[RFC PATCH 1/3] rc-core: Add Manchester encoder (phase encoder) support to rc-core

["Antti Seppälä" <a.seppala@gmail.com>]

Adding a simple Manchester encoder to rc-core.
Manchester coding is used by at least RC-5 protocol and its variants.

Signed-off-by: Antti Seppälä <a.seppala@gmail.com>
---
 drivers/media/rc/ir-raw.c       | 44 +++++++++++++++++++++++++++++++++++++++++
 drivers/media/rc/rc-core-priv.h | 14 +++++++++++++
 2 files changed, 58 insertions(+)

diff --git a/drivers/media/rc/ir-raw.c b/drivers/media/rc/ir-raw.c
index 9d734dd..7fea9ac 100644
--- a/drivers/media/rc/ir-raw.c
+++ b/drivers/media/rc/ir-raw.c
@@ -240,6 +240,50 @@ ir_raw_get_allowed_protocols(void)
 	return protocols;
 }
 
+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;
+	int i, count = 0;
+	i = 1 << (n - 1);
+
+	if (n > max || max < 2)
+		return -EINVAL;
+
+	if (timings->pulse_space_start) {
+		init_ir_raw_event_duration((*ev)++, 1, timings->clock);
+		init_ir_raw_event_duration((*ev), 0, timings->clock);
+		count += 2;
+	} else {
+		init_ir_raw_event_duration((*ev), 1, timings->clock);
+		count++;
+	}
+	i >>= 1;
+
+	while (i > 0) {
+		if (count > max)
+			return -EINVAL;
+
+		need_pulse = !(data & i);
+		if (need_pulse == !!(*ev)->pulse) {
+			(*ev)->duration += timings->clock;
+		} else {
+			init_ir_raw_event_duration(++(*ev), need_pulse,
+						   timings->clock);
+			count++;
+		}
+
+		init_ir_raw_event_duration(++(*ev), !need_pulse,
+					   timings->clock);
+		count++;
+		i >>= 1;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(ir_raw_gen_manchester);
+
 int ir_raw_gen_pd(struct ir_raw_event **ev, unsigned int max,
 		  const struct ir_raw_timings_pd *timings,
 		  unsigned int n, unsigned int data)
diff --git a/drivers/media/rc/rc-core-priv.h b/drivers/media/rc/rc-core-priv.h
index 3bf8c7b..4a2e2b8 100644
--- a/drivers/media/rc/rc-core-priv.h
+++ b/drivers/media/rc/rc-core-priv.h
@@ -173,6 +173,20 @@ static inline void ir_raw_gen_pulse_space(struct ir_raw_event **ev,
 }
 
 /**
+ * struct ir_raw_timings_manchester - manchester coding timings
+ * @pulse_space_start:	1 for starting with pulse (0 for starting with space)
+ * @clock:		duration of each pulse/space in ns
+ */
+struct ir_raw_timings_manchester {
+	unsigned int pulse_space_start:1;
+	unsigned int clock;
+};
+
+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);
+
+/**
  * struct ir_raw_timings_pd - pulse-distance modulation timings
  * @header_pulse:	duration of header pulse in ns (0 for none)
  * @header_space:	duration of header space in ns
-- 
1.8.3.2