diff options
Diffstat (limited to 'drivers/media/rc/ir-rc5-decoder.c')
| -rw-r--r-- | drivers/media/rc/ir-rc5-decoder.c | 296 |
1 files changed, 296 insertions, 0 deletions
diff --git a/drivers/media/rc/ir-rc5-decoder.c b/drivers/media/rc/ir-rc5-decoder.c new file mode 100644 index 000000000..63624654a --- /dev/null +++ b/drivers/media/rc/ir-rc5-decoder.c @@ -0,0 +1,296 @@ +// SPDX-License-Identifier: GPL-2.0 +// ir-rc5-decoder.c - decoder for RC5(x) and StreamZap protocols +// +// Copyright (C) 2010 by Mauro Carvalho Chehab +// Copyright (C) 2010 by Jarod Wilson <jarod@redhat.com> + +/* + * This decoder handles the 14 bit RC5 protocol, 15 bit "StreamZap" protocol + * and 20 bit RC5x protocol. + */ + +#include "rc-core-priv.h" +#include <linux/module.h> + +#define RC5_NBITS 14 +#define RC5_SZ_NBITS 15 +#define RC5X_NBITS 20 +#define CHECK_RC5X_NBITS 8 +#define RC5_UNIT 888888 /* ns */ +#define RC5_BIT_START (1 * RC5_UNIT) +#define RC5_BIT_END (1 * RC5_UNIT) +#define RC5X_SPACE (4 * RC5_UNIT) +#define RC5_TRAILER (6 * RC5_UNIT) /* In reality, approx 100 */ + +enum rc5_state { + STATE_INACTIVE, + STATE_BIT_START, + STATE_BIT_END, + STATE_CHECK_RC5X, + STATE_FINISHED, +}; + +/** + * ir_rc5_decode() - Decode one RC-5 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_decode(struct rc_dev *dev, struct ir_raw_event ev) +{ + struct rc5_dec *data = &dev->raw->rc5; + u8 toggle; + u32 scancode; + enum rc_proto protocol; + + 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: + dev_dbg(&dev->dev, "RC5(x/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; + decrease_duration(&ev, RC5_BIT_START); + goto again; + + case STATE_BIT_START: + if (!ev.pulse && geq_margin(ev.duration, RC5_TRAILER, RC5_UNIT / 2)) { + data->state = STATE_FINISHED; + goto again; + } + + 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 (data->count == CHECK_RC5X_NBITS) + data->state = STATE_CHECK_RC5X; + else + data->state = STATE_BIT_START; + + decrease_duration(&ev, RC5_BIT_END); + goto again; + + case STATE_CHECK_RC5X: + if (!ev.pulse && geq_margin(ev.duration, RC5X_SPACE, RC5_UNIT / 2)) { + data->is_rc5x = true; + decrease_duration(&ev, RC5X_SPACE); + } else + data->is_rc5x = false; + data->state = STATE_BIT_START; + goto again; + + case STATE_FINISHED: + if (ev.pulse) + break; + + if (data->is_rc5x && data->count == RC5X_NBITS) { + /* RC5X */ + u8 xdata, command, system; + if (!(dev->enabled_protocols & RC_PROTO_BIT_RC5X_20)) { + data->state = STATE_INACTIVE; + return 0; + } + xdata = (data->bits & 0x0003F) >> 0; + command = (data->bits & 0x00FC0) >> 6; + system = (data->bits & 0x1F000) >> 12; + toggle = (data->bits & 0x20000) ? 1 : 0; + command += (data->bits & 0x40000) ? 0 : 0x40; + scancode = system << 16 | command << 8 | xdata; + protocol = RC_PROTO_RC5X_20; + + } else if (!data->is_rc5x && data->count == RC5_NBITS) { + /* RC5 */ + u8 command, system; + if (!(dev->enabled_protocols & RC_PROTO_BIT_RC5)) { + data->state = STATE_INACTIVE; + return 0; + } + command = (data->bits & 0x0003F) >> 0; + system = (data->bits & 0x007C0) >> 6; + toggle = (data->bits & 0x00800) ? 1 : 0; + command += (data->bits & 0x01000) ? 0 : 0x40; + scancode = system << 8 | command; + protocol = RC_PROTO_RC5; + + } else if (!data->is_rc5x && data->count == RC5_SZ_NBITS) { + /* RC5 StreamZap */ + u8 command, system; + if (!(dev->enabled_protocols & RC_PROTO_BIT_RC5_SZ)) { + data->state = STATE_INACTIVE; + return 0; + } + command = (data->bits & 0x0003F) >> 0; + system = (data->bits & 0x02FC0) >> 6; + toggle = (data->bits & 0x01000) ? 1 : 0; + scancode = system << 6 | command; + protocol = RC_PROTO_RC5_SZ; + + } else + break; + + dev_dbg(&dev->dev, "RC5(x/sz) scancode 0x%06x (p: %u, t: %u)\n", + scancode, protocol, toggle); + + rc_keydown(dev, protocol, scancode, toggle); + data->state = STATE_INACTIVE; + return 0; + } + +out: + dev_dbg(&dev->dev, "RC5(x/sz) decode failed at state %i count %d (%uus %s)\n", + data->state, data->count, TO_US(ev.duration), TO_STR(ev.pulse)); + data->state = STATE_INACTIVE; + return -EINVAL; +} + +static const struct ir_raw_timings_manchester ir_rc5_timings = { + .leader_pulse = RC5_UNIT, + .clock = RC5_UNIT, + .trailer_space = RC5_UNIT * 10, +}; + +static const struct ir_raw_timings_manchester ir_rc5x_timings[2] = { + { + .leader_pulse = RC5_UNIT, + .clock = RC5_UNIT, + .trailer_space = RC5X_SPACE, + }, + { + .clock = RC5_UNIT, + .trailer_space = RC5_UNIT * 10, + }, +}; + +static const struct ir_raw_timings_manchester ir_rc5_sz_timings = { + .leader_pulse = RC5_UNIT, + .clock = RC5_UNIT, + .trailer_space = RC5_UNIT * 10, +}; + +/** + * ir_rc5_encode() - Encode a scancode as a stream of raw events + * + * @protocol: protocol variant to encode + * @scancode: scancode to encode + * @events: array of raw ir events to write into + * @max: maximum size of @events + * + * Returns: The number of events written. + * -ENOBUFS if there isn't enough space in the array to fit the + * encoding. In this case all @max events will have been written. + * -EINVAL if the scancode is ambiguous or invalid. + */ +static int ir_rc5_encode(enum rc_proto protocol, u32 scancode, + struct ir_raw_event *events, unsigned int max) +{ + int ret; + struct ir_raw_event *e = events; + unsigned int data, xdata, command, commandx, system, pre_space_data; + + /* Detect protocol and convert scancode to raw data */ + if (protocol == RC_PROTO_RC5) { + /* decode scancode */ + command = (scancode & 0x003f) >> 0; + commandx = (scancode & 0x0040) >> 6; + system = (scancode & 0x1f00) >> 8; + /* encode data */ + data = !commandx << 12 | system << 6 | command; + + /* First bit is encoded by leader_pulse */ + ret = ir_raw_gen_manchester(&e, max, &ir_rc5_timings, + RC5_NBITS - 1, data); + if (ret < 0) + return ret; + } else if (protocol == RC_PROTO_RC5X_20) { + /* decode scancode */ + xdata = (scancode & 0x00003f) >> 0; + command = (scancode & 0x003f00) >> 8; + commandx = !(scancode & 0x004000); + system = (scancode & 0x1f0000) >> 16; + + /* encode data */ + data = commandx << 18 | system << 12 | command << 6 | xdata; + + /* First bit is encoded by leader_pulse */ + pre_space_data = data >> (RC5X_NBITS - CHECK_RC5X_NBITS); + ret = ir_raw_gen_manchester(&e, max, &ir_rc5x_timings[0], + CHECK_RC5X_NBITS - 1, + pre_space_data); + if (ret < 0) + return ret; + ret = ir_raw_gen_manchester(&e, max - (e - events), + &ir_rc5x_timings[1], + RC5X_NBITS - CHECK_RC5X_NBITS, + data); + if (ret < 0) + return ret; + } else if (protocol == RC_PROTO_RC5_SZ) { + /* RC5-SZ scancode is raw enough for Manchester as it is */ + /* First bit is encoded by leader_pulse */ + ret = ir_raw_gen_manchester(&e, max, &ir_rc5_sz_timings, + RC5_SZ_NBITS - 1, + scancode & 0x2fff); + if (ret < 0) + return ret; + } else { + return -EINVAL; + } + + return e - events; +} + +static struct ir_raw_handler rc5_handler = { + .protocols = RC_PROTO_BIT_RC5 | RC_PROTO_BIT_RC5X_20 | + RC_PROTO_BIT_RC5_SZ, + .decode = ir_rc5_decode, + .encode = ir_rc5_encode, + .carrier = 36000, + .min_timeout = RC5_TRAILER, +}; + +static int __init ir_rc5_decode_init(void) +{ + ir_raw_handler_register(&rc5_handler); + + printk(KERN_INFO "IR RC5(x/sz) protocol handler initialized\n"); + return 0; +} + +static void __exit ir_rc5_decode_exit(void) +{ + ir_raw_handler_unregister(&rc5_handler); +} + +module_init(ir_rc5_decode_init); +module_exit(ir_rc5_decode_exit); + +MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR("Mauro Carvalho Chehab and Jarod Wilson"); +MODULE_AUTHOR("Red Hat Inc. (http://www.redhat.com)"); +MODULE_DESCRIPTION("RC5(x/sz) IR protocol decoder"); |