HID: added support for the Cando dual touch panel

Added support for the Cando dual touch panels, found in the Lenovo S10-3t.

Signed-off-by: Stephane Chatty <chatty@enac.fr>
Tested-by: Priya Vijayan <priya.vijayan@intel.com>
Tested-by: Florian Echtler <floe@butterbrot.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

1 files changed, 267 insertions, 0 deletions

diff --git a/drivers/hid/hid-cando.c b/drivers/hid/hid-cando.c
new file mode 100644
index 000000000000..4fc8f513dcc5
--- /dev/null
+++ b/drivers/hid/hid-cando.c
@@ -0,0 +1,267 @@
+/*
+ *  HID driver for Cando 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/slab.h>
+
+MODULE_AUTHOR("Stephane Chatty <chatty@enac.fr>");
+MODULE_DESCRIPTION("Cando dual-touch panel");
+MODULE_LICENSE("GPL");
+
+#include "hid-ids.h"
+
+struct cando_data {
+        __u16 x, y;
+        __u8 id;
+        __s8 oldest;            /* id of the oldest finger in previous frame */
+        bool valid;             /* valid finger data, or just placeholder? */
+        bool first;             /* is this the first finger in this frame? */
+        __s8 firstid;           /* id of the first finger in the frame */
+        __u16 firstx, firsty;   /* (x, y) of the first finger in the frame */
+};
+
+static int cando_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:
+                case HID_DG_CONTACTMAX:
+                        return -1;
+                case HID_DG_INRANGE:
+                        /* touchscreen emulation */
+                        hid_map_usage(hi, usage, bit, max, EV_KEY, BTN_TOUCH);
+                        return 1;
+                case HID_DG_CONTACTID:
+                        hid_map_usage(hi, usage, bit, max,
+                                        EV_ABS, ABS_MT_TRACKING_ID);
+                        return 1;
+                }
+                return 0;
+        }
+
+        return 0;
+}
+
+static int cando_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 cando_filter_event(struct cando_data *td, struct input_dev *input)
+{
+        td->first = !td->first; /* touchscreen emulation */
+
+        if (!td->valid) {
+                /*
+                 * touchscreen emulation: if this is the second finger and
+                 * the first was valid, the first was the oldest; if the
+                 * first was not valid and there was a valid finger in the
+                 * previous frame, this is a release.
+                 */
+                if (td->first) {
+                        td->firstid = -1;
+                } else if (td->firstid >= 0) {
+                        input_event(input, EV_ABS, ABS_X, td->firstx);
+                        input_event(input, EV_ABS, ABS_Y, td->firsty);
+                        td->oldest = td->firstid;
+                } else if (td->oldest >= 0) {
+                        input_event(input, EV_KEY, BTN_TOUCH, 0);
+                        td->oldest = -1;
+                }
+
+                return;
+        }
+        
+        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_mt_sync(input);
+
+        /*
+         * touchscreen emulation: if there was no touching finger previously,
+         * emit touch event
+         */
+        if (td->oldest < 0) {
+                input_event(input, EV_KEY, BTN_TOUCH, 1);
+                td->oldest = td->id;
+        }
+
+        /*
+         * touchscreen emulation: if this is the first finger, wait for the
+         * second; the oldest is then the second if it was the oldest already
+         * or if there was no first, the first otherwise.
+         */
+        if (td->first) {
+                td->firstx = td->x;
+                td->firsty = td->y;
+                td->firstid = td->id;
+        } else {
+                int x, y, oldest;
+                if (td->id == td->oldest || td->firstid < 0) {
+                        x = td->x;
+                        y = td->y;
+                        oldest = td->id;
+                } else {
+                        x = td->firstx;
+                        y = td->firsty;
+                        oldest = td->firstid;
+                }
+                input_event(input, EV_ABS, ABS_X, x);
+                input_event(input, EV_ABS, ABS_Y, y);
+                td->oldest = oldest;
+        }
+}
+
+
+static int cando_event(struct hid_device *hid, struct hid_field *field,
+                                struct hid_usage *usage, __s32 value)
+{
+        struct cando_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:
+                        td->valid = 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;
+                        cando_filter_event(td, input);
+                        break;
+                case HID_DG_TIPSWITCH:
+                        /* avoid interference from generic hidinput handling */
+                        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 cando_probe(struct hid_device *hdev, const struct hid_device_id *id)
+{
+        int ret;
+        struct cando_data *td;
+
+        td = kmalloc(sizeof(struct cando_data), GFP_KERNEL);
+        if (!td) {
+                dev_err(&hdev->dev, "cannot allocate Cando Touch data\n");
+                return -ENOMEM;
+        }
+        hid_set_drvdata(hdev, td);
+
+        ret = hid_parse(hdev);
+        if (!ret)
+                ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
+
+        if (ret)
+                kfree(td);
+
+        return ret;
+}
+
+static void cando_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 cando_devices[] = {
+        { HID_USB_DEVICE(USB_VENDOR_ID_CANDO,
+                        USB_DEVICE_ID_CANDO_MULTI_TOUCH) },
+        { }
+};
+MODULE_DEVICE_TABLE(hid, cando_devices);
+
+static const struct hid_usage_id cando_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 cando_driver = {
+        .name = "cando-touch",
+        .id_table = cando_devices,
+        .probe = cando_probe,
+        .remove = cando_remove,
+        .input_mapping = cando_input_mapping,
+        .input_mapped = cando_input_mapped,
+        .usage_table = cando_grabbed_usages,
+        .event = cando_event,
+};
+
+static int __init cando_init(void)
+{
+        return hid_register_driver(&cando_driver);
+}
+
+static void __exit cando_exit(void)
+{
+        hid_unregister_driver(&cando_driver);
+}
+
+module_init(cando_init);
+module_exit(cando_exit);
+