1 // SPDX-License-Identifier: GPL-2.0-only
2 /* ir-sharp-decoder.c - handle Sharp IR Pulse/Space protocol
4  * Copyright (C) 2013-2014 Imagination Technologies Ltd.
12 #include "rc-core-priv.h"
15 #define SHARP_UNIT		40  /* us */
16 #define SHARP_BIT_PULSE		(8    * SHARP_UNIT) /* 320us */
17 #define SHARP_BIT_0_PERIOD	(25   * SHARP_UNIT) /* 1ms (680us space) */
18 #define SHARP_BIT_1_PERIOD	(50   * SHARP_UNIT) /* 2ms (1680us space) */
19 #define SHARP_BIT_0_SPACE	(17   * SHARP_UNIT) /* 680us space */
20 #define SHARP_BIT_1_SPACE	(42   * SHARP_UNIT) /* 1680us space */
34  * ir_sharp_decode() - Decode one Sharp pulse or space
38  * This function returns -EINVAL if the pulse violates the state machine
42 	struct sharp_dec *data = &dev->raw->sharp;  in ir_sharp_decode()
47 			data->state = STATE_INACTIVE;  in ir_sharp_decode()
51 	dev_dbg(&dev->dev, "Sharp decode started at state %d (%uus %s)\n",  in ir_sharp_decode()
52 		data->state, ev.duration, TO_STR(ev.pulse));  in ir_sharp_decode()
54 	switch (data->state) {  in ir_sharp_decode()
60 		if (!eq_margin(ev.duration, SHARP_BIT_PULSE,  in ir_sharp_decode()
64 		data->count = 0;  in ir_sharp_decode()
65 		data->pulse_len = ev.duration;  in ir_sharp_decode()
66 		data->state = STATE_BIT_SPACE;  in ir_sharp_decode()
73 		if (!eq_margin(ev.duration, SHARP_BIT_PULSE,  in ir_sharp_decode()
77 		data->pulse_len = ev.duration;  in ir_sharp_decode()
78 		data->state = STATE_BIT_SPACE;  in ir_sharp_decode()
85 		data->bits <<= 1;  in ir_sharp_decode()
86 		if (eq_margin(data->pulse_len + ev.duration, SHARP_BIT_1_PERIOD,  in ir_sharp_decode()
88 			data->bits |= 1;  in ir_sharp_decode()
89 		else if (!eq_margin(data->pulse_len + ev.duration,  in ir_sharp_decode()
92 		data->count++;  in ir_sharp_decode()
94 		if (data->count == SHARP_NBITS ||  in ir_sharp_decode()
95 		    data->count == SHARP_NBITS * 2)  in ir_sharp_decode()
96 			data->state = STATE_TRAILER_PULSE;  in ir_sharp_decode()
98 			data->state = STATE_BIT_PULSE;  in ir_sharp_decode()
106 		if (!eq_margin(ev.duration, SHARP_BIT_PULSE,  in ir_sharp_decode()
110 		if (data->count == SHARP_NBITS) {  in ir_sharp_decode()
112 			if ((data->bits & 0x3) != 0x2 &&  in ir_sharp_decode()
114 			    (data->bits & 0x3) != 0x0)  in ir_sharp_decode()
116 			data->state = STATE_ECHO_SPACE;  in ir_sharp_decode()
118 			data->state = STATE_TRAILER_SPACE;  in ir_sharp_decode()
126 		if (!eq_margin(ev.duration, SHARP_ECHO_SPACE,  in ir_sharp_decode()
130 		data->state = STATE_BIT_PULSE;  in ir_sharp_decode()
138 		if (!geq_margin(ev.duration, SHARP_TRAILER_SPACE,  in ir_sharp_decode()
142 		/* Validate - command, ext, chk should be inverted in 2nd */  in ir_sharp_decode()
143 		msg = (data->bits >> 15) & 0x7fff;  in ir_sharp_decode()
144 		echo = data->bits & 0x7fff;  in ir_sharp_decode()
146 			dev_dbg(&dev->dev,  in ir_sharp_decode()
156 		dev_dbg(&dev->dev, "Sharp scancode 0x%04x\n", scancode);  in ir_sharp_decode()
159 		data->state = STATE_INACTIVE;  in ir_sharp_decode()
163 	dev_dbg(&dev->dev, "Sharp decode failed at count %d state %d (%uus %s)\n",  in ir_sharp_decode()
164 		data->count, data->state, ev.duration, TO_STR(ev.pulse));  in ir_sharp_decode()
165 	data->state = STATE_INACTIVE;  in ir_sharp_decode()
166 	return -EINVAL;  in ir_sharp_decode()
181  * ir_sharp_encode() - Encode a scancode as a stream of raw events
189  *		-ENOBUFS if there isn't enough space in the array to fit the
206 	max -= ret;  in ir_sharp_encode()
215 	return e - events;  in ir_sharp_encode()