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author | Mauro Carvalho Chehab <mchehab@redhat.com> | 2010-11-10 05:00:14 +0300 |
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committer | Mauro Carvalho Chehab <mchehab@redhat.com> | 2010-12-29 13:16:36 +0300 |
commit | 32cf86f6d16367db5a10039c1dd938a2427d697c (patch) | |
tree | 21e6716b64d80d280da2561efd873430ca833f08 /drivers/media/rc/ir-rc6-decoder.c | |
parent | 3ffea4988be3f3fa65f2104ba31eff2b5e0e82a0 (diff) | |
download | linux-32cf86f6d16367db5a10039c1dd938a2427d697c.tar.xz |
[media] rename drivers/media/IR to drives/media/rc
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'drivers/media/rc/ir-rc6-decoder.c')
-rw-r--r-- | drivers/media/rc/ir-rc6-decoder.c | 281 |
1 files changed, 281 insertions, 0 deletions
diff --git a/drivers/media/rc/ir-rc6-decoder.c b/drivers/media/rc/ir-rc6-decoder.c new file mode 100644 index 000000000000..d25da91f44ff --- /dev/null +++ b/drivers/media/rc/ir-rc6-decoder.c @@ -0,0 +1,281 @@ +/* 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 */ + +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, +}; + +static enum rc6_mode rc6_mode(struct rc6_dec *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 ir_input_dev *ir_dev = input_get_drvdata(input_dev); + struct rc6_dec *data = &ir_dev->raw->rc6; + u32 scancode; + u8 toggle; + + if (!(ir_dev->raw->enabled_protocols & IR_TYPE_RC6)) + return 0; + + if (!is_timing_event(ev)) { + if (ev.reset) + 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->state = STATE_HEADER_BIT_END; + return 0; + + case STATE_HEADER_BIT_END: + if (!is_transition(&ev, &ir_dev->raw->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->state = STATE_TOGGLE_END; + return 0; + + case STATE_TOGGLE_END: + if (!is_transition(&ev, &ir_dev->raw->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; + 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->state = STATE_BODY_BIT_END; + return 0; + + case STATE_BODY_BIT_END: + if (!is_transition(&ev, &ir_dev->raw->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 struct ir_raw_handler rc6_handler = { + .protocols = IR_TYPE_RC6, + .decode = ir_rc6_decode, +}; + +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"); |