to_cpu(child->descriptor.idVendor);
  		child_pid = le16_to_cpu(child->descriptor.idProduct);
  
  		/*
  		 * If one of the devices below is present attached as a sibling of 
  		 * the touch controller then  this is a newer IBM 4820 monitor that 
  		 * does not need the IBM-requested workaround if fw level is
  		 * 0x010d - aka 'M'.
  		 * No other HW can have this combination.
  		 */
  		if (child_vid==0x04b3) {
  			switch (child_pid) {
  			case 0x4676: /* 4820 21x Video */
  			case 0x4677: /* 4820 51x Video */
  			case 0x4678: /* 4820 2Lx Video */
  			case 0x4679: /* 4820 5Lx Video */
  				return false;
  			}
  		}
  	}
  	return true;
  }
  
  static int elo_probe(struct hid_device *hdev, const struct hid_device_id *id)
  {
  	struct elo_priv *priv;
  	int ret;
  
  	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
  	if (!priv)
  		return -ENOMEM;
  
  	INIT_DELAYED_WORK(&priv->work, elo_work);
  	priv->usbdev = interface_to_usbdev(to_usb_interface(hdev->dev.parent));
  
  	hid_set_drvdata(hdev, priv);
  
  	ret = hid_parse(hdev);
  	if (ret) {
  		hid_err(hdev, "parse failed
  ");
  		goto err_free;
  	}
  
  	ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
  	if (ret) {
  		hid_err(hdev, "hw start failed
  ");
  		goto err_free;
  	}
  
  	if (elo_broken_firmware(priv->usbdev)) {
  		hid_info(hdev, "broken firmware found, installing workaround
  ");
  		queue_delayed_work(wq, &priv->work, ELO_PERIODIC_READ_INTERVAL);
  	}
  
  	return 0;
  err_free:
  	kfree(priv);
  	return ret;
  }
  
  static void elo_remove(struct hid_device *hdev)
  {
  	struct elo_priv *priv = hid_get_drvdata(hdev);
  
  	hid_hw_stop(hdev);
  	flush_workqueue(wq);
  	kfree(priv);
  }
  
  static const struct hid_device_id elo_devices[] = {
  	{ HID_USB_DEVICE(USB_VENDOR_ID_ELO, 0x0009), },
  	{ HID_USB_DEVICE(USB_VENDOR_ID_ELO, 0x0030), },
  	{ }
  };
  MODULE_DEVICE_TABLE(hid, elo_devices);
  
  static struct hid_driver elo_driver = {
  	.name = "elo",
  	.id_table = elo_devices,
  	.probe = elo_probe,
  	.remove = elo_remove,
  	.raw_event = elo_raw_event,
  	.input_configured = elo_input_configured,
  };
  
  static int __init elo_driver_init(void)
  {
  	int ret;
  
  	wq = create_singlethread_workqueue("elousb");
  	if (!wq)
  		return -ENOMEM;
  
  	ret = hid_register_driver(&elo_driver);
  	if (ret)
  		destroy_workqueue(wq);
  
  	return ret;
  }
  module_init(elo_driver_init);
  
  static void __exit elo_driver_exit(void)
  {
  	hid_unregister_driver(&elo_driver);
  	destroy_workqueue(wq);
  }
  module_exit(elo_driver_exit);
  
  MODULE_AUTHOR("Jiri Slaby <jslaby@suse.cz>");
  MODULE_LICENSE("GPL");