| /* ir-raw-event.c - handle IR Pulse/Space event |
| * |
| * 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 <media/ir-core.h> |
| |
| /* Start time: 4.5 ms */ |
| #define MIN_START_TIME 3900000 |
| #define MAX_START_TIME 5100000 |
| |
| /* Pulse time: 560 us */ |
| #define MIN_PULSE_TIME 460000 |
| #define MAX_PULSE_TIME 660000 |
| |
| /* Bit 1 space time: 2.25ms-560 us */ |
| #define MIN_BIT1_TIME 1490000 |
| #define MAX_BIT1_TIME 1890000 |
| |
| /* Bit 0 space time: 1.12ms-560 us */ |
| #define MIN_BIT0_TIME 360000 |
| #define MAX_BIT0_TIME 760000 |
| |
| |
| /** Decode NEC pulsecode. This code can take up to 76.5 ms to run. |
| Unfortunately, using IRQ to decode pulse didn't work, since it uses |
| a pulse train of 38KHz. This means one pulse on each 52 us |
| */ |
| |
| int ir_nec_decode(struct input_dev *input_dev, |
| struct ir_raw_event *evs, |
| int len) |
| { |
| int i, count = -1; |
| int ircode = 0, not_code = 0; |
| #if 0 |
| /* Needed only after porting the event code to the decoder */ |
| struct ir_input_dev *ir = input_get_drvdata(input_dev); |
| #endif |
| |
| /* Be sure that the first event is an start one and is a pulse */ |
| for (i = 0; i < len; i++) { |
| if (evs[i].type & (IR_START_EVENT | IR_PULSE)) |
| break; |
| } |
| i++; /* First event doesn't contain data */ |
| |
| if (i >= len) |
| return 0; |
| |
| /* First space should have 4.5 ms otherwise is not NEC protocol */ |
| if ((evs[i].delta.tv_nsec < MIN_START_TIME) | |
| (evs[i].delta.tv_nsec > MAX_START_TIME) | |
| (evs[i].type != IR_SPACE)) |
| goto err; |
| |
| /* |
| * FIXME: need to implement the repeat sequence |
| */ |
| |
| count = 0; |
| for (i++; i < len; i++) { |
| int bit; |
| |
| if ((evs[i].delta.tv_nsec < MIN_PULSE_TIME) | |
| (evs[i].delta.tv_nsec > MAX_PULSE_TIME) | |
| (evs[i].type != IR_PULSE)) |
| goto err; |
| |
| if (++i >= len) |
| goto err; |
| if (evs[i].type != IR_SPACE) |
| goto err; |
| |
| if ((evs[i].delta.tv_nsec > MIN_BIT1_TIME) && |
| (evs[i].delta.tv_nsec < MAX_BIT1_TIME)) |
| bit = 1; |
| else if ((evs[i].delta.tv_nsec > MIN_BIT0_TIME) && |
| (evs[i].delta.tv_nsec < MAX_BIT0_TIME)) |
| bit = 0; |
| else |
| goto err; |
| |
| if (bit) { |
| int shift = count; |
| /* Address first, then command */ |
| if (shift < 8) { |
| shift += 8; |
| ircode |= 1 << shift; |
| } else if (shift < 16) { |
| not_code |= 1 << shift; |
| } else if (shift < 24) { |
| shift -= 16; |
| ircode |= 1 << shift; |
| } else { |
| shift -= 24; |
| not_code |= 1 << shift; |
| } |
| } |
| if (++count == 32) |
| break; |
| } |
| |
| /* |
| * Fixme: may need to accept Extended NEC protocol? |
| */ |
| if ((ircode & ~not_code) != ircode) { |
| IR_dprintk(1, "NEC checksum error: code 0x%04x, not-code 0x%04x\n", |
| ircode, not_code); |
| return -EINVAL; |
| } |
| |
| IR_dprintk(1, "NEC scancode 0x%04x\n", ircode); |
| |
| return ircode; |
| err: |
| IR_dprintk(1, "NEC decoded failed at bit %d while decoding %luus time\n", |
| count, (evs[i].delta.tv_nsec + 500) / 1000); |
| |
| return -EINVAL; |
| } |
| EXPORT_SYMBOL_GPL(ir_nec_decode); |