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
33static __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
108static __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
120static 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
138static 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
157static 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};
162MODULE_DEVICE_TABLE(hid, holtek_kbd_devices);
163
164static 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};
170module_hid_driver(holtek_kbd_driver);
171
172MODULE_LICENSE("GPL");
173