// SPDX-License-Identifier: GPL-2.0-only/* 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 */ #include <linux/bitrev.h>#include <linux/module.h>#include "rc-core-priv.h" #define SHARP_NBITS		15#define SHARP_UNIT		40  /* us */#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 (1680us space) */#define SHARP_BIT_0_SPACE	(17   * SHARP_UNIT) /* 680us space */#define SHARP_BIT_1_SPACE	(42   * SHARP_UNIT) /* 1680us 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 * @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_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.overflow)			data->state = STATE_INACTIVE;		return 0;	} 	dev_dbg(&dev->dev, "Sharp decode started at state %d (%uus %s)\n",		data->state, 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) {			dev_dbg(&dev->dev,				"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;		dev_dbg(&dev->dev, "Sharp scancode 0x%04x\n", scancode); 		rc_keydown(dev, RC_PROTO_SHARP, scancode, 0);		data->state = STATE_INACTIVE;		return 0;	} 	dev_dbg(&dev->dev, "Sharp decode failed at count %d state %d (%uus %s)\n",		data->count, data->state, ev.duration, TO_STR(ev.pulse));	data->state = STATE_INACTIVE;	return -EINVAL;} static const struct ir_raw_timings_pd ir_sharp_timings = {	.header_pulse  = 0,	.header_space  = 0,	.bit_pulse     = SHARP_BIT_PULSE,	.bit_space[0]  = SHARP_BIT_0_SPACE,	.bit_space[1]  = SHARP_BIT_1_SPACE,	.trailer_pulse = SHARP_BIT_PULSE,	.trailer_space = SHARP_ECHO_SPACE,	.msb_first     = 1,}; /** * ir_sharp_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_sharp_encode(enum rc_proto protocol, u32 scancode,			   struct ir_raw_event *events, unsigned int max){	struct ir_raw_event *e = events;	int ret;	u32 raw; 	raw = (((bitrev8(scancode >> 8) >> 3) << 8) & 0x1f00) |		bitrev8(scancode);	ret = ir_raw_gen_pd(&e, max, &ir_sharp_timings, SHARP_NBITS,			    (raw << 2) | 2);	if (ret < 0)		return ret; 	max -= ret; 	raw = (((bitrev8(scancode >> 8) >> 3) << 8) & 0x1f00) |		bitrev8(~scancode);	ret = ir_raw_gen_pd(&e, max, &ir_sharp_timings, SHARP_NBITS,			    (raw << 2) | 1);	if (ret < 0)		return ret; 	return e - events;} static struct ir_raw_handler sharp_handler = {	.protocols	= RC_PROTO_BIT_SHARP,	.decode		= ir_sharp_decode,	.encode		= ir_sharp_encode,	.carrier	= 38000,	.min_timeout	= SHARP_ECHO_SPACE + SHARP_ECHO_SPACE / 4,}; 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 <jhogan@kernel.org>");MODULE_DESCRIPTION("Sharp IR protocol decoder");