linux/drivers/media/rc/ir-nec-decoder.c
Jarod Wilson 4be22b6a7f [media] rc: interim support for 32-bit NEC-ish scancodes
The Apple and TiVo remotes I've got use an NEC-ish protocol, but rather
than a command/not_command pair, they have what appear to be vendor ID
bytes. This change makes the NEC decoder warn if the command/not_command
checksum fails, but then passes along a full 32-bit scancode for keymap
lookup. This change should make no difference for existing keymaps,
since they simply won't have 32-bit scancodes, but allows for a 32-bit
keymap. At the moment, that'll have to be uploaded by the user, but I've
got Apple and TiVo remote keymaps forthcoming.

In the long run (2.6.40, hopefully), we should probably just always use
all 32 bits for all NEC keymaps, but this should get us by for 2.6.39.

(Note that a few of the TiVo keys actuallly *do* pass the command
checksum, so for now, the keymap for this remote will have to be a mix
of 24-bit and 32-bit scancodes, but so be it).

Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2011-03-22 19:24:23 -03:00

226 lines
5.7 KiB
C

/* ir-nec-decoder.c - handle NEC IR Pulse/Space protocol
*
* Copyright (C) 2010 by Mauro Carvalho Chehab <mchehab@redhat.com>
*
* 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 "rc-core-priv.h"
#define NEC_NBITS 32
#define NEC_UNIT 562500 /* ns */
#define NEC_HEADER_PULSE (16 * NEC_UNIT)
#define NECX_HEADER_PULSE (8 * NEC_UNIT) /* Less common NEC variant */
#define NEC_HEADER_SPACE (8 * NEC_UNIT)
#define NEC_REPEAT_SPACE (4 * NEC_UNIT)
#define NEC_BIT_PULSE (1 * NEC_UNIT)
#define NEC_BIT_0_SPACE (1 * NEC_UNIT)
#define NEC_BIT_1_SPACE (3 * NEC_UNIT)
#define NEC_TRAILER_PULSE (1 * NEC_UNIT)
#define NEC_TRAILER_SPACE (10 * NEC_UNIT) /* even longer in reality */
#define NECX_REPEAT_BITS 1
enum nec_state {
STATE_INACTIVE,
STATE_HEADER_SPACE,
STATE_BIT_PULSE,
STATE_BIT_SPACE,
STATE_TRAILER_PULSE,
STATE_TRAILER_SPACE,
};
/**
* ir_nec_decode() - Decode one NEC pulse or space
* @dev: the struct rc_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_nec_decode(struct rc_dev *dev, struct ir_raw_event ev)
{
struct nec_dec *data = &dev->raw->nec;
u32 scancode;
u8 address, not_address, command, not_command;
bool send_32bits = false;
if (!(dev->raw->enabled_protocols & RC_TYPE_NEC))
return 0;
if (!is_timing_event(ev)) {
if (ev.reset)
data->state = STATE_INACTIVE;
return 0;
}
IR_dprintk(2, "NEC 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, NEC_HEADER_PULSE, NEC_UNIT / 2)) {
data->is_nec_x = false;
data->necx_repeat = false;
} else if (eq_margin(ev.duration, NECX_HEADER_PULSE, NEC_UNIT / 2))
data->is_nec_x = true;
else
break;
data->count = 0;
data->state = STATE_HEADER_SPACE;
return 0;
case STATE_HEADER_SPACE:
if (ev.pulse)
break;
if (eq_margin(ev.duration, NEC_HEADER_SPACE, NEC_UNIT / 2)) {
data->state = STATE_BIT_PULSE;
return 0;
} else if (eq_margin(ev.duration, NEC_REPEAT_SPACE, NEC_UNIT / 2)) {
if (!dev->keypressed) {
IR_dprintk(1, "Discarding last key repeat: event after key up\n");
} else {
rc_repeat(dev);
IR_dprintk(1, "Repeat last key\n");
data->state = STATE_TRAILER_PULSE;
}
return 0;
}
break;
case STATE_BIT_PULSE:
if (!ev.pulse)
break;
if (!eq_margin(ev.duration, NEC_BIT_PULSE, NEC_UNIT / 2))
break;
data->state = STATE_BIT_SPACE;
return 0;
case STATE_BIT_SPACE:
if (ev.pulse)
break;
if (data->necx_repeat && data->count == NECX_REPEAT_BITS &&
geq_margin(ev.duration,
NEC_TRAILER_SPACE, NEC_UNIT / 2)) {
IR_dprintk(1, "Repeat last key\n");
rc_repeat(dev);
data->state = STATE_INACTIVE;
return 0;
} else if (data->count > NECX_REPEAT_BITS)
data->necx_repeat = false;
data->bits <<= 1;
if (eq_margin(ev.duration, NEC_BIT_1_SPACE, NEC_UNIT / 2))
data->bits |= 1;
else if (!eq_margin(ev.duration, NEC_BIT_0_SPACE, NEC_UNIT / 2))
break;
data->count++;
if (data->count == NEC_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, NEC_TRAILER_PULSE, NEC_UNIT / 2))
break;
data->state = STATE_TRAILER_SPACE;
return 0;
case STATE_TRAILER_SPACE:
if (ev.pulse)
break;
if (!geq_margin(ev.duration, NEC_TRAILER_SPACE, NEC_UNIT / 2))
break;
address = bitrev8((data->bits >> 24) & 0xff);
not_address = bitrev8((data->bits >> 16) & 0xff);
command = bitrev8((data->bits >> 8) & 0xff);
not_command = bitrev8((data->bits >> 0) & 0xff);
if ((command ^ not_command) != 0xff) {
IR_dprintk(1, "NEC checksum error: received 0x%08x\n",
data->bits);
send_32bits = true;
}
if (send_32bits) {
/* NEC transport, but modified protocol, used by at
* least Apple and TiVo remotes */
scancode = data->bits;
IR_dprintk(1, "NEC (modified) scancode 0x%08x\n", scancode);
} else if ((address ^ not_address) != 0xff) {
/* Extended NEC */
scancode = address << 16 |
not_address << 8 |
command;
IR_dprintk(1, "NEC (Ext) scancode 0x%06x\n", scancode);
} else {
/* Normal NEC */
scancode = address << 8 | command;
IR_dprintk(1, "NEC scancode 0x%04x\n", scancode);
}
if (data->is_nec_x)
data->necx_repeat = true;
rc_keydown(dev, scancode, 0);
data->state = STATE_INACTIVE;
return 0;
}
IR_dprintk(1, "NEC 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 struct ir_raw_handler nec_handler = {
.protocols = RC_TYPE_NEC,
.decode = ir_nec_decode,
};
static int __init ir_nec_decode_init(void)
{
ir_raw_handler_register(&nec_handler);
printk(KERN_INFO "IR NEC protocol handler initialized\n");
return 0;
}
static void __exit ir_nec_decode_exit(void)
{
ir_raw_handler_unregister(&nec_handler);
}
module_init(ir_nec_decode_init);
module_exit(ir_nec_decode_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@redhat.com>");
MODULE_AUTHOR("Red Hat Inc. (http://www.redhat.com)");
MODULE_DESCRIPTION("NEC IR protocol decoder");