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path: root/drivers/media/rc/ir-rc5-decoder.c
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Diffstat (limited to 'drivers/media/rc/ir-rc5-decoder.c')
-rw-r--r--drivers/media/rc/ir-rc5-decoder.c296
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..82d7f6ad2
--- /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 889 /* us */
+#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.overflow)
+ 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, 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, 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");
generated by cgit v1.2.3 (git 2.39.1) at 2024-10-04 15:26:18 +0000