HID: Add driver for Holtek based keyboards with broken HID

Corrects two HID descriptor issues, which prevent some Holtek based
(USB ID 04d9:a055) keyboards from working. The error when not using
the driver is: generic-usb: probe ... failed with error -22 .

Signed-off-by: Tom Harwood <tomharwood@fastmail.fm>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

1 files changed, 183 insertions, 0 deletions

diff --git a/drivers/hid/hid-holtek-kbd.c b/drivers/hid/hid-holtek-kbd.c
new file mode 100644
index 0000000..e0a5d17
--- /dev/null
+++ b/drivers/hid/hid-holtek-kbd.c
@@ -0,0 +1,183 @@
+/*
+ * HID driver for Holtek keyboard
+ * Copyright (c) 2012 Tom Harwood
+*/
+
+/*
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ */
+
+#include <linux/device.h>
+#include <linux/hid.h>
+#include <linux/module.h>
+#include <linux/usb.h>
+
+#include "hid-ids.h"
+#include "usbhid/usbhid.h"
+
+/* Holtek based keyboards (USB ID 04d9:a055) have the following issues:
+ * - The report descriptor specifies an excessively large number of consumer
+ *   usages (2^15), which is more than HID_MAX_USAGES. This prevents proper
+ *   parsing of the report descriptor.
+ * - The report descriptor reports on caps/scroll/num lock key presses, but
+ *   doesn't have an LED output usage block.
+ *
+ * The replacement descriptor below fixes the number of consumer usages,
+ * and provides an LED output usage block. LED output events are redirected
+ * to the boot interface.
+ */
+
+static __u8 holtek_kbd_rdesc_fixed[] = {
+	/* Original report descriptor, with reduced number of consumer usages */
+	0x05, 0x01,         /*  Usage Page (Desktop),                         */
+	0x09, 0x80,         /*  Usage (Sys Control),                          */
+	0xA1, 0x01,         /*  Collection (Application),                     */
+	0x85, 0x01,         /*      Report ID (1),                            */
+	0x19, 0x81,         /*      Usage Minimum (Sys Power Down),           */
+	0x29, 0x83,         /*      Usage Maximum (Sys Wake Up),              */
+	0x15, 0x00,         /*      Logical Minimum (0),                      */
+	0x25, 0x01,         /*      Logical Maximum (1),                      */
+	0x95, 0x03,         /*      Report Count (3),                         */
+	0x75, 0x01,         /*      Report Size (1),                          */
+	0x81, 0x02,         /*      Input (Variable),                         */
+	0x95, 0x01,         /*      Report Count (1),                         */
+	0x75, 0x05,         /*      Report Size (5),                          */
+	0x81, 0x01,         /*      Input (Constant),                         */
+	0xC0,               /*  End Collection,                               */
+	0x05, 0x0C,         /*  Usage Page (Consumer),                        */
+	0x09, 0x01,         /*  Usage (Consumer Control),                     */
+	0xA1, 0x01,         /*  Collection (Application),                     */
+	0x85, 0x02,         /*      Report ID (2),                            */
+	0x19, 0x00,         /*      Usage Minimum (00h),                      */
+	0x2A, 0xFF, 0x2F,   /*      Usage Maximum (0x2FFF), previously 0x7FFF */
+	0x15, 0x00,         /*      Logical Minimum (0),                      */
+	0x26, 0xFF, 0x2F,   /*      Logical Maximum (0x2FFF),previously 0x7FFF*/
+	0x95, 0x01,         /*      Report Count (1),                         */
+	0x75, 0x10,         /*      Report Size (16),                         */
+	0x81, 0x00,         /*      Input,                                    */
+	0xC0,               /*  End Collection,                               */
+	0x05, 0x01,         /*  Usage Page (Desktop),                         */
+	0x09, 0x06,         /*  Usage (Keyboard),                             */
+	0xA1, 0x01,         /*  Collection (Application),                     */
+	0x85, 0x03,         /*      Report ID (3),                            */
+	0x95, 0x38,         /*      Report Count (56),                        */
+	0x75, 0x01,         /*      Report Size (1),                          */
+	0x15, 0x00,         /*      Logical Minimum (0),                      */
+	0x25, 0x01,         /*      Logical Maximum (1),                      */
+	0x05, 0x07,         /*      Usage Page (Keyboard),                    */
+	0x19, 0xE0,         /*      Usage Minimum (KB Leftcontrol),           */
+	0x29, 0xE7,         /*      Usage Maximum (KB Right GUI),             */
+	0x19, 0x00,         /*      Usage Minimum (None),                     */
+	0x29, 0x2F,         /*      Usage Maximum (KB Lboxbracket And Lbrace),*/
+	0x81, 0x02,         /*      Input (Variable),                         */
+	0xC0,               /*  End Collection,                               */
+	0x05, 0x01,         /*  Usage Page (Desktop),                         */
+	0x09, 0x06,         /*  Usage (Keyboard),                             */
+	0xA1, 0x01,         /*  Collection (Application),                     */
+	0x85, 0x04,         /*      Report ID (4),                            */
+	0x95, 0x38,         /*      Report Count (56),                        */
+	0x75, 0x01,         /*      Report Size (1),                          */
+	0x15, 0x00,         /*      Logical Minimum (0),                      */
+	0x25, 0x01,         /*      Logical Maximum (1),                      */
+	0x05, 0x07,         /*      Usage Page (Keyboard),                    */
+	0x19, 0x30,         /*      Usage Minimum (KB Rboxbracket And Rbrace),*/
+	0x29, 0x67,         /*      Usage Maximum (KP Equals),                */
+	0x81, 0x02,         /*      Input (Variable),                         */
+	0xC0,               /*  End Collection                                */
+
+	/* LED usage for the boot protocol interface */
+	0x05, 0x01,         /*  Usage Page (Desktop),                         */
+	0x09, 0x06,         /*  Usage (Keyboard),                             */
+	0xA1, 0x01,         /*  Collection (Application),                     */
+	0x05, 0x08,         /*      Usage Page (LED),                         */
+	0x19, 0x01,         /*      Usage Minimum (01h),                      */
+	0x29, 0x03,         /*      Usage Maximum (03h),                      */
+	0x15, 0x00,         /*      Logical Minimum (0),                      */
+	0x25, 0x01,         /*      Logical Maximum (1),                      */
+	0x75, 0x01,         /*      Report Size (1),                          */
+	0x95, 0x03,         /*      Report Count (3),                         */
+	0x91, 0x02,         /*      Output (Variable),                        */
+	0x95, 0x05,         /*      Report Count (5),                         */
+	0x91, 0x01,         /*      Output (Constant),                        */
+	0xC0,               /*  End Collection                                */
+};
+
+static __u8 *holtek_kbd_report_fixup(struct hid_device *hdev, __u8 *rdesc,
+		unsigned int *rsize)
+{
+	struct usb_interface *intf = to_usb_interface(hdev->dev.parent);
+
+	if (intf->cur_altsetting->desc.bInterfaceNumber == 1) {
+		rdesc = holtek_kbd_rdesc_fixed;
+		*rsize = sizeof(holtek_kbd_rdesc_fixed);
+	}
+	return rdesc;
+}
+
+static int holtek_kbd_input_event(struct input_dev *dev, unsigned int type,
+		unsigned int code,
+		int value)
+{
+	struct hid_device *hid = input_get_drvdata(dev);
+	struct usb_device *usb_dev = hid_to_usb_dev(hid);
+
+	/* Locate the boot interface, to receive the LED change events */
+	struct usb_interface *boot_interface = usb_ifnum_to_if(usb_dev, 0);
+
+	struct hid_device *boot_hid = usb_get_intfdata(boot_interface);
+	struct hid_input *boot_hid_input = list_first_entry(&boot_hid->inputs,
+		struct hid_input, list);
+
+	return boot_hid_input->input->event(boot_hid_input->input, type, code,
+			value);
+}
+
+static int holtek_kbd_probe(struct hid_device *hdev,
+		const struct hid_device_id *id)
+{
+	struct usb_interface *intf = to_usb_interface(hdev->dev.parent);
+	int ret = hid_parse(hdev);
+
+	if (!ret)
+		ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
+
+	if (!ret && intf->cur_altsetting->desc.bInterfaceNumber == 1) {
+		struct hid_input *hidinput;
+		list_for_each_entry(hidinput, &hdev->inputs, list) {
+			hidinput->input->event = holtek_kbd_input_event;
+		}
+	}
+
+	return ret;
+}
+
+static const struct hid_device_id holtek_kbd_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_HOLTEK_ALT,
+			USB_DEVICE_ID_HOLTEK_ALT_KEYBOARD) },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, holtek_kbd_devices);
+
+static struct hid_driver holtek_kbd_driver = {
+	.name = "holtek_kbd",
+	.id_table = holtek_kbd_devices,
+	.report_fixup = holtek_kbd_report_fixup,
+	.probe = holtek_kbd_probe
+};
+
+static int __init holtek_kbd_init(void)
+{
+	return hid_register_driver(&holtek_kbd_driver);
+}
+
+static void __exit holtek_kbd_exit(void)
+{
+	hid_unregister_driver(&holtek_kbd_driver);
+}
+
+module_exit(holtek_kbd_exit);
+module_init(holtek_kbd_init);
+MODULE_LICENSE("GPL");