[linux-2.6-block.git] / drivers / media / rc / ir-rc5-sz-decoder.c

/* ir-rc5-sz-decoder.c - handle RC5 Streamzap IR Pulse/Space protocol
 *
 * Copyright (C) 2010 by Mauro Carvalho Chehab <mchehab@redhat.com>
 * Copyright (C) 2010 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.
 */

/*
 * This code handles the 15 bit RC5-ish protocol used by the Streamzap
 * PC Remote.
 * It considers a carrier of 36 kHz, with a total of 15 bits, where
 * the first two bits are start bits, and a third one is a filing bit
 */

#include "rc-core-priv.h"

#define RC5_SZ_NBITS		15
#define RC5_UNIT		888888 /* ns */
#define RC5_BIT_START		(1 * RC5_UNIT)
#define RC5_BIT_END		(1 * RC5_UNIT)

enum rc5_sz_state {
	STATE_INACTIVE,
	STATE_BIT_START,
	STATE_BIT_END,
	STATE_FINISHED,
};

/**
 * ir_rc5_sz_decode() - Decode one RC-5 Streamzap 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_rc5_sz_decode(struct rc_dev *dev, struct ir_raw_event ev)
{
	struct rc5_sz_dec *data = &dev->raw->rc5_sz;
	u8 toggle, command, system;
	u32 scancode;

        if (!(dev->raw->enabled_protocols & IR_TYPE_RC5_SZ))
                return 0;

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

	if (!geq_margin(ev.duration, RC5_UNIT, RC5_UNIT / 2))
		goto out;

again:
	IR_dprintk(2, "RC5-sz decode started at state %i (%uus %s)\n",
		   data->state, TO_US(ev.duration), TO_STR(ev.pulse));

	if (!geq_margin(ev.duration, RC5_UNIT, RC5_UNIT / 2))
		return 0;

	switch (data->state) {

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

		data->state = STATE_BIT_START;
		data->count = 1;
		data->wanted_bits = RC5_SZ_NBITS;
		decrease_duration(&ev, RC5_BIT_START);
		goto again;

	case STATE_BIT_START:
		if (!eq_margin(ev.duration, RC5_BIT_START, RC5_UNIT / 2))
			break;

		data->bits <<= 1;
		if (!ev.pulse)
			data->bits |= 1;
		data->count++;
		data->state = STATE_BIT_END;
		return 0;

	case STATE_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_BIT_START;

		decrease_duration(&ev, RC5_BIT_END);
		goto again;

	case STATE_FINISHED:
		if (ev.pulse)
			break;

		/* RC5-sz */
		command  = (data->bits & 0x0003F) >> 0;
		system   = (data->bits & 0x02FC0) >> 6;
		toggle   = (data->bits & 0x01000) ? 1 : 0;
		scancode = system << 6 | command;

		IR_dprintk(1, "RC5-sz scancode 0x%04x (toggle: %u)\n",
			   scancode, toggle);

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

out:
	IR_dprintk(1, "RC5-sz 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 rc5_sz_handler = {
	.protocols	= IR_TYPE_RC5_SZ,
	.decode		= ir_rc5_sz_decode,
};

static int __init ir_rc5_sz_decode_init(void)
{
	ir_raw_handler_register(&rc5_sz_handler);

	printk(KERN_INFO "IR RC5 (streamzap) protocol handler initialized\n");
	return 0;
}

static void __exit ir_rc5_sz_decode_exit(void)
{
	ir_raw_handler_unregister(&rc5_sz_handler);
}

module_init(ir_rc5_sz_decode_init);
module_exit(ir_rc5_sz_decode_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Jarod Wilson <jarod@redhat.com>");
MODULE_AUTHOR("Red Hat Inc. (http://www.redhat.com)");
MODULE_DESCRIPTION("RC5 (streamzap) IR protocol decoder");
Commit	Line	Data
7a569f52 JW	1	/* ir-rc5-sz-decoder.c - handle RC5 Streamzap IR Pulse/Space protocol
	2	*
	3	* Copyright (C) 2010 by Mauro Carvalho Chehab <mchehab@redhat.com>
	4	* Copyright (C) 2010 by Jarod Wilson <jarod@redhat.com>
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License as published by
	8	* the Free Software Foundation version 2 of the License.
	9	*
	10	* This program is distributed in the hope that it will be useful,
	11	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	13	* GNU General Public License for more details.
	14	*/
	15
	16	/*
	17	* This code handles the 15 bit RC5-ish protocol used by the Streamzap
	18	* PC Remote.
	19	* It considers a carrier of 36 kHz, with a total of 15 bits, where
	20	* the first two bits are start bits, and a third one is a filing bit
	21	*/
	22
f62de675	23	#include "rc-core-priv.h"
7a569f52 JW	24
	25	#define RC5_SZ_NBITS 15
	26	#define RC5_UNIT 888888 /* ns */
	27	#define RC5_BIT_START (1 * RC5_UNIT)
	28	#define RC5_BIT_END (1 * RC5_UNIT)
	29
	30	enum rc5_sz_state {
	31	STATE_INACTIVE,
	32	STATE_BIT_START,
	33	STATE_BIT_END,
	34	STATE_FINISHED,
	35	};
	36
	37	/**
	38	* ir_rc5_sz_decode() - Decode one RC-5 Streamzap pulse or space
d8b4b582	39	* @dev: the struct rc_dev descriptor of the device
7a569f52 JW	40	* @ev: the struct ir_raw_event descriptor of the pulse/space
	41	*
	42	* This function returns -EINVAL if the pulse violates the state machine
	43	*/
d8b4b582	44	static int ir_rc5_sz_decode(struct rc_dev *dev, struct ir_raw_event ev)
7a569f52	45	{
d8b4b582	46	struct rc5_sz_dec *data = &dev->raw->rc5_sz;
7a569f52 JW	47	u8 toggle, command, system;
	48	u32 scancode;
	49
d8b4b582	50	if (!(dev->raw->enabled_protocols & IR_TYPE_RC5_SZ))
7a569f52 JW	51	return 0;
7a569f52 JW	52
4651918a ML	53	if (!is_timing_event(ev)) {
	54	if (ev.reset)
	55	data->state = STATE_INACTIVE;
7a569f52 JW	56	return 0;
	57	}
	58
	59	if (!geq_margin(ev.duration, RC5_UNIT, RC5_UNIT / 2))
	60	goto out;
	61
	62	again:
	63	IR_dprintk(2, "RC5-sz decode started at state %i (%uus %s)\n",
	64	data->state, TO_US(ev.duration), TO_STR(ev.pulse));
	65
	66	if (!geq_margin(ev.duration, RC5_UNIT, RC5_UNIT / 2))
	67	return 0;
	68
	69	switch (data->state) {
	70
	71	case STATE_INACTIVE:
	72	if (!ev.pulse)
	73	break;
	74
	75	data->state = STATE_BIT_START;
	76	data->count = 1;
	77	data->wanted_bits = RC5_SZ_NBITS;
	78	decrease_duration(&ev, RC5_BIT_START);
	79	goto again;
	80
	81	case STATE_BIT_START:
	82	if (!eq_margin(ev.duration, RC5_BIT_START, RC5_UNIT / 2))
	83	break;
	84
	85	data->bits <<= 1;
	86	if (!ev.pulse)
	87	data->bits \|= 1;
	88	data->count++;
	89	data->state = STATE_BIT_END;
	90	return 0;
	91
	92	case STATE_BIT_END:
d8b4b582	93	if (!is_transition(&ev, &dev->raw->prev_ev))
7a569f52 JW	94	break;
	95
	96	if (data->count == data->wanted_bits)
	97	data->state = STATE_FINISHED;
	98	else
	99	data->state = STATE_BIT_START;
	100
	101	decrease_duration(&ev, RC5_BIT_END);
	102	goto again;
	103
	104	case STATE_FINISHED:
	105	if (ev.pulse)
	106	break;
	107
	108	/* RC5-sz */
	109	command = (data->bits & 0x0003F) >> 0;
	110	system = (data->bits & 0x02FC0) >> 6;
	111	toggle = (data->bits & 0x01000) ? 1 : 0;
	112	scancode = system << 6 \| command;
	113
	114	IR_dprintk(1, "RC5-sz scancode 0x%04x (toggle: %u)\n",
	115	scancode, toggle);
	116
d8b4b582	117	ir_keydown(dev, scancode, toggle);
7a569f52 JW	118	data->state = STATE_INACTIVE;
	119	return 0;
	120	}
	121
	122	out:
	123	IR_dprintk(1, "RC5-sz decode failed at state %i (%uus %s)\n",
	124	data->state, TO_US(ev.duration), TO_STR(ev.pulse));
	125	data->state = STATE_INACTIVE;
	126	return -EINVAL;
	127	}
	128
	129	static struct ir_raw_handler rc5_sz_handler = {
	130	.protocols = IR_TYPE_RC5_SZ,
	131	.decode = ir_rc5_sz_decode,
	132	};
	133
	134	static int __init ir_rc5_sz_decode_init(void)
	135	{
	136	ir_raw_handler_register(&rc5_sz_handler);
	137
	138	printk(KERN_INFO "IR RC5 (streamzap) protocol handler initialized\n");
	139	return 0;
	140	}
	141
	142	static void __exit ir_rc5_sz_decode_exit(void)
	143	{
	144	ir_raw_handler_unregister(&rc5_sz_handler);
	145	}
	146
	147	module_init(ir_rc5_sz_decode_init);
	148	module_exit(ir_rc5_sz_decode_exit);
	149
	150	MODULE_LICENSE("GPL");
	151	MODULE_AUTHOR("Jarod Wilson <jarod@redhat.com>");
	152	MODULE_AUTHOR("Red Hat Inc. (http://www.redhat.com)");
	153	MODULE_DESCRIPTION("RC5 (streamzap) IR protocol decoder");