linux/drivers/media/IR/ir-rc6-decoder.c
David Härdeman e40b1127f9 V4L/DVB: ir-core: change duration to be coded as a u32 integer
This patch implements the agreed upon 1:31 integer encoded pulse/duration
struct for ir-core raw decoders. All decoders have been tested after the
change. Comments are welcome.

Signed-off-by: David Härdeman <david@hardeman.nu>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2010-05-19 12:57:42 -03:00

420 lines
9.5 KiB
C

/* ir-rc6-decoder.c - A decoder for the RC6 IR 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 "ir-core-priv.h"
/*
* This decoder currently supports:
* RC6-0-16 (standard toggle bit in header)
* RC6-6A-24 (no toggle bit)
* RC6-6A-32 (MCE version with toggle bit in body)
*/
#define RC6_UNIT 444444 /* us */
#define RC6_HEADER_NBITS 4 /* not including toggle bit */
#define RC6_0_NBITS 16
#define RC6_6A_SMALL_NBITS 24
#define RC6_6A_LARGE_NBITS 32
#define RC6_PREFIX_PULSE (6 * RC6_UNIT)
#define RC6_PREFIX_SPACE (2 * RC6_UNIT)
#define RC6_BIT_START (1 * RC6_UNIT)
#define RC6_BIT_END (1 * RC6_UNIT)
#define RC6_TOGGLE_START (2 * RC6_UNIT)
#define RC6_TOGGLE_END (2 * RC6_UNIT)
#define RC6_MODE_MASK 0x07 /* for the header bits */
#define RC6_STARTBIT_MASK 0x08 /* for the header bits */
#define RC6_6A_MCE_TOGGLE_MASK 0x8000 /* for the body bits */
/* Used to register rc6_decoder clients */
static LIST_HEAD(decoder_list);
static DEFINE_SPINLOCK(decoder_lock);
enum rc6_mode {
RC6_MODE_0,
RC6_MODE_6A,
RC6_MODE_UNKNOWN,
};
enum rc6_state {
STATE_INACTIVE,
STATE_PREFIX_SPACE,
STATE_HEADER_BIT_START,
STATE_HEADER_BIT_END,
STATE_TOGGLE_START,
STATE_TOGGLE_END,
STATE_BODY_BIT_START,
STATE_BODY_BIT_END,
STATE_FINISHED,
};
struct decoder_data {
struct list_head list;
struct ir_input_dev *ir_dev;
int enabled:1;
/* State machine control */
enum rc6_state state;
u8 header;
u32 body;
struct ir_raw_event prev_ev;
bool toggle;
unsigned count;
unsigned wanted_bits;
};
/**
* get_decoder_data() - gets decoder data
* @input_dev: input device
*
* Returns the struct decoder_data that corresponds to a device
*/
static struct decoder_data *get_decoder_data(struct ir_input_dev *ir_dev)
{
struct decoder_data *data = NULL;
spin_lock(&decoder_lock);
list_for_each_entry(data, &decoder_list, list) {
if (data->ir_dev == ir_dev)
break;
}
spin_unlock(&decoder_lock);
return data;
}
static ssize_t store_enabled(struct device *d,
struct device_attribute *mattr,
const char *buf,
size_t len)
{
unsigned long value;
struct ir_input_dev *ir_dev = dev_get_drvdata(d);
struct decoder_data *data = get_decoder_data(ir_dev);
if (!data)
return -EINVAL;
if (strict_strtoul(buf, 10, &value) || value > 1)
return -EINVAL;
data->enabled = value;
return len;
}
static ssize_t show_enabled(struct device *d,
struct device_attribute *mattr, char *buf)
{
struct ir_input_dev *ir_dev = dev_get_drvdata(d);
struct decoder_data *data = get_decoder_data(ir_dev);
if (!data)
return -EINVAL;
if (data->enabled)
return sprintf(buf, "1\n");
else
return sprintf(buf, "0\n");
}
static DEVICE_ATTR(enabled, S_IRUGO | S_IWUSR, show_enabled, store_enabled);
static struct attribute *decoder_attributes[] = {
&dev_attr_enabled.attr,
NULL
};
static struct attribute_group decoder_attribute_group = {
.name = "rc6_decoder",
.attrs = decoder_attributes,
};
static enum rc6_mode rc6_mode(struct decoder_data *data) {
switch (data->header & RC6_MODE_MASK) {
case 0:
return RC6_MODE_0;
case 6:
if (!data->toggle)
return RC6_MODE_6A;
/* fall through */
default:
return RC6_MODE_UNKNOWN;
}
}
/**
* ir_rc6_decode() - Decode one RC6 pulse or space
* @input_dev: the struct input_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_rc6_decode(struct input_dev *input_dev, struct ir_raw_event ev)
{
struct decoder_data *data;
struct ir_input_dev *ir_dev = input_get_drvdata(input_dev);
u32 scancode;
u8 toggle;
data = get_decoder_data(ir_dev);
if (!data)
return -EINVAL;
if (!data->enabled)
return 0;
if (IS_RESET(ev)) {
data->state = STATE_INACTIVE;
return 0;
}
if (!geq_margin(ev.duration, RC6_UNIT, RC6_UNIT / 2))
goto out;
again:
IR_dprintk(2, "RC6 decode started at state %i (%uus %s)\n",
data->state, TO_US(ev.duration), TO_STR(ev.pulse));
if (!geq_margin(ev.duration, RC6_UNIT, RC6_UNIT / 2))
return 0;
switch (data->state) {
case STATE_INACTIVE:
if (!ev.pulse)
break;
/* Note: larger margin on first pulse since each RC6_UNIT
is quite short and some hardware takes some time to
adjust to the signal */
if (!eq_margin(ev.duration, RC6_PREFIX_PULSE, RC6_UNIT))
break;
data->state = STATE_PREFIX_SPACE;
data->count = 0;
return 0;
case STATE_PREFIX_SPACE:
if (ev.pulse)
break;
if (!eq_margin(ev.duration, RC6_PREFIX_SPACE, RC6_UNIT / 2))
break;
data->state = STATE_HEADER_BIT_START;
return 0;
case STATE_HEADER_BIT_START:
if (!eq_margin(ev.duration, RC6_BIT_START, RC6_UNIT / 2))
break;
data->header <<= 1;
if (ev.pulse)
data->header |= 1;
data->count++;
data->prev_ev = ev;
data->state = STATE_HEADER_BIT_END;
return 0;
case STATE_HEADER_BIT_END:
if (!is_transition(&ev, &data->prev_ev))
break;
if (data->count == RC6_HEADER_NBITS)
data->state = STATE_TOGGLE_START;
else
data->state = STATE_HEADER_BIT_START;
decrease_duration(&ev, RC6_BIT_END);
goto again;
case STATE_TOGGLE_START:
if (!eq_margin(ev.duration, RC6_TOGGLE_START, RC6_UNIT / 2))
break;
data->toggle = ev.pulse;
data->prev_ev = ev;
data->state = STATE_TOGGLE_END;
return 0;
case STATE_TOGGLE_END:
if (!is_transition(&ev, &data->prev_ev) ||
!geq_margin(ev.duration, RC6_TOGGLE_END, RC6_UNIT / 2))
break;
if (!(data->header & RC6_STARTBIT_MASK)) {
IR_dprintk(1, "RC6 invalid start bit\n");
break;
}
data->state = STATE_BODY_BIT_START;
data->prev_ev = ev;
decrease_duration(&ev, RC6_TOGGLE_END);
data->count = 0;
switch (rc6_mode(data)) {
case RC6_MODE_0:
data->wanted_bits = RC6_0_NBITS;
break;
case RC6_MODE_6A:
/* This might look weird, but we basically
check the value of the first body bit to
determine the number of bits in mode 6A */
if ((!ev.pulse && !geq_margin(ev.duration, RC6_UNIT, RC6_UNIT / 2)) ||
geq_margin(ev.duration, RC6_UNIT, RC6_UNIT / 2))
data->wanted_bits = RC6_6A_LARGE_NBITS;
else
data->wanted_bits = RC6_6A_SMALL_NBITS;
break;
default:
IR_dprintk(1, "RC6 unknown mode\n");
goto out;
}
goto again;
case STATE_BODY_BIT_START:
if (!eq_margin(ev.duration, RC6_BIT_START, RC6_UNIT / 2))
break;
data->body <<= 1;
if (ev.pulse)
data->body |= 1;
data->count++;
data->prev_ev = ev;
data->state = STATE_BODY_BIT_END;
return 0;
case STATE_BODY_BIT_END:
if (!is_transition(&ev, &data->prev_ev))
break;
if (data->count == data->wanted_bits)
data->state = STATE_FINISHED;
else
data->state = STATE_BODY_BIT_START;
decrease_duration(&ev, RC6_BIT_END);
goto again;
case STATE_FINISHED:
if (ev.pulse)
break;
switch (rc6_mode(data)) {
case RC6_MODE_0:
scancode = data->body & 0xffff;
toggle = data->toggle;
IR_dprintk(1, "RC6(0) scancode 0x%04x (toggle: %u)\n",
scancode, toggle);
break;
case RC6_MODE_6A:
if (data->wanted_bits == RC6_6A_LARGE_NBITS) {
toggle = data->body & RC6_6A_MCE_TOGGLE_MASK ? 1 : 0;
scancode = data->body & ~RC6_6A_MCE_TOGGLE_MASK;
} else {
toggle = 0;
scancode = data->body & 0xffffff;
}
IR_dprintk(1, "RC6(6A) scancode 0x%08x (toggle: %u)\n",
scancode, toggle);
break;
default:
IR_dprintk(1, "RC6 unknown mode\n");
goto out;
}
ir_keydown(input_dev, scancode, toggle);
data->state = STATE_INACTIVE;
return 0;
}
out:
IR_dprintk(1, "RC6 decode failed at state %i (%uus %s)\n",
data->state, TO_US(ev.duration), TO_STR(ev.pulse));
data->state = STATE_INACTIVE;
return -EINVAL;
}
static int ir_rc6_register(struct input_dev *input_dev)
{
struct ir_input_dev *ir_dev = input_get_drvdata(input_dev);
struct decoder_data *data;
int rc;
rc = sysfs_create_group(&ir_dev->dev.kobj, &decoder_attribute_group);
if (rc < 0)
return rc;
data = kzalloc(sizeof(*data), GFP_KERNEL);
if (!data) {
sysfs_remove_group(&ir_dev->dev.kobj, &decoder_attribute_group);
return -ENOMEM;
}
data->ir_dev = ir_dev;
data->enabled = 1;
spin_lock(&decoder_lock);
list_add_tail(&data->list, &decoder_list);
spin_unlock(&decoder_lock);
return 0;
}
static int ir_rc6_unregister(struct input_dev *input_dev)
{
struct ir_input_dev *ir_dev = input_get_drvdata(input_dev);
static struct decoder_data *data;
data = get_decoder_data(ir_dev);
if (!data)
return 0;
sysfs_remove_group(&ir_dev->dev.kobj, &decoder_attribute_group);
spin_lock(&decoder_lock);
list_del(&data->list);
spin_unlock(&decoder_lock);
return 0;
}
static struct ir_raw_handler rc6_handler = {
.decode = ir_rc6_decode,
.raw_register = ir_rc6_register,
.raw_unregister = ir_rc6_unregister,
};
static int __init ir_rc6_decode_init(void)
{
ir_raw_handler_register(&rc6_handler);
printk(KERN_INFO "IR RC6 protocol handler initialized\n");
return 0;
}
static void __exit ir_rc6_decode_exit(void)
{
ir_raw_handler_unregister(&rc6_handler);
}
module_init(ir_rc6_decode_init);
module_exit(ir_rc6_decode_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("David Härdeman <david@hardeman.nu>");
MODULE_DESCRIPTION("RC6 IR protocol decoder");