drivers/hid/hid-primax.c

   1 /*
   2  * HID driver for primax and similar keyboards with in-band modifiers
   3  *
   4  * Copyright 2011 Google Inc. All Rights Reserved
   5  *
   6  * Author:
   7  *      Terry Lambert <tlambert@google.com>
   8  *
   9  * This software is licensed under the terms of the GNU General Public
  10  * License version 2, as published by the Free Software Foundation, and
  11  * may be copied, distributed, and modified under those terms.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  */
  18
  19 #include <linux/device.h>
  20 #include <linux/hid.h>
  21 #include <linux/module.h>
  22
  23 #include "hid-ids.h"
  24
  25 static int px_raw_event(struct hid_device *hid, struct hid_report *report,
  26          u8 *data, int size)
  27 {
  28         int idx = size;
  29
  30         switch (report->id) {
  31         case 0:         /* keyboard input */
  32                 /*
  33                  * Convert in-band modifier key values into out of band
  34                  * modifier bits and pull the key strokes from the report.
  35                  * Thus a report data set which looked like:
  36                  *
  37                  * [00][00][E0][30][00][00][00][00]
  38                  * (no modifier bits + "Left Shift" key + "1" key)
  39                  *
  40                  * Would be converted to:
  41                  *
  42                  * [01][00][00][30][00][00][00][00]
  43                  * (Left Shift modifier bit + "1" key)
  44                  *
  45                  * As long as it's in the size range, the upper level
  46                  * drivers don't particularly care if there are in-band
  47                  * 0-valued keys, so they don't stop parsing.
  48                  */
  49                 while (--idx > 1) {
  50                         if (data[idx] < 0xE0 || data[idx] > 0xE7)
  51                                 continue;
  52                         data[0] |= (1 << (data[idx] - 0xE0));
  53                         data[idx] = 0;
  54                 }
  55                 hid_report_raw_event(hid, HID_INPUT_REPORT, data, size, 0);
  56                 return 1;
  57
  58         default:        /* unknown report */
  59                 /* Unknown report type; pass upstream */
  60                 hid_info(hid, "unknown report type %d\n", report->id);
  61                 break;
  62         }
  63
  64         return 0;
  65 }
  66
  67 static const struct hid_device_id px_devices[] = {
  68         { HID_USB_DEVICE(USB_VENDOR_ID_PRIMAX, USB_DEVICE_ID_PRIMAX_KEYBOARD) },
  69         { }
  70 };
  71 MODULE_DEVICE_TABLE(hid, px_devices);
  72
  73 static struct hid_driver px_driver = {
  74         .name = "primax",
  75         .id_table = px_devices,
  76         .raw_event = px_raw_event,
  77 };
  78 module_hid_driver(px_driver);
  79
  80 MODULE_AUTHOR("Terry Lambert <tlambert@google.com>");
  81 MODULE_LICENSE("GPL");