diff options
Diffstat (limited to 'drivers/media/rc/ir-jvc-decoder.c')
| -rw-r--r-- | drivers/media/rc/ir-jvc-decoder.c | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/drivers/media/rc/ir-jvc-decoder.c b/drivers/media/rc/ir-jvc-decoder.c new file mode 100644 index 00000000000..624449afaa6 --- /dev/null +++ b/drivers/media/rc/ir-jvc-decoder.c @@ -0,0 +1,198 @@ +/* ir-jvc-decoder.c - handle JVC IR Pulse/Space 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 <linux/bitrev.h> +#include "rc-core-priv.h" + +#define JVC_NBITS 16 /* dev(8) + func(8) */ +#define JVC_UNIT 525000 /* ns */ +#define JVC_HEADER_PULSE (16 * JVC_UNIT) /* lack of header -> repeat */ +#define JVC_HEADER_SPACE (8 * JVC_UNIT) +#define JVC_BIT_PULSE (1 * JVC_UNIT) +#define JVC_BIT_0_SPACE (1 * JVC_UNIT) +#define JVC_BIT_1_SPACE (3 * JVC_UNIT) +#define JVC_TRAILER_PULSE (1 * JVC_UNIT) +#define JVC_TRAILER_SPACE (35 * JVC_UNIT) + +enum jvc_state { + STATE_INACTIVE, + STATE_HEADER_SPACE, + STATE_BIT_PULSE, + STATE_BIT_SPACE, + STATE_TRAILER_PULSE, + STATE_TRAILER_SPACE, + STATE_CHECK_REPEAT, +}; + +/** + * ir_jvc_decode() - Decode one JVC pulse or space + * @dev: the struct rc_dev descriptor of the device + * @duration: the struct ir_raw_event descriptor of the pulse/space + * + * This function returns -EINVAL if the pulse violates the state machine + */ +static int ir_jvc_decode(struct rc_dev *dev, struct ir_raw_event ev) +{ + struct jvc_dec *data = &dev->raw->jvc; + + if (!(dev->raw->enabled_protocols & RC_TYPE_JVC)) + return 0; + + if (!is_timing_event(ev)) { + if (ev.reset) + data->state = STATE_INACTIVE; + return 0; + } + + if (!geq_margin(ev.duration, JVC_UNIT, JVC_UNIT / 2)) + goto out; + + IR_dprintk(2, "JVC decode started at state %d (%uus %s)\n", + data->state, TO_US(ev.duration), TO_STR(ev.pulse)); + +again: + switch (data->state) { + + case STATE_INACTIVE: + if (!ev.pulse) + break; + + if (!eq_margin(ev.duration, JVC_HEADER_PULSE, JVC_UNIT / 2)) + break; + + data->count = 0; + data->first = true; + data->toggle = !data->toggle; + data->state = STATE_HEADER_SPACE; + return 0; + + case STATE_HEADER_SPACE: + if (ev.pulse) + break; + + if (!eq_margin(ev.duration, JVC_HEADER_SPACE, JVC_UNIT / 2)) + break; + + data->state = STATE_BIT_PULSE; + return 0; + + case STATE_BIT_PULSE: + if (!ev.pulse) + break; + + if (!eq_margin(ev.duration, JVC_BIT_PULSE, JVC_UNIT / 2)) + break; + + data->state = STATE_BIT_SPACE; + return 0; + + case STATE_BIT_SPACE: + if (ev.pulse) + break; + + data->bits <<= 1; + if (eq_margin(ev.duration, JVC_BIT_1_SPACE, JVC_UNIT / 2)) { + data->bits |= 1; + decrease_duration(&ev, JVC_BIT_1_SPACE); + } else if (eq_margin(ev.duration, JVC_BIT_0_SPACE, JVC_UNIT / 2)) + decrease_duration(&ev, JVC_BIT_0_SPACE); + else + break; + data->count++; + + if (data->count == JVC_NBITS) + data->state = STATE_TRAILER_PULSE; + else + data->state = STATE_BIT_PULSE; + return 0; + + case STATE_TRAILER_PULSE: + if (!ev.pulse) + break; + + if (!eq_margin(ev.duration, JVC_TRAILER_PULSE, JVC_UNIT / 2)) + break; + + data->state = STATE_TRAILER_SPACE; + return 0; + + case STATE_TRAILER_SPACE: + if (ev.pulse) + break; + + if (!geq_margin(ev.duration, JVC_TRAILER_SPACE, JVC_UNIT / 2)) + break; + + if (data->first) { + u32 scancode; + scancode = (bitrev8((data->bits >> 8) & 0xff) << 8) | + (bitrev8((data->bits >> 0) & 0xff) << 0); + IR_dprintk(1, "JVC scancode 0x%04x\n", scancode); + rc_keydown(dev, scancode, data->toggle); + data->first = false; + data->old_bits = data->bits; + } else if (data->bits == data->old_bits) { + IR_dprintk(1, "JVC repeat\n"); + rc_repeat(dev); + } else { + IR_dprintk(1, "JVC invalid repeat msg\n"); + break; + } + + data->count = 0; + data->state = STATE_CHECK_REPEAT; + return 0; + + case STATE_CHECK_REPEAT: + if (!ev.pulse) + break; + + if (eq_margin(ev.duration, JVC_HEADER_PULSE, JVC_UNIT / 2)) + data->state = STATE_INACTIVE; + else + data->state = STATE_BIT_PULSE; + goto again; + } + +out: + IR_dprintk(1, "JVC decode failed at state %d (%uus %s)\n", + data->state, TO_US(ev.duration), TO_STR(ev.pulse)); + data->state = STATE_INACTIVE; + return -EINVAL; +} + +static struct ir_raw_handler jvc_handler = { + .protocols = RC_TYPE_JVC, + .decode = ir_jvc_decode, +}; + +static int __init ir_jvc_decode_init(void) +{ + ir_raw_handler_register(&jvc_handler); + + printk(KERN_INFO "IR JVC protocol handler initialized\n"); + return 0; +} + +static void __exit ir_jvc_decode_exit(void) +{ + ir_raw_handler_unregister(&jvc_handler); +} + +module_init(ir_jvc_decode_init); +module_exit(ir_jvc_decode_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("David Härdeman <david@hardeman.nu>"); +MODULE_DESCRIPTION("JVC IR protocol decoder"); |