diff options
Diffstat (limited to 'drivers/media/rc/ir-xmp-decoder.c')
| -rw-r--r-- | drivers/media/rc/ir-xmp-decoder.c | 217 |
1 files changed, 217 insertions, 0 deletions
diff --git a/drivers/media/rc/ir-xmp-decoder.c b/drivers/media/rc/ir-xmp-decoder.c new file mode 100644 index 000000000..dc36b6873 --- /dev/null +++ b/drivers/media/rc/ir-xmp-decoder.c @@ -0,0 +1,217 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* ir-xmp-decoder.c - handle XMP IR Pulse/Space protocol + * + * Copyright (C) 2014 by Marcel Mol + * + * - Based on info from http://www.hifi-remote.com + * - Ignore Toggle=9 frames + * - Ignore XMP-1 XMP-2 difference, always store 16 bit OBC + */ + +#include <linux/bitrev.h> +#include <linux/module.h> +#include "rc-core-priv.h" + +#define XMP_UNIT 136 /* us */ +#define XMP_LEADER 210 /* us */ +#define XMP_NIBBLE_PREFIX 760 /* us */ +#define XMP_HALFFRAME_SPACE 13800 /* us */ +/* should be 80ms but not all duration supliers can go that high */ +#define XMP_TRAILER_SPACE 20000 + +enum xmp_state { + STATE_INACTIVE, + STATE_LEADER_PULSE, + STATE_NIBBLE_SPACE, +}; + +/** + * ir_xmp_decode() - Decode one XMP 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_xmp_decode(struct rc_dev *dev, struct ir_raw_event ev) +{ + struct xmp_dec *data = &dev->raw->xmp; + + if (!is_timing_event(ev)) { + if (ev.overflow) + data->state = STATE_INACTIVE; + return 0; + } + + dev_dbg(&dev->dev, "XMP decode started at state %d %d (%uus %s)\n", + data->state, data->count, ev.duration, TO_STR(ev.pulse)); + + switch (data->state) { + + case STATE_INACTIVE: + if (!ev.pulse) + break; + + if (eq_margin(ev.duration, XMP_LEADER, XMP_UNIT / 2)) { + data->count = 0; + data->state = STATE_NIBBLE_SPACE; + } + + return 0; + + case STATE_LEADER_PULSE: + if (!ev.pulse) + break; + + if (eq_margin(ev.duration, XMP_LEADER, XMP_UNIT / 2)) + data->state = STATE_NIBBLE_SPACE; + + return 0; + + case STATE_NIBBLE_SPACE: + if (ev.pulse) + break; + + if (geq_margin(ev.duration, XMP_TRAILER_SPACE, XMP_NIBBLE_PREFIX)) { + int divider, i; + u8 addr, subaddr, subaddr2, toggle, oem, obc1, obc2, sum1, sum2; + u32 *n; + u32 scancode; + + if (data->count != 16) { + dev_dbg(&dev->dev, "received TRAILER period at index %d: %u\n", + data->count, ev.duration); + data->state = STATE_INACTIVE; + return -EINVAL; + } + + n = data->durations; + /* + * the 4th nibble should be 15 so base the divider on this + * to transform durations into nibbles. Subtract 2000 from + * the divider to compensate for fluctuations in the signal + */ + divider = (n[3] - XMP_NIBBLE_PREFIX) / 15 - 2000; + if (divider < 50) { + dev_dbg(&dev->dev, "divider to small %d.\n", + divider); + data->state = STATE_INACTIVE; + return -EINVAL; + } + + /* convert to nibbles and do some sanity checks */ + for (i = 0; i < 16; i++) + n[i] = (n[i] - XMP_NIBBLE_PREFIX) / divider; + sum1 = (15 + n[0] + n[1] + n[2] + n[3] + + n[4] + n[5] + n[6] + n[7]) % 16; + sum2 = (15 + n[8] + n[9] + n[10] + n[11] + + n[12] + n[13] + n[14] + n[15]) % 16; + + if (sum1 != 15 || sum2 != 15) { + dev_dbg(&dev->dev, "checksum errors sum1=0x%X sum2=0x%X\n", + sum1, sum2); + data->state = STATE_INACTIVE; + return -EINVAL; + } + + subaddr = n[0] << 4 | n[2]; + subaddr2 = n[8] << 4 | n[11]; + oem = n[4] << 4 | n[5]; + addr = n[6] << 4 | n[7]; + toggle = n[10]; + obc1 = n[12] << 4 | n[13]; + obc2 = n[14] << 4 | n[15]; + if (subaddr != subaddr2) { + dev_dbg(&dev->dev, "subaddress nibbles mismatch 0x%02X != 0x%02X\n", + subaddr, subaddr2); + data->state = STATE_INACTIVE; + return -EINVAL; + } + if (oem != 0x44) + dev_dbg(&dev->dev, "Warning: OEM nibbles 0x%02X. Expected 0x44\n", + oem); + + scancode = addr << 24 | subaddr << 16 | + obc1 << 8 | obc2; + dev_dbg(&dev->dev, "XMP scancode 0x%06x\n", scancode); + + if (toggle == 0) { + rc_keydown(dev, RC_PROTO_XMP, scancode, 0); + } else { + rc_repeat(dev); + dev_dbg(&dev->dev, "Repeat last key\n"); + } + data->state = STATE_INACTIVE; + + return 0; + + } else if (geq_margin(ev.duration, XMP_HALFFRAME_SPACE, XMP_NIBBLE_PREFIX)) { + /* Expect 8 or 16 nibble pulses. 16 in case of 'final' frame */ + if (data->count == 16) { + dev_dbg(&dev->dev, "received half frame pulse at index %d. Probably a final frame key-up event: %u\n", + data->count, ev.duration); + /* + * TODO: for now go back to half frame position + * so trailer can be found and key press + * can be handled. + */ + data->count = 8; + } + + else if (data->count != 8) + dev_dbg(&dev->dev, "received half frame pulse at index %d: %u\n", + data->count, ev.duration); + data->state = STATE_LEADER_PULSE; + + return 0; + + } else if (geq_margin(ev.duration, XMP_NIBBLE_PREFIX, XMP_UNIT)) { + /* store nibble raw data, decode after trailer */ + if (data->count == 16) { + dev_dbg(&dev->dev, "too many pulses (%d) ignoring: %u\n", + data->count, ev.duration); + data->state = STATE_INACTIVE; + return -EINVAL; + } + data->durations[data->count] = ev.duration; + data->count++; + data->state = STATE_LEADER_PULSE; + + return 0; + + } + + break; + } + + dev_dbg(&dev->dev, "XMP decode failed at count %d state %d (%uus %s)\n", + data->count, data->state, ev.duration, TO_STR(ev.pulse)); + data->state = STATE_INACTIVE; + return -EINVAL; +} + +static struct ir_raw_handler xmp_handler = { + .protocols = RC_PROTO_BIT_XMP, + .decode = ir_xmp_decode, + .min_timeout = XMP_TRAILER_SPACE, +}; + +static int __init ir_xmp_decode_init(void) +{ + ir_raw_handler_register(&xmp_handler); + + printk(KERN_INFO "IR XMP protocol handler initialized\n"); + return 0; +} + +static void __exit ir_xmp_decode_exit(void) +{ + ir_raw_handler_unregister(&xmp_handler); +} + +module_init(ir_xmp_decode_init); +module_exit(ir_xmp_decode_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Marcel Mol <marcel@mesa.nl>"); +MODULE_AUTHOR("MESA Consulting (http://www.mesa.nl)"); +MODULE_DESCRIPTION("XMP IR protocol decoder"); |