ir-rc5-sz-decoder.rar_RC5_space

/* ir-rc5-sz-decoder.c - handle RC5 Streamzap IR Pulse/Space protocol * * * 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. */ /* * This code handles the 15 bit RC5-ish protocol used by the Streamzap * PC Remote. * It considers a carrier of 36 kHz, with a total of 15 bits, where * the first two bits are start bits, and a third one is a filing bit */ #include "rc-core-priv.h" #define RC5_SZ_NBITS 15 #define RC5_UNIT 888888 /* ns */ #define RC5_BIT_START (1 * RC5_UNIT) #define RC5_BIT_END (1 * RC5_UNIT) enum rc5_sz_state { STATE_INACTIVE, STATE_BIT_START, STATE_BIT_END, STATE_FINISHED, }; /** * ir_rc5_sz_decode() - Decode one RC-5 Streamzap pulse or space * @dev: the struct rc_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_rc5_sz_decode(struct rc_dev *dev, struct ir_raw_event ev) { struct rc5_sz_dec *data = &dev->raw->rc5_sz; u8 toggle, command, system; u32 scancode; if (!(dev->raw->enabled_protocols & RC_TYPE_RC5_SZ)) return 0; if (!is_timing_event(ev)) { if (ev.reset) data->state = STATE_INACTIVE; return 0; } if (!geq_margin(ev.duration, RC5_UNIT, RC5_UNIT / 2)) goto out; again: IR_dprintk(2, "RC5-sz decode started at state %i (%uus %s)\n", data->state, TO_US(ev.duration), TO_STR(ev.pulse)); if (!geq_margin(ev.duration, RC5_UNIT, RC5_UNIT / 2)) return 0; switch (data->state) { case STATE_INACTIVE: if (!ev.pulse) break; data->state = STATE_BIT_START; data->count = 1; data->wanted_bits = RC5_SZ_NBITS; decrease_duration(&ev, RC5_BIT_START); goto again; case STATE_BIT_START: if (!eq_margin(ev.duration, RC5_BIT_START, RC5_UNIT / 2)) break; data->bits <<= 1; if (!ev.pulse) data->bits |= 1; data->count++; data->state = STATE_BIT_END; return 0; case STATE_BIT_END: if (!is_transition(&ev, &dev->raw->prev_ev)) break; if (data->count == data->wanted_bits) data->state = STATE_FINISHED; else data->state = STATE_BIT_START; decrease_duration(&ev, RC5_BIT_END); goto again; case STATE_FINISHED: if (ev.pulse) break; /* RC5-sz */ command = (data->bits & 0x0003F) >> 0; system = (data->bits & 0x02FC0) >> 6; toggle = (data->bits & 0x01000) ? 1 : 0; scancode = system << 6 | command; IR_dprintk(1, "RC5-sz scancode 0x%04x (toggle: %u)\n", scancode, toggle); rc_keydown(dev, scancode, toggle); data->state = STATE_INACTIVE; return 0; } out: IR_dprintk(1, "RC5-sz 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 rc5_sz_handler = { .protocols = RC_TYPE_RC5_SZ, .decode = ir_rc5_sz_decode, }; static int __init ir_rc5_sz_decode_init(void) { ir_raw_handler_register(&rc5_sz_handler); printk(KERN_INFO "IR RC5 (streamzap) protocol handler initialized\n"); return 0; } static void __exit ir_rc5_sz_decode_exit(void) { ir_raw_handler_unregister(&rc5_sz_handler); } module_init(ir_rc5_sz_decode_init); module_exit(ir_rc5_sz_decode_exit); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Jarod Wilson <jarod@redhat.com>"); MODULE_AUTHOR("Red Hat Inc. (http://www.redhat.com)"); MODULE_DESCRIPTION("RC5 (streamzap) IR protocol decoder");