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hid-holtek-kbd.c
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1 /*
2  * HID driver for Holtek keyboard
3  * Copyright (c) 2012 Tom Harwood
4 */
5 
6 /*
7  * This program is free software; you can redistribute it and/or modify it
8  * under the terms of the GNU General Public License as published by the Free
9  * Software Foundation; either version 2 of the License, or (at your option)
10  * any later version.
11  */
12 
13 #include <linux/device.h>
14 #include <linux/hid.h>
15 #include <linux/module.h>
16 #include <linux/usb.h>
17 
18 #include "hid-ids.h"
19 #include "usbhid/usbhid.h"
20 
21 /* Holtek based keyboards (USB ID 04d9:a055) have the following issues:
22  * - The report descriptor specifies an excessively large number of consumer
23  * usages (2^15), which is more than HID_MAX_USAGES. This prevents proper
24  * parsing of the report descriptor.
25  * - The report descriptor reports on caps/scroll/num lock key presses, but
26  * doesn't have an LED output usage block.
27  *
28  * The replacement descriptor below fixes the number of consumer usages,
29  * and provides an LED output usage block. LED output events are redirected
30  * to the boot interface.
31  */
32 
33 static __u8 holtek_kbd_rdesc_fixed[] = {
34  /* Original report descriptor, with reduced number of consumer usages */
35  0x05, 0x01, /* Usage Page (Desktop), */
36  0x09, 0x80, /* Usage (Sys Control), */
37  0xA1, 0x01, /* Collection (Application), */
38  0x85, 0x01, /* Report ID (1), */
39  0x19, 0x81, /* Usage Minimum (Sys Power Down), */
40  0x29, 0x83, /* Usage Maximum (Sys Wake Up), */
41  0x15, 0x00, /* Logical Minimum (0), */
42  0x25, 0x01, /* Logical Maximum (1), */
43  0x95, 0x03, /* Report Count (3), */
44  0x75, 0x01, /* Report Size (1), */
45  0x81, 0x02, /* Input (Variable), */
46  0x95, 0x01, /* Report Count (1), */
47  0x75, 0x05, /* Report Size (5), */
48  0x81, 0x01, /* Input (Constant), */
49  0xC0, /* End Collection, */
50  0x05, 0x0C, /* Usage Page (Consumer), */
51  0x09, 0x01, /* Usage (Consumer Control), */
52  0xA1, 0x01, /* Collection (Application), */
53  0x85, 0x02, /* Report ID (2), */
54  0x19, 0x00, /* Usage Minimum (00h), */
55  0x2A, 0xFF, 0x2F, /* Usage Maximum (0x2FFF), previously 0x7FFF */
56  0x15, 0x00, /* Logical Minimum (0), */
57  0x26, 0xFF, 0x2F, /* Logical Maximum (0x2FFF),previously 0x7FFF*/
58  0x95, 0x01, /* Report Count (1), */
59  0x75, 0x10, /* Report Size (16), */
60  0x81, 0x00, /* Input, */
61  0xC0, /* End Collection, */
62  0x05, 0x01, /* Usage Page (Desktop), */
63  0x09, 0x06, /* Usage (Keyboard), */
64  0xA1, 0x01, /* Collection (Application), */
65  0x85, 0x03, /* Report ID (3), */
66  0x95, 0x38, /* Report Count (56), */
67  0x75, 0x01, /* Report Size (1), */
68  0x15, 0x00, /* Logical Minimum (0), */
69  0x25, 0x01, /* Logical Maximum (1), */
70  0x05, 0x07, /* Usage Page (Keyboard), */
71  0x19, 0xE0, /* Usage Minimum (KB Leftcontrol), */
72  0x29, 0xE7, /* Usage Maximum (KB Right GUI), */
73  0x19, 0x00, /* Usage Minimum (None), */
74  0x29, 0x2F, /* Usage Maximum (KB Lboxbracket And Lbrace),*/
75  0x81, 0x02, /* Input (Variable), */
76  0xC0, /* End Collection, */
77  0x05, 0x01, /* Usage Page (Desktop), */
78  0x09, 0x06, /* Usage (Keyboard), */
79  0xA1, 0x01, /* Collection (Application), */
80  0x85, 0x04, /* Report ID (4), */
81  0x95, 0x38, /* Report Count (56), */
82  0x75, 0x01, /* Report Size (1), */
83  0x15, 0x00, /* Logical Minimum (0), */
84  0x25, 0x01, /* Logical Maximum (1), */
85  0x05, 0x07, /* Usage Page (Keyboard), */
86  0x19, 0x30, /* Usage Minimum (KB Rboxbracket And Rbrace),*/
87  0x29, 0x67, /* Usage Maximum (KP Equals), */
88  0x81, 0x02, /* Input (Variable), */
89  0xC0, /* End Collection */
90 
91  /* LED usage for the boot protocol interface */
92  0x05, 0x01, /* Usage Page (Desktop), */
93  0x09, 0x06, /* Usage (Keyboard), */
94  0xA1, 0x01, /* Collection (Application), */
95  0x05, 0x08, /* Usage Page (LED), */
96  0x19, 0x01, /* Usage Minimum (01h), */
97  0x29, 0x03, /* Usage Maximum (03h), */
98  0x15, 0x00, /* Logical Minimum (0), */
99  0x25, 0x01, /* Logical Maximum (1), */
100  0x75, 0x01, /* Report Size (1), */
101  0x95, 0x03, /* Report Count (3), */
102  0x91, 0x02, /* Output (Variable), */
103  0x95, 0x05, /* Report Count (5), */
104  0x91, 0x01, /* Output (Constant), */
105  0xC0, /* End Collection */
106 };
107 
108 static __u8 *holtek_kbd_report_fixup(struct hid_device *hdev, __u8 *rdesc,
109  unsigned int *rsize)
110 {
111  struct usb_interface *intf = to_usb_interface(hdev->dev.parent);
112 
113  if (intf->cur_altsetting->desc.bInterfaceNumber == 1) {
114  rdesc = holtek_kbd_rdesc_fixed;
115  *rsize = sizeof(holtek_kbd_rdesc_fixed);
116  }
117  return rdesc;
118 }
119 
120 static int holtek_kbd_input_event(struct input_dev *dev, unsigned int type,
121  unsigned int code,
122  int value)
123 {
124  struct hid_device *hid = input_get_drvdata(dev);
125  struct usb_device *usb_dev = hid_to_usb_dev(hid);
126 
127  /* Locate the boot interface, to receive the LED change events */
128  struct usb_interface *boot_interface = usb_ifnum_to_if(usb_dev, 0);
129 
130  struct hid_device *boot_hid = usb_get_intfdata(boot_interface);
131  struct hid_input *boot_hid_input = list_first_entry(&boot_hid->inputs,
132  struct hid_input, list);
133 
134  return boot_hid_input->input->event(boot_hid_input->input, type, code,
135  value);
136 }
137 
138 static int holtek_kbd_probe(struct hid_device *hdev,
139  const struct hid_device_id *id)
140 {
141  struct usb_interface *intf = to_usb_interface(hdev->dev.parent);
142  int ret = hid_parse(hdev);
143 
144  if (!ret)
145  ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
146 
147  if (!ret && intf->cur_altsetting->desc.bInterfaceNumber == 1) {
148  struct hid_input *hidinput;
149  list_for_each_entry(hidinput, &hdev->inputs, list) {
150  hidinput->input->event = holtek_kbd_input_event;
151  }
152  }
153 
154  return ret;
155 }
156 
157 static const struct hid_device_id holtek_kbd_devices[] = {
158  { HID_USB_DEVICE(USB_VENDOR_ID_HOLTEK_ALT,
159  USB_DEVICE_ID_HOLTEK_ALT_KEYBOARD) },
160  { }
161 };
162 MODULE_DEVICE_TABLE(hid, holtek_kbd_devices);
163 
164 static struct hid_driver holtek_kbd_driver = {
165  .name = "holtek_kbd",
166  .id_table = holtek_kbd_devices,
167  .report_fixup = holtek_kbd_report_fixup,
168  .probe = holtek_kbd_probe
169 };
170 
171 static int __init holtek_kbd_init(void)
172 {
173  return hid_register_driver(&holtek_kbd_driver);
174 }
175 
176 static void __exit holtek_kbd_exit(void)
177 {
178  hid_unregister_driver(&holtek_kbd_driver);
179 }
180 
181 module_exit(holtek_kbd_exit);
182 module_init(holtek_kbd_init);
183 MODULE_LICENSE("GPL");
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