[deliverable/linux.git] / drivers / media / rc / ir-rc6-decoder.c

/* ir-rc6-decoder.c - A decoder for the RC6 IR protocol
 *
 * Copyright (C) 2010 by David Härdeman <david@hardeman.nu>
 *
 * 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"
#include <linux/module.h>

/*
 * This decoder currently supports:
 * RC6-0-16	(standard toggle bit in header)
 * RC6-6A-20	(no toggle bit)
 * RC6-6A-24	(no toggle bit)
 * RC6-6A-32	(MCE version with toggle bit in body)
 */

#define RC6_UNIT		444444	/* nanosecs */
#define RC6_HEADER_NBITS	4	/* not including toggle bit */
#define RC6_0_NBITS		16
#define RC6_6A_32_NBITS		32
#define RC6_6A_NBITS		128	/* Variable 8..128 */
#define RC6_PREFIX_PULSE	(6 * RC6_UNIT)
#define RC6_PREFIX_SPACE	(2 * RC6_UNIT)
#define RC6_BIT_START		(1 * RC6_UNIT)
#define RC6_BIT_END		(1 * RC6_UNIT)
#define RC6_TOGGLE_START	(2 * RC6_UNIT)
#define RC6_TOGGLE_END		(2 * RC6_UNIT)
#define RC6_SUFFIX_SPACE	(6 * RC6_UNIT)
#define RC6_MODE_MASK		0x07	/* for the header bits */
#define RC6_STARTBIT_MASK	0x08	/* for the header bits */
#define RC6_6A_MCE_TOGGLE_MASK	0x8000	/* for the body bits */
#define RC6_6A_LCC_MASK		0xffff0000 /* RC6-6A-32 long customer code mask */
#define RC6_6A_MCE_CC		0x800f0000 /* MCE customer code */
#ifndef CHAR_BIT
#define CHAR_BIT 8	/* Normally in <limits.h> */
#endif

enum rc6_mode {
	RC6_MODE_0,
	RC6_MODE_6A,
	RC6_MODE_UNKNOWN,
};

enum rc6_state {
	STATE_INACTIVE,
	STATE_PREFIX_SPACE,
	STATE_HEADER_BIT_START,
	STATE_HEADER_BIT_END,
	STATE_TOGGLE_START,
	STATE_TOGGLE_END,
	STATE_BODY_BIT_START,
	STATE_BODY_BIT_END,
	STATE_FINISHED,
};

static enum rc6_mode rc6_mode(struct rc6_dec *data)
{
	switch (data->header & RC6_MODE_MASK) {
	case 0:
		return RC6_MODE_0;
	case 6:
		if (!data->toggle)
			return RC6_MODE_6A;
		/* fall through */
	default:
		return RC6_MODE_UNKNOWN;
	}
}

/**
 * ir_rc6_decode() - Decode one RC6 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_rc6_decode(struct rc_dev *dev, struct ir_raw_event ev)
{
	struct rc6_dec *data = &dev->raw->rc6;
	u32 scancode;
	u8 toggle;

	if (!(dev->raw->enabled_protocols &
	      (RC_BIT_RC6_0 | RC_BIT_RC6_6A_20 | RC_BIT_RC6_6A_24 |
	       RC_BIT_RC6_6A_32 | RC_BIT_RC6_MCE)))
		return 0;

	if (!is_timing_event(ev)) {
		if (ev.reset)
			data->state = STATE_INACTIVE;
		return 0;
	}

	if (!geq_margin(ev.duration, RC6_UNIT, RC6_UNIT / 2))
		goto out;

again:
	IR_dprintk(2, "RC6 decode started at state %i (%uus %s)\n",
		   data->state, TO_US(ev.duration), TO_STR(ev.pulse));

	if (!geq_margin(ev.duration, RC6_UNIT, RC6_UNIT / 2))
		return 0;

	switch (data->state) {

	case STATE_INACTIVE:
		if (!ev.pulse)
			break;

		/* Note: larger margin on first pulse since each RC6_UNIT
		   is quite short and some hardware takes some time to
		   adjust to the signal */
		if (!eq_margin(ev.duration, RC6_PREFIX_PULSE, RC6_UNIT))
			break;

		data->state = STATE_PREFIX_SPACE;
		data->count = 0;
		return 0;

	case STATE_PREFIX_SPACE:
		if (ev.pulse)
			break;

		if (!eq_margin(ev.duration, RC6_PREFIX_SPACE, RC6_UNIT / 2))
			break;

		data->state = STATE_HEADER_BIT_START;
		data->header = 0;
		return 0;

	case STATE_HEADER_BIT_START:
		if (!eq_margin(ev.duration, RC6_BIT_START, RC6_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;

		if (data->count == RC6_HEADER_NBITS)
			data->state = STATE_TOGGLE_START;
		else
			data->state = STATE_HEADER_BIT_START;

		decrease_duration(&ev, RC6_BIT_END);
		goto again;

	case STATE_TOGGLE_START:
		if (!eq_margin(ev.duration, RC6_TOGGLE_START, RC6_UNIT / 2))
			break;

		data->toggle = ev.pulse;
		data->state = STATE_TOGGLE_END;
		return 0;

	case STATE_TOGGLE_END:
		if (!is_transition(&ev, &dev->raw->prev_ev) ||
		    !geq_margin(ev.duration, RC6_TOGGLE_END, RC6_UNIT / 2))
			break;

		if (!(data->header & RC6_STARTBIT_MASK)) {
			IR_dprintk(1, "RC6 invalid start bit\n");
			break;
		}

		data->state = STATE_BODY_BIT_START;
		decrease_duration(&ev, RC6_TOGGLE_END);
		data->count = 0;
		data->body = 0;

		switch (rc6_mode(data)) {
		case RC6_MODE_0:
			data->wanted_bits = RC6_0_NBITS;
			break;
		case RC6_MODE_6A:
			data->wanted_bits = RC6_6A_NBITS;
			break;
		default:
			IR_dprintk(1, "RC6 unknown mode\n");
			goto out;
		}
		goto again;

	case STATE_BODY_BIT_START:
		if (eq_margin(ev.duration, RC6_BIT_START, RC6_UNIT / 2)) {
			/* Discard LSB's that won't fit in data->body */
			if (data->count++ < CHAR_BIT * sizeof data->body) {
				data->body <<= 1;
				if (ev.pulse)
					data->body |= 1;
			}
			data->state = STATE_BODY_BIT_END;
			return 0;
		} else if (RC6_MODE_6A == rc6_mode(data) && !ev.pulse &&
				geq_margin(ev.duration, RC6_SUFFIX_SPACE, RC6_UNIT / 2)) {
			data->state = STATE_FINISHED;
			goto again;
		}
		break;

	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, RC6_BIT_END);
		goto again;

	case STATE_FINISHED:
		if (ev.pulse)
			break;

		switch (rc6_mode(data)) {
		case RC6_MODE_0:
			scancode = data->body;
			toggle = data->toggle;
			IR_dprintk(1, "RC6(0) scancode 0x%04x (toggle: %u)\n",
				   scancode, toggle);
			break;
		case RC6_MODE_6A:
			if (data->count > CHAR_BIT * sizeof data->body) {
				IR_dprintk(1, "RC6 too many (%u) data bits\n",
					data->count);
				goto out;
			}

			scancode = data->body;
			if (data->count == RC6_6A_32_NBITS &&
					(scancode & RC6_6A_LCC_MASK) == RC6_6A_MCE_CC) {
				/* MCE RC */
				toggle = (scancode & RC6_6A_MCE_TOGGLE_MASK) ? 1 : 0;
				scancode &= ~RC6_6A_MCE_TOGGLE_MASK;
			} else {
				toggle = 0;
			}
			IR_dprintk(1, "RC6(6A) scancode 0x%08x (toggle: %u)\n",
				   scancode, toggle);
			break;
		default:
			IR_dprintk(1, "RC6 unknown mode\n");
			goto out;
		}

		rc_keydown(dev, scancode, toggle);
		data->state = STATE_INACTIVE;
		return 0;
	}

out:
	IR_dprintk(1, "RC6 decode failed at state %i (%uus %s)\n",
		   data->state, TO_US(ev.duration), TO_STR(ev.pulse));
	data->state = STATE_INACTIVE;
	return -EINVAL;
}

static struct ir_raw_handler rc6_handler = {
	.protocols	= RC_BIT_RC6_0 | RC_BIT_RC6_6A_20 |
			  RC_BIT_RC6_6A_24 | RC_BIT_RC6_6A_32 |
			  RC_BIT_RC6_MCE,
	.decode		= ir_rc6_decode,
};

static int __init ir_rc6_decode_init(void)
{
	ir_raw_handler_register(&rc6_handler);

	printk(KERN_INFO "IR RC6 protocol handler initialized\n");
	return 0;
}

static void __exit ir_rc6_decode_exit(void)
{
	ir_raw_handler_unregister(&rc6_handler);
}

module_init(ir_rc6_decode_init);
module_exit(ir_rc6_decode_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("David Härdeman <david@hardeman.nu>");
MODULE_DESCRIPTION("RC6 IR protocol decoder");
Commit	Line	Data
784a4931 DH	1	/* ir-rc6-decoder.c - A decoder for the RC6 IR protocol
	2	*
	3	* Copyright (C) 2010 by David Härdeman <david@hardeman.nu>
	4	*
	5	* This program is free software; you can redistribute it and/or modify
	6	* it under the terms of the GNU General Public License as published by
	7	* the Free Software Foundation version 2 of the License.
	8	*
	9	* This program is distributed in the hope that it will be useful,
	10	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	12	* GNU General Public License for more details.
	13	*/
	14
f62de675	15	#include "rc-core-priv.h"
7a707b89	16	#include <linux/module.h>
784a4931 DH	17
	18	/*
	19	* This decoder currently supports:
	20	* RC6-0-16 (standard toggle bit in header)
db9bc660	21	* RC6-6A-20 (no toggle bit)
784a4931 DH	22	* RC6-6A-24 (no toggle bit)
	23	* RC6-6A-32 (MCE version with toggle bit in body)
	24	*/
	25
db9bc660	26	#define RC6_UNIT 444444 /* nanosecs */
784a4931 DH	27	#define RC6_HEADER_NBITS 4 /* not including toggle bit */
784a4931 DH	28	#define RC6_0_NBITS 16
db9bc660	29	#define RC6_6A_32_NBITS 32
db9bc660	30	#define RC6_6A_NBITS 128 /* Variable 8..128 */
e40b1127 DH	31	#define RC6_PREFIX_PULSE (6 * RC6_UNIT)
	32	#define RC6_PREFIX_SPACE (2 * RC6_UNIT)
	33	#define RC6_BIT_START (1 * RC6_UNIT)
	34	#define RC6_BIT_END (1 * RC6_UNIT)
	35	#define RC6_TOGGLE_START (2 * RC6_UNIT)
	36	#define RC6_TOGGLE_END (2 * RC6_UNIT)
db9bc660	37	#define RC6_SUFFIX_SPACE (6 * RC6_UNIT)
784a4931 DH	38	#define RC6_MODE_MASK 0x07 /* for the header bits */
	39	#define RC6_STARTBIT_MASK 0x08 /* for the header bits */
	40	#define RC6_6A_MCE_TOGGLE_MASK 0x8000 /* for the body bits */
db9bc660	41	#define RC6_6A_LCC_MASK 0xffff0000 /* RC6-6A-32 long customer code mask */
	42	#define RC6_6A_MCE_CC 0x800f0000 /* MCE customer code */
	43	#ifndef CHAR_BIT
	44	#define CHAR_BIT 8 /* Normally in <limits.h> */
	45	#endif
784a4931	46
784a4931 DH	47	enum rc6_mode {
	48	RC6_MODE_0,
	49	RC6_MODE_6A,
	50	RC6_MODE_UNKNOWN,
	51	};
	52
	53	enum rc6_state {
	54	STATE_INACTIVE,
	55	STATE_PREFIX_SPACE,
	56	STATE_HEADER_BIT_START,
	57	STATE_HEADER_BIT_END,
	58	STATE_TOGGLE_START,
	59	STATE_TOGGLE_END,
	60	STATE_BODY_BIT_START,
	61	STATE_BODY_BIT_END,
	62	STATE_FINISHED,
	63	};
	64
c216369e	65	static enum rc6_mode rc6_mode(struct rc6_dec *data)
784a4931	66	{
784a4931 DH	67	switch (data->header & RC6_MODE_MASK) {
	68	case 0:
	69	return RC6_MODE_0;
	70	case 6:
	71	if (!data->toggle)
	72	return RC6_MODE_6A;
	73	/* fall through */
	74	default:
	75	return RC6_MODE_UNKNOWN;
	76	}
	77	}
	78
	79	/**
	80	* ir_rc6_decode() - Decode one RC6 pulse or space
d8b4b582	81	* @dev: the struct rc_dev descriptor of the device
e40b1127	82	* @ev: the struct ir_raw_event descriptor of the pulse/space
784a4931 DH	83	*
	84	* This function returns -EINVAL if the pulse violates the state machine
	85	*/
d8b4b582	86	static int ir_rc6_decode(struct rc_dev *dev, struct ir_raw_event ev)
784a4931	87	{
d8b4b582	88	struct rc6_dec *data = &dev->raw->rc6;
784a4931 DH	89	u32 scancode;
784a4931 DH	90	u8 toggle;
784a4931	91
c003ab1b DH	92	if (!(dev->raw->enabled_protocols &
	93	(RC_BIT_RC6_0 \| RC_BIT_RC6_6A_20 \| RC_BIT_RC6_6A_24 \|
	94	RC_BIT_RC6_6A_32 \| RC_BIT_RC6_MCE)))
784a4931 DH	95	return 0;
784a4931 DH	96
4651918a ML	97	if (!is_timing_event(ev)) {
	98	if (ev.reset)
	99	data->state = STATE_INACTIVE;
784a4931 DH	100	return 0;
	101	}
	102
e40b1127	103	if (!geq_margin(ev.duration, RC6_UNIT, RC6_UNIT / 2))
784a4931 DH	104	goto out;
	105
	106	again:
e40b1127 DH	107	IR_dprintk(2, "RC6 decode started at state %i (%uus %s)\n",
e40b1127 DH	108	data->state, TO_US(ev.duration), TO_STR(ev.pulse));
784a4931	109
e40b1127	110	if (!geq_margin(ev.duration, RC6_UNIT, RC6_UNIT / 2))
784a4931 DH	111	return 0;
	112
	113	switch (data->state) {
	114
	115	case STATE_INACTIVE:
e40b1127 DH	116	if (!ev.pulse)
	117	break;
	118
	119	/* Note: larger margin on first pulse since each RC6_UNIT
	120	is quite short and some hardware takes some time to
	121	adjust to the signal */
	122	if (!eq_margin(ev.duration, RC6_PREFIX_PULSE, RC6_UNIT))
	123	break;
	124
	125	data->state = STATE_PREFIX_SPACE;
	126	data->count = 0;
	127	return 0;
784a4931 DH	128
784a4931 DH	129	case STATE_PREFIX_SPACE:
e40b1127 DH	130	if (ev.pulse)
	131	break;
	132
	133	if (!eq_margin(ev.duration, RC6_PREFIX_SPACE, RC6_UNIT / 2))
	134	break;
	135
	136	data->state = STATE_HEADER_BIT_START;
db9bc660	137	data->header = 0;
e40b1127	138	return 0;
784a4931 DH	139
784a4931 DH	140	case STATE_HEADER_BIT_START:
e40b1127 DH	141	if (!eq_margin(ev.duration, RC6_BIT_START, RC6_UNIT / 2))
	142	break;
	143
	144	data->header <<= 1;
	145	if (ev.pulse)
	146	data->header \|= 1;
	147	data->count++;
e40b1127 DH	148	data->state = STATE_HEADER_BIT_END;
e40b1127 DH	149	return 0;
784a4931 DH	150
784a4931 DH	151	case STATE_HEADER_BIT_END:
d8b4b582	152	if (!is_transition(&ev, &dev->raw->prev_ev))
e40b1127	153	break;
784a4931	154
e40b1127 DH	155	if (data->count == RC6_HEADER_NBITS)
	156	data->state = STATE_TOGGLE_START;
	157	else
	158	data->state = STATE_HEADER_BIT_START;
	159
	160	decrease_duration(&ev, RC6_BIT_END);
	161	goto again;
784a4931 DH	162
784a4931 DH	163	case STATE_TOGGLE_START:
e40b1127 DH	164	if (!eq_margin(ev.duration, RC6_TOGGLE_START, RC6_UNIT / 2))
	165	break;
	166
	167	data->toggle = ev.pulse;
e40b1127 DH	168	data->state = STATE_TOGGLE_END;
e40b1127 DH	169	return 0;
784a4931 DH	170
784a4931 DH	171	case STATE_TOGGLE_END:
d8b4b582	172	if (!is_transition(&ev, &dev->raw->prev_ev) \|\|
e40b1127 DH	173	!geq_margin(ev.duration, RC6_TOGGLE_END, RC6_UNIT / 2))
e40b1127 DH	174	break;
784a4931	175
e40b1127 DH	176	if (!(data->header & RC6_STARTBIT_MASK)) {
	177	IR_dprintk(1, "RC6 invalid start bit\n");
	178	break;
	179	}
784a4931	180
e40b1127	181	data->state = STATE_BODY_BIT_START;
e40b1127 DH	182	decrease_duration(&ev, RC6_TOGGLE_END);
e40b1127 DH	183	data->count = 0;
db9bc660	184	data->body = 0;
e40b1127 DH	185
	186	switch (rc6_mode(data)) {
	187	case RC6_MODE_0:
	188	data->wanted_bits = RC6_0_NBITS;
	189	break;
	190	case RC6_MODE_6A:
db9bc660	191	data->wanted_bits = RC6_6A_NBITS;
e40b1127 DH	192	break;
	193	default:
	194	IR_dprintk(1, "RC6 unknown mode\n");
	195	goto out;
784a4931	196	}
e40b1127	197	goto again;
784a4931 DH	198
784a4931 DH	199	case STATE_BODY_BIT_START:
db9bc660	200	if (eq_margin(ev.duration, RC6_BIT_START, RC6_UNIT / 2)) {
	201	/* Discard LSB's that won't fit in data->body */
	202	if (data->count++ < CHAR_BIT * sizeof data->body) {
	203	data->body <<= 1;
	204	if (ev.pulse)
	205	data->body \|= 1;
	206	}
	207	data->state = STATE_BODY_BIT_END;
	208	return 0;
	209	} else if (RC6_MODE_6A == rc6_mode(data) && !ev.pulse &&
	210	geq_margin(ev.duration, RC6_SUFFIX_SPACE, RC6_UNIT / 2)) {
	211	data->state = STATE_FINISHED;
	212	goto again;
	213	}
	214	break;
784a4931 DH	215
784a4931 DH	216	case STATE_BODY_BIT_END:
d8b4b582	217	if (!is_transition(&ev, &dev->raw->prev_ev))
e40b1127	218	break;
784a4931	219
e40b1127 DH	220	if (data->count == data->wanted_bits)
	221	data->state = STATE_FINISHED;
	222	else
	223	data->state = STATE_BODY_BIT_START;
	224
	225	decrease_duration(&ev, RC6_BIT_END);
	226	goto again;
784a4931 DH	227
784a4931 DH	228	case STATE_FINISHED:
e40b1127 DH	229	if (ev.pulse)
	230	break;
	231
784a4931 DH	232	switch (rc6_mode(data)) {
784a4931 DH	233	case RC6_MODE_0:
db9bc660	234	scancode = data->body;
784a4931 DH	235	toggle = data->toggle;
	236	IR_dprintk(1, "RC6(0) scancode 0x%04x (toggle: %u)\n",
	237	scancode, toggle);
	238	break;
	239	case RC6_MODE_6A:
db9bc660	240	if (data->count > CHAR_BIT * sizeof data->body) {
	241	IR_dprintk(1, "RC6 too many (%u) data bits\n",
	242	data->count);
	243	goto out;
	244	}
	245
	246	scancode = data->body;
	247	if (data->count == RC6_6A_32_NBITS &&
	248	(scancode & RC6_6A_LCC_MASK) == RC6_6A_MCE_CC) {
	249	/* MCE RC */
	250	toggle = (scancode & RC6_6A_MCE_TOGGLE_MASK) ? 1 : 0;
	251	scancode &= ~RC6_6A_MCE_TOGGLE_MASK;
784a4931 DH	252	} else {
784a4931 DH	253	toggle = 0;
784a4931	254	}
784a4931 DH	255	IR_dprintk(1, "RC6(6A) scancode 0x%08x (toggle: %u)\n",
	256	scancode, toggle);
	257	break;
	258	default:
	259	IR_dprintk(1, "RC6 unknown mode\n");
	260	goto out;
	261	}
	262
ca86674b	263	rc_keydown(dev, scancode, toggle);
784a4931 DH	264	data->state = STATE_INACTIVE;
	265	return 0;
	266	}
	267
	268	out:
e40b1127 DH	269	IR_dprintk(1, "RC6 decode failed at state %i (%uus %s)\n",
e40b1127 DH	270	data->state, TO_US(ev.duration), TO_STR(ev.pulse));
784a4931 DH	271	data->state = STATE_INACTIVE;
	272	return -EINVAL;
	273	}
	274
784a4931	275	static struct ir_raw_handler rc6_handler = {
c003ab1b DH	276	.protocols = RC_BIT_RC6_0 \| RC_BIT_RC6_6A_20 \|
	277	RC_BIT_RC6_6A_24 \| RC_BIT_RC6_6A_32 \|
	278	RC_BIT_RC6_MCE,
784a4931	279	.decode = ir_rc6_decode,
784a4931 DH	280	};
	281
	282	static int __init ir_rc6_decode_init(void)
	283	{
	284	ir_raw_handler_register(&rc6_handler);
	285
	286	printk(KERN_INFO "IR RC6 protocol handler initialized\n");
	287	return 0;
	288	}
	289
	290	static void __exit ir_rc6_decode_exit(void)
	291	{
	292	ir_raw_handler_unregister(&rc6_handler);
	293	}
	294
	295	module_init(ir_rc6_decode_init);
	296	module_exit(ir_rc6_decode_exit);
	297
	298	MODULE_LICENSE("GPL");
	299	MODULE_AUTHOR("David Härdeman <david@hardeman.nu>");
	300	MODULE_DESCRIPTION("RC6 IR protocol decoder");