text: /* ir-sony-decoder.c - handle Sony IR Pulse/Space 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 <linux/bitrev.h>
  #include <linux/module.h>
  #include "rc-core-priv.h"
  
  #define SONY_UNIT		600000 /* ns */
  #define SONY_HEADER_PULSE	(4 * SONY_UNIT)
  #define	SONY_HEADER_SPACE	(1 * SONY_UNIT)
  #define SONY_BIT_0_PULSE	(1 * SONY_UNIT)
  #define SONY_BIT_1_PULSE	(2 * SONY_UNIT)
  #define SONY_BIT_SPACE		(1 * SONY_UNIT)
  #define SONY_TRAILER_SPACE	(10 * SONY_UNIT) /* minimum */
  
  enum sony_state {
  	STATE_INACTIVE,
  	STATE_HEADER_SPACE,
  	STATE_BIT_PULSE,
  	STATE_BIT_SPACE,
  	STATE_FINISHED,
  };
  
  /**
   * ir_sony_decode() - Decode one Sony 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_sony_decode(struct rc_dev *dev, struct ir_raw_event ev)
  {
  	struct sony_dec *data = &dev->raw->sony;
  	enum rc_type protocol;
  	u32 scancode;
  	u8 device, subdevice, function;
  
  	if (!is_timing_event(ev)) {
  		if (ev.reset)
  			data->state = STATE_INACTIVE;
  		return 0;
  	}
  
  	if (!geq_margin(ev.duration, SONY_UNIT, SONY_UNIT / 2))
  		goto out;
  
  	IR_dprintk(2, "Sony 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, SONY_HEADER_PULSE, SONY_UNIT / 2))
  			break;
  
  		data->count = 0;
  		data->state = STATE_HEADER_SPACE;
  		return 0;
  
  	case STATE_HEADER_SPACE:
  		if (ev.pulse)
  			break;
  
  		if (!eq_margin(ev.duration, SONY_HEADER_SPACE, SONY_UNIT / 2))
  			break;
  
  		data->state = STATE_BIT_PULSE;
  		return 0;
  
  	case STATE_BIT_PULSE:
  		if (!ev.pulse)
  			break;
  
  		data->bits <<= 1;
  		if (eq_margin(ev.duration, SONY_BIT_1_PULSE, SONY_UNIT / 2))
  			data->bits |= 1;
  		else if (!eq_margin(ev.duration, SONY_BIT_0_PULSE, SONY_UNIT / 2))
  			break;
  
  		data->count++;
  		data->state = STATE_BIT_SPACE;
  		return 0;
  
  	case STATE_BIT_SPACE:
  		if (ev.pulse)
  			break;
  
  		if (!geq_margin(ev.duration, SONY_BIT_SPACE, SONY_UNIT / 2))
  			break;
  
  		decrease_duration(&ev, SONY_BIT_SPACE);
  
  		if (!geq_margin(ev.duration, SONY_UNIT, SONY_UNIT / 2)) {
  			data->state = STATE_BIT_PULSE;
  			return 0;
  		}
  
  		data->state = STATE_FINISHED;
  		/* Fall through */
  
  	case STATE_FINISHED:
  		if (ev.pulse)
  			break;
  
  		if (!geq_margin(ev.duration, SONY_TRAILER_SPACE, SONY_UNIT / 2))
  			break;
  
  		switch (data->count) {
  		case 12:
  			if (!(dev->enabled_protocols & RC_BIT_SONY12))
  				goto finish_state_machine;
  
  			device    = bitrev8((data->bits <<  3) & 0xF8);
  			subdevice = 0;
  			function  = bitrev8((data->bits >>  4) & 0xFE);
  			protocol = RC_TYPE_SONY12;
  			break;
  		case 15:
  			if (!(dev->enabled_protocols & RC_BIT_SONY15))
  				goto finish_state_machine;
  
  			device    = bitrev8((data->bits >>  0) & 0xFF);
  			subdevice = 0;
  			function  = bitrev8((data->bits >>  7) & 0xFE);
  			protocol = RC_TYPE_SONY15;
  			break;
  		case 20:
  			if (!(dev->enabled_protocols & RC_BIT_SONY20))
  				goto finish_state_machine;
  
  			device    = bitrev8((data->bits >>  5) & 0xF8);
  			subdevice = bitrev8((data->bits >>  0) & 0xFF);
  			function  = bitrev8((data->bits >> 12) & 0xFE);
  			protocol = RC_TYPE_SONY20;
  			break;
  		default:
  			IR_dprintk(1, "Sony invalid bitcount %u\n", data->count);
  			goto out;
  		}
  
  		scancode = device << 16 | subdevice << 8 | function;
  		IR_dprintk(1, "Sony(%u) scancode 0x%05x\n", data->count, scancode);
  		rc_keydown(dev, protocol, scancode, 0);
  		goto finish_state_machine;
  	}
  
  out:
  	IR_dprintk(1, "Sony decode failed at state %d (%uus %s)\n",
  		   data->state, TO_US(ev.duration), TO_STR(ev.pulse));
  	data->state = STATE_INACTIVE;
  	return -EINVAL;
  
  finish_state_machine:
  	data->state = STATE_INACTIVE;
  	return 0;
  }
  
  static const struct ir_raw_timings_pl ir_sony_timings = {
  	.header_pulse  = SONY_HEADER_PULSE,
  	.bit_space     = SONY_BIT_SPACE,
  	.bit_pulse[0]  = SONY_BIT_0_PULSE,
  	.bit_pulse[1]  = SONY_BIT_1_PULSE,
  	.trailer_space = SONY_TRAILER_SPACE + SONY_BIT_SPACE,
  	.msb_first     = 0,
  };
  
  /**
   * ir_sony_encode() - Encode a scancode as a stream of raw events
   *
   * @protocol:	protocol 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.
   */
  static int ir_sony_encode(enum rc_type protocol, u32 scancode,
  			  struct ir_raw_event *events, unsigned int max)
  {
  	struct ir_raw_event *e = events;
  	u32 raw, len;
  	int ret;
  
  	if (protocol == RC_TYPE_SONY12) {
  		raw = (scancode & 0x7f) | ((scancode & 0x1f0000) >> 9);
  		len = 12;
  	} else if (protocol == RC_TYPE_SONY15) {
  		raw = (scancode & 0x7f) | ((scancode & 0xff0000) >> 9);
  		len = 15;
  	} else {
  		raw = (scancode & 0x7f) | ((scancode & 0x1f0000) >> 9) |
  		       ((scancode & 0xff00) << 4);
  		len = 20;
  	}
  
  	ret = ir_raw_gen_pl(&e, max, &ir_sony_timings, len, raw);
  	if (ret < 0)
  		return ret;
  
  	return e - events;
  }
  
  static struct ir_raw_handler sony_handler = {
  	.protocols	= RC_BIT_SONY12 | RC_BIT_SONY15 | RC_BIT_SONY20,
  	.decode		= ir_sony_decode,
  	.encode		= ir_sony_encode,
  };
  
  static int __init ir_sony_decode_init(void)
  {
  	ir_raw_handler_register(&sony_handler);
  
  	printk(KERN_INFO "IR Sony protocol handler initialized\n");
  	return 0;
  }
  
  static void __exit ir_sony_decode_exit(void)
  {
  	ir_raw_handler_unregister(&sony_handler);
  }
  
  module_init(ir_sony_decode_init);
  module_exit(ir_sony_decode_exit);
  
  MODULE_LICENSE("GPL");
  MODULE_AUTHOR("David Härdeman <david@hardeman.nu>");
  MODULE_DESCRIPTION("Sony IR protocol decoder");
  