Commit 60f68735 authored by Antti Palosaari's avatar Antti Palosaari Committed by Mauro Carvalho Chehab
Browse files

[media] vivid: sdr cap: few enhancements 



* Constify struct

* Fix comments

* Fix alignment

* Use modulus to transfer phase angles

* Correct float [-1.0, +1.0] to s8 [-128, 127] conversion

Signed-off-by: default avatarAntti Palosaari <crope@iki.fi>
Signed-off-by: default avatarHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@osg.samsung.com>
parent f335c3f2

drivers/media/platform/vivid/vivid-sdr-cap.c

+12 −19
Original line number Diff line number Diff line
@@ -41,7 +41,7 @@ struct vivid_format { 
};



/* format descriptions for capture and preview */

static struct vivid_format formats[] = {

static const struct vivid_format formats[] = {

	{

		.pixelformat	= V4L2_SDR_FMT_CU8,

		.buffersize	= SDR_CAP_SAMPLES_PER_BUF * 2,
@@ -502,12 +502,6 @@ void vivid_sdr_cap_process(struct vivid_dev *dev, struct vivid_buffer *buf) 
	s32 fixp_i;

	s32 fixp_q;



	/*

	 * TODO: Generated beep tone goes very crackly when sample rate is

	 * increased to ~1Msps or more. That is because of huge rounding error

	 * of phase angle caused by used cosine implementation.

	 */



	/* calculate phase step */

	#define BEEP_FREQ 1000 /* 1kHz beep */

	src_phase_step = DIV_ROUND_CLOSEST(FIXP_2PI * BEEP_FREQ,
@@ -522,17 +516,15 @@ void vivid_sdr_cap_process(struct vivid_dev *dev, struct vivid_buffer *buf) 
		dev->sdr_fixp_mod_phase += div_s64(s64tmp, M_100000PI);



		/*

		 * Transfer phases to [0 / 2xPI] in order to avoid variable

		 * Transfer phase angle to [0, 2xPI] in order to avoid variable

		 * overflow and make it suitable for cosine implementation

		 * used, which does not support negative angles.

		 */

		while (dev->sdr_fixp_mod_phase < FIXP_2PI)

			dev->sdr_fixp_mod_phase += FIXP_2PI;

		while (dev->sdr_fixp_mod_phase > FIXP_2PI)

			dev->sdr_fixp_mod_phase -= FIXP_2PI;

		dev->sdr_fixp_src_phase %= FIXP_2PI;

		dev->sdr_fixp_mod_phase %= FIXP_2PI;



		while (dev->sdr_fixp_src_phase > FIXP_2PI)

			dev->sdr_fixp_src_phase -= FIXP_2PI;

		if (dev->sdr_fixp_mod_phase < 0)

			dev->sdr_fixp_mod_phase += FIXP_2PI;



		fixp_i = fixp_cos32_rad(dev->sdr_fixp_mod_phase, FIXP_2PI);

		fixp_q = fixp_sin32_rad(dev->sdr_fixp_mod_phase, FIXP_2PI);
@@ -544,7 +536,7 @@ void vivid_sdr_cap_process(struct vivid_dev *dev, struct vivid_buffer *buf) 


		switch (dev->sdr_pixelformat) {

		case V4L2_SDR_FMT_CU8:

			/* convert 'fixp float' to u8 */

			/* convert 'fixp float' to u8 [0, +255] */

			/* u8 = X * 127.5 + 127.5; X is float [-1.0, +1.0] */

			fixp_i = fixp_i * 1275 + FIXP_FRAC * 1275;

			fixp_q = fixp_q * 1275 + FIXP_FRAC * 1275;
@@ -552,9 +544,10 @@ void vivid_sdr_cap_process(struct vivid_dev *dev, struct vivid_buffer *buf) 
			*vbuf++ = DIV_ROUND_CLOSEST(fixp_q, FIXP_FRAC * 10);

			break;

		case V4L2_SDR_FMT_CS8:

			/* convert 'fixp float' to s8 */

			fixp_i = fixp_i * 1275;

			fixp_q = fixp_q * 1275;

			/* convert 'fixp float' to s8 [-128, +127] */

			/* s8 = X * 127.5 - 0.5; X is float [-1.0, +1.0] */

			fixp_i = fixp_i * 1275 - FIXP_FRAC * 5;

			fixp_q = fixp_q * 1275 - FIXP_FRAC * 5;

			*vbuf++ = DIV_ROUND_CLOSEST(fixp_i, FIXP_FRAC * 10);

			*vbuf++ = DIV_ROUND_CLOSEST(fixp_q, FIXP_FRAC * 10);

			break;