1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * HID driver for Holtek keyboard
4 * Copyright (c) 2012 Tom Harwood
5 */
6
7 /*
8 */
9
10 #include <linux/device.h>
11 #include <linux/hid.h>
12 #include <linux/module.h>
13 #include <linux/usb.h>
14
15 #include "hid-ids.h"
16 #include "usbhid/usbhid.h"
17
18 /* Holtek based keyboards (USB ID 04d9:a055) have the following issues:
19 * - The report descriptor specifies an excessively large number of consumer
20 * usages (2^15), which is more than HID_MAX_USAGES. This prevents proper
21 * parsing of the report descriptor.
22 * - The report descriptor reports on caps/scroll/num lock key presses, but
23 * doesn't have an LED output usage block.
24 *
25 * The replacement descriptor below fixes the number of consumer usages,
26 * and provides an LED output usage block. LED output events are redirected
27 * to the boot interface.
28 */
29
30 static __u8 holtek_kbd_rdesc_fixed[] = {
31 /* Original report descriptor, with reduced number of consumer usages */
32 0x05, 0x01, /* Usage Page (Desktop), */
33 0x09, 0x80, /* Usage (Sys Control), */
34 0xA1, 0x01, /* Collection (Application), */
35 0x85, 0x01, /* Report ID (1), */
36 0x19, 0x81, /* Usage Minimum (Sys Power Down), */
37 0x29, 0x83, /* Usage Maximum (Sys Wake Up), */
38 0x15, 0x00, /* Logical Minimum (0), */
39 0x25, 0x01, /* Logical Maximum (1), */
40 0x95, 0x03, /* Report Count (3), */
41 0x75, 0x01, /* Report Size (1), */
42 0x81, 0x02, /* Input (Variable), */
43 0x95, 0x01, /* Report Count (1), */
44 0x75, 0x05, /* Report Size (5), */
45 0x81, 0x01, /* Input (Constant), */
46 0xC0, /* End Collection, */
47 0x05, 0x0C, /* Usage Page (Consumer), */
48 0x09, 0x01, /* Usage (Consumer Control), */
49 0xA1, 0x01, /* Collection (Application), */
50 0x85, 0x02, /* Report ID (2), */
51 0x19, 0x00, /* Usage Minimum (00h), */
52 0x2A, 0xFF, 0x2F, /* Usage Maximum (0x2FFF), previously 0x7FFF */
53 0x15, 0x00, /* Logical Minimum (0), */
54 0x26, 0xFF, 0x2F, /* Logical Maximum (0x2FFF),previously 0x7FFF*/
55 0x95, 0x01, /* Report Count (1), */
56 0x75, 0x10, /* Report Size (16), */
57 0x81, 0x00, /* Input, */
58 0xC0, /* End Collection, */
59 0x05, 0x01, /* Usage Page (Desktop), */
60 0x09, 0x06, /* Usage (Keyboard), */
61 0xA1, 0x01, /* Collection (Application), */
62 0x85, 0x03, /* Report ID (3), */
63 0x95, 0x38, /* Report Count (56), */
64 0x75, 0x01, /* Report Size (1), */
65 0x15, 0x00, /* Logical Minimum (0), */
66 0x25, 0x01, /* Logical Maximum (1), */
67 0x05, 0x07, /* Usage Page (Keyboard), */
68 0x19, 0xE0, /* Usage Minimum (KB Leftcontrol), */
69 0x29, 0xE7, /* Usage Maximum (KB Right GUI), */
70 0x19, 0x00, /* Usage Minimum (None), */
71 0x29, 0x2F, /* Usage Maximum (KB Lboxbracket And Lbrace),*/
72 0x81, 0x02, /* Input (Variable), */
73 0xC0, /* End Collection, */
74 0x05, 0x01, /* Usage Page (Desktop), */
75 0x09, 0x06, /* Usage (Keyboard), */
76 0xA1, 0x01, /* Collection (Application), */
77 0x85, 0x04, /* Report ID (4), */
78 0x95, 0x38, /* Report Count (56), */
79 0x75, 0x01, /* Report Size (1), */
80 0x15, 0x00, /* Logical Minimum (0), */
81 0x25, 0x01, /* Logical Maximum (1), */
82 0x05, 0x07, /* Usage Page (Keyboard), */
83 0x19, 0x30, /* Usage Minimum (KB Rboxbracket And Rbrace),*/
84 0x29, 0x67, /* Usage Maximum (KP Equals), */
85 0x81, 0x02, /* Input (Variable), */
86 0xC0, /* End Collection */
87
88 /* LED usage for the boot protocol interface */
89 0x05, 0x01, /* Usage Page (Desktop), */
90 0x09, 0x06, /* Usage (Keyboard), */
91 0xA1, 0x01, /* Collection (Application), */
92 0x05, 0x08, /* Usage Page (LED), */
93 0x19, 0x01, /* Usage Minimum (01h), */
94 0x29, 0x03, /* Usage Maximum (03h), */
95 0x15, 0x00, /* Logical Minimum (0), */
96 0x25, 0x01, /* Logical Maximum (1), */
97 0x75, 0x01, /* Report Size (1), */
98 0x95, 0x03, /* Report Count (3), */
99 0x91, 0x02, /* Output (Variable), */
100 0x95, 0x05, /* Report Count (5), */
101 0x91, 0x01, /* Output (Constant), */
102 0xC0, /* End Collection */
103 };
104
105 static __u8 *holtek_kbd_report_fixup(struct hid_device *hdev, __u8 *rdesc,
106 unsigned int *rsize)
107 {
108 struct usb_interface *intf = to_usb_interface(hdev->dev.parent);
109
110 if (intf->cur_altsetting->desc.bInterfaceNumber == 1) {
111 rdesc = holtek_kbd_rdesc_fixed;
112 *rsize = sizeof(holtek_kbd_rdesc_fixed);
113 }
114 return rdesc;
115 }
116
117 static int holtek_kbd_input_event(struct input_dev *dev, unsigned int type,
118 unsigned int code,
119 int value)
120 {
121 struct hid_device *hid = input_get_drvdata(dev);
122 struct usb_device *usb_dev = hid_to_usb_dev(hid);
123
124 /* Locate the boot interface, to receive the LED change events */
125 struct usb_interface *boot_interface = usb_ifnum_to_if(usb_dev, 0);
126 struct hid_device *boot_hid;
127 struct hid_input *boot_hid_input;
128
129 if (unlikely(boot_interface == NULL))
130 return -ENODEV;
131
132 boot_hid = usb_get_intfdata(boot_interface);
133 boot_hid_input = list_first_entry(&boot_hid->inputs,
134 struct hid_input, list);
135
136 return boot_hid_input->input->event(boot_hid_input->input, type, code,
137 value);
138 }
139
140 static int holtek_kbd_probe(struct hid_device *hdev,
141 const struct hid_device_id *id)
142 {
143 struct usb_interface *intf = to_usb_interface(hdev->dev.parent);
144 int ret = hid_parse(hdev);
145
146 if (!ret)
147 ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
148
149 if (!ret && intf->cur_altsetting->desc.bInterfaceNumber == 1) {
150 struct hid_input *hidinput;
151 list_for_each_entry(hidinput, &hdev->inputs, list) {
152 hidinput->input->event = holtek_kbd_input_event;
153 }
154 }
155
156 return ret;
157 }
158
159 static const struct hid_device_id holtek_kbd_devices[] = {
160 { HID_USB_DEVICE(USB_VENDOR_ID_HOLTEK_ALT,
161 USB_DEVICE_ID_HOLTEK_ALT_KEYBOARD) },
162 { }
163 };
164 MODULE_DEVICE_TABLE(hid, holtek_kbd_devices);
165
166 static struct hid_driver holtek_kbd_driver = {
167 .name = "holtek_kbd",
168 .id_table = holtek_kbd_devices,
169 .report_fixup = holtek_kbd_report_fixup,
170 .probe = holtek_kbd_probe
171 };
172 module_hid_driver(holtek_kbd_driver);
173
174 MODULE_LICENSE("GPL");