summaryrefslogtreecommitdiffstats
path: root/drivers/media/rc/ir-rc6-decoder.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/media/rc/ir-rc6-decoder.c')
-rw-r--r--drivers/media/rc/ir-rc6-decoder.c407
1 files changed, 407 insertions, 0 deletions
diff --git a/drivers/media/rc/ir-rc6-decoder.c b/drivers/media/rc/ir-rc6-decoder.c
new file mode 100644
index 0000000000..3b2c8bab3e
--- /dev/null
+++ b/drivers/media/rc/ir-rc6-decoder.c
@@ -0,0 +1,407 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* ir-rc6-decoder.c - A decoder for the RC6 IR protocol
+ *
+ * Copyright (C) 2010 by David Härdeman <david@hardeman.nu>
+ */
+
+#include "rc-core-priv.h"
+#include <linux/module.h>
+
+/*
+ * This decoder currently supports:
+ * RC6-0-16 (standard toggle bit in header)
+ * RC6-6A-20 (no toggle bit)
+ * RC6-6A-24 (no toggle bit)
+ * RC6-6A-32 (MCE version with toggle bit in body)
+ */
+
+#define RC6_UNIT 444 /* microseconds */
+#define RC6_HEADER_NBITS 4 /* not including toggle bit */
+#define RC6_0_NBITS 16
+#define RC6_6A_32_NBITS 32
+#define RC6_6A_NBITS 128 /* Variable 8..128 */
+#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_SUFFIX_SPACE (6 * 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 */
+#define RC6_6A_LCC_MASK 0xffff0000 /* RC6-6A-32 long customer code mask */
+#define RC6_6A_MCE_CC 0x800f0000 /* MCE customer code */
+#define RC6_6A_ZOTAC_CC 0x80340000 /* Zotac customer code */
+#define RC6_6A_KATHREIN_CC 0x80460000 /* Kathrein RCU-676 customer code */
+#ifndef CHAR_BIT
+#define CHAR_BIT 8 /* Normally in <limits.h> */
+#endif
+
+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,
+};
+
+static enum rc6_mode rc6_mode(struct rc6_dec *data)
+{
+ switch (data->header & RC6_MODE_MASK) {
+ case 0:
+ return RC6_MODE_0;
+ case 6:
+ if (!data->toggle)
+ return RC6_MODE_6A;
+ fallthrough;
+ default:
+ return RC6_MODE_UNKNOWN;
+ }
+}
+
+/**
+ * ir_rc6_decode() - Decode one RC6 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_rc6_decode(struct rc_dev *dev, struct ir_raw_event ev)
+{
+ struct rc6_dec *data = &dev->raw->rc6;
+ u32 scancode;
+ u8 toggle;
+ enum rc_proto protocol;
+
+ if (!is_timing_event(ev)) {
+ if (ev.overflow)
+ data->state = STATE_INACTIVE;
+ return 0;
+ }
+
+ if (!geq_margin(ev.duration, RC6_UNIT, RC6_UNIT / 2))
+ goto out;
+
+again:
+ dev_dbg(&dev->dev, "RC6 decode started at state %i (%uus %s)\n",
+ data->state, 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;
+ data->header = 0;
+ 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->state = STATE_HEADER_BIT_END;
+ return 0;
+
+ case STATE_HEADER_BIT_END:
+ 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->state = STATE_TOGGLE_END;
+ return 0;
+
+ case STATE_TOGGLE_END:
+ if (!(data->header & RC6_STARTBIT_MASK)) {
+ dev_dbg(&dev->dev, "RC6 invalid start bit\n");
+ break;
+ }
+
+ data->state = STATE_BODY_BIT_START;
+ decrease_duration(&ev, RC6_TOGGLE_END);
+ data->count = 0;
+ data->body = 0;
+
+ switch (rc6_mode(data)) {
+ case RC6_MODE_0:
+ data->wanted_bits = RC6_0_NBITS;
+ break;
+ case RC6_MODE_6A:
+ data->wanted_bits = RC6_6A_NBITS;
+ break;
+ default:
+ dev_dbg(&dev->dev, "RC6 unknown mode\n");
+ goto out;
+ }
+ goto again;
+
+ case STATE_BODY_BIT_START:
+ if (eq_margin(ev.duration, RC6_BIT_START, RC6_UNIT / 2)) {
+ /* Discard LSB's that won't fit in data->body */
+ if (data->count++ < CHAR_BIT * sizeof data->body) {
+ data->body <<= 1;
+ if (ev.pulse)
+ data->body |= 1;
+ }
+ data->state = STATE_BODY_BIT_END;
+ return 0;
+ } else if (RC6_MODE_6A == rc6_mode(data) && !ev.pulse &&
+ geq_margin(ev.duration, RC6_SUFFIX_SPACE, RC6_UNIT / 2)) {
+ data->state = STATE_FINISHED;
+ goto again;
+ }
+ break;
+
+ case STATE_BODY_BIT_END:
+ 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;
+ toggle = data->toggle;
+ protocol = RC_PROTO_RC6_0;
+ dev_dbg(&dev->dev, "RC6(0) scancode 0x%04x (toggle: %u)\n",
+ scancode, toggle);
+ break;
+
+ case RC6_MODE_6A:
+ if (data->count > CHAR_BIT * sizeof data->body) {
+ dev_dbg(&dev->dev, "RC6 too many (%u) data bits\n",
+ data->count);
+ goto out;
+ }
+
+ scancode = data->body;
+ switch (data->count) {
+ case 20:
+ protocol = RC_PROTO_RC6_6A_20;
+ toggle = 0;
+ break;
+ case 24:
+ protocol = RC_PROTO_RC6_6A_24;
+ toggle = 0;
+ break;
+ case 32:
+ switch (scancode & RC6_6A_LCC_MASK) {
+ case RC6_6A_MCE_CC:
+ case RC6_6A_KATHREIN_CC:
+ case RC6_6A_ZOTAC_CC:
+ protocol = RC_PROTO_RC6_MCE;
+ toggle = !!(scancode & RC6_6A_MCE_TOGGLE_MASK);
+ scancode &= ~RC6_6A_MCE_TOGGLE_MASK;
+ break;
+ default:
+ protocol = RC_PROTO_RC6_6A_32;
+ toggle = 0;
+ break;
+ }
+ break;
+ default:
+ dev_dbg(&dev->dev, "RC6(6A) unsupported length\n");
+ goto out;
+ }
+
+ dev_dbg(&dev->dev, "RC6(6A) proto 0x%04x, scancode 0x%08x (toggle: %u)\n",
+ protocol, scancode, toggle);
+ break;
+ default:
+ dev_dbg(&dev->dev, "RC6 unknown mode\n");
+ goto out;
+ }
+
+ rc_keydown(dev, protocol, scancode, toggle);
+ data->state = STATE_INACTIVE;
+ return 0;
+ }
+
+out:
+ dev_dbg(&dev->dev, "RC6 decode failed at state %i (%uus %s)\n",
+ data->state, ev.duration, TO_STR(ev.pulse));
+ data->state = STATE_INACTIVE;
+ return -EINVAL;
+}
+
+static const struct ir_raw_timings_manchester ir_rc6_timings[4] = {
+ {
+ .leader_pulse = RC6_PREFIX_PULSE,
+ .leader_space = RC6_PREFIX_SPACE,
+ .clock = RC6_UNIT,
+ .invert = 1,
+ },
+ {
+ .clock = RC6_UNIT * 2,
+ .invert = 1,
+ },
+ {
+ .clock = RC6_UNIT,
+ .invert = 1,
+ .trailer_space = RC6_SUFFIX_SPACE,
+ },
+};
+
+/**
+ * ir_rc6_encode() - Encode a scancode as a stream of raw events
+ *
+ * @protocol: protocol 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_rc6_encode(enum rc_proto protocol, u32 scancode,
+ struct ir_raw_event *events, unsigned int max)
+{
+ int ret;
+ struct ir_raw_event *e = events;
+
+ if (protocol == RC_PROTO_RC6_0) {
+ /* Modulate the header (Start Bit & Mode-0) */
+ ret = ir_raw_gen_manchester(&e, max - (e - events),
+ &ir_rc6_timings[0],
+ RC6_HEADER_NBITS, (1 << 3));
+ if (ret < 0)
+ return ret;
+
+ /* Modulate Trailer Bit */
+ ret = ir_raw_gen_manchester(&e, max - (e - events),
+ &ir_rc6_timings[1], 1, 0);
+ if (ret < 0)
+ return ret;
+
+ /* Modulate rest of the data */
+ ret = ir_raw_gen_manchester(&e, max - (e - events),
+ &ir_rc6_timings[2], RC6_0_NBITS,
+ scancode);
+ if (ret < 0)
+ return ret;
+
+ } else {
+ int bits;
+
+ switch (protocol) {
+ case RC_PROTO_RC6_MCE:
+ case RC_PROTO_RC6_6A_32:
+ bits = 32;
+ break;
+ case RC_PROTO_RC6_6A_24:
+ bits = 24;
+ break;
+ case RC_PROTO_RC6_6A_20:
+ bits = 20;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ /* Modulate the header (Start Bit & Header-version 6 */
+ ret = ir_raw_gen_manchester(&e, max - (e - events),
+ &ir_rc6_timings[0],
+ RC6_HEADER_NBITS, (1 << 3 | 6));
+ if (ret < 0)
+ return ret;
+
+ /* Modulate Trailer Bit */
+ ret = ir_raw_gen_manchester(&e, max - (e - events),
+ &ir_rc6_timings[1], 1, 0);
+ if (ret < 0)
+ return ret;
+
+ /* Modulate rest of the data */
+ ret = ir_raw_gen_manchester(&e, max - (e - events),
+ &ir_rc6_timings[2],
+ bits,
+ scancode);
+ if (ret < 0)
+ return ret;
+ }
+
+ return e - events;
+}
+
+static struct ir_raw_handler rc6_handler = {
+ .protocols = RC_PROTO_BIT_RC6_0 | RC_PROTO_BIT_RC6_6A_20 |
+ RC_PROTO_BIT_RC6_6A_24 | RC_PROTO_BIT_RC6_6A_32 |
+ RC_PROTO_BIT_RC6_MCE,
+ .decode = ir_rc6_decode,
+ .encode = ir_rc6_encode,
+ .carrier = 36000,
+ .min_timeout = RC6_SUFFIX_SPACE,
+};
+
+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");
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-12 07:18:20 +0000