drivers/media/rc/ir-rc5-decoder.c - arm/linux - Git at Google

 /* ir-rc5-decoder.c - decoder for RC5(x) and StreamZap protocols
  *
  * Copyright (C) 2010 by Mauro Carvalho Chehab
  * 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 decoder handles the 14 bit RC5 protocol, 15 bit "StreamZap" protocol
  * and 20 bit RC5x protocol.
  */

 #include "rc-core-priv.h"
 #include <linux/module.h>

 #define RC5_NBITS		14
 #define RC5_SZ_NBITS		15
 #define RC5X_NBITS		20
 #define CHECK_RC5X_NBITS	8
 #define RC5_UNIT		888888 /* ns */
 #define RC5_BIT_START		(1 * RC5_UNIT)
 #define RC5_BIT_END		(1 * RC5_UNIT)
 #define RC5X_SPACE		(4 * RC5_UNIT)
 #define RC5_TRAILER		(6 * RC5_UNIT) /* In reality, approx 100 */

 enum rc5_state {
 	STATE_INACTIVE,
 	STATE_BIT_START,
 	STATE_BIT_END,
 	STATE_CHECK_RC5X,
 	STATE_FINISHED,
 };

 /**
  * ir_rc5_decode() - Decode one RC-5 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_decode(struct rc_dev *dev, struct ir_raw_event ev)
 {
 	struct rc5_dec *data = &dev->raw->rc5;
 	u8 toggle;
 	u32 scancode;
 	enum rc_proto protocol;

 	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(x/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;
 		decrease_duration(&ev, RC5_BIT_START);
 		goto again;

 	case STATE_BIT_START:
 		if (!ev.pulse && geq_margin(ev.duration, RC5_TRAILER, RC5_UNIT / 2)) {
 			data->state = STATE_FINISHED;
 			goto again;
 		}

 		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 == CHECK_RC5X_NBITS)
 			data->state = STATE_CHECK_RC5X;
 		else
 			data->state = STATE_BIT_START;

 		decrease_duration(&ev, RC5_BIT_END);
 		goto again;

 	case STATE_CHECK_RC5X:
 		if (!ev.pulse && geq_margin(ev.duration, RC5X_SPACE, RC5_UNIT / 2)) {
 			data->is_rc5x = true;
 			decrease_duration(&ev, RC5X_SPACE);
 		} else
 			data->is_rc5x = false;
 		data->state = STATE_BIT_START;
 		goto again;

 	case STATE_FINISHED:
 		if (ev.pulse)
 			break;

 		if (data->is_rc5x && data->count == RC5X_NBITS) {
 			/* RC5X */
 			u8 xdata, command, system;
 			if (!(dev->enabled_protocols & RC_PROTO_BIT_RC5X_20)) {
 				data->state = STATE_INACTIVE;
 				return 0;
 			}
 			xdata    = (data->bits & 0x0003F) >> 0;
 			command  = (data->bits & 0x00FC0) >> 6;
 			system   = (data->bits & 0x1F000) >> 12;
 			toggle   = (data->bits & 0x20000) ? 1 : 0;
 			command += (data->bits & 0x40000) ? 0 : 0x40;
 			scancode = system << 16 | command << 8 | xdata;
 			protocol = RC_PROTO_RC5X_20;

 		} else if (!data->is_rc5x && data->count == RC5_NBITS) {
 			/* RC5 */
 			u8 command, system;
 			if (!(dev->enabled_protocols & RC_PROTO_BIT_RC5)) {
 				data->state = STATE_INACTIVE;
 				return 0;
 			}
 			command  = (data->bits & 0x0003F) >> 0;
 			system   = (data->bits & 0x007C0) >> 6;
 			toggle   = (data->bits & 0x00800) ? 1 : 0;
 			command += (data->bits & 0x01000) ? 0 : 0x40;
 			scancode = system << 8 | command;
 			protocol = RC_PROTO_RC5;

 		} else if (!data->is_rc5x && data->count == RC5_SZ_NBITS) {
 			/* RC5 StreamZap */
 			u8 command, system;
 			if (!(dev->enabled_protocols & RC_PROTO_BIT_RC5_SZ)) {
 				data->state = STATE_INACTIVE;
 				return 0;
 			}
 			command  = (data->bits & 0x0003F) >> 0;
 			system   = (data->bits & 0x02FC0) >> 6;
 			toggle   = (data->bits & 0x01000) ? 1 : 0;
 			scancode = system << 6 | command;
 			protocol = RC_PROTO_RC5_SZ;

 		} else
 			break;

 		IR_dprintk(1, "RC5(x/sz) scancode 0x%06x (p: %u, t: %u)\n",
 			   scancode, protocol, toggle);

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

 out:
 	IR_dprintk(1, "RC5(x/sz) decode failed at state %i count %d (%uus %s)\n",
 		   data->state, data->count, TO_US(ev.duration), TO_STR(ev.pulse));
 	data->state = STATE_INACTIVE;
 	return -EINVAL;
 }

 static const struct ir_raw_timings_manchester ir_rc5_timings = {
 	.leader			= RC5_UNIT,
 	.pulse_space_start	= 0,
 	.clock			= RC5_UNIT,
 	.trailer_space		= RC5_UNIT * 10,
 };

 static const struct ir_raw_timings_manchester ir_rc5x_timings[2] = {
 	{
 		.leader			= RC5_UNIT,
 		.pulse_space_start	= 0,
 		.clock			= RC5_UNIT,
 		.trailer_space		= RC5X_SPACE,
 	},
 	{
 		.clock			= RC5_UNIT,
 		.trailer_space		= RC5_UNIT * 10,
 	},
 };

 static const struct ir_raw_timings_manchester ir_rc5_sz_timings = {
 	.leader				= RC5_UNIT,
 	.pulse_space_start		= 0,
 	.clock				= RC5_UNIT,
 	.trailer_space			= RC5_UNIT * 10,
 };

 /**
  * ir_rc5_encode() - Encode a scancode as a stream of raw events
  *
  * @protocol:	protocol variant to encode
  * @scancode:	scancode to encode
  * @events:	array of raw ir events to write into
  * @max:	maximum size of @events
  *
  * Returns:	The number of events written.
  *		-ENOBUFS if there isn't enough space in the array to fit the
  *		encoding. In this case all @max events will have been written.
  *		-EINVAL if the scancode is ambiguous or invalid.
  */
 static int ir_rc5_encode(enum rc_proto protocol, u32 scancode,
 			 struct ir_raw_event *events, unsigned int max)
 {
 	int ret;
 	struct ir_raw_event *e = events;
 	unsigned int data, xdata, command, commandx, system, pre_space_data;

 	/* Detect protocol and convert scancode to raw data */
 	if (protocol == RC_PROTO_RC5) {
 		/* decode scancode */
 		command  = (scancode & 0x003f) >> 0;
 		commandx = (scancode & 0x0040) >> 6;
 		system   = (scancode & 0x1f00) >> 8;
 		/* encode data */
 		data = !commandx << 12 | system << 6 | command;

 		/* Modulate the data */
 		ret = ir_raw_gen_manchester(&e, max, &ir_rc5_timings,
 					    RC5_NBITS, data);
 		if (ret < 0)
 			return ret;
 	} else if (protocol == RC_PROTO_RC5X_20) {
 		/* decode scancode */
 		xdata    = (scancode & 0x00003f) >> 0;
 		command  = (scancode & 0x003f00) >> 8;
 		commandx = !(scancode & 0x004000);
 		system   = (scancode & 0x1f0000) >> 16;

 		/* encode data */
 		data = commandx << 18 | system << 12 | command << 6 | xdata;

 		/* Modulate the data */
 		pre_space_data = data >> (RC5X_NBITS - CHECK_RC5X_NBITS);
 		ret = ir_raw_gen_manchester(&e, max, &ir_rc5x_timings[0],
 					    CHECK_RC5X_NBITS, pre_space_data);
 		if (ret < 0)
 			return ret;
 		ret = ir_raw_gen_manchester(&e, max - (e - events),
 					    &ir_rc5x_timings[1],
 					    RC5X_NBITS - CHECK_RC5X_NBITS,
 					    data);
 		if (ret < 0)
 			return ret;
 	} else if (protocol == RC_PROTO_RC5_SZ) {
 		/* RC5-SZ scancode is raw enough for Manchester as it is */
 		ret = ir_raw_gen_manchester(&e, max, &ir_rc5_sz_timings,
 					    RC5_SZ_NBITS, scancode & 0x2fff);
 		if (ret < 0)
 			return ret;
 	} else {
 		return -EINVAL;
 	}

 	return e - events;
 }

 static struct ir_raw_handler rc5_handler = {
 	.protocols	= RC_PROTO_BIT_RC5 | RC_PROTO_BIT_RC5X_20 |
 							RC_PROTO_BIT_RC5_SZ,
 	.decode		= ir_rc5_decode,
 	.encode		= ir_rc5_encode,
 };

 static int __init ir_rc5_decode_init(void)
 {
 	ir_raw_handler_register(&rc5_handler);

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

 static void __exit ir_rc5_decode_exit(void)
 {
 	ir_raw_handler_unregister(&rc5_handler);
 }

 module_init(ir_rc5_decode_init);
 module_exit(ir_rc5_decode_exit);

 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Mauro Carvalho Chehab and Jarod Wilson");
 MODULE_AUTHOR("Red Hat Inc. (http://www.redhat.com)");
 MODULE_DESCRIPTION("RC5(x/sz) IR protocol decoder");
	/* ir-rc5-decoder.c - decoder for RC5(x) and StreamZap protocols
	*
	* Copyright (C) 2010 by Mauro Carvalho Chehab
	* 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 decoder handles the 14 bit RC5 protocol, 15 bit "StreamZap" protocol
	* and 20 bit RC5x protocol.
	*/

	#include "rc-core-priv.h"
	#include <linux/module.h>

	#define RC5_NBITS 14
	#define RC5_SZ_NBITS 15
	#define RC5X_NBITS 20
	#define CHECK_RC5X_NBITS 8
	#define RC5_UNIT 888888 /* ns */
	#define RC5_BIT_START (1 * RC5_UNIT)
	#define RC5_BIT_END (1 * RC5_UNIT)
	#define RC5X_SPACE (4 * RC5_UNIT)
	#define RC5_TRAILER (6 * RC5_UNIT) /* In reality, approx 100 */

	enum rc5_state {
	STATE_INACTIVE,
	STATE_BIT_START,
	STATE_BIT_END,
	STATE_CHECK_RC5X,
	STATE_FINISHED,
	};

	/**
	* ir_rc5_decode() - Decode one RC-5 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_decode(struct rc_dev *dev, struct ir_raw_event ev)
	{
	struct rc5_dec *data = &dev->raw->rc5;
	u8 toggle;
	u32 scancode;
	enum rc_proto protocol;

	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(x/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;
	decrease_duration(&ev, RC5_BIT_START);
	goto again;

	case STATE_BIT_START:
	if (!ev.pulse && geq_margin(ev.duration, RC5_TRAILER, RC5_UNIT / 2)) {
	data->state = STATE_FINISHED;
	goto again;
	}

	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 == CHECK_RC5X_NBITS)
	data->state = STATE_CHECK_RC5X;
	else
	data->state = STATE_BIT_START;

	decrease_duration(&ev, RC5_BIT_END);
	goto again;

	case STATE_CHECK_RC5X:
	if (!ev.pulse && geq_margin(ev.duration, RC5X_SPACE, RC5_UNIT / 2)) {
	data->is_rc5x = true;
	decrease_duration(&ev, RC5X_SPACE);
	} else
	data->is_rc5x = false;
	data->state = STATE_BIT_START;
	goto again;

	case STATE_FINISHED:
	if (ev.pulse)
	break;

	if (data->is_rc5x && data->count == RC5X_NBITS) {
	/* RC5X */
	u8 xdata, command, system;
	if (!(dev->enabled_protocols & RC_PROTO_BIT_RC5X_20)) {
	data->state = STATE_INACTIVE;
	return 0;
	}
	xdata = (data->bits & 0x0003F) >> 0;
	command = (data->bits & 0x00FC0) >> 6;
	system = (data->bits & 0x1F000) >> 12;
	toggle = (data->bits & 0x20000) ? 1 : 0;
	command += (data->bits & 0x40000) ? 0 : 0x40;
	scancode = system << 16 \| command << 8 \| xdata;
	protocol = RC_PROTO_RC5X_20;

	} else if (!data->is_rc5x && data->count == RC5_NBITS) {
	/* RC5 */
	u8 command, system;
	if (!(dev->enabled_protocols & RC_PROTO_BIT_RC5)) {
	data->state = STATE_INACTIVE;
	return 0;
	}
	command = (data->bits & 0x0003F) >> 0;
	system = (data->bits & 0x007C0) >> 6;
	toggle = (data->bits & 0x00800) ? 1 : 0;
	command += (data->bits & 0x01000) ? 0 : 0x40;
	scancode = system << 8 \| command;
	protocol = RC_PROTO_RC5;

	} else if (!data->is_rc5x && data->count == RC5_SZ_NBITS) {
	/* RC5 StreamZap */
	u8 command, system;
	if (!(dev->enabled_protocols & RC_PROTO_BIT_RC5_SZ)) {
	data->state = STATE_INACTIVE;
	return 0;
	}
	command = (data->bits & 0x0003F) >> 0;
	system = (data->bits & 0x02FC0) >> 6;
	toggle = (data->bits & 0x01000) ? 1 : 0;
	scancode = system << 6 \| command;
	protocol = RC_PROTO_RC5_SZ;

	} else
	break;

	IR_dprintk(1, "RC5(x/sz) scancode 0x%06x (p: %u, t: %u)\n",
	scancode, protocol, toggle);

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

	out:
	IR_dprintk(1, "RC5(x/sz) decode failed at state %i count %d (%uus %s)\n",
	data->state, data->count, TO_US(ev.duration), TO_STR(ev.pulse));
	data->state = STATE_INACTIVE;
	return -EINVAL;
	}

	static const struct ir_raw_timings_manchester ir_rc5_timings = {
	.leader = RC5_UNIT,
	.pulse_space_start = 0,
	.clock = RC5_UNIT,
	.trailer_space = RC5_UNIT * 10,
	};

	static const struct ir_raw_timings_manchester ir_rc5x_timings[2] = {
	{
	.leader = RC5_UNIT,
	.pulse_space_start = 0,
	.clock = RC5_UNIT,
	.trailer_space = RC5X_SPACE,
	},
	{
	.clock = RC5_UNIT,
	.trailer_space = RC5_UNIT * 10,
	},
	};

	static const struct ir_raw_timings_manchester ir_rc5_sz_timings = {
	.leader = RC5_UNIT,
	.pulse_space_start = 0,
	.clock = RC5_UNIT,
	.trailer_space = RC5_UNIT * 10,
	};

	/**
	* ir_rc5_encode() - Encode a scancode as a stream of raw events
	*
	* @protocol: protocol variant to encode
	* @scancode: scancode to encode
	* @events: array of raw ir events to write into
	* @max: maximum size of @events
	*
	* Returns: The number of events written.
	* -ENOBUFS if there isn't enough space in the array to fit the
	* encoding. In this case all @max events will have been written.
	* -EINVAL if the scancode is ambiguous or invalid.
	*/
	static int ir_rc5_encode(enum rc_proto protocol, u32 scancode,
	struct ir_raw_event *events, unsigned int max)
	{
	int ret;
	struct ir_raw_event *e = events;
	unsigned int data, xdata, command, commandx, system, pre_space_data;

	/* Detect protocol and convert scancode to raw data */
	if (protocol == RC_PROTO_RC5) {
	/* decode scancode */
	command = (scancode & 0x003f) >> 0;
	commandx = (scancode & 0x0040) >> 6;
	system = (scancode & 0x1f00) >> 8;
	/* encode data */
	data = !commandx << 12 \| system << 6 \| command;

	/* Modulate the data */
	ret = ir_raw_gen_manchester(&e, max, &ir_rc5_timings,
	RC5_NBITS, data);
	if (ret < 0)
	return ret;
	} else if (protocol == RC_PROTO_RC5X_20) {
	/* decode scancode */
	xdata = (scancode & 0x00003f) >> 0;
	command = (scancode & 0x003f00) >> 8;
	commandx = !(scancode & 0x004000);
	system = (scancode & 0x1f0000) >> 16;

	/* encode data */
	data = commandx << 18 \| system << 12 \| command << 6 \| xdata;

	/* Modulate the data */
	pre_space_data = data >> (RC5X_NBITS - CHECK_RC5X_NBITS);
	ret = ir_raw_gen_manchester(&e, max, &ir_rc5x_timings[0],
	CHECK_RC5X_NBITS, pre_space_data);
	if (ret < 0)
	return ret;
	ret = ir_raw_gen_manchester(&e, max - (e - events),
	&ir_rc5x_timings[1],
	RC5X_NBITS - CHECK_RC5X_NBITS,
	data);
	if (ret < 0)
	return ret;
	} else if (protocol == RC_PROTO_RC5_SZ) {
	/* RC5-SZ scancode is raw enough for Manchester as it is */
	ret = ir_raw_gen_manchester(&e, max, &ir_rc5_sz_timings,
	RC5_SZ_NBITS, scancode & 0x2fff);
	if (ret < 0)
	return ret;
	} else {
	return -EINVAL;
	}

	return e - events;
	}

	static struct ir_raw_handler rc5_handler = {
	.protocols = RC_PROTO_BIT_RC5 \| RC_PROTO_BIT_RC5X_20 \|
	RC_PROTO_BIT_RC5_SZ,
	.decode = ir_rc5_decode,
	.encode = ir_rc5_encode,
	};

	static int __init ir_rc5_decode_init(void)
	{
	ir_raw_handler_register(&rc5_handler);

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

	static void __exit ir_rc5_decode_exit(void)
	{
	ir_raw_handler_unregister(&rc5_handler);
	}

	module_init(ir_rc5_decode_init);
	module_exit(ir_rc5_decode_exit);

	MODULE_LICENSE("GPL");
	MODULE_AUTHOR("Mauro Carvalho Chehab and Jarod Wilson");
	MODULE_AUTHOR("Red Hat Inc. (http://www.redhat.com)");
	MODULE_DESCRIPTION("RC5(x/sz) IR protocol decoder");