[media] rc: rc-ir-raw: Add pulse-distance modulation helper

Add IR encoding helper for pulse-distance modulation as used by the NEC
protocol.

Signed-off-by: James Hogan <james@albanarts.com>
Signed-off-by: Sean Young <sean@mess.org>
Cc: Antti Seppälä <a.seppala@gmail.com>
Cc: David Härdeman <david@hardeman.nu>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

diff --git a/drivers/media/rc/rc-core-priv.h b/drivers/media/rc/rc-core-priv.h
index b8d40e6..2471a3c 100644 (file)
--- a/drivers/media/rc/rc-core-priv.h
+++ b/drivers/media/rc/rc-core-priv.h
@@ -187,6 +187,58 @@ 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);
 
+/**
+ * ir_raw_gen_pulse_space() - generate pulse and space raw events.
+ * @ev:                        Pointer to pointer to next free raw event.
+ *                     Will be incremented for each raw event written.
+ * @max:               Pointer to number of raw events available in buffer.
+ *                     Will be decremented for each raw event written.
+ * @pulse_width:       Width of pulse in ns.
+ * @space_width:       Width of space in ns.
+ *
+ * Returns:    0 on success.
+ *             -ENOBUFS if there isn't enough buffer space to write both raw
+ *             events. In this case @max events will have been written.
+ */
+static inline int ir_raw_gen_pulse_space(struct ir_raw_event **ev,
+                                        unsigned int *max,
+                                        unsigned int pulse_width,
+                                        unsigned int space_width)
+{
+       if (!*max)
+               return -ENOBUFS;
+       init_ir_raw_event_duration((*ev)++, 1, pulse_width);
+       if (!--*max)
+               return -ENOBUFS;
+       init_ir_raw_event_duration((*ev)++, 0, space_width);
+       --*max;
+       return 0;
+}
+
+/**
+ * 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
+ * @bit_pulse:         duration of bit pulse in ns
+ * @bit_space:         duration of bit space (for logic 0 and 1) in ns
+ * @trailer_pulse:     duration of trailer pulse in ns
+ * @trailer_space:     duration of trailer space in ns
+ * @msb_first:         1 if most significant bit is sent first
+ */
+struct ir_raw_timings_pd {
+       unsigned int header_pulse;
+       unsigned int header_space;
+       unsigned int bit_pulse;
+       unsigned int bit_space[2];
+       unsigned int trailer_pulse;
+       unsigned int trailer_space;
+       unsigned int msb_first:1;
+};
+
+int ir_raw_gen_pd(struct ir_raw_event **ev, unsigned int max,
+                 const struct ir_raw_timings_pd *timings,
+                 unsigned int n, u64 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 85ac507..58039e6 100644 (file)
--- a/drivers/media/rc/rc-ir-raw.c
+++ b/drivers/media/rc/rc-ir-raw.c
@@ -324,6 +324,65 @@ nobufs:
 EXPORT_SYMBOL(ir_raw_gen_manchester);
 
 /**
+ * ir_raw_gen_pd() - Encode data to raw events with pulse-distance 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:   Pulse distance modulation timings.
+ * @n:         Number of bits of data.
+ * @data:      Data bits to encode.
+ *
+ * Encodes the @n least significant bits of @data using pulse-distance
+ * 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_pd(struct ir_raw_event **ev, unsigned int max,
+                 const struct ir_raw_timings_pd *timings,
+                 unsigned int n, u64 data)
+{
+       int i;
+       int ret;
+       unsigned int space;
+
+       if (timings->header_pulse) {
+               ret = ir_raw_gen_pulse_space(ev, &max, timings->header_pulse,
+                                            timings->header_space);
+               if (ret)
+                       return ret;
+       }
+
+       if (timings->msb_first) {
+               for (i = n - 1; i >= 0; --i) {
+                       space = timings->bit_space[(data >> i) & 1];
+                       ret = ir_raw_gen_pulse_space(ev, &max,
+                                                    timings->bit_pulse,
+                                                    space);
+                       if (ret)
+                               return ret;
+               }
+       } else {
+               for (i = 0; i < n; ++i, data >>= 1) {
+                       space = timings->bit_space[data & 1];
+                       ret = ir_raw_gen_pulse_space(ev, &max,
+                                                    timings->bit_pulse,
+                                                    space);
+                       if (ret)
+                               return ret;
+               }
+       }
+
+       ret = ir_raw_gen_pulse_space(ev, &max, timings->trailer_pulse,
+                                    timings->trailer_space);
+       return ret;
+}
+EXPORT_SYMBOL(ir_raw_gen_pd);
+
+/**
  * ir_raw_encode_scancode() - Encode a scancode as raw events
  *
  * @protocol:          protocol