From: Antti Seppälä <a.seppala@xxxxxxxxx>
Adding a simple Manchester encoder to rc-core.
Manchester coding is used by at least RC-5 and RC-6 protocols and their
variants.
Signed-off-by: Antti Seppälä <a.seppala@xxxxxxxxx>
Signed-off-by: James Hogan <james@xxxxxxxxxxxxx>
Signed-off-by: Sean Young <sean@xxxxxxxx>
Cc: David Härdeman <david@xxxxxxxxxxx>
---
drivers/media/rc/rc-core-priv.h | 33 ++++++++++++++++
drivers/media/rc/rc-ir-raw.c | 85 +++++++++++++++++++++++++++++++++++++++++
2 files changed, 118 insertions(+)
diff --git a/drivers/media/rc/rc-core-priv.h b/drivers/media/rc/rc-core-priv.h
index 98cc0cf..b175bf3 100644
--- a/drivers/media/rc/rc-core-priv.h
+++ b/drivers/media/rc/rc-core-priv.h
@@ -157,6 +157,39 @@ static inline bool is_timing_event(struct ir_raw_event ev)
#define TO_US(duration) DIV_ROUND_CLOSEST((duration), 1000)
#define TO_STR(is_pulse) ((is_pulse) ? "pulse" : "space")
+/* functions for IR encoders */
+
+static inline void init_ir_raw_event_duration(struct ir_raw_event *ev,
+ unsigned int pulse,
+ u32 duration)
+{
+ init_ir_raw_event(ev);
+ ev->duration = duration;
+ ev->pulse = pulse;
+}
+
+/**
+ * struct ir_raw_timings_manchester - Manchester coding timings
+ * @leader: duration of leader pulse (if any) 0 if continuing
+ * existing signal (see @pulse_space_start)
+ * @pulse_space_start: 1 for starting with pulse (0 for starting with space)
+ * @clock: duration of each pulse/space in ns
+ * @invert: if set clock logic is inverted
+ * (0 = space + pulse, 1 = pulse + space)
+ * @trailer_space: duration of trailer space in ns
+ */
+struct ir_raw_timings_manchester {
+ unsigned int leader;
+ unsigned int pulse_space_start:1;
+ unsigned int clock;
+ unsigned int invert:1;
+ unsigned int trailer_space;
+};
+
+int ir_raw_gen_manchester(struct ir_raw_event **ev, unsigned int max,
+ const struct ir_raw_timings_manchester *timings,
+ unsigned int n, unsigned int data);
+
/*
* Routines from rc-raw.c to be used internally and by decoders
*/
diff --git a/drivers/media/rc/rc-ir-raw.c b/drivers/media/rc/rc-ir-raw.c
index 1b229ef..072b4bd 100644
--- a/drivers/media/rc/rc-ir-raw.c
+++ b/drivers/media/rc/rc-ir-raw.c
@@ -250,6 +250,91 @@ static void ir_raw_disable_protocols(struct rc_dev *dev, u64 protocols)
}
/**
+ * ir_raw_gen_manchester() - Encode data with Manchester (bi-phase) modulation.
+ * @ev: Pointer to pointer to next free event. *@ev is incremented for
+ * each raw event filled.
+ * @max: Maximum number of raw events to fill.
+ * @timings: Manchester modulation timings.
+ * @n: Number of bits of data.
+ * @data: Data bits to encode.
+ *
+ * Encodes the @n least significant bits of @data using Manchester (bi-phase)
+ * modulation with the timing characteristics described by @timings, writing up
+ * to @max raw IR events using the *@ev pointer.
+ *
+ * Returns: 0 on success.
+ * -ENOBUFS if there isn't enough space in the array to fit the
+ * full encoded data. In this case all @max events will have been
+ * written.
+ */
+int ir_raw_gen_manchester(struct ir_raw_event **ev, unsigned int max,
+ const struct ir_raw_timings_manchester *timings,
+ unsigned int n, unsigned int data)
+{
+ bool need_pulse;
+ unsigned int i;
+ int ret = -ENOBUFS;
+
+ i = 1 << (n - 1);
+
+ if (timings->leader) {
+ if (!max--)
+ return ret;
+ if (timings->pulse_space_start) {
+ init_ir_raw_event_duration((*ev)++, 1, timings->leader);
+
+ if (!max--)
+ return ret;
+ init_ir_raw_event_duration((*ev), 0, timings->leader);
+ } else {
+ init_ir_raw_event_duration((*ev), 1, timings->leader);
+ }
+ i >>= 1;
+ } else {
+ /* continue existing signal */
+ --(*ev);
+ }
+ /* from here on *ev will point to the last event rather than the next */
+
+ while (n && i > 0) {
+ need_pulse = !(data & i);
+ if (timings->invert)
+ need_pulse = !need_pulse;
+ if (need_pulse == !!(*ev)->pulse) {
+ (*ev)->duration += timings->clock;
+ } else {
+ if (!max--)
+ goto nobufs;
+ init_ir_raw_event_duration(++(*ev), need_pulse,
+ timings->clock);
+ }
+
+ if (!max--)
+ goto nobufs;
+ init_ir_raw_event_duration(++(*ev), !need_pulse,
+ timings->clock);
+ i >>= 1;
+ }
+
+ if (timings->trailer_space) {
+ if (!(*ev)->pulse)
+ (*ev)->duration += timings->trailer_space;
+ else if (!max--)
+ goto nobufs;
+ else
+ init_ir_raw_event_duration(++(*ev), 0,
+ timings->trailer_space);
+ }
+
+ ret = 0;
+nobufs:
+ /* point to the next event rather than last event before returning */
+ ++(*ev);
+ return ret;
+}
+EXPORT_SYMBOL(ir_raw_gen_manchester);
+
+/**
* ir_raw_encode_scancode() - Encode a scancode as raw events
*
* @protocol: protocol
--
2.9.3
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