drivers/hid/hid-holtek-kbd.c

   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         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
 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");