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Commit 844a4f45 authored by Antti Seppälä's avatar Antti Seppälä Committed by Mauro Carvalho Chehab
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[media] rc: rc-ir-raw: Add Manchester encoder (phase encoder) helper 



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: default avatarAntti Seppälä <a.seppala@gmail.com>
Signed-off-by: default avatarJames Hogan <james@albanarts.com>
Signed-off-by: default avatarSean Young <sean@mess.org>
Cc: David Härdeman <david@hardeman.nu>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@s-opensource.com>
parent 3875233d

drivers/media/rc/rc-core-priv.h

+33 −0
Original line number Original line Diff line number Diff line
@@ -154,6 +154,39 @@ static inline bool is_timing_event(struct ir_raw_event ev) 
#define TO_US(duration)			DIV_ROUND_CLOSEST((duration), 1000)

#define TO_US(duration)			DIV_ROUND_CLOSEST((duration), 1000)

#define TO_STR(is_pulse)		((is_pulse) ? "pulse" : "space")

#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

 * Routines from rc-raw.c to be used internally and by decoders

 */

 */

drivers/media/rc/rc-ir-raw.c

+85 −0
Original line number Original line Diff line number Diff line
@@ -238,6 +238,91 @@ static void ir_raw_disable_protocols(struct rc_dev *dev, u64 protocols) 
	mutex_unlock(&dev->lock);

	mutex_unlock(&dev->lock);

}

}





/**

 * 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

 * ir_raw_encode_scancode() - Encode a scancode as raw events

 *

 *