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

/* ir-sharp-decoder.c - handle Sharp IR Pulse/Space protocol
 *
 * Copyright (C) 2013-2014 Imagination Technologies Ltd.
 *
 * Based on NEC decoder:
 * Copyright (C) 2010 by Mauro Carvalho Chehab
 *
 * 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 <linux/bitrev.h>
#include <linux/module.h>
#include "rc-core-priv.h"

#define SHARP_NBITS		15
#define SHARP_UNIT		40000  /* ns */
#define SHARP_BIT_PULSE		(8    * SHARP_UNIT) /* 320us */
#define SHARP_BIT_0_PERIOD	(25   * SHARP_UNIT) /* 1ms (680us space) */
#define SHARP_BIT_1_PERIOD	(50   * SHARP_UNIT) /* 2ms (1680ms space) */
#define SHARP_ECHO_SPACE	(1000 * SHARP_UNIT) /* 40 ms */
#define SHARP_TRAILER_SPACE	(125  * SHARP_UNIT) /* 5 ms (even longer) */

enum sharp_state {
	STATE_INACTIVE,
	STATE_BIT_PULSE,
	STATE_BIT_SPACE,
	STATE_TRAILER_PULSE,
	STATE_ECHO_SPACE,
	STATE_TRAILER_SPACE,
};

/**
 * ir_sharp_decode() - Decode one Sharp pulse or space
 * @dev:	the struct rc_dev descriptor of the device
 * @duration:	the struct ir_raw_event descriptor of the pulse/space
 *
 * This function returns -EINVAL if the pulse violates the state machine
 */
static int ir_sharp_decode(struct rc_dev *dev, struct ir_raw_event ev)
{
	struct sharp_dec *data = &dev->raw->sharp;
	u32 msg, echo, address, command, scancode;

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

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

	switch (data->state) {

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

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

		data->count = 0;
		data->pulse_len = ev.duration;
		data->state = STATE_BIT_SPACE;
		return 0;

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

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

		data->pulse_len = ev.duration;
		data->state = STATE_BIT_SPACE;
		return 0;

	case STATE_BIT_SPACE:
		if (ev.pulse)
			break;

		data->bits <<= 1;
		if (eq_margin(data->pulse_len + ev.duration, SHARP_BIT_1_PERIOD,
			      SHARP_BIT_PULSE * 2))
			data->bits |= 1;
		else if (!eq_margin(data->pulse_len + ev.duration,
				    SHARP_BIT_0_PERIOD, SHARP_BIT_PULSE * 2))
			break;
		data->count++;

		if (data->count == SHARP_NBITS ||
		    data->count == SHARP_NBITS * 2)
			data->state = STATE_TRAILER_PULSE;
		else
			data->state = STATE_BIT_PULSE;

		return 0;

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

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

		if (data->count == SHARP_NBITS) {
			/* exp,chk bits should be 1,0 */
			if ((data->bits & 0x3) != 0x2 &&
			/* DENON variant, both chk bits 0 */
			    (data->bits & 0x3) != 0x0)
				break;
			data->state = STATE_ECHO_SPACE;
		} else {
			data->state = STATE_TRAILER_SPACE;
		}
		return 0;

	case STATE_ECHO_SPACE:
		if (ev.pulse)
			break;

		if (!eq_margin(ev.duration, SHARP_ECHO_SPACE,
			       SHARP_ECHO_SPACE / 4))
			break;

		data->state = STATE_BIT_PULSE;

		return 0;

	case STATE_TRAILER_SPACE:
		if (ev.pulse)
			break;

		if (!geq_margin(ev.duration, SHARP_TRAILER_SPACE,
				SHARP_BIT_PULSE / 2))
			break;

		/* Validate - command, ext, chk should be inverted in 2nd */
		msg = (data->bits >> 15) & 0x7fff;
		echo = data->bits & 0x7fff;
		if ((msg ^ echo) != 0x3ff) {
			IR_dprintk(1,
				   "Sharp checksum error: received 0x%04x, 0x%04x\n",
				   msg, echo);
			break;
		}

		address = bitrev8((msg >> 7) & 0xf8);
		command = bitrev8((msg >> 2) & 0xff);

		scancode = address << 8 | command;
		IR_dprintk(1, "Sharp scancode 0x%04x\n", scancode);

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

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

static struct ir_raw_handler sharp_handler = {
	.protocols	= RC_BIT_SHARP,
	.decode		= ir_sharp_decode,
};

static int __init ir_sharp_decode_init(void)
{
	ir_raw_handler_register(&sharp_handler);

	pr_info("IR Sharp protocol handler initialized\n");
	return 0;
}

static void __exit ir_sharp_decode_exit(void)
{
	ir_raw_handler_unregister(&sharp_handler);
}

module_init(ir_sharp_decode_init);
module_exit(ir_sharp_decode_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("James Hogan <james.hogan@imgtec.com>");
MODULE_DESCRIPTION("Sharp IR protocol decoder");
Commit	Line	Data
1d184b0b JH	1	/* ir-sharp-decoder.c - handle Sharp IR Pulse/Space protocol
	2	*
	3	* Copyright (C) 2013-2014 Imagination Technologies Ltd.
	4	*
	5	* Based on NEC decoder:
37e59f87	6	* Copyright (C) 2010 by Mauro Carvalho Chehab
1d184b0b JH	7	*
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License as published by
	10	* the Free Software Foundation version 2 of the License.
	11	*
	12	* This program is distributed in the hope that it will be useful,
	13	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	14	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	15	* GNU General Public License for more details.
	16	*/
	17
	18	#include <linux/bitrev.h>
	19	#include <linux/module.h>
	20	#include "rc-core-priv.h"
	21
	22	#define SHARP_NBITS 15
	23	#define SHARP_UNIT 40000 /* ns */
	24	#define SHARP_BIT_PULSE (8 * SHARP_UNIT) /* 320us */
	25	#define SHARP_BIT_0_PERIOD (25 * SHARP_UNIT) /* 1ms (680us space) */
	26	#define SHARP_BIT_1_PERIOD (50 * SHARP_UNIT) /* 2ms (1680ms space) */
	27	#define SHARP_ECHO_SPACE (1000 * SHARP_UNIT) /* 40 ms */
	28	#define SHARP_TRAILER_SPACE (125 * SHARP_UNIT) /* 5 ms (even longer) */
	29
	30	enum sharp_state {
	31	STATE_INACTIVE,
	32	STATE_BIT_PULSE,
	33	STATE_BIT_SPACE,
	34	STATE_TRAILER_PULSE,
	35	STATE_ECHO_SPACE,
	36	STATE_TRAILER_SPACE,
	37	};
	38
	39	/**
	40	* ir_sharp_decode() - Decode one Sharp pulse or space
	41	* @dev: the struct rc_dev descriptor of the device
	42	* @duration: the struct ir_raw_event descriptor of the pulse/space
	43	*
	44	* This function returns -EINVAL if the pulse violates the state machine
	45	*/
	46	static int ir_sharp_decode(struct rc_dev *dev, struct ir_raw_event ev)
	47	{
	48	struct sharp_dec *data = &dev->raw->sharp;
	49	u32 msg, echo, address, command, scancode;
	50
1d184b0b JH	51	if (!is_timing_event(ev)) {
	52	if (ev.reset)
	53	data->state = STATE_INACTIVE;
	54	return 0;
	55	}
	56
	57	IR_dprintk(2, "Sharp decode started at state %d (%uus %s)\n",
	58	data->state, TO_US(ev.duration), TO_STR(ev.pulse));
	59
	60	switch (data->state) {
	61
	62	case STATE_INACTIVE:
	63	if (!ev.pulse)
	64	break;
	65
	66	if (!eq_margin(ev.duration, SHARP_BIT_PULSE,
	67	SHARP_BIT_PULSE / 2))
	68	break;
	69
	70	data->count = 0;
	71	data->pulse_len = ev.duration;
	72	data->state = STATE_BIT_SPACE;
	73	return 0;
	74
	75	case STATE_BIT_PULSE:
	76	if (!ev.pulse)
	77	break;
	78
	79	if (!eq_margin(ev.duration, SHARP_BIT_PULSE,
	80	SHARP_BIT_PULSE / 2))
	81	break;
	82
	83	data->pulse_len = ev.duration;
	84	data->state = STATE_BIT_SPACE;
	85	return 0;
	86
	87	case STATE_BIT_SPACE:
	88	if (ev.pulse)
	89	break;
	90
	91	data->bits <<= 1;
	92	if (eq_margin(data->pulse_len + ev.duration, SHARP_BIT_1_PERIOD,
	93	SHARP_BIT_PULSE * 2))
	94	data->bits \|= 1;
	95	else if (!eq_margin(data->pulse_len + ev.duration,
	96	SHARP_BIT_0_PERIOD, SHARP_BIT_PULSE * 2))
	97	break;
	98	data->count++;
	99
	100	if (data->count == SHARP_NBITS \|\|
	101	data->count == SHARP_NBITS * 2)
	102	data->state = STATE_TRAILER_PULSE;
	103	else
	104	data->state = STATE_BIT_PULSE;
	105
	106	return 0;
	107
	108	case STATE_TRAILER_PULSE:
	109	if (!ev.pulse)
	110	break;
	111
	112	if (!eq_margin(ev.duration, SHARP_BIT_PULSE,
	113	SHARP_BIT_PULSE / 2))
	114	break;
115
116	if (data->count == SHARP_NBITS) {
117	/* exp,chk bits should be 1,0 */
1b0621af HK	118	if ((data->bits & 0x3) != 0x2 &&
	119	/* DENON variant, both chk bits 0 */
	120	(data->bits & 0x3) != 0x0)
1d184b0b JH	121	break;
	122	data->state = STATE_ECHO_SPACE;
	123	} else {
	124	data->state = STATE_TRAILER_SPACE;
	125	}
	126	return 0;
	127
	128	case STATE_ECHO_SPACE:
	129	if (ev.pulse)
	130	break;
	131
	132	if (!eq_margin(ev.duration, SHARP_ECHO_SPACE,
	133	SHARP_ECHO_SPACE / 4))
	134	break;
	135
	136	data->state = STATE_BIT_PULSE;
	137
	138	return 0;
	139
	140	case STATE_TRAILER_SPACE:
	141	if (ev.pulse)
	142	break;
	143
	144	if (!geq_margin(ev.duration, SHARP_TRAILER_SPACE,
	145	SHARP_BIT_PULSE / 2))
	146	break;
	147
	148	/* Validate - command, ext, chk should be inverted in 2nd */
	149	msg = (data->bits >> 15) & 0x7fff;
	150	echo = data->bits & 0x7fff;
	151	if ((msg ^ echo) != 0x3ff) {
	152	IR_dprintk(1,
	153	"Sharp checksum error: received 0x%04x, 0x%04x\n",
	154	msg, echo);
	155	break;
	156	}
	157
	158	address = bitrev8((msg >> 7) & 0xf8);
	159	command = bitrev8((msg >> 2) & 0xff);
	160
	161	scancode = address << 8 \| command;
	162	IR_dprintk(1, "Sharp scancode 0x%04x\n", scancode);
	163
120703f9	164	rc_keydown(dev, RC_TYPE_SHARP, scancode, 0);
1d184b0b JH	165	data->state = STATE_INACTIVE;
	166	return 0;
	167	}
	168
	169	IR_dprintk(1, "Sharp decode failed at count %d state %d (%uus %s)\n",
	170	data->count, data->state, TO_US(ev.duration),
	171	TO_STR(ev.pulse));
	172	data->state = STATE_INACTIVE;
	173	return -EINVAL;
	174	}
	175
	176	static struct ir_raw_handler sharp_handler = {
	177	.protocols = RC_BIT_SHARP,
	178	.decode = ir_sharp_decode,
	179	};
	180
	181	static int __init ir_sharp_decode_init(void)
	182	{
	183	ir_raw_handler_register(&sharp_handler);
	184
	185	pr_info("IR Sharp protocol handler initialized\n");
	186	return 0;
	187	}
	188
	189	static void __exit ir_sharp_decode_exit(void)
	190	{
	191	ir_raw_handler_unregister(&sharp_handler);
	192	}
	193
	194	module_init(ir_sharp_decode_init);
	195	module_exit(ir_sharp_decode_exit);
	196
	197	MODULE_LICENSE("GPL");
	198	MODULE_AUTHOR("James Hogan <james.hogan@imgtec.com>");
	199	MODULE_DESCRIPTION("Sharp IR protocol decoder");