wacom_sys.c

/*
 * drivers/input/tablet/wacom_sys.c
 *
 *  USB Wacom tablet support - system specific code
 */

/*
 * 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.
 */

#include "wacom_wac.h"
#include "wacom.h"
#include <linux/input/mt.h>

#define WAC_MSG_RETRIES		5
#define WAC_CMD_RETRIES		10

#define DEV_ATTR_RW_PERM (S_IRUGO | S_IWUSR | S_IWGRP)
#define DEV_ATTR_WO_PERM (S_IWUSR | S_IWGRP)
#define DEV_ATTR_RO_PERM (S_IRUSR | S_IRGRP)

static int wacom_get_report(struct hid_device *hdev, u8 type, u8 *buf,
			    size_t size, unsigned int retries)
{
	int retval;

	do {
		retval = hid_hw_raw_request(hdev, buf[0], buf, size, type,
				HID_REQ_GET_REPORT);
	} while ((retval == -ETIMEDOUT || retval == -EAGAIN) && --retries);

	if (retval < 0)
		hid_err(hdev, "wacom_get_report: ran out of retries "
			"(last error = %d)\n", retval);

	return retval;
}

static int wacom_set_report(struct hid_device *hdev, u8 type, u8 *buf,
			    size_t size, unsigned int retries)
{
	int retval;

	do {
		retval = hid_hw_raw_request(hdev, buf[0], buf, size, type,
				HID_REQ_SET_REPORT);
	} while ((retval == -ETIMEDOUT || retval == -EAGAIN) && --retries);

	if (retval < 0)
		hid_err(hdev, "wacom_set_report: ran out of retries "
			"(last error = %d)\n", retval);

	return retval;
}

static void wacom_wac_queue_insert(struct hid_device *hdev,
				   struct kfifo_rec_ptr_2 *fifo,
				   u8 *raw_data, int size)
{
	bool warned = false;

	while (kfifo_avail(fifo) < size) {
		if (!warned)
			hid_warn(hdev, "%s: kfifo has filled, starting to drop events\n", __func__);
		warned = true;

		kfifo_skip(fifo);
	}

	kfifo_in(fifo, raw_data, size);
}

static void wacom_wac_queue_flush(struct hid_device *hdev,
				  struct kfifo_rec_ptr_2 *fifo)
{
	while (!kfifo_is_empty(fifo)) {
		u8 buf[WACOM_PKGLEN_MAX];
		int size;
		int err;

		size = kfifo_out(fifo, buf, sizeof(buf));
		err = hid_report_raw_event(hdev, HID_INPUT_REPORT, buf, size, false);
		if (err) {
			hid_warn(hdev, "%s: unable to flush event due to error %d\n",
				 __func__, err);
		}
	}
}

static int wacom_wac_pen_serial_enforce(struct hid_device *hdev,
		struct hid_report *report, u8 *raw_data, int report_size)
{
	struct wacom *wacom = hid_get_drvdata(hdev);
	struct wacom_wac *wacom_wac = &wacom->wacom_wac;
	struct wacom_features *features = &wacom_wac->features;
	bool flush = false;
	bool insert = false;
	int i, j;

	if (wacom_wac->serial[0] || !(features->quirks & WACOM_QUIRK_TOOLSERIAL))
		return 0;

	/* Queue events which have invalid tool type or serial number */
	for (i = 0; i < report->maxfield; i++) {
		for (j = 0; j < report->field[i]->maxusage; j++) {
			struct hid_field *field = report->field[i];
			struct hid_usage *usage = &field->usage[j];
			unsigned int equivalent_usage = wacom_equivalent_usage(usage->hid);
			unsigned int offset;
			unsigned int size;
			unsigned int value;

			if (equivalent_usage != HID_DG_INRANGE &&
			    equivalent_usage != HID_DG_TOOLSERIALNUMBER &&
			    equivalent_usage != WACOM_HID_WD_SERIALHI &&
			    equivalent_usage != WACOM_HID_WD_TOOLTYPE)
				continue;

			offset = field->report_offset;
			size = field->report_size;
			value = hid_field_extract(hdev, raw_data+1, offset + j * size, size);

			/* If we go out of range, we need to flush the queue ASAP */
			if (equivalent_usage == HID_DG_INRANGE)
				value = !value;

			if (value) {
				flush = true;
				switch (equivalent_usage) {
				case HID_DG_TOOLSERIALNUMBER:
					wacom_wac->serial[0] = value;
					break;

				case WACOM_HID_WD_SERIALHI:
					wacom_wac->serial[0] |= ((__u64)value) << 32;
					break;

				case WACOM_HID_WD_TOOLTYPE:
					wacom_wac->id[0] = value;
					break;
				}
			}
			else {
				insert = true;
			}
		}
	}

	if (flush)
		wacom_wac_queue_flush(hdev, &wacom_wac->pen_fifo);
	else if (insert)
		wacom_wac_queue_insert(hdev, &wacom_wac->pen_fifo,
				       raw_data, report_size);

	return insert && !flush;
}

static int wacom_raw_event(struct hid_device *hdev, struct hid_report *report,
		u8 *raw_data, int size)
{
	struct wacom *wacom = hid_get_drvdata(hdev);

	if (size > WACOM_PKGLEN_MAX)
		return 1;

	if (wacom_wac_pen_serial_enforce(hdev, report, raw_data, size))
		return -1;

	memcpy(wacom->wacom_wac.data, raw_data, size);

	wacom_wac_irq(&wacom->wacom_wac, size);

	return 0;
}

static int wacom_open(struct input_dev *dev)
{
	struct wacom *wacom = input_get_drvdata(dev);

	return hid_hw_open(wacom->hdev);
}

static void wacom_close(struct input_dev *dev)
{
	struct wacom *wacom = input_get_drvdata(dev);

	/*
	 * wacom->hdev should never be null, but surprisingly, I had the case
	 * once while unplugging the Wacom Wireless Receiver.
	 */
	if (wacom->hdev)
		hid_hw_close(wacom->hdev);
}

/*
 * Calculate the resolution of the X or Y axis using hidinput_calc_abs_res.
 */
static int wacom_calc_hid_res(int logical_extents, int physical_extents,
			       unsigned unit, int exponent)
{
	struct hid_field field = {
		.logical_maximum = logical_extents,
		.physical_maximum = physical_extents,
		.unit = unit,
		.unit_exponent = exponent,
	};

	return hidinput_calc_abs_res(&field, ABS_X);
}

static void wacom_hid_usage_quirk(struct hid_device *hdev,
		struct hid_field *field, struct hid_usage *usage)
{
	struct wacom *wacom = hid_get_drvdata(hdev);
	struct wacom_features *features = &wacom->wacom_wac.features;
	unsigned int equivalent_usage = wacom_equivalent_usage(usage->hid);

	/*
	 * The Dell Canvas 27 needs to be switched to its vendor-defined
	 * report to provide the best resolution.
	 */
	if (hdev->vendor == USB_VENDOR_ID_WACOM &&
	    hdev->product == 0x4200 &&
	    field->application == HID_UP_MSVENDOR) {
		wacom->wacom_wac.mode_report = field->report->id;
		wacom->wacom_wac.mode_value = 2;
	}

	/*
	 * ISDv4 devices which predate HID's adoption of the
	 * HID_DG_BARELSWITCH2 usage use 0x000D0000 in its
	 * position instead. We can accurately detect if a
	 * usage with that value should be HID_DG_BARRELSWITCH2
	 * based on the surrounding usages, which have remained
	 * constant across generations.
	 */
	if (features->type == HID_GENERIC &&
	    usage->hid == 0x000D0000 &&
	    field->application == HID_DG_PEN &&
	    field->physical == HID_DG_STYLUS) {
		int i = usage->usage_index;

		if (i-4 >= 0 && i+1 < field->maxusage &&
		    field->usage[i-4].hid == HID_DG_TIPSWITCH &&
		    field->usage[i-3].hid == HID_DG_BARRELSWITCH &&
		    field->usage[i-2].hid == HID_DG_ERASER &&
		    field->usage[i-1].hid == HID_DG_INVERT &&
		    field->usage[i+1].hid == HID_DG_INRANGE) {
			usage->hid = HID_DG_BARRELSWITCH2;
		}
	}

	/* 2nd-generation Intuos Pro Large has incorrect Y maximum */
	if (hdev->vendor == USB_VENDOR_ID_WACOM &&
	    hdev->product == 0x0358 &&
	    WACOM_PEN_FIELD(field) &&
	    equivalent_usage == HID_GD_Y) {
		field->logical_maximum = 43200;
	}
}

static void wacom_feature_mapping(struct hid_device *hdev,
		struct hid_field *field, struct hid_usage *usage)
{
	struct wacom *wacom = hid_get_drvdata(hdev);
	struct wacom_features *features = &wacom->wacom_wac.features;
	struct hid_data *hid_data = &wacom->wacom_wac.hid_data;
	unsigned int equivalent_usage = wacom_equivalent_usage(usage->hid);
	u8 *data;
	int ret;
	u32 n;

	wacom_hid_usage_quirk(hdev, field, usage);

	switch (equivalent_usage) {
	case WACOM_HID_WD_TOUCH_RING_SETTING:
		wacom->generic_has_leds = true;
		break;
	case HID_DG_CONTACTMAX:
		/* leave touch_max as is if predefined */
		if (!features->touch_max) {
			/* read manually */
			n = hid_report_len(field->report);
			data = hid_alloc_report_buf(field->report, GFP_KERNEL);
			if (!data)
				break;
			data[0] = field->report->id;
			ret = wacom_get_report(hdev, HID_FEATURE_REPORT,
					       data, n, WAC_CMD_RETRIES);
			if (ret == n) {
				ret = hid_report_raw_event(hdev,
					HID_FEATURE_REPORT, data, n, 0);
			} else {
				features->touch_max = 16;
				hid_warn(hdev, "wacom_feature_mapping: "
					 "could not get HID_DG_CONTACTMAX, "
					 "defaulting to %d\n",
					  features->touch_max);
			}
			kfree(data);
		}
		break;
	case HID_DG_INPUTMODE:
		/* Ignore if value index is out of bounds. */
		if (usage->usage_index >= field->report_count) {
			dev_err(&hdev->dev, "HID_DG_INPUTMODE out of range\n");
			break;
		}

		hid_data->inputmode = field->report->id;
		hid_data->inputmode_index = usage->usage_index;
		break;

	case HID_UP_DIGITIZER:
		if (field->report->id == 0x0B &&
		    (field->application == WACOM_HID_G9_PEN ||
		     field->application == WACOM_HID_G11_PEN)) {
			wacom->wacom_wac.mode_report = field->report->id;
			wacom->wacom_wac.mode_value = 0;
		}
		break;

	case WACOM_HID_WD_DATAMODE:
		wacom->wacom_wac.mode_report = field->report->id;
		wacom->wacom_wac.mode_value = 2;
		break;

	case WACOM_HID_UP_G9:
	case WACOM_HID_UP_G11:
		if (field->report->id == 0x03 &&
		    (field->application == WACOM_HID_G9_TOUCHSCREEN ||
		     field->application == WACOM_HID_G11_TOUCHSCREEN)) {
			wacom->wacom_wac.mode_report = field->report->id;
			wacom->wacom_wac.mode_value = 0;
		}
		break;
	case WACOM_HID_WD_OFFSETLEFT:
	case WACOM_HID_WD_OFFSETTOP:
	case WACOM_HID_WD_OFFSETRIGHT:
	case WACOM_HID_WD_OFFSETBOTTOM:
		/* read manually */
		n = hid_report_len(field->report);
		data = hid_alloc_report_buf(field->report, GFP_KERNEL);
		if (!data)
			break;
		data[0] = field->report->id;
		ret = wacom_get_report(hdev, HID_FEATURE_REPORT,
					data, n, WAC_CMD_RETRIES);
		if (ret == n) {
			ret = hid_report_raw_event(hdev, HID_FEATURE_REPORT,
						   data, n, 0);
		} else {
			hid_warn(hdev, "%s: could not retrieve sensor offsets\n",
				 __func__);
		}
		kfree(data);
		break;
	}
}

/*
 * Interface Descriptor of wacom devices can be incomplete and
 * inconsistent so wacom_features table is used to store stylus
 * device's packet lengths, various maximum values, and tablet
 * resolution based on product ID's.
 *
 * For devices that contain 2 interfaces, wacom_features table is
 * inaccurate for the touch interface.  Since the Interface Descriptor
 * for touch interfaces has pretty complete data, this function exists
 * to query tablet for this missing information instead of hard coding in
 * an additional table.
 *
 * A typical Interface Descriptor for a stylus will contain a
 * boot mouse application collection that is not of interest and this
 * function will ignore it.
 *
 * It also contains a digitizer application collection that also is not
 * of interest since any information it contains would be duplicate
 * of what is in wacom_features. Usually it defines a report of an array
 * of bytes that could be used as max length of the stylus packet returned.
 * If it happens to define a Digitizer-Stylus Physical Collection then
 * the X and Y logical values contain valid data but it is ignored.
 *
 * A typical Interface Descriptor for a touch interface will contain a
 * Digitizer-Finger Physical Collection which will define both logical
 * X/Y maximum as well as the physical size of tablet. Since touch
 * interfaces haven't supported pressure or distance, this is enough
 * information to override invalid values in the wacom_features table.
 *
 * Intuos5 touch interface and 3rd gen Bamboo Touch do not contain useful
 * data. We deal with them after returning from this function.
 */
static void wacom_usage_mapping(struct hid_device *hdev,
		struct hid_field *field, struct hid_usage *usage)
{
	struct wacom *wacom = hid_get_drvdata(hdev);
	struct wacom_features *features = &wacom->wacom_wac.features;
	bool finger = WACOM_FINGER_FIELD(field);
	bool pen = WACOM_PEN_FIELD(field);
	unsigned equivalent_usage = wacom_equivalent_usage(usage->hid);

	/*
	* Requiring Stylus Usage will ignore boot mouse
	* X/Y values and some cases of invalid Digitizer X/Y
	* values commonly reported.
	*/
	if (pen)
		features->device_type |= WACOM_DEVICETYPE_PEN;
	else if (finger)
		features->device_type |= WACOM_DEVICETYPE_TOUCH;
	else
		return;

	wacom_hid_usage_quirk(hdev, field, usage);

	switch (equivalent_usage) {
	case HID_GD_X:
		features->x_max = field->logical_maximum;
		if (finger) {
			features->x_phy = field->physical_maximum;
			if ((features->type != BAMBOO_PT) &&
			    (features->type != BAMBOO_TOUCH)) {
				features->unit = field->unit;
				features->unitExpo = field->unit_exponent;
			}
		}
		break;
	case HID_GD_Y:
		features->y_max = field->logical_maximum;
		if (finger) {
			features->y_phy = field->physical_maximum;
			if ((features->type != BAMBOO_PT) &&
			    (features->type != BAMBOO_TOUCH)) {
				features->unit = field->unit;
				features->unitExpo = field->unit_exponent;
			}
		}
		break;
	case HID_DG_TIPPRESSURE:
		if (pen)
			features->pressure_max = field->logical_maximum;
		break;
	}

	if (features->type == HID_GENERIC)
		wacom_wac_usage_mapping(hdev, field, usage);
}

static void wacom_post_parse_hid(struct hid_device *hdev,
				 struct wacom_features *features)
{
	struct wacom *wacom = hid_get_drvdata(hdev);
	struct wacom_wac *wacom_wac = &wacom->wacom_wac;

	if (features->type == HID_GENERIC) {
		/* Any last-minute generic device setup */
		if (wacom_wac->has_mode_change) {
			if (wacom_wac->is_direct_mode)
				features->device_type |= WACOM_DEVICETYPE_DIRECT;
			else
				features->device_type &= ~WACOM_DEVICETYPE_DIRECT;
		}

		if (features->touch_max > 1) {
			if (features->device_type & WACOM_DEVICETYPE_DIRECT)
				input_mt_init_slots(wacom_wac->touch_input,
						    wacom_wac->features.touch_max,
						    INPUT_MT_DIRECT);
			else
				input_mt_init_slots(wacom_wac->touch_input,
						    wacom_wac->features.touch_max,
						    INPUT_MT_POINTER);
		}
	}
}

static void wacom_parse_hid(struct hid_device *hdev,
			   struct wacom_features *features)
{
	struct hid_report_enum *rep_enum;
	struct hid_report *hreport;
	int i, j;

	/* check features first */
	rep_enum = &hdev->report_enum[HID_FEATURE_REPORT];
	list_for_each_entry(hreport, &rep_enum->report_list, list) {
		for (i = 0; i < hreport->maxfield; i++) {
			/* Ignore if report count is out of bounds. */
			if (hreport->field[i]->report_count < 1)
				continue;

			for (j = 0; j < hreport->field[i]->maxusage; j++) {
				wacom_feature_mapping(hdev, hreport->field[i],
						hreport->field[i]->usage + j);
			}
		}
	}

	/* now check the input usages */
	rep_enum = &hdev->report_enum[HID_INPUT_REPORT];
	list_for_each_entry(hreport, &rep_enum->report_list, list) {

		if (!hreport->maxfield)
			continue;

		for (i = 0; i < hreport->maxfield; i++)
			for (j = 0; j < hreport->field[i]->maxusage; j++)
				wacom_usage_mapping(hdev, hreport->field[i],
						hreport->field[i]->usage + j);
	}

	wacom_post_parse_hid(hdev, features);
}

static int wacom_hid_set_device_mode(struct hid_device *hdev)
{
	struct wacom *wacom = hid_get_drvdata(hdev);
	struct hid_data *hid_data = &wacom->wacom_wac.hid_data;
	struct hid_report *r;
	struct hid_report_enum *re;

	if (hid_data->inputmode < 0)
		return 0;

	re = &(hdev->report_enum[HID_FEATURE_REPORT]);
	r = re->report_id_hash[hid_data->inputmode];
	if (r) {
		r->field[0]->value[hid_data->inputmode_index] = 2;
		hid_hw_request(hdev, r, HID_REQ_SET_REPORT);
	}
	return 0;
}

static int wacom_set_device_mode(struct hid_device *hdev,
				 struct wacom_wac *wacom_wac)
{
	u8 *rep_data;
	struct hid_report *r;
	struct hid_report_enum *re;
	u32 length;
	int error = -ENOMEM, limit = 0;

	if (wacom_wac->mode_report < 0)
		return 0;

	re = &(hdev->report_enum[HID_FEATURE_REPORT]);
	r = re->report_id_hash[wacom_wac->mode_report];
	if (!r)
		return -EINVAL;

	rep_data = hid_alloc_report_buf(r, GFP_KERNEL);
	if (!rep_data)
		return -ENOMEM;

	length = hid_report_len(r);

	do {
		rep_data[0] = wacom_wac->mode_report;
		rep_data[1] = wacom_wac->mode_value;

		error = wacom_set_report(hdev, HID_FEATURE_REPORT, rep_data,
					 length, 1);
		if (error >= 0)
			error = wacom_get_report(hdev, HID_FEATURE_REPORT,
			                         rep_data, length, 1);
	} while (error >= 0 &&
		 rep_data[1] != wacom_wac->mode_report &&
		 limit++ < WAC_MSG_RETRIES);

	kfree(rep_data);

	return error < 0 ? error : 0;
}

static int wacom_bt_query_tablet_data(struct hid_device *hdev, u8 speed,
		struct wacom_features *features)
{
	struct wacom *wacom = hid_get_drvdata(hdev);
	int ret;
	u8 rep_data[2];

	switch (features->type) {
	case GRAPHIRE_BT:
		rep_data[0] = 0x03;
		rep_data[1] = 0x00;
		ret = wacom_set_report(hdev, HID_FEATURE_REPORT, rep_data, 2,
					3);

		if (ret >= 0) {
			rep_data[0] = speed == 0 ? 0x05 : 0x06;
			rep_data[1] = 0x00;

			ret = wacom_set_report(hdev, HID_FEATURE_REPORT,
						rep_data, 2, 3);

			if (ret >= 0) {
				wacom->wacom_wac.bt_high_speed = speed;
				return 0;
			}
		}

		/*
		 * Note that if the raw queries fail, it's not a hard failure
		 * and it is safe to continue
		 */
		hid_warn(hdev, "failed to poke device, command %d, err %d\n",
			 rep_data[0], ret);
		break;
	case INTUOS4WL:
		if (speed == 1)
			wacom->wacom_wac.bt_features &= ~0x20;
		else
			wacom->wacom_wac.bt_features |= 0x20;

		rep_data[0] = 0x03;
		rep_data[1] = wacom->wacom_wac.bt_features;

		ret = wacom_set_report(hdev, HID_FEATURE_REPORT, rep_data, 2,
					1);
		if (ret >= 0)
			wacom->wacom_wac.bt_high_speed = speed;
		break;
	}

	return 0;
}

/*
 * Switch the tablet into its most-capable mode. Wacom tablets are
 * typically configured to power-up in a mode which sends mouse-like
 * reports to the OS. To get absolute position, pressure data, etc.
 * from the tablet, it is necessary to switch the tablet out of this
 * mode and into one which sends the full range of tablet data.
 */
static int _wacom_query_tablet_data(struct wacom *wacom)
{
	struct hid_device *hdev = wacom->hdev;
	struct wacom_wac *wacom_wac = &wacom->wacom_wac;
	struct wacom_features *features = &wacom_wac->features;

	if (hdev->bus == BUS_BLUETOOTH)
		return wacom_bt_query_tablet_data(hdev, 1, features);

	if (features->type != HID_GENERIC) {
		if (features->device_type & WACOM_DEVICETYPE_TOUCH) {
			if (features->type > TABLETPC) {
				/* MT Tablet PC touch */
				wacom_wac->mode_report = 3;
				wacom_wac->mode_value = 4;
			} else if (features->type == WACOM_24HDT) {
				wacom_wac->mode_report = 18;
				wacom_wac->mode_value = 2;
			} else if (features->type == WACOM_27QHDT) {
				wacom_wac->mode_report = 131;
				wacom_wac->mode_value = 2;
			} else if (features->type == BAMBOO_PAD) {
				wacom_wac->mode_report = 2;
				wacom_wac->mode_value = 2;
			}
		} else if (features->device_type & WACOM_DEVICETYPE_PEN) {
			if (features->type <= BAMBOO_PT) {
				wacom_wac->mode_report = 2;
				wacom_wac->mode_value = 2;
			}
		}
	}

	wacom_set_device_mode(hdev, wacom_wac);

	if (features->type == HID_GENERIC)
		return wacom_hid_set_device_mode(hdev);

	return 0;
}

static void wacom_retrieve_hid_descriptor(struct hid_device *hdev,
					 struct wacom_features *features)
{
	struct wacom *wacom = hid_get_drvdata(hdev);
	struct usb_interface *intf = wacom->intf;

	/* default features */
	features->x_fuzz = 4;
	features->y_fuzz = 4;
	features->pressure_fuzz = 0;
	features->distance_fuzz = 1;
	features->tilt_fuzz = 1;

	/*
	 * The wireless device HID is basic and layout conflicts with
	 * other tablets (monitor and touch interface can look like pen).
	 * Skip the query for this type and modify defaults based on
	 * interface number.
	 */
	if (features->type == WIRELESS) {
		if (intf->cur_altsetting->desc.bInterfaceNumber == 0)
			features->device_type = WACOM_DEVICETYPE_WL_MONITOR;
		else
			features->device_type = WACOM_DEVICETYPE_NONE;
		return;
	}

	wacom_parse_hid(hdev, features);
}

struct wacom_hdev_data {
	struct list_head list;
	struct kref kref;
	struct hid_device *dev;
	struct wacom_shared shared;
};

static LIST_HEAD(wacom_udev_list);
static DEFINE_MUTEX(wacom_udev_list_lock);

static bool wacom_are_sibling(struct hid_device *hdev,
		struct hid_device *sibling)
{
	struct wacom *wacom = hid_get_drvdata(hdev);
	struct wacom_features *features = &wacom->wacom_wac.features;
	struct wacom *sibling_wacom = hid_get_drvdata(sibling);
	struct wacom_features *sibling_features = &sibling_wacom->wacom_wac.features;
	__u32 oVid = features->oVid ? features->oVid : hdev->vendor;
	__u32 oPid = features->oPid ? features->oPid : hdev->product;

	/* The defined oVid/oPid must match that of the sibling */
	if (features->oVid != HID_ANY_ID && sibling->vendor != oVid)
		return false;
	if (features->oPid != HID_ANY_ID && sibling->product != oPid)
		return false;

	/*
	 * Devices with the same VID/PID must share the same physical
	 * device path, while those with different VID/PID must share
	 * the same physical parent device path.
	 */
	if (hdev->vendor == sibling->vendor && hdev->product == sibling->product) {
		if (!hid_compare_device_paths(hdev, sibling, '/'))
			return false;
	} else {
		if (!hid_compare_device_paths(hdev, sibling, '.'))
			return false;
	}

	/* Skip the remaining heuristics unless you are a HID_GENERIC device */
	if (features->type != HID_GENERIC)
		return true;

	/*
	 * Direct-input devices may not be siblings of indirect-input
	 * devices.
	 */
	if ((features->device_type & WACOM_DEVICETYPE_DIRECT) &&
	    !(sibling_features->device_type & WACOM_DEVICETYPE_DIRECT))
		return false;

	/*
	 * Indirect-input devices may not be siblings of direct-input
	 * devices.
	 */
	if (!(features->device_type & WACOM_DEVICETYPE_DIRECT) &&
	    (sibling_features->device_type & WACOM_DEVICETYPE_DIRECT))
		return false;

	/* Pen devices may only be siblings of touch devices */
	if ((features->device_type & WACOM_DEVICETYPE_PEN) &&
	    !(sibling_features->device_type & WACOM_DEVICETYPE_TOUCH))
		return false;

	/* Touch devices may only be siblings of pen devices */
	if ((features->device_type & WACOM_DEVICETYPE_TOUCH) &&
	    !(sibling_features->device_type & WACOM_DEVICETYPE_PEN))
		return false;

	/*
	 * No reason could be found for these two devices to NOT be
	 * siblings, so there's a good chance they ARE siblings
	 */
	return true;
}

static struct wacom_hdev_data *wacom_get_hdev_data(struct hid_device *hdev)
{
	struct wacom_hdev_data *data;

	/* Try to find an already-probed interface from the same device */
	list_for_each_entry(data, &wacom_udev_list, list) {
		if (hid_compare_device_paths(hdev, data->dev, '/')) {
			kref_get(&data->kref);
			return data;
		}
	}

	/* Fallback to finding devices that appear to be "siblings" */
	list_for_each_entry(data, &wacom_udev_list, list) {
		if (wacom_are_sibling(hdev, data->dev)) {
			kref_get(&data->kref);
			return data;
		}
	}

	return NULL;
}

static void wacom_release_shared_data(struct kref *kref)
{
	struct wacom_hdev_data *data =
		container_of(kref, struct wacom_hdev_data, kref);

	mutex_lock(&wacom_udev_list_lock);
	list_del(&data->list);
	mutex_unlock(&wacom_udev_list_lock);

	kfree(data);
}

static void wacom_remove_shared_data(void *res)
{
	struct wacom *wacom = res;
	struct wacom_hdev_data *data;
	struct wacom_wac *wacom_wac = &wacom->wacom_wac;

	if (wacom_wac->shared) {
		data = container_of(wacom_wac->shared, struct wacom_hdev_data,
				    shared);

		if (wacom_wac->shared->touch == wacom->hdev)
			wacom_wac->shared->touch = NULL;
		else if (wacom_wac->shared->pen == wacom->hdev)
			wacom_wac->shared->pen = NULL;

		kref_put(&data->kref, wacom_release_shared_data);
		wacom_wac->shared = NULL;
	}
}

static int wacom_add_shared_data(struct hid_device *hdev)
{
	struct wacom *wacom = hid_get_drvdata(hdev);
	struct wacom_wac *wacom_wac = &wacom->wacom_wac;
	struct wacom_hdev_data *data;
	int retval = 0;

	mutex_lock(&wacom_udev_list_lock);

	data = wacom_get_hdev_data(hdev);
	if (!data) {
		data = kzalloc(sizeof(struct wacom_hdev_data), GFP_KERNEL);
		if (!data) {
			retval = -ENOMEM;
			goto out;
		}

		kref_init(&data->kref);
		data->dev = hdev;
		list_add_tail(&data->list, &wacom_udev_list);
	}

	wacom_wac->shared = &data->shared;

	retval = devm_add_action(&hdev->dev, wacom_remove_shared_data, wacom);
	if (retval) {
		mutex_unlock(&wacom_udev_list_lock);
		wacom_remove_shared_data(wacom);
		return retval;
	}

	if (wacom_wac->features.device_type & WACOM_DEVICETYPE_TOUCH)
		wacom_wac->shared->touch = hdev;
	else if (wacom_wac->features.device_type & WACOM_DEVICETYPE_PEN)
		wacom_wac->shared->pen = hdev;

out:
	mutex_unlock(&wacom_udev_list_lock);
	return retval;
}

static int wacom_led_control(struct wacom *wacom)
{
	unsigned char *buf;
	int retval;
	unsigned char report_id = WAC_CMD_LED_CONTROL;
	int buf_size = 9;

	if (!wacom->led.groups)
		return -ENOTSUPP;

	if (wacom->wacom_wac.features.type == REMOTE)
		return -ENOTSUPP;

	if (wacom->wacom_wac.pid) { /* wireless connected */
		report_id = WAC_CMD_WL_LED_CONTROL;
		buf_size = 13;
	}
	else if (wacom->wacom_wac.features.type == INTUOSP2_BT) {
		report_id = WAC_CMD_WL_INTUOSP2;
		buf_size = 51;
	}
	buf = kzalloc(buf_size, GFP_KERNEL);
	if (!buf)
		return -ENOMEM;

	if (wacom->wacom_wac.features.type == HID_GENERIC) {
		buf[0] = WAC_CMD_LED_CONTROL_GENERIC;
		buf[1] = wacom->led.llv;
		buf[2] = wacom->led.groups[0].select & 0x03;

	} else if ((wacom->wacom_wac.features.type >= INTUOS5S &&
	    wacom->wacom_wac.features.type <= INTUOSPL)) {
		/*
		 * Touch Ring and crop mark LED luminance may take on
		 * one of four values:
		 *    0 = Low; 1 = Medium; 2 = High; 3 = Off
		 */
		int ring_led = wacom->led.groups[0].select & 0x03;
		int ring_lum = (((wacom->led.llv & 0x60) >> 5) - 1) & 0x03;
		int crop_lum = 0;
		unsigned char led_bits = (crop_lum << 4) | (ring_lum << 2) | (ring_led);

		buf[0] = report_id;
		if (wacom->wacom_wac.pid) {
			wacom_get_report(wacom->hdev, HID_FEATURE_REPORT,
					 buf, buf_size, WAC_CMD_RETRIES);
			buf[0] = report_id;
			buf[4] = led_bits;
		} else
			buf[1] = led_bits;
	}
	else if (wacom->wacom_wac.features.type == INTUOSP2_BT) {
		buf[0] = report_id;
		buf[4] = 100; // Power Connection LED (ORANGE)
		buf[5] = 100; // BT Connection LED (BLUE)
		buf[6] = 100; // Paper Mode (RED?)
		buf[7] = 100; // Paper Mode (GREEN?)
		buf[8] = 100; // Paper Mode (BLUE?)
		buf[9] = wacom->led.llv;
		buf[10] = wacom->led.groups[0].select & 0x03;
	}
	else {
		int led = wacom->led.groups[0].select | 0x4;

		if (wacom->wacom_wac.features.type == WACOM_21UX2 ||
		    wacom->wacom_wac.features.type == WACOM_24HD)
			led |= (wacom->led.groups[1].select << 4) | 0x40;

		buf[0] = report_id;
		buf[1] = led;
		buf[2] = wacom->led.llv;
		buf[3] = wacom->led.hlv;
		buf[4] = wacom->led.img_lum;
	}

	retval = wacom_set_report(wacom->hdev, HID_FEATURE_REPORT, buf, buf_size,
				  WAC_CMD_RETRIES);
	kfree(buf);

	return retval;
}

static int wacom_led_putimage(struct wacom *wacom, int button_id, u8 xfer_id,
		const unsigned len, const void *img)
{
	unsigned char *buf;
	int i, retval;
	const unsigned chunk_len = len / 4; /* 4 chunks are needed to be sent */

	buf = kzalloc(chunk_len + 3 , GFP_KERNEL);
	if (!buf)
		return -ENOMEM;

	/* Send 'start' command */
	buf[0] = WAC_CMD_ICON_START;
	buf[1] = 1;
	retval = wacom_set_report(wacom->hdev, HID_FEATURE_REPORT, buf, 2,
				  WAC_CMD_RETRIES);
	if (retval < 0)
		goto out;

	buf[0] = xfer_id;
	buf[1] = button_id & 0x07;
	for (i = 0; i < 4; i++) {
		buf[2] = i;
		memcpy(buf + 3, img + i * chunk_len, chunk_len);

		retval = wacom_set_report(wacom->hdev, HID_FEATURE_REPORT,
					  buf, chunk_len + 3, WAC_CMD_RETRIES);
		if (retval < 0)
			break;
	}

	/* Send 'stop' */
	buf[0] = WAC_CMD_ICON_START;
	buf[1] = 0;
	wacom_set_report(wacom->hdev, HID_FEATURE_REPORT, buf, 2,
			 WAC_CMD_RETRIES);

out:
	kfree(buf);
	return retval;
}

static ssize_t wacom_led_select_store(struct device *dev, int set_id,
				      const char *buf, size_t count)
{
	struct hid_device *hdev = to_hid_device(dev);
	struct wacom *wacom = hid_get_drvdata(hdev);
	unsigned int id;
	int err;

	err = kstrtouint(buf, 10, &id);
	if (err)
		return err;

	mutex_lock(&wacom->lock);

	wacom->led.groups[set_id].select = id & 0x3;
	err = wacom_led_control(wacom);

	mutex_unlock(&wacom->lock);

	return err < 0 ? err : count;
}

#define DEVICE_LED_SELECT_ATTR(SET_ID)					\
static ssize_t wacom_led##SET_ID##_select_store(struct device *dev,	\
	struct device_attribute *attr, const char *buf, size_t count)	\
{									\
	return wacom_led_select_store(dev, SET_ID, buf, count);		\
}									\
static ssize_t wacom_led##SET_ID##_select_show(struct device *dev,	\
	struct device_attribute *attr, char *buf)			\
{									\
	struct hid_device *hdev = to_hid_device(dev);\
	struct wacom *wacom = hid_get_drvdata(hdev);			\
	return scnprintf(buf, PAGE_SIZE, "%d\n",			\
			 wacom->led.groups[SET_ID].select);		\
}									\
static DEVICE_ATTR(status_led##SET_ID##_select, DEV_ATTR_RW_PERM,	\
		    wacom_led##SET_ID##_select_show,			\
		    wacom_led##SET_ID##_select_store)

DEVICE_LED_SELECT_ATTR(0);
DEVICE_LED_SELECT_ATTR(1);

static ssize_t wacom_luminance_store(struct wacom *wacom, u8 *dest,
				     const char *buf, size_t count)
{
	unsigned int value;
	int err;

	err = kstrtouint(buf, 10, &value);
	if (err)
		return err;

	mutex_lock(&wacom->lock);

	*dest = value & 0x7f;
	err = wacom_led_control(wacom);

	mutex_unlock(&wacom->lock);

	return err < 0 ? err : count;
}

#define DEVICE_LUMINANCE_ATTR(name, field)				\
static ssize_t wacom_##name##_luminance_store(struct device *dev,	\
	struct device_attribute *attr, const char *buf, size_t count)	\
{									\
	struct hid_device *hdev = to_hid_device(dev);\
	struct wacom *wacom = hid_get_drvdata(hdev);			\
									\
	return wacom_luminance_store(wacom, &wacom->led.field,		\
				     buf, count);			\
}									\
static ssize_t wacom_##name##_luminance_show(struct device *dev,	\
	struct device_attribute *attr, char *buf)			\
{									\
	struct wacom *wacom = dev_get_drvdata(dev);			\
	return scnprintf(buf, PAGE_SIZE, "%d\n", wacom->led.field);	\
}									\
static DEVICE_ATTR(name##_luminance, DEV_ATTR_RW_PERM,			\
		   wacom_##name##_luminance_show,			\
		   wacom_##name##_luminance_store)

DEVICE_LUMINANCE_ATTR(status0, llv);
DEVICE_LUMINANCE_ATTR(status1, hlv);
DEVICE_LUMINANCE_ATTR(buttons, img_lum);

static ssize_t wacom_button_image_store(struct device *dev, int button_id,
					const char *buf, size_t count)
{
	struct hid_device *hdev = to_hid_device(dev);
	struct wacom *wacom = hid_get_drvdata(hdev);
	int err;
	unsigned len;
	u8 xfer_id;

	if (hdev->bus == BUS_BLUETOOTH) {
		len = 256;
		xfer_id = WAC_CMD_ICON_BT_XFER;
	} else {
		len = 1024;
		xfer_id = WAC_CMD_ICON_XFER;
	}

	if (count != len)
		return -EINVAL;

	mutex_lock(&wacom->lock);

	err = wacom_led_putimage(wacom, button_id, xfer_id, len, buf);

	mutex_unlock(&wacom->lock);

	return err < 0 ? err : count;
}

#define DEVICE_BTNIMG_ATTR(BUTTON_ID)					\
static ssize_t wacom_btnimg##BUTTON_ID##_store(struct device *dev,	\
	struct device_attribute *attr, const char *buf, size_t count)	\
{									\
	return wacom_button_image_store(dev, BUTTON_ID, buf, count);	\
}									\
static DEVICE_ATTR(button##BUTTON_ID##_rawimg, DEV_ATTR_WO_PERM,	\
		   NULL, wacom_btnimg##BUTTON_ID##_store)

DEVICE_BTNIMG_ATTR(0);
DEVICE_BTNIMG_ATTR(1);
DEVICE_BTNIMG_ATTR(2);
DEVICE_BTNIMG_ATTR(3);
DEVICE_BTNIMG_ATTR(4);
DEVICE_BTNIMG_ATTR(5);
DEVICE_BTNIMG_ATTR(6);
DEVICE_BTNIMG_ATTR(7);

static struct attribute *cintiq_led_attrs[] = {
	&dev_attr_status_led0_select.attr,
	&dev_attr_status_led1_select.attr,
	NULL
};

static struct attribute_group cintiq_led_attr_group = {
	.name = "wacom_led",
	.attrs = cintiq_led_attrs,
};

static struct attribute *intuos4_led_attrs[] = {
	&dev_attr_status0_luminance.attr,
	&dev_attr_status1_luminance.attr,
	&dev_attr_status_led0_select.attr,
	&dev_attr_buttons_luminance.attr,
	&dev_attr_button0_rawimg.attr,
	&dev_attr_button1_rawimg.attr,
	&dev_attr_button2_rawimg.attr,
	&dev_attr_button3_rawimg.attr,
	&dev_attr_button4_rawimg.attr,
	&dev_attr_button5_rawimg.attr,
	&dev_attr_button6_rawimg.attr,
	&dev_attr_button7_rawimg.attr,
	NULL
};

static struct attribute_group intuos4_led_attr_group = {
	.name = "wacom_led",
	.attrs = intuos4_led_attrs,
};

static struct attribute *intuos5_led_attrs[] = {
	&dev_attr_status0_luminance.attr,
	&dev_attr_status_led0_select.attr,
	NULL
};

static struct attribute_group intuos5_led_attr_group = {
	.name = "wacom_led",
	.attrs = intuos5_led_attrs,
};

static struct attribute *generic_led_attrs[] = {
	&dev_attr_status0_luminance.attr,
	&dev_attr_status_led0_select.attr,
	NULL
};

static struct attribute_group generic_led_attr_group = {
	.name = "wacom_led",
	.attrs = generic_led_attrs,
};

struct wacom_sysfs_group_devres {
	struct attribute_group *group;
	struct kobject *root;
};

static void wacom_devm_sysfs_group_release(struct device *dev, void *res)
{
	struct wacom_sysfs_group_devres *devres = res;
	struct kobject *kobj = devres->root;

	dev_dbg(dev, "%s: dropping reference to %s\n",
		__func__, devres->group->name);
	sysfs_remove_group(kobj, devres->group);
}

static int __wacom_devm_sysfs_create_group(struct wacom *wacom,
					   struct kobject *root,
					   struct attribute_group *group)
{
	struct wacom_sysfs_group_devres *devres;
	int error;

	devres = devres_alloc(wacom_devm_sysfs_group_release,
			      sizeof(struct wacom_sysfs_group_devres),
			      GFP_KERNEL);
	if (!devres)
		return -ENOMEM;

	devres->group = group;
	devres->root = root;

	error = sysfs_create_group(devres->root, group);
	if (error) {
		devres_free(devres);
		return error;
	}

	devres_add(&wacom->hdev->dev, devres);

	return 0;
}

static int wacom_devm_sysfs_create_group(struct wacom *wacom,
					 struct attribute_group *group)
{
	return __wacom_devm_sysfs_create_group(wacom, &wacom->hdev->dev.kobj,
					       group);
}

enum led_brightness wacom_leds_brightness_get(struct wacom_led *led)
{
	struct wacom *wacom = led->wacom;

	if (wacom->led.max_hlv)
		return led->hlv * LED_FULL / wacom->led.max_hlv;

	if (wacom->led.max_llv)
		return led->llv * LED_FULL / wacom->led.max_llv;

	/* device doesn't support brightness tuning */
	return LED_FULL;
}

static enum led_brightness __wacom_led_brightness_get(struct led_classdev *cdev)
{
	struct wacom_led *led = container_of(cdev, struct wacom_led, cdev);
	struct wacom *wacom = led->wacom;

	if (wacom->led.groups[led->group].select != led->id)
		return LED_OFF;

	return wacom_leds_brightness_get(led);
}

static int wacom_led_brightness_set(struct led_classdev *cdev,
				    enum led_brightness brightness)
{
	struct wacom_led *led = container_of(cdev, struct wacom_led, cdev);
	struct wacom *wacom = led->wacom;
	int error;

	mutex_lock(&wacom->lock);

	if (!wacom->led.groups || (brightness == LED_OFF &&
	    wacom->led.groups[led->group].select != led->id)) {
		error = 0;
		goto out;
	}

	led->llv = wacom->led.llv = wacom->led.max_llv * brightness / LED_FULL;
	led->hlv = wacom->led.hlv = wacom->led.max_hlv * brightness / LED_FULL;

	wacom->led.groups[led->group].select = led->id;

	error = wacom_led_control(wacom);

out:
	mutex_unlock(&wacom->lock);

	return error;
}

static void wacom_led_readonly_brightness_set(struct led_classdev *cdev,
					       enum led_brightness brightness)
{
}

static int wacom_led_register_one(struct device *dev, struct wacom *wacom,
				  struct wacom_led *led, unsigned int group,
				  unsigned int id, bool read_only)
{
	int error;
	char *name;

	name = devm_kasprintf(dev, GFP_KERNEL,
			      "%s::wacom-%d.%d",
			      dev_name(dev),
			      group,
			      id);
	if (!name)
		return -ENOMEM;

	if (!read_only) {
		led->trigger.name = name;
		error = devm_led_trigger_register(dev, &led->trigger);
		if (error) {
			hid_err(wacom->hdev,
				"failed to register LED trigger %s: %d\n",
				led->cdev.name, error);
			return error;
		}
	}

	led->group = group;
	led->