linux/drivers/media/rc/ir-sharp-decoder.c
Sean Young 528222d853 media: rc: harmonize infrared durations to microseconds
rc-core kapi uses nanoseconds for infrared durations for receiving, and
microseconds for sending. The uapi already uses microseconds for both,
so this patch does not change the uapi.

Infrared durations do not need nanosecond resolution. IR protocols do not
have durations shorter than about 100 microseconds. Some IR hardware offers
250 microseconds resolution, which is sufficient for most protocols.
Better hardware has 50 microsecond resolution and is enough for every
protocol I am aware off.

Unify on microseconds everywhere. This simplifies the code since less
conversion between microseconds and nanoseconds needs to be done.

This affects:
 - rx_resolution member of struct rc_dev
 - timeout member of struct rc_dev
 - duration member in struct ir_raw_event

Cc: "Bruno Prémont" <bonbons@linux-vserver.org>
Cc: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Cc: Maxim Levitsky <maximlevitsky@gmail.com>
Cc: Patrick Lerda <patrick9876@free.fr>
Cc: Kevin Hilman <khilman@baylibre.com>
Cc: Neil Armstrong <narmstrong@baylibre.com>
Cc: Jerome Brunet <jbrunet@baylibre.com>
Cc: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Cc: Sean Wang <sean.wang@mediatek.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Patrice Chotard <patrice.chotard@st.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Chen-Yu Tsai <wens@csie.org>
Cc: "David Härdeman" <david@hardeman.nu>
Cc: Benjamin Valentin <benpicco@googlemail.com>
Cc: Antti Palosaari <crope@iki.fi>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-09-03 16:18:55 +02:00

243 lines
5.8 KiB
C

// 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 (1680ms 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.reset)
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_PERIOD,
.bit_space[1] = SHARP_BIT_1_PERIOD,
.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");