rc-core support for Microsoft IR keyboard/mouse

diff --git a/drivers/media/rc/Kconfig b/drivers/media/rc/Kconfig
index 7d4bbc2..899f783 100644
--- a/drivers/media/rc/Kconfig
+++ b/drivers/media/rc/Kconfig
@@ -87,6 +87,17 @@  config IR_RC5_SZ_DECODER
 	   uses an IR protocol that is almost standard RC-5, but not quite,
 	   as it uses an additional bit).
 
+config IR_MCE_KBD_DECODER
+	tristate "Enable IR raw decoder for the MCE keyboard/mouse protocol"
+	depends on RC_CORE
+	select BITREVERSE
+	default y
+
+	---help---
+	   Enable this option if you have a Microsoft Remote Keyboard for
+	   Windows Media Center Edition, which you would like to use with
+	   a raw IR receiver in your system.
+
 config IR_LIRC_CODEC
 	tristate "Enable IR to LIRC bridge"
 	depends on RC_CORE
diff --git a/drivers/media/rc/Makefile b/drivers/media/rc/Makefile
index 52830e5..f224db0 100644
--- a/drivers/media/rc/Makefile
+++ b/drivers/media/rc/Makefile
@@ -10,6 +10,7 @@  obj-$(CONFIG_IR_RC6_DECODER) += ir-rc6-decoder.o
 obj-$(CONFIG_IR_JVC_DECODER) += ir-jvc-decoder.o
 obj-$(CONFIG_IR_SONY_DECODER) += ir-sony-decoder.o
 obj-$(CONFIG_IR_RC5_SZ_DECODER) += ir-rc5-sz-decoder.o
+obj-$(CONFIG_IR_MCE_KBD_DECODER) += ir-mce_kbd-decoder.o
 obj-$(CONFIG_IR_LIRC_CODEC) += ir-lirc-codec.o
 
 # stand-alone IR receivers/transmitters
diff --git a/drivers/media/rc/ir-mce_kbd-decoder.c b/drivers/media/rc/ir-mce_kbd-decoder.c
new file mode 100644
index 0000000..98d3bf5
--- /dev/null
+++ b/drivers/media/rc/ir-mce_kbd-decoder.c
@@ -0,0 +1,383 @@ 
+/* ir-mce_kbd-decoder.c - A decoder for the RC6-ish keyboard/mouse IR protocol
+ * used by the Microsoft Remote Keyboard for Windows Media Center Edition
+ *
+ * Copyright (C) 2011 by Jarod Wilson <jarod@redhat.com>
+ *
+ * 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 version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include "rc-core-priv.h"
+
+/*
+ * This decoder currently supports:
+ * - RC6-like 29-bit IR signals used for mouse movement and buttons
+ * - RC6-like 32-bit IR signals used for standard keyboard keys
+ *
+ * The media keys on the keyboard send RC-6 signals that are inditinguishable
+ * from the keys of the same name on the stock MCE remote, and will be handled
+ * by the standard RC-6 decoder, and be made available to the system via the
+ * input device for the remote, rather than the keyboard/mouse one.
+ */
+
+#define MCE_KBD_UNIT		333333	/* ns */
+#define MCE_KBD_HEADER_NBITS	5
+#define MCE_KBD_MOUSE_NBITS	29
+#define MCE_KBD_KEYBOARD_NBITS	32
+#define MCE_KBD_PREFIX_PULSE	(8 * MCE_KBD_UNIT)
+#define MCE_KBD_PREFIX_SPACE	(1 * MCE_KBD_UNIT)
+#define MCE_KBD_MAX_LEN		(3 * MCE_KBD_UNIT)
+#define MCE_KBD_BIT_START	(1 * MCE_KBD_UNIT)
+#define MCE_KBD_BIT_END		(1 * MCE_KBD_UNIT)
+#define MCE_KBD_BIT_0		(1 * MCE_KBD_UNIT)
+#define MCE_KBD_BIT_SET		(2 * MCE_KBD_UNIT)
+#define MCE_KBD_MODE_MASK	0xf	/* for the header bits */
+#define MCE_KBD_HEADER		0x4
+#define MCE_MOUSE_HEADER	0x1
+#define MCE_KBD_MASK_KEYS_START	0xe0
+
+enum mce_kbd_mode {
+	MCE_KBD_MODE_KEYBOARD,
+	MCE_KBD_MODE_MOUSE,
+	MCE_KBD_MODE_UNKNOWN,
+};
+
+enum mce_kbd_state {
+	STATE_INACTIVE,
+	STATE_HEADER_BIT_START,
+	STATE_HEADER_BIT_END,
+	STATE_BODY_BIT_START,
+	STATE_BODY_BIT_END,
+	STATE_FINISHED,
+};
+
+static unsigned char kbd_keycodes[256] = {
+          0,   0,   0,   0,  30,  48,  46,  32,  18,  33,  34,  35,  23,  36,  37,  38,
+         50,  49,  24,  25,  16,  19,  31,  20,  22,  47,  17,  45,  21,  44,   2,   3,
+          4,   5,   6,   7,   8,   9,  10,  11,  28,   1,  14,  15,  57,  12,  13,  26,
+         27,  43,  43,  39,  40,  41,  51,  52,  53,  58,  59,  60,  61,  62,  63,  64,
+         65,  66,  67,  68,  87,  88,  99,  70, 119, 110, 102, 104, 111, 107, 109, 106,
+        105, 108, 103,  69,  98,  55,  74,  78,  96,  79,  80,  81,  75,  76,  77,  71,
+         72,  73,  82,  83,  86, 127, 116, 117, 183, 184, 185, 186, 187, 188, 189, 190,
+        191, 192, 193, 194, 134, 138, 130, 132, 128, 129, 131, 137, 133, 135, 136, 113,
+        115, 114,   0,   0,   0, 121,   0,  89,  93, 124,  92,  94,  95,   0,   0,   0,
+        122, 123,  90,  91,  85,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+          0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+          0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+          0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+          0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+         29,  42,  56, 125,  97,  54, 100, 126, 164, 166, 165, 163, 161, 115, 114, 113,
+        150, 158, 159, 128, 136, 177, 178, 176, 142, 152, 173, 140
+};
+
+static enum mce_kbd_mode mce_kbd_mode(struct mce_kbd_dec *data)
+{
+	switch (data->header & MCE_KBD_MODE_MASK) {
+	case MCE_KBD_HEADER:
+		return MCE_KBD_MODE_KEYBOARD;
+	case MCE_MOUSE_HEADER:
+		return MCE_KBD_MODE_MOUSE;
+	default:
+		return MCE_KBD_MODE_UNKNOWN;
+	}
+}
+
+static void ir_mce_kbd_process_keyboard_data(struct input_dev *idev,
+					     u32 scancode)
+{
+	u8 keydata   = (scancode >> 8) & 0xff;
+	u8 shiftmask = scancode & 0xff;
+	unsigned char keycode, maskcode;
+	int i, keystate;
+
+	IR_dprintk(1, "keyboard: keydata = 0x%02x, shiftmask = 0x%02x\n",
+		   keydata, shiftmask);
+
+	for (i = 0; i < 7; i++) {
+		maskcode = kbd_keycodes[MCE_KBD_MASK_KEYS_START + i];
+		if (shiftmask & (1 << i))
+			keystate = 1;
+		else
+			keystate = 0;
+		input_report_key(idev, maskcode, keystate);
+	}
+
+	if (keydata) {
+		keycode = kbd_keycodes[keydata];
+		input_report_key(idev, keycode, 1);
+	} else {
+		for (i = 0; i < MCE_KBD_MASK_KEYS_START; i++)
+			input_report_key(idev, kbd_keycodes[i], 0);
+	}
+}
+
+static void ir_mce_kbd_process_mouse_data(struct input_dev *idev, u32 scancode)
+{
+	/* raw mouse coordinates */
+	u8 xdata = (scancode >> 7) & 0x7f;
+	u8 ydata = (scancode >> 14) & 0x7f;
+	int x, y;
+	/* mouse buttons */
+	bool right = scancode & 0x40;
+	bool left  = scancode & 0x20;
+
+	if (xdata & 0x40)
+		x = -((~xdata & 0x7f) + 1);
+	else
+		x = xdata;
+
+	if (ydata & 0x40)
+		y = -((~ydata & 0x7f) + 1);
+	else
+		y = ydata;
+
+	IR_dprintk(1, "mouse: x = %d, y = %d, btns = %s%s\n",
+		   x, y, left ? "L" : "", right ? "R" : "");
+
+	input_report_rel(idev, REL_X, x);
+	input_report_rel(idev, REL_Y, y);
+
+	input_report_key(idev, BTN_LEFT, left);
+	input_report_key(idev, BTN_RIGHT, right);
+}
+
+/**
+ * ir_mce_kbd_decode() - Decode one mce_kbd pulse or space
+ * @dev:	the struct rc_dev descriptor of the device
+ * @ev:		the struct ir_raw_event descriptor of the pulse/space
+ *
+ * This function returns -EINVAL if the pulse violates the state machine
+ */
+static int ir_mce_kbd_decode(struct rc_dev *dev, struct ir_raw_event ev)
+{
+	struct mce_kbd_dec *data = &dev->raw->mce_kbd;
+	u32 scancode;
+
+	if (!(dev->raw->enabled_protocols & RC_TYPE_MCE_KBD))
+		return 0;
+
+	if (!is_timing_event(ev)) {
+		if (ev.reset)
+			data->state = STATE_INACTIVE;
+		return 0;
+	}
+
+	if (!geq_margin(ev.duration, MCE_KBD_UNIT, MCE_KBD_UNIT / 2))
+		goto out;
+
+again:
+	IR_dprintk(2, "started at state %i (%uus %s)\n",
+		   data->state, TO_US(ev.duration), TO_STR(ev.pulse));
+
+	if (!geq_margin(ev.duration, MCE_KBD_UNIT, MCE_KBD_UNIT / 2))
+		return 0;
+
+	switch (data->state) {
+
+	case STATE_INACTIVE:
+		if (!ev.pulse)
+			break;
+
+		/* Note: larger margin on first pulse since each MCE_KBD_UNIT
+		   is quite short and some hardware takes some time to
+		   adjust to the signal */
+		if (!eq_margin(ev.duration, MCE_KBD_PREFIX_PULSE, MCE_KBD_UNIT))
+			break;
+
+		data->state = STATE_HEADER_BIT_START;
+		data->count = 0;
+		data->header = 0;
+		return 0;
+
+	case STATE_HEADER_BIT_START:
+		if (geq_margin(ev.duration, MCE_KBD_MAX_LEN, MCE_KBD_UNIT / 2))
+			break;
+
+		data->header <<= 1;
+		if (ev.pulse)
+			data->header |= 1;
+		data->count++;
+		data->state = STATE_HEADER_BIT_END;
+		return 0;
+
+	case STATE_HEADER_BIT_END:
+		if (!is_transition(&ev, &dev->raw->prev_ev))
+			break;
+
+		decrease_duration(&ev, MCE_KBD_BIT_END);
+
+		if (data->count != MCE_KBD_HEADER_NBITS) {
+			data->state = STATE_HEADER_BIT_START;
+			goto again;
+		}
+
+		switch (mce_kbd_mode(data)) {
+		case MCE_KBD_MODE_KEYBOARD:
+			data->wanted_bits = MCE_KBD_KEYBOARD_NBITS;
+			break;
+		case MCE_KBD_MODE_MOUSE:
+			data->wanted_bits = MCE_KBD_MOUSE_NBITS;
+			break;
+		default:
+			IR_dprintk(1, "not keyboard or mouse data\n");
+			goto out;
+		}
+
+		data->count = 0;
+		data->body = 0;
+		data->state = STATE_BODY_BIT_START;
+		goto again;
+
+	case STATE_BODY_BIT_START:
+		if (geq_margin(ev.duration, MCE_KBD_MAX_LEN, MCE_KBD_UNIT / 2))
+			break;
+
+		data->body <<= 1;
+		if (ev.pulse)
+			data->body |= 1;
+		data->count++;
+		data->state = STATE_BODY_BIT_END;
+		return 0;
+
+	case STATE_BODY_BIT_END:
+		if (!is_transition(&ev, &dev->raw->prev_ev))
+			break;
+
+		if (data->count == data->wanted_bits)
+			data->state = STATE_FINISHED;
+		else
+			data->state = STATE_BODY_BIT_START;
+
+		decrease_duration(&ev, MCE_KBD_BIT_END);
+		goto again;
+
+	case STATE_FINISHED:
+		if (ev.pulse)
+			break;
+
+		switch (data->wanted_bits) {
+		case MCE_KBD_KEYBOARD_NBITS:
+			scancode = data->body & 0xffff;
+			IR_dprintk(1, "keyboard data 0x%08x\n", data->body);
+			/* Pass data to keyboard buffer parser */
+			ir_mce_kbd_process_keyboard_data(data->idev, scancode);
+			break;
+		case MCE_KBD_MOUSE_NBITS:
+			scancode = data->body & 0x1fffff;
+			IR_dprintk(1, "mouse data 0x%06x\n", scancode);
+			/* Pass data to mouse buffer parser */
+			ir_mce_kbd_process_mouse_data(data->idev, scancode);
+			break;
+		default:
+			IR_dprintk(1, "not keyboard or mouse data\n");
+			goto out;
+		}
+
+		data->state = STATE_INACTIVE;
+		input_sync(data->idev);
+		return 0;
+	}
+
+out:
+	IR_dprintk(1, "failed at state %i (%uus %s)\n",
+		   data->state, TO_US(ev.duration), TO_STR(ev.pulse));
+	data->state = STATE_INACTIVE;
+	input_sync(data->idev);
+	return -EINVAL;
+}
+
+static int ir_mce_kbd_register(struct rc_dev *dev)
+{
+	struct mce_kbd_dec *mce_kbd = &dev->raw->mce_kbd;
+	struct input_dev *idev;
+	int i, ret;
+
+	idev = input_allocate_device();
+	if (!idev)
+		return -ENOMEM;
+
+	snprintf(mce_kbd->name, sizeof(mce_kbd->name),
+		 "MCE IR Keyboard/Mouse (%s)", dev->driver_name);
+	strlcat(mce_kbd->phys, "/input0", sizeof(mce_kbd->phys));
+
+	idev->name = mce_kbd->name;
+	idev->phys = mce_kbd->phys;
+
+	/* Keyboard bits */
+	set_bit(EV_KEY, idev->evbit);
+	set_bit(EV_REP, idev->evbit);
+	for (i = 0; i < sizeof(kbd_keycodes); i++)
+		set_bit(kbd_keycodes[i], idev->keybit);
+
+	/* Mouse bits */
+	set_bit(EV_REL, idev->evbit);
+	set_bit(REL_X, idev->relbit);
+	set_bit(REL_Y, idev->relbit);
+	set_bit(BTN_LEFT, idev->keybit);
+	set_bit(BTN_RIGHT, idev->keybit);
+
+	/* Report scancodes too */
+	set_bit(EV_MSC, idev->evbit);
+	set_bit(MSC_SCAN, idev->mscbit);
+
+	input_set_drvdata(idev, mce_kbd);
+
+#if 0
+	/* Adding this reference means two input devices are associated with
+	 * this rc-core device, which ir-keytable doesn't cope with yet */
+	idev->dev.parent = &dev->dev;
+#endif
+
+	ret = input_register_device(idev);
+	if (ret < 0) {
+		input_free_device(idev);
+		return -EIO;
+	}
+
+	mce_kbd->idev = idev;
+
+	return 0;
+}
+
+static int ir_mce_kbd_unregister(struct rc_dev *dev)
+{
+	struct mce_kbd_dec *mce_kbd = &dev->raw->mce_kbd;
+	struct input_dev *idev = mce_kbd->idev;
+
+	input_unregister_device(idev);
+
+	return 0;
+}
+
+static struct ir_raw_handler mce_kbd_handler = {
+	.protocols	= RC_TYPE_MCE_KBD,
+	.decode		= ir_mce_kbd_decode,
+	.raw_register	= ir_mce_kbd_register,
+	.raw_unregister	= ir_mce_kbd_unregister,
+};
+
+static int __init ir_mce_kbd_decode_init(void)
+{
+	ir_raw_handler_register(&mce_kbd_handler);
+
+	printk(KERN_INFO "IR MCE Keyboard/mouse protocol handler initialized\n");
+	return 0;
+}
+
+static void __exit ir_mce_kbd_decode_exit(void)
+{
+	ir_raw_handler_unregister(&mce_kbd_handler);
+}
+
+module_init(ir_mce_kbd_decode_init);
+module_exit(ir_mce_kbd_decode_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Jarod Wilson <jarod@redhat.com>");
+MODULE_DESCRIPTION("MCE Keyboard/mouse IR protocol decoder");
diff --git a/drivers/media/rc/ir-raw.c b/drivers/media/rc/ir-raw.c
index 11c19d8..f4efd2f 100644
--- a/drivers/media/rc/ir-raw.c
+++ b/drivers/media/rc/ir-raw.c
@@ -353,6 +353,7 @@  static void init_decoders(struct work_struct *work)
 	load_rc6_decode();
 	load_jvc_decode();
 	load_sony_decode();
+	load_mce_kbd_decode();
 	load_lirc_codec();
 
 	/* If needed, we may later add some init code. In this case,
diff --git a/drivers/media/rc/rc-core-priv.h b/drivers/media/rc/rc-core-priv.h
index 873b387..e268254 100644
--- a/drivers/media/rc/rc-core-priv.h
+++ b/drivers/media/rc/rc-core-priv.h
@@ -84,6 +84,16 @@  struct ir_raw_event_ctrl {
 		unsigned count;
 		unsigned wanted_bits;
 	} rc5_sz;
+	struct mce_kbd_dec {
+		struct input_dev *idev;
+		char name[64];
+		char phys[64];
+		int state;
+		u8 header;
+		u32 body;
+		unsigned count;
+		unsigned wanted_bits;
+	} mce_kbd;
 	struct lirc_codec {
 		struct rc_dev *dev;
 		struct lirc_driver *drv;
@@ -182,6 +192,13 @@  void ir_raw_init(void);
 #define load_sony_decode()	0
 #endif
 
+/* from ir-mce_kbd-decoder.c */
+#ifdef CONFIG_IR_MCE_KBD_DECODER_MODULE
+#define load_mce_kbd_decode()	request_module("ir-mce_kbd-decoder")
+#else
+#define load_mce_kbd_decode()	0
+#endif
+
 /* from ir-lirc-codec.c */
 #ifdef CONFIG_IR_LIRC_CODEC_MODULE
 #define load_lirc_codec()	request_module("ir-lirc-codec")
diff --git a/drivers/media/rc/rc-main.c b/drivers/media/rc/rc-main.c
index f57cd56..20048c3 100644
--- a/drivers/media/rc/rc-main.c
+++ b/drivers/media/rc/rc-main.c
@@ -733,6 +733,7 @@  static struct {
 	{ RC_TYPE_JVC,		"jvc"		},
 	{ RC_TYPE_SONY,		"sony"		},
 	{ RC_TYPE_RC5_SZ,	"rc-5-sz"	},
+	{ RC_TYPE_MCE_KBD,	"mce_kbd"	},
 	{ RC_TYPE_LIRC,		"lirc"		},
 	{ RC_TYPE_OTHER,	"other"		},
 };
diff --git a/include/media/rc-map.h b/include/media/rc-map.h
index 4e1409e..17c9759 100644
--- a/include/media/rc-map.h
+++ b/include/media/rc-map.h
@@ -18,12 +18,13 @@ 
 #define RC_TYPE_JVC	(1  << 3)	/* JVC protocol */
 #define RC_TYPE_SONY	(1  << 4)	/* Sony12/15/20 protocol */
 #define RC_TYPE_RC5_SZ	(1  << 5)	/* RC5 variant used by Streamzap */
+#define RC_TYPE_MCE_KBD	(1  << 29)	/* RC6-ish MCE keyboard/mouse */
 #define RC_TYPE_LIRC	(1  << 30)	/* Pass raw IR to lirc userspace */
 #define RC_TYPE_OTHER	(1u << 31)
 
 #define RC_TYPE_ALL (RC_TYPE_RC5 | RC_TYPE_NEC  | RC_TYPE_RC6  | \
 		     RC_TYPE_JVC | RC_TYPE_SONY | RC_TYPE_LIRC | \
-		     RC_TYPE_RC5_SZ | RC_TYPE_OTHER)
+		     RC_TYPE_RC5_SZ | RC_TYPE_MCE_KBD | RC_TYPE_OTHER)
 
 struct rc_map_table {
 	u32	scancode;