HID: add support for the eGalax dual-touch panel

Added support for the eGalax dual-touch panel, found on the Asus EeePC T101MT

Signed-off-by: Stephane Chatty <chatty@enac.fr>
Tested-by: Philipp Merkel <linux@philmerk.de>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

1 files changed, 280 insertions, 0 deletions

diff --git a/drivers/hid/hid-egalax.c b/drivers/hid/hid-egalax.c
new file mode 100644
index 00000000000..8b48d5a0717
--- /dev/null
+++ b/drivers/hid/hid-egalax.c
@@ -0,0 +1,280 @@
+/*
+ *  HID driver for eGalax dual-touch panels
+ *
+ *  Copyright (c) 2010 Stephane Chatty <chatty@enac.fr>
+ *
+ */
+
+/*
+ * 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 <linux/device.h>
+#include <linux/hid.h>
+#include <linux/module.h>
+#include <linux/usb.h>
+#include "usbhid/usbhid.h"
+
+MODULE_AUTHOR("Stephane Chatty <chatty@enac.fr>");
+MODULE_DESCRIPTION("eGalax dual-touch panel");
+MODULE_LICENSE("GPL");
+
+#include "hid-ids.h"
+
+struct egalax_data {
+        __u16 x, y, z;
+        __u8 id;
+        bool first;             /* is this the first finger in the frame? */
+        bool valid;             /* valid finger data, or just placeholder? */
+        bool activity;          /* at least one active finger previously? */
+        __u16 lastx, lasty;     /* latest valid (x, y) in the frame */
+};
+
+static int egalax_input_mapping(struct hid_device *hdev, struct hid_input *hi,
+                struct hid_field *field, struct hid_usage *usage,
+                unsigned long **bit, int *max)
+{
+        switch (usage->hid & HID_USAGE_PAGE) {
+
+        case HID_UP_GENDESK:
+                switch (usage->hid) {
+                case HID_GD_X:
+                        hid_map_usage(hi, usage, bit, max,
+                                        EV_ABS, ABS_MT_POSITION_X);
+                        /* touchscreen emulation */
+                        input_set_abs_params(hi->input, ABS_X,
+                                                field->logical_minimum,
+                                                field->logical_maximum, 0, 0);
+                        return 1;
+                case HID_GD_Y:
+                        hid_map_usage(hi, usage, bit, max,
+                                        EV_ABS, ABS_MT_POSITION_Y);
+                        /* touchscreen emulation */
+                        input_set_abs_params(hi->input, ABS_Y,
+                                                field->logical_minimum,
+                                                field->logical_maximum, 0, 0);
+                        return 1;
+                }
+                return 0;
+
+        case HID_UP_DIGITIZER:
+                switch (usage->hid) {
+                case HID_DG_TIPSWITCH:
+                        /* touchscreen emulation */
+                        hid_map_usage(hi, usage, bit, max, EV_KEY, BTN_TOUCH);
+                        return 1;
+                case HID_DG_INRANGE:
+                case HID_DG_CONFIDENCE:
+                case HID_DG_CONTACTCOUNT:
+                case HID_DG_CONTACTMAX:
+                        return -1;
+                case HID_DG_CONTACTID:
+                        hid_map_usage(hi, usage, bit, max,
+                                        EV_ABS, ABS_MT_TRACKING_ID);
+                        return 1;
+                case HID_DG_TIPPRESSURE:
+                        hid_map_usage(hi, usage, bit, max,
+                                        EV_ABS, ABS_MT_PRESSURE);
+                        return 1;
+                }
+                return 0;
+        }
+
+        /* ignore others (from other reports we won't get anyway) */
+        return -1;
+}
+
+static int egalax_input_mapped(struct hid_device *hdev, struct hid_input *hi,
+                struct hid_field *field, struct hid_usage *usage,
+                unsigned long **bit, int *max)
+{
+        if (usage->type == EV_KEY || usage->type == EV_ABS)
+                clear_bit(usage->code, *bit);
+
+        return 0;
+}
+
+/*
+ * this function is called when a whole finger has been parsed,
+ * so that it can decide what to send to the input layer.
+ */
+static void egalax_filter_event(struct egalax_data *td, struct input_dev *input)
+{
+        td->first = !td->first; /* touchscreen emulation */
+
+        if (td->valid) {
+                /* emit multitouch events */
+                input_event(input, EV_ABS, ABS_MT_TRACKING_ID, td->id);
+                input_event(input, EV_ABS, ABS_MT_POSITION_X, td->x);
+                input_event(input, EV_ABS, ABS_MT_POSITION_Y, td->y);
+                input_event(input, EV_ABS, ABS_MT_PRESSURE, td->z);
+
+                input_mt_sync(input);
+
+                /*
+                 * touchscreen emulation: store (x, y) as
+                 * the last valid values in this frame
+                 */
+                td->lastx = td->x;
+                td->lasty = td->y;
+        }
+
+        /*
+         * touchscreen emulation: if this is the second finger and at least
+         * one in this frame is valid, the latest valid in the frame is
+         * the oldest on the panel, the one we want for single touch
+         */
+        if (!td->first && td->activity) {
+                input_event(input, EV_ABS, ABS_X, td->lastx);
+                input_event(input, EV_ABS, ABS_Y, td->lasty);
+        }
+
+        if (!td->valid) {
+                /*
+                 * touchscreen emulation: if the first finger is invalid
+                 * and there previously was finger activity, this is a release
+                 */ 
+                if (td->first && td->activity) {
+                        input_event(input, EV_KEY, BTN_TOUCH, 0);
+                        td->activity = false;
+                }
+                return;
+        }
+
+
+        /* touchscreen emulation: if no previous activity, emit touch event */
+        if (!td->activity) {
+                input_event(input, EV_KEY, BTN_TOUCH, 1);
+                td->activity = true;
+        }
+}
+
+
+static int egalax_event(struct hid_device *hid, struct hid_field *field,
+                                struct hid_usage *usage, __s32 value)
+{
+        struct egalax_data *td = hid_get_drvdata(hid);
+
+        if (hid->claimed & HID_CLAIMED_INPUT) {
+                struct input_dev *input = field->hidinput->input;
+
+                switch (usage->hid) {
+                case HID_DG_INRANGE:
+                case HID_DG_CONFIDENCE:
+                        /* avoid interference from generic hidinput handling */
+                        break;
+                case HID_DG_TIPSWITCH:
+                        td->valid = value;
+                        break;
+                case HID_DG_TIPPRESSURE:
+                        td->z = value;
+                        break;
+                case HID_DG_CONTACTID:
+                        td->id = value;
+                        break;
+                case HID_GD_X:
+                        td->x = value;
+                        break;
+                case HID_GD_Y:
+                        td->y = value;
+                        /* this is the last field in a finger */
+                        egalax_filter_event(td, input);
+                        break;
+                case HID_DG_CONTACTCOUNT:
+                        /* touch emulation: this is the last field in a frame */
+                        td->first = false;
+                        break;
+
+                default:
+                        /* fallback to the generic hidinput handling */
+                        return 0;
+                }
+        }
+
+        /* we have handled the hidinput part, now remains hiddev */
+        if (hid->claimed & HID_CLAIMED_HIDDEV && hid->hiddev_hid_event)
+                hid->hiddev_hid_event(hid, field, usage, value);
+
+        return 1;
+}
+
+static int egalax_probe(struct hid_device *hdev, const struct hid_device_id *id)
+{
+        int ret;
+        struct egalax_data *td;
+        struct hid_report *report;
+
+        td = kmalloc(sizeof(struct egalax_data), GFP_KERNEL);
+        if (!td) {
+                dev_err(&hdev->dev, "cannot allocate eGalax data\n");
+                return -ENOMEM;
+        }
+        hid_set_drvdata(hdev, td);
+
+        ret = hid_parse(hdev);
+        if (ret)
+                goto end;
+
+        ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
+        if (ret)
+                goto end;
+
+        report = hdev->report_enum[HID_FEATURE_REPORT].report_id_hash[5]; 
+        if (report) {
+                report->field[0]->value[0] = 2;
+                usbhid_submit_report(hdev, report, USB_DIR_OUT);
+        }
+
+end:
+        if (ret)
+                kfree(td);
+
+        return ret;
+}
+
+static void egalax_remove(struct hid_device *hdev)
+{
+        hid_hw_stop(hdev);
+        kfree(hid_get_drvdata(hdev));
+        hid_set_drvdata(hdev, NULL);
+}
+
+static const struct hid_device_id egalax_devices[] = {
+        { HID_USB_DEVICE(USB_VENDOR_ID_DWAV,
+                        USB_DEVICE_ID_DWAV_EGALAX_MULTITOUCH) },
+        { }
+};
+MODULE_DEVICE_TABLE(hid, egalax_devices);
+
+static const struct hid_usage_id egalax_grabbed_usages[] = {
+        { HID_ANY_ID, HID_ANY_ID, HID_ANY_ID },
+        { HID_ANY_ID - 1, HID_ANY_ID - 1, HID_ANY_ID - 1}
+};
+
+static struct hid_driver egalax_driver = {
+        .name = "egalax-touch",
+        .id_table = egalax_devices,
+        .probe = egalax_probe,
+        .remove = egalax_remove,
+        .input_mapping = egalax_input_mapping,
+        .input_mapped = egalax_input_mapped,
+        .usage_table = egalax_grabbed_usages,
+        .event = egalax_event,
+};
+
+static int __init egalax_init(void)
+{
+        return hid_register_driver(&egalax_driver);
+}
+
+static void __exit egalax_exit(void)
+{
+        hid_unregister_driver(&egalax_driver);
+}
+
+module_init(egalax_init);
+module_exit(egalax_exit);
+