| /* 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 */ |
| |
| /* Used to register rc6_decoder clients */ |
| static LIST_HEAD(decoder_list); |
| static DEFINE_SPINLOCK(decoder_lock); |
| |
| 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, |
| }; |
| |
| struct decoder_data { |
| struct list_head list; |
| struct ir_input_dev *ir_dev; |
| int enabled:1; |
| |
| /* State machine control */ |
| enum rc6_state state; |
| u8 header; |
| u32 body; |
| struct ir_raw_event prev_ev; |
| bool toggle; |
| unsigned count; |
| unsigned wanted_bits; |
| }; |
| |
| |
| /** |
| * 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; |
| } |
| |
| static ssize_t store_enabled(struct device *d, |
| struct device_attribute *mattr, |
| const char *buf, |
| size_t len) |
| { |
| unsigned long value; |
| struct ir_input_dev *ir_dev = dev_get_drvdata(d); |
| struct decoder_data *data = get_decoder_data(ir_dev); |
| |
| if (!data) |
| return -EINVAL; |
| |
| if (strict_strtoul(buf, 10, &value) || value > 1) |
| return -EINVAL; |
| |
| data->enabled = value; |
| |
| return len; |
| } |
| |
| static ssize_t show_enabled(struct device *d, |
| struct device_attribute *mattr, char *buf) |
| { |
| struct ir_input_dev *ir_dev = dev_get_drvdata(d); |
| struct decoder_data *data = get_decoder_data(ir_dev); |
| |
| if (!data) |
| return -EINVAL; |
| |
| if (data->enabled) |
| return sprintf(buf, "1\n"); |
| else |
| return sprintf(buf, "0\n"); |
| } |
| |
| static DEVICE_ATTR(enabled, S_IRUGO | S_IWUSR, show_enabled, store_enabled); |
| |
| static struct attribute *decoder_attributes[] = { |
| &dev_attr_enabled.attr, |
| NULL |
| }; |
| |
| static struct attribute_group decoder_attribute_group = { |
| .name = "rc6_decoder", |
| .attrs = decoder_attributes, |
| }; |
| |
| static enum rc6_mode rc6_mode(struct decoder_data *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 decoder_data *data; |
| struct ir_input_dev *ir_dev = input_get_drvdata(input_dev); |
| u32 scancode; |
| u8 toggle; |
| |
| data = get_decoder_data(ir_dev); |
| if (!data) |
| return -EINVAL; |
| |
| if (!data->enabled) |
| return 0; |
| |
| if (IS_RESET(ev)) { |
| 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->prev_ev = ev; |
| data->state = STATE_HEADER_BIT_END; |
| return 0; |
| |
| case STATE_HEADER_BIT_END: |
| if (!is_transition(&ev, &data->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->prev_ev = ev; |
| data->state = STATE_TOGGLE_END; |
| return 0; |
| |
| case STATE_TOGGLE_END: |
| if (!is_transition(&ev, &data->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; |
| data->prev_ev = ev; |
| 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->prev_ev = ev; |
| |
| data->state = STATE_BODY_BIT_END; |
| return 0; |
| |
| case STATE_BODY_BIT_END: |
| if (!is_transition(&ev, &data->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 int ir_rc6_register(struct input_dev *input_dev) |
| { |
| struct ir_input_dev *ir_dev = input_get_drvdata(input_dev); |
| struct decoder_data *data; |
| int rc; |
| |
| rc = sysfs_create_group(&ir_dev->dev.kobj, &decoder_attribute_group); |
| if (rc < 0) |
| return rc; |
| |
| data = kzalloc(sizeof(*data), GFP_KERNEL); |
| if (!data) { |
| sysfs_remove_group(&ir_dev->dev.kobj, &decoder_attribute_group); |
| return -ENOMEM; |
| } |
| |
| data->ir_dev = ir_dev; |
| data->enabled = 1; |
| |
| spin_lock(&decoder_lock); |
| list_add_tail(&data->list, &decoder_list); |
| spin_unlock(&decoder_lock); |
| |
| return 0; |
| } |
| |
| static int ir_rc6_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; |
| |
| sysfs_remove_group(&ir_dev->dev.kobj, &decoder_attribute_group); |
| |
| spin_lock(&decoder_lock); |
| list_del(&data->list); |
| spin_unlock(&decoder_lock); |
| |
| return 0; |
| } |
| |
| static struct ir_raw_handler rc6_handler = { |
| .decode = ir_rc6_decode, |
| .raw_register = ir_rc6_register, |
| .raw_unregister = ir_rc6_unregister, |
| }; |
| |
| 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"); |