xref: /openbmc/linux/drivers/hid/hid-holtek-kbd.c (revision ffe3b783)
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 
holtek_kbd_report_fixup(struct hid_device * hdev,__u8 * rdesc,unsigned int * rsize)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 
holtek_kbd_input_event(struct input_dev * dev,unsigned int type,unsigned int code,int value)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 	if (list_empty(&boot_hid->inputs)) {
134 		hid_err(hid, "no inputs found\n");
135 		return -ENODEV;
136 	}
137 	boot_hid_input = list_first_entry(&boot_hid->inputs,
138 		struct hid_input, list);
139 
140 	return boot_hid_input->input->event(boot_hid_input->input, type, code,
141 			value);
142 }
143 
holtek_kbd_probe(struct hid_device * hdev,const struct hid_device_id * id)144 static int holtek_kbd_probe(struct hid_device *hdev,
145 		const struct hid_device_id *id)
146 {
147 	struct usb_interface *intf;
148 	int ret;
149 
150 	if (!hid_is_usb(hdev))
151 		return -EINVAL;
152 
153 	ret = hid_parse(hdev);
154 	if (!ret)
155 		ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
156 
157 	intf = to_usb_interface(hdev->dev.parent);
158 	if (!ret && intf->cur_altsetting->desc.bInterfaceNumber == 1) {
159 		struct hid_input *hidinput;
160 		list_for_each_entry(hidinput, &hdev->inputs, list) {
161 			hidinput->input->event = holtek_kbd_input_event;
162 		}
163 	}
164 
165 	return ret;
166 }
167 
168 static const struct hid_device_id holtek_kbd_devices[] = {
169 	{ HID_USB_DEVICE(USB_VENDOR_ID_HOLTEK_ALT,
170 			USB_DEVICE_ID_HOLTEK_ALT_KEYBOARD) },
171 	{ }
172 };
173 MODULE_DEVICE_TABLE(hid, holtek_kbd_devices);
174 
175 static struct hid_driver holtek_kbd_driver = {
176 	.name = "holtek_kbd",
177 	.id_table = holtek_kbd_devices,
178 	.report_fixup = holtek_kbd_report_fixup,
179 	.probe = holtek_kbd_probe
180 };
181 module_hid_driver(holtek_kbd_driver);
182 
183 MODULE_LICENSE("GPL");
184