drivers/hid/hid-cando.c

   1 /*
   2  *  HID driver for Cando dual-touch panels
   3  *
   4  *  Copyright (c) 2010 Stephane Chatty <chatty@enac.fr>
   5  *
   6  */
   7
   8 /*
   9  * This program is free software; you can redistribute it and/or modify it
  10  * under the terms of the GNU General Public License as published by the Free
  11  * Software Foundation; either version 2 of the License, or (at your option)
  12  * any later version.
  13  */
  14
  15 #include <linux/device.h>
  16 #include <linux/hid.h>
  17 #include <linux/module.h>
  18 #include <linux/slab.h>
  19
  20 MODULE_AUTHOR("Stephane Chatty <chatty@enac.fr>");
  21 MODULE_DESCRIPTION("Cando dual-touch panel");
  22 MODULE_LICENSE("GPL");
  23
  24 #include "hid-ids.h"
  25
  26 struct cando_data {
  27         __u16 x, y;
  28         __u8 id;
  29         __s8 oldest;            /* id of the oldest finger in previous frame */
  30         bool valid;             /* valid finger data, or just placeholder? */
  31         bool first;             /* is this the first finger in this frame? */
  32         __s8 firstid;           /* id of the first finger in the frame */
  33         __u16 firstx, firsty;   /* (x, y) of the first finger in the frame */
  34 };
  35
  36 static int cando_input_mapping(struct hid_device *hdev, struct hid_input *hi,
  37                 struct hid_field *field, struct hid_usage *usage,
  38                 unsigned long **bit, int *max)
  39 {
  40         switch (usage->hid & HID_USAGE_PAGE) {
  41
  42         case HID_UP_GENDESK:
  43                 switch (usage->hid) {
  44                 case HID_GD_X:
  45                         hid_map_usage(hi, usage, bit, max,
  46                                         EV_ABS, ABS_MT_POSITION_X);
  47                         /* touchscreen emulation */
  48                         input_set_abs_params(hi->input, ABS_X,
  49                                                 field->logical_minimum,
  50                                                 field->logical_maximum, 0, 0);
  51                         return 1;
  52                 case HID_GD_Y:
  53                         hid_map_usage(hi, usage, bit, max,
  54                                         EV_ABS, ABS_MT_POSITION_Y);
  55                         /* touchscreen emulation */
  56                         input_set_abs_params(hi->input, ABS_Y,
  57                                                 field->logical_minimum,
  58                                                 field->logical_maximum, 0, 0);
  59                         return 1;
  60                 }
  61                 return 0;
  62
  63         case HID_UP_DIGITIZER:
  64                 switch (usage->hid) {
  65                 case HID_DG_TIPSWITCH:
  66                 case HID_DG_CONTACTMAX:
  67                         return -1;
  68                 case HID_DG_INRANGE:
  69                         /* touchscreen emulation */
  70                         hid_map_usage(hi, usage, bit, max, EV_KEY, BTN_TOUCH);
  71                         return 1;
  72                 case HID_DG_CONTACTID:
  73                         hid_map_usage(hi, usage, bit, max,
  74                                         EV_ABS, ABS_MT_TRACKING_ID);
  75                         return 1;
  76                 }
  77                 return 0;
  78         }
  79
  80         return 0;
  81 }
  82
  83 static int cando_input_mapped(struct hid_device *hdev, struct hid_input *hi,
  84                 struct hid_field *field, struct hid_usage *usage,
  85                 unsigned long **bit, int *max)
  86 {
  87         if (usage->type == EV_KEY || usage->type == EV_ABS)
  88                 clear_bit(usage->code, *bit);
  89
  90         return 0;
  91 }
  92
  93 /*
  94  * this function is called when a whole finger has been parsed,
  95  * so that it can decide what to send to the input layer.
  96  */
  97 static void cando_filter_event(struct cando_data *td, struct input_dev *input)
  98 {
  99         td->first = !td->first; /* touchscreen emulation */
 100
 101         if (!td->valid) {
 102                 /*
 103                  * touchscreen emulation: if this is the second finger and
 104                  * the first was valid, the first was the oldest; if the
 105                  * first was not valid and there was a valid finger in the
 106                  * previous frame, this is a release.
 107                  */
 108                 if (td->first) {
 109                         td->firstid = -1;
 110                 } else if (td->firstid >= 0) {
 111                         input_event(input, EV_ABS, ABS_X, td->firstx);
 112                         input_event(input, EV_ABS, ABS_Y, td->firsty);
 113                         td->oldest = td->firstid;
 114                 } else if (td->oldest >= 0) {
 115                         input_event(input, EV_KEY, BTN_TOUCH, 0);
 116                         td->oldest = -1;
 117                 }
 118
 119                 return;
 120         }
 121
 122         input_event(input, EV_ABS, ABS_MT_TRACKING_ID, td->id);
 123         input_event(input, EV_ABS, ABS_MT_POSITION_X, td->x);
 124         input_event(input, EV_ABS, ABS_MT_POSITION_Y, td->y);
 125
 126         input_mt_sync(input);
 127
 128         /*
 129          * touchscreen emulation: if there was no touching finger previously,
 130          * emit touch event
 131          */
 132         if (td->oldest < 0) {
 133                 input_event(input, EV_KEY, BTN_TOUCH, 1);
 134                 td->oldest = td->id;
 135         }
 136
 137         /*
 138          * touchscreen emulation: if this is the first finger, wait for the
 139          * second; the oldest is then the second if it was the oldest already
 140          * or if there was no first, the first otherwise.
 141          */
 142         if (td->first) {
 143                 td->firstx = td->x;
 144                 td->firsty = td->y;
 145                 td->firstid = td->id;
 146         } else {
 147                 int x, y, oldest;
 148                 if (td->id == td->oldest || td->firstid < 0) {
 149                         x = td->x;
 150                         y = td->y;
 151                         oldest = td->id;
 152                 } else {
 153                         x = td->firstx;
 154                         y = td->firsty;
 155                         oldest = td->firstid;
 156                 }
 157                 input_event(input, EV_ABS, ABS_X, x);
 158                 input_event(input, EV_ABS, ABS_Y, y);
 159                 td->oldest = oldest;
 160         }
 161 }
 162
 163
 164 static int cando_event(struct hid_device *hid, struct hid_field *field,
 165                                 struct hid_usage *usage, __s32 value)
 166 {
 167         struct cando_data *td = hid_get_drvdata(hid);
 168
 169         if (hid->claimed & HID_CLAIMED_INPUT) {
 170                 struct input_dev *input = field->hidinput->input;
 171
 172                 switch (usage->hid) {
 173                 case HID_DG_INRANGE:
 174                         td->valid = value;
 175                         break;
 176                 case HID_DG_CONTACTID:
 177                         td->id = value;
 178                         break;
 179                 case HID_GD_X:
 180                         td->x = value;
 181                         break;
 182                 case HID_GD_Y:
 183                         td->y = value;
 184                         cando_filter_event(td, input);
 185                         break;
 186                 case HID_DG_TIPSWITCH:
 187                         /* avoid interference from generic hidinput handling */
 188                         break;
 189
 190                 default:
 191                         /* fallback to the generic hidinput handling */
 192                         return 0;
 193                 }
 194         }
 195
 196         /* we have handled the hidinput part, now remains hiddev */
 197         if (hid->claimed & HID_CLAIMED_HIDDEV && hid->hiddev_hid_event)
 198                 hid->hiddev_hid_event(hid, field, usage, value);
 199
 200         return 1;
 201 }
 202
 203 static int cando_probe(struct hid_device *hdev, const struct hid_device_id *id)
 204 {
 205         int ret;
 206         struct cando_data *td;
 207
 208         td = kmalloc(sizeof(struct cando_data), GFP_KERNEL);
 209         if (!td) {
 210                 dev_err(&hdev->dev, "cannot allocate Cando Touch data\n");
 211                 return -ENOMEM;
 212         }
 213         hid_set_drvdata(hdev, td);
 214         td->first = false;
 215         td->oldest = -1;
 216         td->valid = false;
 217
 218         ret = hid_parse(hdev);
 219         if (!ret)
 220                 ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
 221
 222         if (ret)
 223                 kfree(td);
 224
 225         return ret;
 226 }
 227
 228 static void cando_remove(struct hid_device *hdev)
 229 {
 230         hid_hw_stop(hdev);
 231         kfree(hid_get_drvdata(hdev));
 232         hid_set_drvdata(hdev, NULL);
 233 }
 234
 235 static const struct hid_device_id cando_devices[] = {
 236         { HID_USB_DEVICE(USB_VENDOR_ID_CANDO,
 237                         USB_DEVICE_ID_CANDO_MULTI_TOUCH) },
 238         { HID_USB_DEVICE(USB_VENDOR_ID_CANDO,
 239                         USB_DEVICE_ID_CANDO_MULTI_TOUCH_11_6) },
 240         { HID_USB_DEVICE(USB_VENDOR_ID_CANDO,
 241                 USB_DEVICE_ID_CANDO_MULTI_TOUCH_15_6) },
 242         { }
 243 };
 244 MODULE_DEVICE_TABLE(hid, cando_devices);
 245
 246 static const struct hid_usage_id cando_grabbed_usages[] = {
 247         { HID_ANY_ID, HID_ANY_ID, HID_ANY_ID },
 248         { HID_ANY_ID - 1, HID_ANY_ID - 1, HID_ANY_ID - 1}
 249 };
 250
 251 static struct hid_driver cando_driver = {
 252         .name = "cando-touch",
 253         .id_table = cando_devices,
 254         .probe = cando_probe,
 255         .remove = cando_remove,
 256         .input_mapping = cando_input_mapping,
 257         .input_mapped = cando_input_mapped,
 258         .usage_table = cando_grabbed_usages,
 259         .event = cando_event,
 260 };
 261
 262 static int __init cando_init(void)
 263 {
 264         return hid_register_driver(&cando_driver);
 265 }
 266
 267 static void __exit cando_exit(void)
 268 {
 269         hid_unregister_driver(&cando_driver);
 270 }
 271
 272 module_init(cando_init);
 273 module_exit(cando_exit);
 274