/* ir-jvc-decoder.c - handle JVC 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 "ir-core-priv.h"
#define JVC_NBITS 16 /* dev(8) + func(8) */
#define JVC_UNIT 525000 /* ns */
#define JVC_HEADER_PULSE (16 * JVC_UNIT) /* lack of header -> repeat */
#define JVC_HEADER_SPACE (8 * JVC_UNIT)
#define JVC_BIT_PULSE (1 * JVC_UNIT)
#define JVC_BIT_0_SPACE (1 * JVC_UNIT)
#define JVC_BIT_1_SPACE (3 * JVC_UNIT)
#define JVC_TRAILER_PULSE (1 * JVC_UNIT)
#define JVC_TRAILER_SPACE (35 * JVC_UNIT)
/* Used to register jvc_decoder clients */
static LIST_HEAD(decoder_list);
DEFINE_SPINLOCK(decoder_lock);
enum jvc_state {
STATE_INACTIVE,
STATE_HEADER_SPACE,
STATE_BIT_PULSE,
STATE_BIT_SPACE,
STATE_TRAILER_PULSE,
STATE_TRAILER_SPACE,
};
struct decoder_data {
struct list_head list;
struct ir_input_dev *ir_dev;
/* State machine control */
enum jvc_state state;
u16 jvc_bits;
u16 jvc_old_bits;
unsigned count;
bool first;
bool toggle;
};
/**
* 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;
}
/**
* ir_jvc_decode() - Decode one JVC pulse or space
* @input_dev: the struct input_dev descriptor of the device
* @duration: the struct ir_raw_event descriptor of the pulse/space
*
* This function returns -EINVAL if the pulse violates the state machine
*/
static int ir_jvc_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);
data = get_decoder_data(ir_dev);
if (!data)
return -EINVAL;
if (!(ir_dev->raw->enabled_protocols & IR_TYPE_JVC))
return 0;
if (IS_RESET(ev)) {
data->state = STATE_INACTIVE;
return 0;
}
if (!geq_margin(ev.duration, JVC_UNIT, JVC_UNIT / 2))
goto out;
IR_dprintk(2, "JVC 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, JVC_HEADER_PULSE, JVC_UNIT / 2))
break;
data->count = 0;
data->first = true;
data->toggle = !data->toggle;
data->state = STATE_HEADER_SPACE;
return 0;
case STATE_HEADER_SPACE:
if (ev.pulse)
break;
if (!eq_margin(ev.duration, JVC_HEADER_SPACE, JVC_UNIT / 2))
break;
data->state = STATE_BIT_PULSE;
return 0;
case STATE_BIT_PULSE:
if (!ev.pulse)
break;
if (!eq_margin(ev.duration, JVC_BIT_PULSE, JVC_UNIT / 2))
break;
data->state = STATE_BIT_SPACE;
return 0;
case STATE_BIT_SPACE:
if (ev.pulse)
break;
data->jvc_bits <<= 1;
if (eq_margin(ev.duration, JVC_BIT_1_SPACE, JVC_UNIT / 2)) {
data->jvc_bits |= 1;
decrease_duration(&ev, JVC_BIT_1_SPACE);
} else if (eq_margin(ev.duration, JVC_BIT_0_SPACE, JVC_UNIT / 2))
decrease_duration(&ev, JVC_BIT_0_SPACE);
else
break;
data->count++;
if (data->count == JVC_NBITS)
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, JVC_TRAILER_PULSE, JVC_UNIT / 2))
break;
data->state = STATE_TRAILER_SPACE;
return 0;
case STATE_TRAILER_SPACE:
if (ev.pulse)
break;
if (!geq_margin(ev.duration, JVC_TRAILER_SPACE, JVC_UNIT / 2))
break;
if (data->first) {
u32 scancode;
scancode = (bitrev8((data->jvc_bits >> 8) & 0xff) << 8) |
(bitrev8((data->jvc_bits >> 0) & 0xff) << 0);
IR_dprintk(1, "JVC scancode 0x%04x\n", scancode);
ir_keydown(input_dev, scancode, data->toggle);
data->first = false;
data->jvc_old_bits = data->jvc_bits;
} else if (data->jvc_bits == data->jvc_old_bits) {
IR_dprintk(1, "JVC repeat\n");
ir_repeat(input_dev);
} else {
IR_dprintk(1, "JVC invalid repeat msg\n");
break;
}
data->count = 0;
data->state = STATE_BIT_PULSE;
return 0;
}
out:
IR_dprintk(1, "JVC decode failed at state %d (%uus %s)\n",
data->state, TO_US(ev.duration), TO_STR(ev.pulse));
data->state = STATE_INACTIVE;
return -EINVAL;
}
static int ir_jvc_register(struct input_dev *input_dev)
{
struct ir_input_dev *ir_dev = input_get_drvdata(input_dev);
struct decoder_data *data;
data = kzalloc(sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
data->ir_dev = ir_dev;
spin_lock(&decoder_lock);
list_add_tail(&data->list, &decoder_list);
spin_unlock(&decoder_lock);
return 0;
}
static int ir_jvc_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;
spin_lock(&decoder_lock);
list_del(&data->list);
spin_unlock(&decoder_lock);
return 0;
}
static struct ir_raw_handler jvc_handler = {
.protocols = IR_TYPE_JVC,
.decode = ir_jvc_decode,
.raw_register = ir_jvc_register,
.raw_unregister = ir_jvc_unregister,
};
static int __init ir_jvc_decode_init(void)
{
ir_raw_handler_register(&jvc_handler);
printk(KERN_INFO "IR JVC protocol handler initialized\n");
return 0;
}
static void __exit ir_jvc_decode_exit(void)
{
ir_raw_handler_unregister(&jvc_handler);
}
module_init(ir_jvc_decode_init);
module_exit(ir_jvc_decode_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("David Härdeman <david@hardeman.nu>");
MODULE_DESCRIPTION("JVC IR protocol decoder");
