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Commit e9ab364a authored by James Hogan's avatar James Hogan Committed by Mauro Carvalho Chehab
Browse files

[media] rc: ir-rc5-decoder: Add encode capability 



Add the capability to encode RC-5, RC-5X and RC-5-SZ scancodes as raw
events.

The Manchester modulation helper is used, and for RC-5X it is used twice
with two sets of timings, the first with a short trailer space for the
space in the middle, and the second with no leader so that it can
continue the space.

The encoding in RC-5-SZ first inserts a pulse and then simply utilizes
the generic Manchester encoder available in rc-core.

Signed-off-by: default avatarJames Hogan <james@albanarts.com>
Signed-off-by: default avatarAntti Seppälä <a.seppala@gmail.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 caec0984

drivers/media/rc/ir-rc5-decoder.c

+97 −0
Original line number Diff line number Diff line
@@ -181,9 +181,106 @@ static int ir_rc5_decode(struct rc_dev *dev, struct ir_raw_event ev) 
	return -EINVAL;

}



static const struct ir_raw_timings_manchester ir_rc5_timings = {

	.leader			= RC5_UNIT,

	.pulse_space_start	= 0,

	.clock			= RC5_UNIT,

	.trailer_space		= RC5_UNIT * 10,

};



static const struct ir_raw_timings_manchester ir_rc5x_timings[2] = {

	{

		.leader			= RC5_UNIT,

		.pulse_space_start	= 0,

		.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				= RC5_UNIT,

	.pulse_space_start		= 0,

	.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_type 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_TYPE_RC5) {

		/* decode scancode */

		command  = (scancode & 0x003f) >> 0;

		commandx = (scancode & 0x0040) >> 6;

		system   = (scancode & 0x1f00) >> 8;

		/* encode data */

		data = !commandx << 12 | system << 6 | command;



		/* Modulate the data */

		ret = ir_raw_gen_manchester(&e, max, &ir_rc5_timings,

					    RC5_NBITS, data);

		if (ret < 0)

			return ret;

	} else if (protocol == RC_TYPE_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;



		/* Modulate the data */

		pre_space_data = data >> (RC5X_NBITS - CHECK_RC5X_NBITS);

		ret = ir_raw_gen_manchester(&e, max, &ir_rc5x_timings[0],

					    CHECK_RC5X_NBITS, 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_TYPE_RC5_SZ) {

		/* RC5-SZ scancode is raw enough for Manchester as it is */

		ret = ir_raw_gen_manchester(&e, max, &ir_rc5_sz_timings,

					    RC5_SZ_NBITS, scancode & 0x2fff);

		if (ret < 0)

			return ret;

	} else {

		return -EINVAL;

	}



	return e - events;

}



static struct ir_raw_handler rc5_handler = {

	.protocols	= RC_BIT_RC5 | RC_BIT_RC5X_20 | RC_BIT_RC5_SZ,

	.decode		= ir_rc5_decode,

	.encode		= ir_rc5_encode,

};



static int __init ir_rc5_decode_init(void)