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267 lines
6.5 KiB
267 lines
6.5 KiB
// SPDX-License-Identifier: GPL-2.0+ |
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// ir-imon-decoder.c - handle iMon protocol |
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// |
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// Copyright (C) 2018 by Sean Young <[email protected]> |
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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#include <linux/module.h> |
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#include "rc-core-priv.h" |
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#define IMON_UNIT 416 /* us */ |
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#define IMON_BITS 30 |
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#define IMON_CHKBITS (BIT(30) | BIT(25) | BIT(24) | BIT(22) | \ |
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BIT(21) | BIT(20) | BIT(19) | BIT(18) | \ |
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BIT(17) | BIT(16) | BIT(14) | BIT(13) | \ |
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BIT(12) | BIT(11) | BIT(10) | BIT(9)) |
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/* |
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* This protocol has 30 bits. The format is one IMON_UNIT header pulse, |
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* followed by 30 bits. Each bit is one IMON_UNIT check field, and then |
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* one IMON_UNIT field with the actual bit (1=space, 0=pulse). |
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* The check field is always space for some bits, for others it is pulse if |
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* both the preceding and current bit are zero, else space. IMON_CHKBITS |
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* defines which bits are of type check. |
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* |
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* There is no way to distinguish an incomplete message from one where |
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* the lower bits are all set, iow. the last pulse is for the lowest |
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* bit which is 0. |
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*/ |
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enum imon_state { |
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STATE_INACTIVE, |
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STATE_BIT_CHK, |
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STATE_BIT_START, |
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STATE_FINISHED, |
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STATE_ERROR, |
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}; |
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static void ir_imon_decode_scancode(struct rc_dev *dev) |
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{ |
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struct imon_dec *imon = &dev->raw->imon; |
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/* Keyboard/Mouse toggle */ |
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if (imon->bits == 0x299115b7) |
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imon->stick_keyboard = !imon->stick_keyboard; |
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if ((imon->bits & 0xfc0000ff) == 0x680000b7) { |
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int rel_x, rel_y; |
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u8 buf; |
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buf = imon->bits >> 16; |
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rel_x = (buf & 0x08) | (buf & 0x10) >> 2 | |
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(buf & 0x20) >> 4 | (buf & 0x40) >> 6; |
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if (imon->bits & 0x02000000) |
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rel_x |= ~0x0f; |
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buf = imon->bits >> 8; |
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rel_y = (buf & 0x08) | (buf & 0x10) >> 2 | |
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(buf & 0x20) >> 4 | (buf & 0x40) >> 6; |
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if (imon->bits & 0x01000000) |
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rel_y |= ~0x0f; |
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if (rel_x && rel_y && imon->stick_keyboard) { |
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if (abs(rel_y) > abs(rel_x)) |
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imon->bits = rel_y > 0 ? |
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0x289515b7 : /* KEY_DOWN */ |
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0x2aa515b7; /* KEY_UP */ |
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else |
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imon->bits = rel_x > 0 ? |
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0x2ba515b7 : /* KEY_RIGHT */ |
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0x29a515b7; /* KEY_LEFT */ |
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} |
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if (!imon->stick_keyboard) { |
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input_report_rel(dev->input_dev, REL_X, rel_x); |
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input_report_rel(dev->input_dev, REL_Y, rel_y); |
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input_report_key(dev->input_dev, BTN_LEFT, |
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(imon->bits & 0x00010000) != 0); |
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input_report_key(dev->input_dev, BTN_RIGHT, |
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(imon->bits & 0x00040000) != 0); |
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} |
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} |
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rc_keydown(dev, RC_PROTO_IMON, imon->bits, 0); |
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} |
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/** |
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* ir_imon_decode() - Decode one iMON pulse or space |
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* @dev: the struct rc_dev descriptor of the device |
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* @ev: the struct ir_raw_event descriptor of the pulse/space |
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* |
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* This function returns -EINVAL if the pulse violates the state machine |
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*/ |
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static int ir_imon_decode(struct rc_dev *dev, struct ir_raw_event ev) |
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{ |
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struct imon_dec *data = &dev->raw->imon; |
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if (!is_timing_event(ev)) { |
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if (ev.reset) |
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data->state = STATE_INACTIVE; |
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return 0; |
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} |
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dev_dbg(&dev->dev, |
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"iMON decode started at state %d bitno %d (%uus %s)\n", |
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data->state, data->count, ev.duration, TO_STR(ev.pulse)); |
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/* |
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* Since iMON protocol is a series of bits, if at any point |
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* we encounter an error, make sure that any remaining bits |
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* aren't parsed as a scancode made up of less bits. |
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* |
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* Note that if the stick is held, then the remote repeats |
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* the scancode with about 12ms between them. So, make sure |
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* we have at least 10ms of space after an error. That way, |
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* we're at a new scancode. |
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*/ |
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if (data->state == STATE_ERROR) { |
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if (!ev.pulse && ev.duration > MS_TO_US(10)) |
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data->state = STATE_INACTIVE; |
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return 0; |
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} |
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for (;;) { |
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if (!geq_margin(ev.duration, IMON_UNIT, IMON_UNIT / 2)) |
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return 0; |
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decrease_duration(&ev, IMON_UNIT); |
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switch (data->state) { |
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case STATE_INACTIVE: |
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if (ev.pulse) { |
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data->state = STATE_BIT_CHK; |
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data->bits = 0; |
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data->count = IMON_BITS; |
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} |
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break; |
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case STATE_BIT_CHK: |
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if (IMON_CHKBITS & BIT(data->count)) |
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data->last_chk = ev.pulse; |
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else if (ev.pulse) |
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goto err_out; |
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data->state = STATE_BIT_START; |
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break; |
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case STATE_BIT_START: |
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data->bits <<= 1; |
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if (!ev.pulse) |
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data->bits |= 1; |
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if (IMON_CHKBITS & BIT(data->count)) { |
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if (data->last_chk != !(data->bits & 3)) |
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goto err_out; |
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} |
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if (!data->count--) |
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data->state = STATE_FINISHED; |
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else |
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data->state = STATE_BIT_CHK; |
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break; |
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case STATE_FINISHED: |
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if (ev.pulse) |
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goto err_out; |
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ir_imon_decode_scancode(dev); |
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data->state = STATE_INACTIVE; |
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break; |
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} |
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} |
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err_out: |
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dev_dbg(&dev->dev, |
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"iMON decode failed at state %d bitno %d (%uus %s)\n", |
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data->state, data->count, ev.duration, TO_STR(ev.pulse)); |
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data->state = STATE_ERROR; |
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return -EINVAL; |
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} |
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/** |
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* ir_imon_encode() - Encode a scancode as a stream of raw events |
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* |
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* @protocol: protocol to encode |
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* @scancode: scancode to encode |
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* @events: array of raw ir events to write into |
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* @max: maximum size of @events |
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* |
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* Returns: The number of events written. |
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* -ENOBUFS if there isn't enough space in the array to fit the |
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* encoding. In this case all @max events will have been written. |
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*/ |
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static int ir_imon_encode(enum rc_proto protocol, u32 scancode, |
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struct ir_raw_event *events, unsigned int max) |
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{ |
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struct ir_raw_event *e = events; |
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int i, pulse; |
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if (!max--) |
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return -ENOBUFS; |
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init_ir_raw_event_duration(e, 1, IMON_UNIT); |
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for (i = IMON_BITS; i >= 0; i--) { |
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if (BIT(i) & IMON_CHKBITS) |
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pulse = !(scancode & (BIT(i) | BIT(i + 1))); |
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else |
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pulse = 0; |
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if (pulse == e->pulse) { |
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e->duration += IMON_UNIT; |
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} else { |
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if (!max--) |
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return -ENOBUFS; |
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init_ir_raw_event_duration(++e, pulse, IMON_UNIT); |
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} |
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pulse = !(scancode & BIT(i)); |
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if (pulse == e->pulse) { |
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e->duration += IMON_UNIT; |
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} else { |
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if (!max--) |
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return -ENOBUFS; |
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init_ir_raw_event_duration(++e, pulse, IMON_UNIT); |
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} |
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} |
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if (e->pulse) |
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e++; |
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return e - events; |
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} |
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static int ir_imon_register(struct rc_dev *dev) |
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{ |
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struct imon_dec *imon = &dev->raw->imon; |
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imon->stick_keyboard = false; |
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return 0; |
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} |
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static struct ir_raw_handler imon_handler = { |
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.protocols = RC_PROTO_BIT_IMON, |
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.decode = ir_imon_decode, |
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.encode = ir_imon_encode, |
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.carrier = 38000, |
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.raw_register = ir_imon_register, |
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.min_timeout = IMON_UNIT * IMON_BITS * 2, |
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}; |
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static int __init ir_imon_decode_init(void) |
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{ |
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ir_raw_handler_register(&imon_handler); |
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pr_info("IR iMON protocol handler initialized\n"); |
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return 0; |
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} |
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static void __exit ir_imon_decode_exit(void) |
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{ |
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ir_raw_handler_unregister(&imon_handler); |
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} |
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module_init(ir_imon_decode_init); |
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module_exit(ir_imon_decode_exit); |
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MODULE_LICENSE("GPL"); |
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MODULE_AUTHOR("Sean Young <[email protected]>"); |
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MODULE_DESCRIPTION("iMON IR protocol decoder");
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