HID: add driver for ELO 4000/4500

This is a driver for ELO 4000/4500 devices which report themselves as
HID devices, but do not really send HID events on touch. So we
introduce a new HID 'quirk' driver with a raw_event handler where we
take care of those events.

What we need additionally is an input_configured hook, because the
device does not mention anything about PRESSURE and TOUCH in its
report descriptor, but it actually generate those. So we set the bits
in the corresponding input_dev in that hook.

Thanks to Petr Ostadal who was willing to test the driver. The rest of
Cc's listed below had something to do with that driver over the years
in our enterprise tree.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Tested-by: Petr Ostadal <postadal@suse.cz>
Cc: Oliver Neukum <oliver@neukum.org>
Cc: Vojtech Pavlik <vojtech@suse.cz>
Cc: Egbert Eich <eich@suse.com>
Cc: Libor Pechacek <lpechacek@suse.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/Kconfig

@@ -217,6 +217,13 @@ config HID_ELECOM
 	---help---
 	Support for the ELECOM BM084 (bluetooth mouse).
 
+config HID_ELO
+	tristate "ELO USB 4000/4500 touchscreen"
+	depends on USB_HID
+	---help---
+	Support for the ELO USB 4000/4500 touchscreens. Note that this is for
+	different devices than those handled by CONFIG_TOUCHSCREEN_USB_ELO.
+
 config HID_EZKEY
 	tristate "Ezkey BTC 8193 keyboard" if EXPERT
 	depends on HID

drivers/hid/Makefile

@@ -48,6 +48,7 @@ obj-$(CONFIG_HID_CYPRESS)	+= hid-cypress.o
 obj-$(CONFIG_HID_DRAGONRISE)	+= hid-dr.o
 obj-$(CONFIG_HID_EMS_FF)	+= hid-emsff.o
 obj-$(CONFIG_HID_ELECOM)	+= hid-elecom.o
+obj-$(CONFIG_HID_ELO)		+= hid-elo.o
 obj-$(CONFIG_HID_EZKEY)		+= hid-ezkey.o
 obj-$(CONFIG_HID_GYRATION)	+= hid-gyration.o
 obj-$(CONFIG_HID_HOLTEK)	+= hid-holtek-kbd.o

drivers/hid/hid-core.c

@@ -1573,6 +1573,8 @@ static const struct hid_device_id hid_have_special_driver[] = {
 	{ HID_USB_DEVICE(USB_VENDOR_ID_DRAGONRISE, 0x0006) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_DRAGONRISE, 0x0011) },
 	{ HID_BLUETOOTH_DEVICE(USB_VENDOR_ID_ELECOM, USB_DEVICE_ID_ELECOM_BM084) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_ELO, 0x0009) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_ELO, 0x0030) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_EMS, USB_DEVICE_ID_EMS_TRIO_LINKER_PLUS_II) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_EZKEY, USB_DEVICE_ID_BTC_8193) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_GAMERON, USB_DEVICE_ID_GAMERON_DUAL_PSX_ADAPTOR) },

drivers/hid/hid-elo.c

+/*
+ * 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 "hid-ids.h"
+
+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\n", report->id);
+		break;
+	}
+
+	return 0;
+}
+
+static int elo_probe(struct hid_device *hdev, const struct hid_device_id *id)
+{
+	int ret;
+
+	ret = hid_parse(hdev);
+	if (ret) {
+		hid_err(hdev, "parse failed\n");
+		goto err_free;
+	}
+
+	ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
+	if (ret) {
+		hid_err(hdev, "hw start failed\n");
+		goto err_free;
+	}
+
+	return 0;
+err_free:
+	return ret;
+}
+
+static void elo_remove(struct hid_device *hdev)
+{
+	hid_hw_stop(hdev);
+}
+
+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)
+{
+	return hid_register_driver(&elo_driver);
+}
+module_init(elo_driver_init);
+
+static void __exit elo_driver_exit(void)
+{
+	hid_unregister_driver(&elo_driver);
+}
+module_exit(elo_driver_exit);
+
+MODULE_AUTHOR("Jiri Slaby <jslaby@suse.cz>");
+MODULE_LICENSE("GPL");